reactivities of low-valen latt e transition meta amidel s4,6-^u2c6h2), the bulky thiophenol arsh (ar...

Synthesis，Structures and Reactivities of Low-Valent Late

Transition Metal Amides

by

Chung Hei LAM

淋頌禧）

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of

Master of Philosophy in

Chemistry

©The Chinese University of Hong Kong September 2001

The Chinese University of Hong Kong holds the copyright o f this thesis. Any person(s) intending to use a part or whole o f the materials in the thesis in a proposed publication must seek copyright release from the Dean of the Graduate School.

fUf统系館書圖\ A

S( I 1 • Ml 1 一 . ’rj

UNIVERSITY“一 j ' XLIBRARY SYSTEI^ f

Thesis Committee: Prof. Hung Kay LEE (Supervisor) Prof. Kevin W , R LEUNG Prof. Dennis K. P. NG

Prof. Michael F. LAPPERT (External Examiner, The University of Sussex)

Table of Contents

PAGE

Table o f Contents i

Acknowledgements iv

Abstracts v

摘要 v i i

List o f Compounds ix

List o f Tables x i i

List o f Figures xiv

Abbreviations xv

CHAPTER 1. SYNTHESIS OF LATE TRANSITION METAL

AMIDES 1.1 GENERAL BACKGROUND 1

1.2 PREPARATIONS OF LATE TRANSITION M E T A L AMIDES 2

1.3 OBJECTIVES OF THIS WORK 3

1.4 REEERENCES FOR CHAPTER. 1 5

CHAPTER 2. SYNTHESIS, STRUCTURES AND REACTrVITIES

OF IRON(II) AND COBALT(II) AMIDES 2.1 INTRODUCTION 7

2.1.1 A General Review on Iron(II) and Cob alt (II) Amides 7

27.2 A General Review on Iron(II) and Cobalt(II) Thiolates 9

2.1.3 A General Review on Iron(II) and Cobalt(II) Alkoxides and 11

Aryloxides

2.2 RESULTS A N D DISCUSSION 13

2.2.1 Synthesis of the Ligand Precursor LH (1) and the Corresponding 13

Lithium Reagents [Li(L)(TMEDA)] (2) andLiL (3)

i

2.2.2 Synthesis’ Structures and Reactivities of Mononuclear Iron(II) 14

and Cobalt(II) Amides

2.2.2.1 Synthesis of Mononuclear Iron(II) and Cobalt(n) Amides 14

2.2.2.2 Reactions of Compound 4 with Ar^^OH and ArSH 18

2.2.2.3 Physical Characterization of Compounds 4-6 19

2.2.2.4 Molecular Structures of Compounds 4-6 20

2.2.3 Synthesis, Structures and Reactivities of Binuclear Iron(II) and 31

Cobalt(II) Amides

2.2.3.1 Synthesis of Binuclear Iron(n) and Cobalt(II) Amides 31

2.2.3.i Reactions of Compounds 7 and 8 wi th Protic Reagents 33

2.2.3.3 Attempted Reactions o f Compounds 7 and 8 with 3,5-di-rer^ 35

butylcatechol

2.2.3.4 Physical Characterization of Compounds 7-14 35

2.2.3.5 Molecular Structures o f Compounds 7-10 and 13-14 38

2.3 EXPERIMENTALS FOR CHAPTER 2 57

2.4 REFERENCES FOR CHAPTER 2 64

CHAPTER 3. SYNTHESIS AND STRUCTURES OF

MANGANESE(n) AMIDES 3.1 INTRODUCTION 68

3.2 RESULTS A N D DISCUSSION 70

3.2.1 Synthesis of Manganese(II) Amide 70

2.2.2 Physical Characterization of Compound 15 72

2.2.3 Molecular Structure of Compound 15 73

3.3 EXPERIMENTALS FOR CHAPTER 3 78

3.4 REFERENCES FOR CHAPTER 3 79

ii

APPENDIX 1 General Procedures, Physical Measurements and X-ray Structure 81

Analysis

APPENDIX 2 Table A-1. Selected crystallographic data for compounds 4-6. 84

Table A-2. Selected crystallographic data for compounds 7-10. 85

Table A-3. Selected crystallographic data for compounds 13-15 86

iii

Acknowledgements I wish to express my sincere thanks to my supervisor. Prof. Hung Kay Lee, for

his guidance, invaluable advice and continuous encouragement throughout the course

o f my research study and the preparation o f this thesis.

I would also like to thank Prof. Thomas C. W. Mak, Prof. Song-Lin Li , Prof.

Qingchim Yang, Prof. Ze-Ying Zhang and Miss Hung Wing L i , for carrying out the

X-ray structural analysis. Thanks also go to Dr. Yu San Cheung and Mr. Kwok Wai

Kwong for their respective assistance in measuring magnetic moments and the mass

spectra o f some of the transition metal complexes.

M y appreciation must also go to other labmates. Miss Edith S. H. Chan, Mr.

Steven C. F. Kui, Mr. Aries C. P. Lam and Miss Ruby T. S. Lam for sharing with me

their "inspirations" and listening to all my complaints, and most importantly, the nice

concern and excellent support from my beloved family and my love, Polly S. M.

Chan.

Financial support from The Chinese University o f Hong Kong in the form of a

Postgraduate Studentship is gratefully acknowledged.

Chung Hei L A M Department of Chemistry The Chinese University of Hong Kong September, 2001

iv

Abstracts

Thermally stable late transition metal amido complexes have been synthesized by

employing the sterically hindered pyridine-fiinctionalized amido ligand [N(Si'BuMe2)(2-

CsHgN-b-Me)]— (L). Reactivities of these amido complexes towards protic reagents such

as the bulky phenols Ar^ÔH (Ar^^ = 2,6-û^"4-MeQH2) and 2-MeCH(Ar'OH)2 (Ar' 二

4,6-Û2C6H2), the bulky thiophenol ArSH (Ar 二 2,4，6-TBu3QH2), and 3,5'di'tert-

butylcatechol (dbcH�）were also investigated.

In Chapter 1, a general background on the synthesis o f late transition metal amides

and the objectives of this research project are stated.

Chapter 2 deals with the synthesis o f iron(II) and cobalt(n) amido complexes. First

o f all，the preparation of the mononuclear iron(n) amide [Fe{N(SiûMe2)(2-C5H3N-6-

M e ) } J (4) and the ionic cobalt(n) amido complex [Co{N(Si'BuMe2)(2-C5H3N-6-

Me)}{N(Si它uMe2)(2-C5H3N-6-CH2)} • Li(THF)]2 (5)，are described. Reaction of

compound 4 with the bulky phenol Ar^ÔH gave the novel mononuclear mixed-ligand

iron(n) complex [Fe {N(SffiiiMe2)(2-C5H3N-6-Me)} {OQH2-2,6-Û2-4-

Me} {HN(SiTBiiMe2)(2-C5H3N-6-Me)}] (6).

Secondly, the synthesis of the novel binuclear iron(n) and cobalt(n) amido

complexes [{M[N(SiTBuMe2)(2-C5H3N-6-Me)L}2(TMEDA)] ( M = Fe 7, Co 8), are

described. Subsequent reactions of compounds 7 and 8 with Ar^®OH and 2-

MeCH(Ar'0H)2 gave the mononuclear metal(n) bis(aryloxide) complexes

[M(0Arê)2(TMEDA)] ( M = Fe 9, Co 10) and [M{(OAr')2(2-CHMe)}(TMEDA)] ( M = Fe

11 Co 12), respectively. Compounds 7 and 8 also reacted with ArSH to give the

V

mononuclear metal(n) dithiolates [M(SAr)2(TMEDA)] (M 二 Fe 13，Co 14).

Chapter 3 begins with a brief review on manganese(n) amido complexes. An ionic

manganese(II) amido complex [{Mn[N(Si它uMe^Xl-CsHgN-b-Me)]]} • Li(THF)] (15)

was prepared by the reaction of manganese(II) chloride wi th the appropriate lithium

reagent.

vi

摘要

應用有立體位阻的官能團的胺基地咬類配體 [N(Sff iuMe2)(2-C5H3N-6-Me)] 一

(L)，熱力學穩定的後過渡金屬胺基°比a定配合物被合成。並對這類胺基a比a定配

合物對質子化試劑如有位阻的紛 A 严 0 H (A严=2 ,6 -TBu2-4 -MeC6H2)及2-

MeCH(Ar'0H)2 (Ar' 二 ‘ - S - B u ^ C y ^，琉紛 ArSH (Ar 二 2,4，6-TBu3C6H2)和 3，5-di-

rgr^^butylcatechol (dbcH〗)的反應活性進行研究。

第一章主要對後過渡金屬胺基a比定類配合物的合成進行了綜述，同時還洽

述了本課題的研究目標。

第二章主要講述了二價鐵和二價链的胺基。比a定類配合物的合成°首先介紹

了單核的二價鐵胺基a比咬配合物[Fe{N(SffiuMe2)(2-C5H3N-6-Me)}2] ( 4 ) 及離子

化的二價链胺基此 a定配合物[Co{N(SffiuMe2)(2-QH3N-6-Me)} {N(SffiuMe2)(2-

C5H3N-6-CH2)} • Li(THF)]2 ( 5 ) 的製備 °化合物 4 與有位阻的紛 A r ^ e o H 反應可

得到一新颖的混配體的單核胺基。比咬配合物 [ F e { N ( S i l B u M e 2 ) ( 2 - C 5 H 3 N - 6 -

Me)}{OC6H2-2,6-它U2"4-Me}{HN(SiTBuMe2)(2-C5H3N-6-Me)}] (6) °

其次主要介紹新型的雙核胺基也a定配合物 [ {M[N(S] f f iuMe2) (2 -C5H3N-6-

Me)]2}2(TMEDA)] (M = Fe 7, Co 8 ) 的合成。化合物 7 和 8 分別與有位阻的酚

A i ^ ^ O H和2 - M e C H ( A r ' O H ) 2反應，可分別得到單核的雙芳氧基二價金屬化合

物[M(0Ar^e)2(xMEDA)] ( M = Fe 9, Co 10)和 [M{(OAr i )2(2-CHMe)} (TMEDA)]

vii

( M = Fe 11，Co 1 2 ) 。化合物 7和 8分別與琉紛A r S H反應，可得到單核的二硫

紛二價金屬配合物 [M(SAr)2(TMEDA)] ( M = Fe 13, Co 14)。

第三章首先對二價金屬猛的胺基a比咬配合物進行綜述。應用氯化猛與相應

的有機鍾試劑反應，離子化的胺基a比定配位的猛配合物 [ {Mn [N (S i它uMe2 ) (2 -

QH3N-6-Me)]3} • Li(THF)] ( 1 5 )被合成。

viii

List of Compounds

N N Compound 1 [HN(SffiuMe2)(2-C5H3N-6-Me)] or L H ^ V xs^uMe。

\ / " A z z、jjZ \

Compound 2 [Li{N(Si它uMe2)(2-C5H3N-6- ^ \ Me)}(TMEDA)] or [L i (L)(TMEDA)] 丫 xs^uMe^

Compound 3 Li[N(Si'BuMe2)(2-C5H3N-6-Me)] or L i L Not available

- r ^ 日u S i 、人N人

\ X Compound 4 [Fe{N(SffiuMe2)(2-C5H3N-6-Me)}2]

Compound 5 [Co{N(Si它uMe2)(2-C5H3N-6- Me.Busi X X ^ c ^ X i — t h f Me)}{N(SiTBiiMe,)(2-C3H3N-6.CH,)} • | \ ( Li(THF)L " ' " K T ^ ^ O ^

, n ‘ Me。旧uSi \

Compound 6 [Fe{N(SffiuMe2)(2-C5H3N-6-Me)} {OC6H2-2,6-'Bii2-4-Me}- ^ n ^ {HN(SffiuMe,)(2-C3H3N-6-Me)}] k A ^ H

Si'BuMej

ix

Si 伯 uMe2

A f o N

Me2 饥 Si ( Compound 7 [{Fe[N(Si"BuMe2)(2-C5H3N-6- J

Me)]2}2(TMEDA)] 〉N ^si^uMe^

Me:它 uSi Z

SiBuMej

A / -o N z

/ n C Compound 8 [{Co[N(Si'BiiMe2)(2-C5H3N-6- Me BuSi 广

Me)] , } , (TMEDA)] ^ ；

^^ /Si 书 uMe

Me2 旧 uSi /

Bu 'Bu

Compound 9 [Fe(OQH2-2,6-TBu2-4-Me)2(TMEDA)] or J. o o ^ ^ _ [Fe(OAr^0^(TMEDA)] f Y 丫 I

'Bu 'Bu

归 u Co ®u

Compound 10 [Co(OQH2-2,6-泡U2-4-Me)2(TMEDA)] or 丄 / \ [Co(OAr^^)2(TMEDA)] V ]

©u ©u Compound 11 [Fe{(OQH2-4,6-l3ii2)2(2-CHMe)}- 旧"

(TMEDA)] or ) f \ [Fe{(OAr')2(2-CHMe)}(TMEDA)]

Bu 'Bu

X

z \ / \ 伯 U qzCO、。旧 U

Compound 12 [Co{(OQH2-4,6-^U2)2(2-CHMe)}- ] r \ (TMEDA)] or [Co{(OAr') , (2-CHMe)}(TMEDA)]

z z \

Compound 13 [Fe(SQH2-2,4,6-它U3)2(TMEDA)] or [Fe(SAr),(TMEDA)] X C X X

旧u 'Bu

y v ' 、 V \ 'Bu 屯 u

Compound 14 [Co(SC6H2-2,4，6,U3)2(TMEDA)] or l i [Co(SArMTMEDA)] X X . X X

<f /SiBuMe2 ‘ 、 / ^ N N si'BuMe,

Compound 15 [{Mn[N(SiT3iiMe2)(2-C5H3N-6-Me)] 3} • | / Li(THF)]

Vy\ / SiBuMej

xi

List of Tables

PAGE

Table 2-1. Some physical properties o f compounds 4-6. 19

Table 2-2. Selected bond distances (A) and angles (。）for compound 4. 23

Table 2-3. Selected bond distances (A) and angles (°) for compound 5. 27


Table 2-5. Some physical properties of compounds 7-14. 37






Table 2-11. Selected bond distances (A) and angles (。) for compound 14. 56

Table 3-1. Some physical properties o f compound 15. 73



xii



xiii

List of Figures

PAGE

Figure 1-1. Diagrammatic representation o f a metal amide. 1

Figure 2-1. Molecular structure of [Fe{N(SilBuMe2)(2-C5H3N-6-Me)}2] (4). 22

Figure 2-2. Molecular structure of [Co{N(SffiiiMe2)(2-C5H3N-6- 26 Me)}{N(Si它uMe2)(2-C5H3N-6-CH2)} • LiCTHF)]^ (5).

Figure 2-3. Molecular structure of [Fe{N(SffiuMe2)(2-C5H3N-6-Me)} {OQH2- 29 2,6-'Bu^-4-Me}{HN(SffiuMe2)(2-C5H3N-6-Me)}] (6).

Figure 2-4. Molecular structure of [{Fe[N(SffiuMe2)(2-C5H3N-6- 40 Me) ] , } , (TMEDA)] (7).

Figure 2-5. Molecular structure of [{Co[N(SffiuMe2)(2-C5H3N-6- 43 Me)] , } , (TMEDA)] (8).

Figure 2-6. Molecular structure of [Fe(OC6H2-2,6-lBu2-4-Me)2(TMEDA)] (9). 46

Figure 2-7. Molecular structure of [Co(OC6H2-2，6-TBu2"4-Me)2(TMEDA)] (10). 49

Figure 2-8. Molecular structure of [Fe(SQH2-2,4,6-^U3)2(TMEDA)] (13). 52

Figure 2-9. Molecular structure of [Co(SC6H2-2,4,6-泡U3)2(TMEDA)] (14). 55

Figure 3-1. Molecular structure of [{Mn{N(Sffii iMe2)(2-C5H3N-6-Me)}3} • 76 Li(THF)] (15).

xiv

Abbreviations

Anal analysis

A r 2,4,6-tri-/er^butylphenyl

Ar' 4,6-di-^er^butylphenyl

Ar^e 2，6-di"抓 butyl-4-methylphenyl

Ar^®OH 2,6-di-rerrtutyl-4-methylphenol

A rSH 2,4,6-tnke 灯-butylthiophenol

av average

"Bu «-butyl

它 u /树-butyl

Calc calculated

dbcH〕 3,5-di-rerr-butylcatechol

dec decomposed

Et ethyl

Et20 diethyl ether

M+ parent peak

Me methyl

2-MeCH(Ar'OH)2 2,2'-ethylidenebis(4,6-di-rerr-butylphenol)

Mes 2,4,6-trimethylphenyl

Mes* 2,4,6-tri-/erf-butylphenyl

M.P. melting point

MS mass spectroscopy

xviii

Ph phenyl

/^o-propyl

R alkyl group (or aryl group i f state otherwise)

THF tetrahydrofuran

T M E D A A/;A/;iV;#-tetramethylethylenediamine

X y l 2,6-dimethylphenyl

xvi

CHAPTER 1. SYNTHESIS OF LATE TRANSITION METAL AMIDES

1.1 GENERAL BACKGROUND

Metal amides are compounds which contain one or more -NRR ' (R or R•二 H,

alkyl, aryl, alkenyl, alkynyl or silyl) ligand(s) bonded to a metal center (Figure 1-1)/

• • / R

M - N \

R'

Figure 1-1. Diagrammatic representation of a metal amide.

Amides represent one of the most prolif ic ligands. Stable amido compounds

have been reported for almost all the elements. The compounds formed may be mono-,

bi-，tri-, oligo-，or poly-nuclear, and homoleptic or heteroleptic. Metal amides,

especially transition metal amides, have attracted considerable interest due to the

varieties o f bonding modes and coordination numbers in their structures, and their

reactivities towards other chemical substrates.^ I -

The first metal amide, Zn(NEt2)2, was reported by Frankland in 1856. It was

synthesized by the reaction of diethyl zinc wi th diethylamine (Equation 1-1).

ZnEt2 + 2HNEt2 Zn(NEt2)2 + 2 CsHg (1-1)

After the report o f [TiCNPh])』〗 in 1935，no other transition metal amides have

been reported until the late 1950's. In fact, only few structural data o f late transition

1

metal amides have been reported until the 1950's. The scarcity of late transition metal

amides may be attributed to an unfavorable combination between the "hard" anionic

amido ligand and the “soft，，low-valent late transition metal center. Moreover, the

"reluctance" of the low-valent late transition metal center to function as a tt -acceptor for

the lone-pair electrons of the amido moiety through { d ^ p ) ;r-bonding interaction may

also impose an unfavorable effect on the stability of the M - N bond. " To date, a number

o f early and late transition metal amides have been structurally characterized."^ The rapid

growth in this aspect may be attributed to a rapid development in the area of low-

temperature X-ray crystallography and crystal mounting techniques.^

1.2 PREPARATIONS OF LATE TRANSITION METAL AMIDES

Several synthetic methods^ are commonly employed in the synthesis of late

transition metal amides. They are summarized as follows.

1. Transmetallation

This is the most commonly used synthetic route to late transition metal amides.

It is also an almost exclusive process for the preparation of homoleptic metal amido

compounds (Equation 1-2).

MCI„ + n M'NR2 [M(NR2)J + nMC\ (M' = Li, Na, K, etc.) (1-2)

2. Transamination

Transamination involves the reaction of a metal amide with a less volatile amine

(Equation 1-3).

LM(NRR') + HNR•丨 FT LM(NR"R"') + HNRR' (1-3)

2

However, transamination reactions are l imited in their application due to steric

factors and the choice of an appropriate amine.

1.3 OBJECTIVES OF THIS WORK

In recent years, the chemistry o f A^-ftmctionalized amido ligands, e.g. [N(Ph)(2-

C5H4N)r，9-i2 [ N ( 2 - C A N ) 2 ] " V [N(SiMe3)(2-C5H3N-6-Me)r严6 [N(SiMe3)(2-C5H3N-

4-Me)r,27-33 [N(Ad)(2-C5H3N-6-Me)]" (Ad = adamanty l ) , [N(SiMe3)(2-C5H4N)r产

have attracted much interest, and a number o f main group and transition metal amido

complexes wi th unusual coordination geometry have been isolated. However, reports o f

late transition metal amides derived from these ligands remain s c a r c e . i4-i5，i8-2(U7 w e

reason that steric bulkiness of substituents on the amido nitrogen center plays an

important role on the stability and structure o f the corresponding metal amido complexes.

We embark from this direction and launch a research project in order to investigate the

chemistry o f late transition metal amido complexes.

The objective of this research work is synthesis and structural characterization o f

late transition metal amido complexes by employing the bulky pyridine-fimctionalized

amido Hgand [N(Si'BuMe2)(2-C5H3N-6-Me)]~ (L), which bear the sterically demanding

^erf-butyldimethylsilyl group (Scheme 1-1).

旧 uMe2 (L)

Scheme 2-11

3

The amido ligand L and its amine precursor L H (1) have recently been developed

in our laboratory. ^ Late transition metal amides derived from L were prepared by

treating the appropriate metal halides wi th the l i thium reagents [L i (L)(TMEDA)] (2) or

L i L (3). Reactivities of these transition metal amides towards the bulky phenols 2,6-

TBu2-4-MeC6H20H and 2-MeCH(4,6-TBu2C6H20H)2, the thiophenol 2,4,6-^U3C6H2SH,

and 3,5-d“份灯-butylcatechol (dbcH:) have also been investigated. The structures of the

bulky phenols, thiophenol and 3,5-di-秘r广butylcatechol were shown in Scheme 1-2.

OU Su ©U ？ \ OHHO、 /

旧 u 'Bu

2,6-'Bu2-4-MeCeH20H 2-MeCH(4,6 Bu2C6H20H)2

SH ^ 阳u

T I A t ^ O H ^ ^ I

2,4.6-Bu3CeH2SH dbcH?

Scheme 1-2

4

1.4 REFERENCES FOR CHAPTER 1

1. Lappert, M. E; Power, P. P.; Sanger, A. R.; Srivastava, R. C. Metal and Metalloid

Amides; Ellis Horwood: Chichester, 1980.

2. Frankland, E. Proc. Roy. Soc. 1856-7, 8, 502. 3. Dermer, O. C ; Femelius, W. C. Z Anorg. Chem. 1935, 221, 83. 4. Fryzuk, M. D.; Montgomery, C. D. Coord. Chem. Rev. 1989, 95, 1. 5. Fryzuk, M. D.; MacNeil, R A. J. Am. Chem. Soc. 1981,103, 3592. 6. Fryzuk, M. D.; MacNeil, R A.; Rettig, S. J.; Secco, A. S.; Trotter, J.

Organometallics 1982, 7,918. 7. Mayer，J. M. Comments Inorg. Chem. 1988, S, 125. 8. Hope, H. Acta. Crystallogn, Sect. B 1988, B44, 22. 9. Ban, D.; Clegg, W.; Mulvey, R. E.; Snaith, R. J. Chem. Soc” Chem. Commun.

1984, 469.

10. Barr, D.; Clegg, W.; Mulvey, R. E.; Snaith, R. J. Chem. Soc., Chem. Commun.

1984, 700.

11. Polamo, M.; Leskela, M. J. Chem. Soc” Dalton Trans. 1996, 4345. 12. Polamo, M.; Leskela, M. Acta Chem. Scand. 1997, 57, 449. 13. Wu, L.-R; Field, R; Morrissey, T.; Muiphy, C ; Nagle，R; Hathaway, B.; Simmons,

C ; Thornton, P. J. Chem. Soc” Dalton Trans. 1990, 3835. 14. Cotton, F. A.; Daniels, L. M.; Jordan, G. T., I V Chem. Commun. 1997，421. 15. Cotton, F. A.; Daniels, L. M.; Muri l lo, C. A.; Pascual, L J. Am. Chem. Soc. 1997,

119, 10223. 16. Cotton, E A.; Daniels, L. M.; Jordan, G. T., IV; Muri l lo, C. A. Pascual, 1. J. Am.

Chem. Soc. 1997，119, 10377. 17. Cotton, R A.; Daniels, L. M.; Muri l lo, C. A.; Pascual, I. Inorg. Chem. Commun.

1998, 7，1.

18. Clerac, R.; Cotton, F. A.; Dunbar, K. R.; Muri l lo, C. A.; Pascual, L; Wang, X. Inorg. Chem. 1999，38, 2655.

19. Clerac, R.; Cotton, F. A.; Dunbar, K. R.; Lu, T.; Muri l lo, C. A.; Wang, X. Inorg.

Chem. 2000, 39, 3065. 20. Clerac, R.; Cotton, K A.; Daniel, L. M. ; Dunbar, K. R.; Kirschbaum, K.; Muri l lo,

C. A.; Pinkerton, A. A.; Schultz, A. J.; Wang, X. J. Am. Chem. Soc. 2000，122,

6226. 21. Engelhardt, L. M.; Jacobsen，G. E.; Junk, P. C•； Raston, C. L.; Skelton, B. W.;

White, A. H. J. Chem. Soc., Dalton Trans. 1988, 1011. 22. Engelhardt, L. M.; Jacobsen, G. E.; Junk, R C ; Raston, C. L.; White, A. H. J.

Chem. Soc” Chem. Commun. 1990, 89.

5

23. Engelhardt, L. M.; Jacobsen, Patalinghug, W. C.; Skelton, B. W.; Raston, C. L.;

White, A. H. J. Chem. Soc.’ Dalton Trans, 1991, 2859. 24. Engelhardt, L. M.; Gardiner, M. G.; Jones, C ; Junk, R C ; Raston, C. L.; White,

A. H. J. Chem. Soc” Dalton Trans. 1996, 3053. 25. Raston, C. L.; Skelton, B. W.; Tolhurst, V.-A.; White, A. H. Polyhedron 1998,17,

935. 26. Raston, C. L ; Skelton, B. W.; Tolhurst, V.-A.; White, A. H. J. Chem. Soc”

Dalton Trans. 2000, 1279. 27. Kempe, R.; Amdt, P. Inorg. Chem. 1996，25, 2644. 28. Oberthiir, M.; Hillerbrand, G.; Amdt, P.; Kempe, R. Chem. Ber. 1997,130, 789.

29. Spannenberg, A.; Amdt, P.; Kempe, R. Angew. Chem. Int. Ed. 1998, 57, 832. 30. Spannenberg, A.; Oberthiir, M.; Noss, H.; Tillack, A.; Amdt, R; Kempe, R.

Angew. Chem. Int. Ed. 1998，57, 2079. 31. Spannenberg, A.; Fuhrmann, H.; Amdt, R; Baumann, W ; Kempe, R. Angew.

Chem. Int. Ed 1998, 37, 3363. 32. Noss, H.; Oberthiir,.M.; Fischer, C ; Kretschmer, W. P.; Kempe，R. Eur. J. Inorg.

Chem. 1999, 2283. 33. Kempe, R. Angew. Chem. Int. Ed. 2000, 39, 468; and references cited therein. 34. Morton, C ; O'Shaughnessy, R; Scott, P. Chem. Commun. 2000，2099.

35. Liddle, S. T.; Clegg, W. J. Chem. Soa, Dalton Trans. 2001, 402. 36. Peng, Y. M Phil. Thesis, The Chinese University of Hong Kong, 1999.

6

CHAPTER 2. SYNTHESIS, STRUCTURES AND REACTIVITIES OF IRON(II) AND COBALT(II) AMIDES

2.1 INTRODUCTION

The chemistry of transition metal amides has attracted much attention due to

their importance in various industrial^'^ and biological p r o c e s s e s 尸 as well as their

potential application in the synthesis of amines and other nitrogen-containing

compounds.4-18

2.1.1 A General Review on Iron(lI) and Cobalt(II) Amides

The first iron(n) and cobalt(n) amides, namely Fe[N(SiMe3)2]2 and

Co[N(SiMe3)2]2，were synthesized by Burger and Wannagat in 1963 using the bulky

bis(trimethylsilyl)amido l i g a n d . The molecular structure o f the cobalt complex was

later established by Power and co-workers to be the dimeric [Co{N(SiMe3)2}2L in the

solid state〗。and monomelic Co[N(SiMe3)2]2 in the gas phase.^^ The triphenylphosphine

adduct, [Co{N(SiMe3)2}2(PPh3)] was reported by Bradley and Hursthouse in 1972.二

Besides the bis(trimethylsilyl)amido ligand, the diphenylamido ligand [NPhj；

was also shown to be capable of stabilizing low-valent iron(n) and cobalt(II) amido

complexes。 For example, Frohlich and co-workers reported the preparation and

structure o f the dimeric [Co(NPli2)2]2 in 1979.^ However, the structure of the complex

reported at that time was not correct. I t was until 1985 that Power and co-workers

reported the correct structure of the compound,

7

Wi th the use of the sterically more demanding bis(diphenylmethylsilyl)amido

ligand [NCSiMePh〗)〗]—, Power and co-workers have successfully isolated the first two-

coordinate iron(n) and cobalt(n) amides [M{N(SiMePli2)2}2] ( M = Fe, Co), which are

monomeric in the solid state.^^ It has been reported that the sterically demanding

borylamide [N(R)(BR2)]~ (R and R' 二 Ph, Mes or Xy l ) could also support two-

coordinate i r o n ( n f and cobal t (n / ' ' ' ' amido complexes. In 1991, [Fe(NPh2)2]2,

[Fe{N(SiMe3)2}2L and its Lewis base adduct [Fe{N(SiMe3)2}2(THF)] were successfully

synthesized.^^ The former two complexes are dimeric in the solid state.

Furthermore, iron(II) and cobalt(n) amido complexes containing the

•ClLi(丁HF)3] group as a ligand have also been reported. Examples are

[Fe{N(SiMe3)2}2 • a L i C I T O ^ f and [Co{N(SiMe3)2}2 • ClLi(THF)3].26 Anionic amido

complexes [M{N(SiMe3)2}3]一 ( M 二 Fe, Co) have been reported by Dehnicke and co-

workers in 1996.30

The molecular structures of some iron(n) and cobalt(n) amido complexes are

illustrated in Scheme 2-1.

Recently, Cotton and co-workers have reported a number o f iron(n) and cobalt(n)

amido complexes which contain M - M bond by employing di(2-pyridyl)amide [N(2-

C5H4N)2]-，3i-34 and amidinates [RC(NPh)2]~ (R 二 H or Ph).' '" ' ' Complexes derived from

these ligands include [Co3(dpa)4Cy (dpa = di(2-pyridyl)amide)/^ [M2{RC(NPh)2}3] ( M

=Fe,36 Co35; R = H o r Ph). Some of these complexes are depicted in Scheme 2-2.

8

SiMe3 ph Ph MeaSi

Me3Si^N； P \ X / h Me3S 丨 < 广 3 3 〕C。—PPh3 N—Co Co-N N - C o ^Co-N

Me3Si、N p / N 、ph M e ^ s / N ^SiMe〕 \ / \ / Sme, Ph Ph Me3Si SiMe。

Mes

Mes 一日 \ /Mes Ph2MeSi\ /SiMePh? N - F e - N N-Fe—N

Mes Ph^Mea/ \siMePh2 /

Mes

SiMeg T H F 〜严 SiMeg - -

MegSi/N THF<L|\ /SiMe。

“ 。 • ；Fe—O I 3 Co—M MesSi、/ Me3Si \ /e \ ,S iMe3 MegSi、/ \siMe3

\ N N | \ . SiMes Me3sf \iMe3 ^ 識。」

Scheme 2-1

/ \ / \ ( f ^ L ^ L-^ y^N^N-^N^/ l ^ k A N ^ N - ^ ^ / l ^ ^ N - ^ N - ^ i

CI—Co—Co—Co—CI \ A \ 八

Fe—Fe Co—Co

Scheme 2-2

2.1,2 A General Review on Iron(n) and Cobalt(II) Thiolates

The chemistry of transition metal thiolates constitutes a large and rapidly

expanding area of research.^恥 The relevance of such complexes to the structure,

bonding, and function of biologically active reaction centers in metalloproteins such as

ferredoxins, nitrogenases, blue copper proteins, and metallothioneins bears a significant

impetus for their studies,

I

9

Ho lm and co-workers have carried out a pioneer work on iron(n) and cobalt(n)

thiolate complexes. Most o f these compounds are ionic in nature, containing Fe-S or

Co-S clusters. Representative examples include the mononuclear [M(SEt)4f- ( M =

Fe,42，43 C o , , the binuclear [M^CSEt)^'- ( M 二 Fe, C o ) , the trinuclear [Fe3(SPh)3Cl6]^''

and the tetranuclear [M/SPhX。]〗—（M 二 Fe,*"^ Cc/s，’. Some of these complexes are

depicted in Scheme 2-3.

r oct - 1 2 - r Et n 2 - 「 Et n 2 -厂 SEt 1 「 E t S 、、入 , . S E t ] EtS 入 SEt

E t S 〉 F e ZC。 \ 9 。 \ / F e Fe

EtS ^ \ S B E t S ^ S 、SEt EtS^ | 、sEt - J L Et 」 L t t 一

Scheme 2-3

Very bulky thiolato ligands have been employed for the synthesis o f neutral

homoleptic transition metal thiolato complexes wi th a low degree o f association.

Representative examples are the ionic [Co2(SQHr2,4，6々r3)5r，5i the neutral [FeCSC^Hj-

2，4，6-它U3)2]2，52 and the two-coordinate [Fe(SC6H3-2，6-Mes2)2] (Scheme 2-4), ' '

ArS—Fe Fe—SAr // 。 \ )>

’

Scheme 2-11

10

2.1.3 A General Review on Iroii(n) and Cobalt(II) Alkoxides and

Aryloxides

In general, transition metal alkoxides or aryloxides are often more diff icult to

study as compared to their isoelectronic amido and alkyl counterparts. This is due to the

excellent bridging ability and a lower steric requirement o f the alkoxo group. Thus, they

are often oligomeric and have poor solubility in common hydrocarbon solvents.^

The use o f alkoxide ligands which contain sterically demanding hydrocarbon

substituents is effective to reduce the extent o f alkoxide bridging.^^ In 1980，Wilkinson

and co-workers reported the use o f the very bulky 1-adamantoxy and 1-

adamantylmethoxy group to prepare a series o f transition metal alkoxides such as the

cobalt(n) alkoxides Co(l-ado)2 and Co(l-admeo)2 (1-ado = 1- adamantoxy，1-admeo =

1-adamantylmethoxy), However, these complexes are insoluble polymers. In the same

year，they reported a series o f transition metal alkoxides containing the h\s{tert-

butyl)methoxide [OCH'Bus]". The cobalt(n) alkoxide has an empirical formula

Co(OCirBu2)2 and is dimeric in the solution s ta te"

The first solid state structure o f cobalt(n) alkoxide was reported by Power and

co-workers in 1985. The compound reported was the trinuclear cobalt(n) alkoxide

[{Co3(/7-r日灯-butylcalix[4]arene〇SiMe3)2(THF)} • 5PhMe].^^ They also employed the

bulky tris(/er?-butyl)methoxide to synthesize a series o f cobalt(n) alkoxide complexes

[Co (a ) (OC 它 U3)2 • Li(THF)3], [Li(THF)4.5][Co{N(SiMe3)2}(OCSu3)2], and

[Li{Co[N(SiMe3)J(OCBu3)2}]，59 which are ionic in nature. Besides, the bulky alkoxide

and aryloxide ligands Vh^SiOT and (4-MeC6H4)3CCr were

employed to prepare the corresponding neutral mononuclear cobalt(n) alkoxides.

11

Typical examples include [{Co[OC(C6Hii)3]2}2 • CH3OH • • THP],

[Co(OCPh3)2(THF)2]，[Co(OSiPli3)2(THF)L and [Co{OC(QIV4-Me)3}2(THF)J.6o

Structural characterization of iron(n) alkoxides or aryloxides have also been reported by

Power and co-workers. Wi th the sterically demanding bulky aryloxide ligand Mes*0—，

a number o f iron(n) alkoxides and aryloxides complexes such as [Fe(OMes*)2]2 and

[Fe(OCPh3)2(THF)2] have been synthesized and structurally characterized (Scheme 2-

5).55

THF JHF I OSiPhg

T H F “ ' \ c i T H F ' - i o

^ T H F ^ \OSiPh3

iBufiO^ \0C旧U3

Mes* OCPhg 〇

THF"".pe Mes*〇一F气 Fe—OMes* T H F ^ \OCPh3 \〇

Mes*

Scheme 2-5

12

12 RESULTS AND DISCUSSION

2.2.1 Synthesis of the Ligand Precursor LH (1) and the Corresponding

Lithium Reagents [Li(L)(TMEDA)] (2) and LiL (3)

Synthesis of the ligand precursor L H (1) and the corresponding l i thium reagents

[L i (L ) (TMEDA) ] (2) and L i L (3) is illustrated in Scheme

丫 N , 仙， T _ A ， E t ^ O _ 丫丫口 - L — E D A ) Me,^uSiCI. Et,0

J r.t.. 4 h r.t., 8 h ^ ^ 83 %

\ r~\ / / N N〔

Z、 \ Li,

y \ "Buli. TMEDA, Et,0 ^ ^ ^ ^ ^ s V B u M e ,

r.t., 15 min I ^ 97 % ^ ^

2 H

\SKBuMe2

1 nDi i| ！ hAYflnfi ， Li[N(SBuMe2)(2-C5H3N-6-Me)]

r.t., 2 h 87 % 3

Scheme 2-6

Compound 1 was obtained by silylation o f 2-aniino-6-picoline. Treatment o f 2-

amino-6-picoline with one equivalent o f^BuLi and one equivalent of TMEDA, followed

by quenching of the resulting solution wi th one equivalent of 秘灯-butyldimethylsilyl

chloride gave compound 1 in 83 % yield. Lithiation of 1 wi th one equivalent o f "BuL i in

13

the presence o f one equivalent of TMEDA gave the compound 2 in 97 % yield. On the

other hand, lithiation of 1 with one equivalent o f ^ u L i in the absence of TMEDA gave

compound 3 in 87 % yield^^

2.2.2 Synthesis, Structures and Reactivities of Mononuclear Iron(n)

and Cobalt(II) Amides

2.2.2.1 Synthesis of Mononuclear Iroii(II) and Cobalt(II) Amides

Synthesis of a mononuclear iron(n) amido complex has been achieved by the

reaction o f anhydrous iron(n) chloride wi th the appropriate l i thium amide (Scheme 2-7).

FeCl2 + 2 U[N(Si'BuMe2)(2-C5H3N-6-Me)] ^ ^ ^ ^Fe

3 58% 丫 N 丫 N \ s 編巧

4

Scheme 2-7

Reaction of anhydrous FeCljWith two equivalents o f compound 3 in diethyl ether

afforded compound 4 as an olive-green crystalline solid in 58 % yield. Compound 4 can

be recrystallized from toluene.

Attempts to synthesize an analogous monomeric cobalt(n) amide by the reaction

o f two equivalents of compound 3 wi th anhydrous C0CI2 in diethyl ether were

14

unsuccessful (Scheme 2-8). Only an air-sensitive intractable oil has been obtained after

the reaction.

COCI. + 2Li[N(SiBuMe,)(2.C,H3N.6-Me)] _ _ ^ ^ 10 =93「=1丨卜 yellow

3

Scheme 2-8

Attempts to synthesize neutral monomeric cobalt(II) amide by metathetical

exchange between cobalt(n) chloride and compound 3 in THF were also unsuccessful

Unexpectedly, an imreproducible ionic cobalt(n) amido complex was isolated (Scheme

2-9). Compound 5 was isolated as greenish brown crystals in 11 % yield.

A Me 'BuSi、人N 人

A M Li 一丁 HF

2C0CI2 + 4 U[N(Si'BuMe2)(2-C5H3N-6-IVIe)] ^ \ t T H F - U\ ^ d o - ^ V ^ S i ^ u M e ,

U 5

Scheme 2-9

15

There are two proposed explanations for the formation of compound 5. One

explanation may be attributed to contamination o f compound 3 by the dil ithium reagent

Li2[N(SffiiiMe2)(2-C5H3N-6-CH2)] (proposed formation o f U2MSi'BuMQ2)(2-C,11,1^-6-

CH2)] is illustrated in Scheme 2-10). As shown in Scheme 2-11, both the dilithium

reagent Li2[N(Si'BuMe2)(2-C5H3N-6-CH2)] and compound 3 react simultaneously with

C0CI2 to give compound 5.

H . ^ ^ N y N ^ s ^ u M e a 1.2 eqv."BuLi ^ Li[N(S 阳 uMe^Xa-CgHsN-e-Me)] +

. J hexane little amount U2[N(Si旧uMejXS-CsHsN^SCHs)] ^ ^ r.t., 8 h

• 1

Scheme 2-10

2 C0CI2 + 2 Li[N(SifBuMe2)(2-C5H3N-6-Me)] + 2 Li2[N(Si旧uMesXa-CsHsN-e-Chg]

3

2 N \

A M + 2 THF • \ \

- 4 L丨CI T H F - L i

5

Scheme 2-11

16

On the other hand, metathetical exchange between one equivalent o f C0CI2 and

one equivalent of compound 3，followed by C - H bond activation o f the 6-methyl group

on the pyridine ring may give a neutral binuclear cobalt(n) amido complex as an

reaction intermediate. This intermediate further reacts wi th two equivalents o f

compound 3 to give the mixed-metal complex. Coordination o f two THF molecules

leads to the formation of compound 5 (Scheme 2-12).

CI

H Co 9 I i广丨 Z \

2 C0CI2 + 2 U[N(Si'BuMe2)(2-C5H3N-6-Me)] ^ ^ ^ 2 H^C^^N^N^^.^^^^^ 3

C —H bond activation ^ \ Z j + 2 U[N(S阳uMe2)(2~CsH3N~6~Me)] ^ ‘ ^ ^ I� / \ “

2 丫 \ &旧uMe2

A I \1 n l \ l

j i N i ^ ^ N 丫 _ t l l H F _ _ ^ THF-

5

Scheme 2-11

17

2.2.2.2 Reactions of Compound 4 with Ar^'OH and ArSH

Protolysis reaction of compound 4 wi th one equivalent of the bulky phenol

Ar^^OH in hexane gave the novel mixed-ligand compound 6 in 75 % yield (Scheme 2-

13). Compound 6 can be recrystallized from toluene as pale green crystals.

z I /'Bu

, hexane . 丄〜 ^ ‘ '^u ^ \ r.t., 8 h ” r ^ N ^

75% L i T |

SKBuMej

4 6

Scheme 2-13

Attempted reactions of compound 4 wi th the bulky thiophenol ArSH were

unsuccessful. Only an air-sensitive intractable oi l was isolated (Scheme 2-14).

A /'Bu

r ^ iri 1 or 2 e q v .旧 u ~ f y - s H

Me2 饥 S i X y / ^ N ^ W \ y \<Bu ’ hexane

Fe — Intractable oil \ \ r.t•，8 h

4

Scheme 2-14

I

18 V

2.2.2.3 Physical Characterization of Compounds 4-6

Compounds 4-6 were characterized by melting point determination, mass

spectrometry (E. L 70 eV), magnetic moment measurement and elemental analysis, in

addition to single-crystal X-ray dif&action studies. Table 2-1 lists some physical

properties o f compounds 4-6.

Table 2-1. Some physical properties of compounds 4-6.

Compound Yield (%) Color M.p. (。C)

4 58 Olive-green crystals 107-110

5 1 1 Greenish brown crystals 163-165

6 75 Pale green crystals 155-158 (dec.)

The mass spectrum of compound 4 shows a molecular ion peak [M]+ {miz = 500，

21 %). Other fragmentation peaks include [M-它u]+ (443, 40 %); \LY (221, 9 %);

[ L -它 11]+(165,100 %) and [它 11]+ (57, 30 %).

No molecular ion peak was observed in the mass spectrum o f compound 5.

Other fragmentation peaks observed include [Co(L)(L')]^ [L’ 二 N(SffiuMe2)(2-C5H3N-6-

CH2)] (501, 4 %), [Co (L ) (L ’HBur (445，17 %), [Up (221，4 %), [L-它u]+(165，100 %)

and 阳 11]+(57，15%).

The mass spectrum of compound 6 shows fragmentation due to [Fe(L)(LH)]+

(496, 29 %), [Fe(L)(LH)-Me]^ (481，7 %), [Fe(L)(LH)-®u]^ (439, 36 %)，[L]^ (222，10

0 / 0 ) ， ( 2 2 0 , 15 %), [Ar^^O-Me]" (205, 37 %)， [L-它u]. (165, 91 %) and

(57,100 %).

19

The magnetic moments o f the iron(n) compounds 4 and 6, viz. 4.87 /Zg and 4.97

"B, respectively, have been determined by the Evans method^^ in toluene solution at 298

K. These values are consistent wi th a high-spin cf electronic configuration, with four

unpaired electrons.

The magnetic moment of compound 5 has been found to be 4.20 f i^ per Co at

298 K. This result implies that each cobalt(n) center in compound 5 is in a high-spin (£

electronic configuration wi th three unpaired electrons.

Elemental analysis of compounds 4 -6 were consistent wi th their empirical

formula.

2.2.2.4 Molecular Structures of Compounds

1. Molecular Structure of Compound 4

The molecular structure of compound 4 wi th the atom numbering scheme is

depicted in Figure 2-1. Selected bond lengths (A) and angles (。) are listed in Table 2-2.

Compound 4 crystallizes in a monoclinic crystal system wi th space group C2c.

Compound 4 is a neutral monomeric iron(n) diamide. The two amido ligands

coordinate to the iron(n) center in a iV;A^-chelating fashion, forming a distorted

tetrahedral coordination environment around the metal center.

The Fe-N3^do bond distances [Fe(l>-N(2) and Fe( l ) -N(2A) ] o f 2.010(3) A in 4

are longer than those of 1.84 A in the monomeric Fe[N(SiMe3)2]2，2i 1.925(3) A in the

dimeric [Fe{N(SiMe3)2}2]2严 and 1.916(2)~1.918(2) A in the two-coordinate

[Fe{N(SiMePli2)2}2].25 This may be a consequence o f a more crowded coordination

environment around the iron(n) center in compound 4. The Fe—Np dyi bond distances

20

[ F e ( l ) - N ( l ) and Fe( l ) -N(1A)] are 2.124(3) A . The S i -N bond distance Si ( l ) -N(2) of

1.720(3)入 is comparable with those reported for other silylamido complexes.^^ The

Caromatic-Nanudo distoiice C( l ) -N(2) is shoft, viz. 1.353(4) A, suggesting the presence of

delocalization of the lone-pair electron density onto the pyridyl

The N a - o - F e — 丨 angles [N( l>-Fe( l ) -N(2) and N(1A>-Fe( l ) -N(2A),

66.0(1)0] are small This may be due to the highly strained four-member metallacycle

ring. The inter-ligand angle >Cid。-Fe—IS^d。，* 155.6(1)。，is large due to steric

repulsion between two silyl groups on the same molecule. The amido nitrogen centers

[N(2) andN(2A)] exhibit a trigonal planar geometry [sum of bond angles = 359.9。（av,)]

which are consistent with ^y-hybridized nitrogen atoms.

21

^^

C(IO

)

Figu

re 2

-1.

Mol

ecul

ar s

truc

ture

of [

Fe{N

(Si'B

uMe,)

(2-C

sH3N

-6-M

e)}2

] (4

).

Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.

[Fe{N(SffiuMe2)(2-C5H3N-6-Me)}J (4)

F e ( l 肩） 2.124(3) N ( l > - N ( l ) 1.370(4)

Fe( l>-N(1A) 2.124(3) N (2 ) -C( l ) 1.353(4)

Fe(l>-N(2) 2.010(3) Si(l>-N(2) 1.720(3)

Fe( l ) -N(2A) 2.010(3)

N( l> -Fe( l ) -N(1A) 137.1(1) Si(l>-N(2>-Fe(l) 132.6(1)

N( l>-Fe( l ) -N(2) 66.0(1) C ( l ) - N ( 2 ^ S i ( l ) 133.5(2)

N( l>-Fe( l>-N(2A) 124.2(1) C(l>-N(2>-Fe(l) 93.8(2)

N(2)-Fe( l>-N(1A) 124.2(1)

N(2) -Fe( l ) -N(2A) 155.6(1)

N(1A>-Fe( l ) -N(2A) 66.0(1)

23


The solid state structure of compound 5 with the atom numbering scheme is

depicted in Figure 2-2. Selected bond lengths (A) and angles (。）are listed in Table 2-3.

Compound 5 crystallizes in a monoclinic crystal system with space group P l j n ,

The solid state structure of compound 5 is worth discussing. Two types of amido

ligands, namely the amido ligand L and a dianionic alkyl-amido ligand L', are observed

in the dimeric compound 5，which consists o f two [Co(L)(L') • Li(THF)] units. As

shown in Figure 2-2, the amido nitrogens N(2) (of L) and N(4) (of L') bridge between

L i ( l ) and Co(l) , resulting in a [CoNsLi] core. I t should be noteworthy that the 6-methyl

carbon C(12) of L' is coordinating to Co( lA). In other words, L' coordinates to two

cobalt(n) centers through a C,A^-bridging fashion.

The observed Co-N^dobond distances in 5 [Co( l ) -N(2) 2.045(3) A, Co(l>-N(4)

2.089(3) A ] are longer than those of 1.84 A in [Co{N(SiMe3)2}2]严 and those of

1.898(3)-1.904(3) A in the monomeric [Co{N(SiMePh2)2}2].25 They are also longer than

the Co-N^^do distances of 1.910(5)-1.922(5) A for the terminal ligands in the dimeric

[Co{N(SiMe3)2}2L，20 and 1.889(8) A in [Co(NPh2)2]2."^ The Co—Li distance of 2.723(6)

A in 5 is longer than that of 2.573(17) A in [Li{Co[N(SiMe3)2](OCBu3)2}].59 Also, The

L i - 0 bond distance of 1.966(7) A in 5 is longer than that of 1.922(10) A (av.) in

[Co(Cl)(OCTBii3)2 • Li(THF)3].59 The longer Co^N^^d。，Co—Li and L i - 0 distances in

our current complex may be ascribed to a more crowded four-coordinate environment

around the metal centers. The observed Si-N bond distances in 5 [1.724(5)-L728(3) A；

63 are similar to the S i -N distances found in other silylamido complexes.

24

The N讓d。-M-N—yi ( M = Co or L i ) [N (3^Co( l )~N(4 ) 65.0(1 广

N(2) 63.8(2)。] are small due to the highly strained metallacycle ring.

\

25

am

Figu

re 2

-2.

Mol

ecul

ar s

truc

ture

of [

C:o

{N(S

i'BuM

e2)(2

-CsH

3N-6

-Me)

} {N

(Si'B

uMe,

)(2.C

5H3N

-6-C

Hi)}

‘ L

i(TH

F)],

(5).

Table 2-9. Selected bond distances (A) and angles (。) for compound 10.

[Co{N(SmuMe2) (2 -C5H3N-6-Me) } {N(S iûMe2) (2 -C5H3N-6-CH2) } • L i ( T H F ) L (5)

Co(l ) -C(12A) 2.043(3) L i ( l> -0 (2) 1.966(7)

Co( l^L i ( l ) 2.723(6) N(1H:(1) 1-389(5)

Co( l ) -N(2) 2.045(3) N ( 2 > ^ ( 1 ) 1.382(5)

Co(l>-N(3) 2.096(3) N ( 3 H X 7 ) 1.373(5)

Co( l ) -N(4) 2.089(3) N(4^C(7) 1-380(4)

L i ( l > - N ( l ) 2.063(8) N(2>-Si(3) 1.724(3)

L i ( l>-N(2) 2.371(7) N(4)-Si(2) 1.728(3)

L i ( l ) -N (4 ) 2.136(7)

C(12A>-Co( l^N(2) 124.3(1) C ( l > -N (2>ô ( l ) 108.0(2)

C(12A) -Co( l^N(3) 109.7(1) C( l>-N(2) -L i ( l ) 85.7(3)

C(12A^Co(l>-N(4) 125.8(1) C( l>-N(2^Si(3) 124.9(2)

N(2^Co( l>-N(3) 110.3(1) Co ( l> -N(2^L i ( l ) 77.0(1)

N(2>-Co(l>-N(4) 105.7(1) Co(l>-N(2>-Si(3) 119.2(1)

N (3 ) -Co( l ^N(4 ) 65.0(1) Li( l>-N(2)-Si(3) 129.8(2)

N ( l ) - L i ( l ) - N ( 2 ) 63.8(2) _ C(7>-N(4Kô( l ) 92.6(2)

N ( l ^ L i ( l ) - N ( 4 ) 115.4(3) C ( 7 ^ N ( 4 ^ L i ( l ) 98.9(3)

N ( l ^ L i ( l ) - 0 ( 2 ) 108.9 ⑶ C(7>~N(4)~Si(2) 125.6(2)

N(2>-L i ( l ^N(4 ) 95.4 ⑶ Co( l>~N(4Hî( l ) 80.3(2)

N(2>-L i (1^0(2) 131.8(3) Co(l>-N(4^Si(2) 132.0 ⑴

N(4>-L i ( l ) -0(2) 126.3(4) Li( l>-N(4)-Si(2) 115.6(2)

27


The molecular structure of compound 6 with the atom numbering scheme is

shown in Figure 2-3. Selected bond distances (A) and angles (。）are listed in Table 2-4.

Compound 6 crystallizes in a triclinic crystal system with space group P\.

Compound 6 is a mixed-ligand complex. The iron(n) center is bound by one

amido ligand L and one aryloxide ligand Ar^ 'O. The former binds to the metal center in

a i\/,A^-chelating fashion and the latter binds in a monodentate manner. Coordination of

a free amine ligand L H completes a distorted tetrahedral environment around the iron(n)

center.

The Fe -0 bond length in compound 6 [Fe( l ) -0(1) 1.853(1) A] is longer than

those of 1.822(5>-1.822(6) A for the terminal F e - 0 bond lengths in the dimeric

[Fe(OMes*)2L.55 However, it is shorter than that o f 1.883(1) A in the monomeric

[Fe(OCPh3)2(THF)2]?5 A longer F e - 0 bond distance in 6 is attributed to a more

crowded environment around the metal center. The Fe-N�(do bond in compound 6

•Fe(l)-N(2) 2.016(2) A] is comparable to the corresponding distance of 2.010(3) A in 4.

28

。’

、

C{2

)0

• C4

91

\ /

C{48)

I

Figu

re 2

-3.

Mol

ecul

ar st

ruct

ure

of [

Fe{N

(SnB

uMe2

)(2-C

sH3N

-6-M

e)} {

OQ

Hr2

,6-'

Bur

4-M

e}-

{HN

(Si'B

uMe,

)(2-

C5H

3N-6

-Me)

}] (6

).


[Fe {N(S iTBuMe2) (2 -C5H3N-6-Me) } {OQH2-2 ,6 - l B u 2 -4 - M e } -

{ H N ( S f f i u M e 2 ) ( 2 - C 5 H 3 N - 6 - M e ) } ] (6)

C(41)-0(l) 1.343(3) Fe(lHXl) 1.853(1)

Fe( l> -N( l ) 2.154(2) N(l>-C(21) 1.374(4)

F e ( l ^ N ( 2 ) 2.016(2) N (3^C(1 ) 1.352(4)

Fe( l ) -N(3) 2.145(2)

N( l>-Fe( l>-N(2) 64.8(1) 0 (1>-Fe( l ) -N( l ) 111.6(9)

N ( l ^ F e ( l ) - N ( 3 ) 117.2(9) 0(1>-Fe( l ) -N(2) 148.9(9)

N(2)-Fe(l>-N(3) 106.8(3) 0(1>-Fe( l ) -N(3) 102.1(8)

30

(

2.2.3 Synthesis，Structures and Reactivities of Binuclear Iroii(II) and

CobaIt(]I) Amides

2.2.3.1 Synthesis of Binuclear Iron(II) and Cobalt(II) Amides

The binuclear iron(n) amido complex 7 was prepared in 59 % yield by the

reaction o f two equivalents of compound 2 with one equivalent o f anhydrous FeCl〗 in

diethyl ether (Scheme 2-15). The analogous binuclear cobalt(n) amido complex 8 was

prepared by a similar procedure in 68 % yield.

Si'BuMe2

/ \ / N z \ \ Me2'BuSi (

J EtO 2MCI2 + 4 / \

2 M = Fe, 59 % \

2 \ Mej'BuSi /

7: M = Fe 8: M = Co

Scheme 2-15

Alternatively, compound 7 has also been prepared by treating the mononuclear

iron(n) amide 4 with 0.5 equivalents o f T M E D A in diethyl ether in 52 % yield (Scheme

2-16).

31

smuMe^

fU f Y ^

Me^BuSi T hC \ y Me^BuSi f ,Fe 0.5 eqv. TMEDA, Et2〇— \ ,

N\s 丨吼 ,t..6h > /Si'BuMe, 52% \ ^ N

4 Mej'BuSi Z

7

Scheme 2-16

I t has been mentioned that reaction o f C0CI2 with compound 3 gave a dark

greenish yellow intractable oil (Scheme 2-8). Treatment o f this intractable oil wi th an

excess of TMEDA in diethyl ether also afforded the binuclear cobalt(n) amido complex

8 (Scheme 2-17).

COC, + 2_S細e )(2_C5H3N_6_Me)] ~ ~ ^ P n ^ ^ l ^ 丫和

3

SreuMej

K / 力 N z /

excess TMEDA, Et,0

6q。(知 Me2 旧 uSi /

8

Scheme 2-11

32

Both compounds 7 and 8 are extremely air sensitive compounds. They are

soluble in common organic solvents such as diethyl ether, hexane, THF and toluene.

2.2.3.2 Reactions of Compounds 7 and 8 with Protic Reagents

Both compounds 7 and 8 reacted readily with protic reagents such as phenols

Ar^«OH and 2-MeCH(Ar'〇H)2，and thiophenol ArSH to give the corresponding metal(n)

bis(aryloxide) and dithiolate complexes, respectively (Scheme 2-18).

Treatment of compound 7 with four equivalents of Ar^ 'OH in hexane afforded

the neutral mononuclear iroii(n) bis(aryloxide) compound 9 in 49 % yield. The product

was isolated as white crystals. The analogous cobalt(n) bis(aryloxide) compound 10,

was also prepared according to a similar procedure, starting from compound 8.

Compound 10 was obtained as green crystals in 46 % yield.

Reaction of compound 7 with 2-MeCH(Ar'〇H)2 in hexane gave the neutral

mononuclear [Fe{(OAr')2(2-CHMe)} (TMEDA)] 11 in 45 % yield. Compound 11 was

isolated as white crystals. Reaction of one equivalent of the binuclear cobalt(n) amide 8

wi th two equivalents of 2-MeCH(Ar'OH)2 gave the analogous cobalt(n) bis(aryloxide)

12 as bluish green crystals in 49 % yield. Crystals suitable for X-ray diffraction studies

for both compounds could not be isolated. Nevertheless, results of elemental analysis of

both compounds are consistent with their corresponding empirical formula. Their mass

spectra also showed their respective molecular ion peaks.

Treatment of compound 7 with four equivalents of ArSH in hexane gave the

neutral mononuclear iron(n) dithiolate compound 13 as yellowish brown crystals in 48

% yield. The analogous cobalt(n) dithiolate compound 14, was prepared by a similar

33

procedure, starting with compound 8. Compound 14 was isolated as reddish brown

crystals in 44 % yield.

/'Bu 〉 N

4 - H ^ ^ o h 、！旧 u

\'Bu , hexane —

r.t, 8 h 、 I \ Bu Bu

9: M = Fe 10:M = Co

SI'BuMe2

f j ^ f Y ^ z 4 -bu / N

• 抓 V ^ u Me^BuSi r 丨 BU, hexane ^ J j

\ J �t.,8h /SiBuMe^ / \ \ Bu

产厂 r 、 1 1 : M = Fe

Me BuSi /

7; M = Fe 8: M = Co 、 / “ \ z

/^u �N N\ 4 ^ u - ^ K S H 吼

, hexane 广 Sv；；；;^ Bu旧u

13: M = Fe 14:M = Co

Scheme 2-18

？

34

2.2.3.3 Attempted Reactions of Compounds 7 and 8 with d^S-di-tert-

butylcatechol

Attempts to synthesize metal(n) catecholates by the reaction of compounds 7 or

8 w i th 3,5-di-re灯-butylcatechol (dbcH〗) were unsuccessful (Scheme 2-19). Only an air-

sensitive intractable oi l was obtained in both cases.

mu ^ ^ ^ O H hexane , ^

7 or 8 + f Intractable oil r.t.， 8 h

Scheme 2-19

2.2.3.4 Physical Characterization of Compounds 7-14

Compounds 7-14 have been characterized by melting point determination, mass

spectrometry (E. I. 70 eV), magnetic moment measurement and elemental analysis. In

addition, compounds 7-10，13-14 have also been characterized by single-crystal X-ray

diffraction studies. Table 2-5 lists some physical properties o f compounds 7—14.

Not all the compounds 7-14 showed their molecular ion peak [M]+ in their

respective mass spectra, probably due to their high molecular weights and, thus, low

volatility. However, molecular fragment peaks were observed.

Compound 7 showed major fragmentation peaks o f [FeLJ. (499，53 %), [FeL。-

它u]+ (443，100 %), [ L r (221，12 %), [L-®u]+ (165, 81 %), [ T M E D A f (116, 6 %), and

[它 11]+ (57, 48 %). Compound 8 showed a similar pattern of [ C o I J . (502, 11 %)，[CoL〗-

它 11]+ (445，35 %), [ L r (223, 5 %), [L-TBuf (165, 100 %)，and [它11]+ (57, 13 %) in its

35

mass spectrum. These indicated that the T M E D A ligand in both compounds 7 and 8

dissociates readily to give the monomeric species [ M L J ( M = Fe, Co).

The mass spectrum o f compound 9 show fragmentation due to [Ai^ 'O]^ (220, 35

%), [Ar^Ô-Me]^ (205，100 %), [TMEDA]+ (115，5 %) and [它u]+ (57, 24 %). A similar

pattern, viz. (498, 17 %), [Ar^Ô]^ (220, 33 %), [Ar^Ô-Me]^ (205，100

%), [TMEDA]+ (117, 9 %) and [ 它 ( 5 7 , 90 %) was also observed in the mass

spectrum o f 10.

Compound 11 shows a molecular ion peak [M]+ (m/z = 608，90 %). Other peaks

include [M—Mer (593, 7 %), [M-它u]+ (551, 1 %), [M-Ar '0 ]+ (403，4 %), [TMEDA]^

(117，62 %) and _ + (57，100 %). A similar pattern, viz. [M]+ (611, 57 %)， [M-Me]+

(596, 5 %), [M—它 11]+ (554, 2 %), [M -A r ' 0 ]+ (406, 5 %), [TMEDA] " (117，58 %) and

"BuY (57, 100 %) was also observed in the mass spectrum o f 12.

Compound 13 shows peaks due to [ArS]+ (278, 14 %), [ArS~Me]+ (263, 10 %),

[Ar]+ (245，9 %), [A r -Me ] . (231，17 %), [ArS~它u]+ (221, 8 %), [TMEDA]+ (116，9 %)

and ["Bu]. (57,100 %). A similar pattern was observed for compound 14, viz. [ArS].

(278, 26 %), [ArS~Me]+ (263, 33 %)，[Ar]+ (244，18 %), [Ar-Me]+ (229，56 %)’ [A rS-

它u]+ (221, 5 %), [TMEDA]" (115,7 %) and [TBuT (57, 100 %),

The magnetic moment of compounds 7, 9’ 11 and 13 were found to be 4.86 [ i 它

per Fe, 4.83 / i^, 4.92 ul^ and 4.96 n它,respectively at 298 K by the Evans method.' '

These values are consistent wi th a high-spin ( f electronic configuration wi th four

unpaired electrons.

36

The magnetic moment of 5.31 fi丑 per Co，3.64 //g, 4.46 f i^ and 3.78 //g for

compounds 8,10,12 and 14, respectively, at 298 K suggest that the cobalt(n) centers in

these compounds have a high-spin electronic configuration.

Results of elemental analysis for compounds 7-14 were consistent with their

empirical formula.

Table 2-5. Some physical properties of compounds 7 -14

Compound Yield (%) Color M.p.(。(：）

7 59 Pale green crystals 55-58

8 68 Green crystals 66-69

9 49 White crystals 212-214 (dec.)

10 46 Green crystals 227-230 (dec.)

11 45 White crystals 270-273 (dec.)

12 49 Bluish green crystals 305-308

13 48 Yellowish brown crystals 197-200 (dec.)

14 44 Reddish brown crystals 197-202 (dec.)

37

2.2.3.5 Molecular Structures of Compounds 7-10 and 13-14



shown in Figure 2-4。Selected bond distances (A) and angles (。）are listed in Table 2-6.

Compound 7 crystallizes in a triclinic crystal system with space group P\. It is a

binuclear complex that consists of two bis(amido)iron(n) units which are bridged by a

T M E D A molecule. The amido ligand L binds to the iron(II) center in a A^,A^-chelating

fashion, forming a [FeNJ moiety. Coordination from one dimethylamino unit of the

T M E D A molecule completes a distorted trigonal bipyramidal coordination geometry

around each iron(n) center. The two amido nitrogens N(2) and N(4), and the amino

nitrogen N(5) from TMEDA molecule define the trigonal plane [sum of the bond angles

二 359.8。]. The remaining two axial positions are occupied the pyridyl nitrogens N ( l )

and N(3). Deformation of the N( l>-Fe( l ) -N(3) angle from the linearity [N ( l ) -Fe ( l ) -

N(3) = 173.9(1)。] may be a consequence of highly strained four-member metallacycle

rings: the N-d。-Fe-Npy^dyi bite angles being 61.4(1 >-62.9(1)^.

A noteworthy feature of compound 7 is an unusual iV;i\^七ridging coordination

mode of the TMEDA molecule. Examples of this type coordination mode for TMEDA

have been reported for certain main-group metal alkyls and hydrides^^"^^ but are rare in

transition metal complexes.龍 The TMEDA might be expected to bind in a bidentate

manner to the same iron(II) center, forming a six-coordinate mononuclear complex.

Presumably, the large steric requirement o f ligand L prevents the TMEDA molecule

from ligating in a bidentate fashion in our complex.

38

The bond distances of compound 7 [Fe(l)-N(2) 2.025(5) A, Fe(l>-N(4)

2.051(5) A] are comparable to those of 2.010(3)人 in compound 4，but slightly longer

than that of 1.84 A in the monomeric [Fe{N(SiMe3)2}2],2i 1.925(3) A (average) in the

dimeric [Fe{N(SiMe3)2}2L尸 and those of 1.916(2) and 1.918(2) A in two-coordinate

[Fe{N(SiMePh2)2}2].25 The longer Fe-N^do bond distances in 7 may be ascribed to a

more crowded environment around the metal center. The observed Si -N bond distances

in 7 [1.725(5)~1.739(5) A ] are similar to the S i -N distances found in other silylamido

complexes.63 Moreover, delocalization o f the lone-pair electrons onto the pyridyl ring is

evidenced by the short Cp鄉厂&細i o distances of 1.351(7H-362(7) A in 7. They are

- c l o s e to the observed C^^ tic-Nanndo distances in other metal arylamido complexes, in

which delocalization of electron density onto the aromatic substituents have been

s u g g e s t e d . 体 7 0 Apparently, ligand L behaves as a weak tt-acceptor in complex 7 and

this may account for the stability of the complex.

The amido nitrogen centers [N(2) and N(4)] exhibit a nearly trigonal planar

geometry [sum of bond angles = 358.9。（av.)], which is consistent with 华（hybridized

nitrogen atom.

39

«

奋：、

C15

Figu

re 2

-4.

Mol

ecul

ar s

truc

ture

of

[{Fe

[N(S

iTBu

Me2

)(2-C

5H3N

-6-M

e)]i}

i(TM

EDA

)] (7

).


[{Fe[N(SffiuMe2)(2-C5H3N-6-Me)]2}2(TMEDA)] (7)

Fe( l>-N( l ) 2.359(5) N(2>-C(5) 1.362(7)

Fe(l>-N(2) 2.025(5) N(3^C(17) 1.372(7)

Fe( l ) -N(3) 2.274(6) N(4>-C(17) 1.351(7)

Fe(l>-N(4) 2.051(5) Si ( l ) -N(2) 1.739(5)

Fe(l>-N(5) 2.214(5) Si ( l ) -N(4) 1.725(5)

N ( l ) -C (5 ) 1.367(7)

N(2)-Fe(l>-N(4) 122.3(2) C(5>-N(2)-Fe(l) 100.7(4)

N(2)-Fe(l>-N(5) 127.1(1) C(5>-N(2)-Si(l) 126.0(5)

N(4)-Fe( l ) -N(5) 110.4(2) Fe( l>-N(2)-Si( l ) 131.6(3)

N(l>-Fe(l>-N(2) 61.4(1) C(17)-N(4)-Fe(l) 97.2(4)

N(3>-Fe(l)-N(4) 62.9(1) C(17>-N(4)-Si(2) 128.3(5)

N(l>-Fe(l>-N(3) 173.9(1) . Fe(l)-N(4>-Si(2) 134.0(3)

41


The molecular structure o f compound 8 wi th atom numbering scheme is depicted

in Figure 2-5. Selected bond distances (A) and bond angles (°) are listed in Table 2-7.

Compound 8 crystallizes in a triclinic crystal system wi th space group PI The solid

state structure o f compound 8 is analogous to that o f compound 7.

The observed Co-N^dobond distances in 8 [Co(l>-N(2) 2.007(4) A，Co(l)-N(4)

1.998(3) A] are slightly shorter than those of Fe-N^idobond distances [2.025(5)-2.051(5)

A ] in compound 7. However, they are longer than those o f 1.84 A in the monomeric

Co[N(SiMe3)2]2,2i and 1.898(3)-1.904(3) A in the monomeric [Co{N(SiMePh2)2}2].""

They are also longer than the Co~]SUd。distances o f 1.910(5>"1.922(5) A for the

terminal ligands in the dimeric [Co{N(SiMe3)2}2]2尸 and 1.889 (8) A in [CoCNPh:)〗]:.:'

The longer Co~N细id。bond distances in our current complex may be ascribed to a more

crowded five-coordinate environment around the metal centers. The S i -N bond

distances of 1.725(4) A and 1.735(3) A are similar to those observed in other silylamido

complexes.63 Moreover，delocalization o f the lone-pair electrons onto the pyridyl ring is

evidenced by the short Cpy^^yi-N细id。distances o f 1.359(5>-1-362(5) A in 8. They are

close to the observed distances in other metal arylamido complexes, in

which delocalization of electron density onto the aromatic substituents has been

suggested.� 9

The amido nitrogens N(2) and N(4) in compound 8 exhibit a trigonal planar

geometry [sum of bond angles = 359.0。（av,)].

42

C15

Figu

re 2

-5.

Mol

ecul

ar s

truc

ture

of

[{C

o�N

(Si%

uMe2

)(2“Q

H3N

-6-M

e)�

2}2(

TMED

A)l

(8

).


[ { C o [ N ( S i T B i i M e 2 ) ( 2 . C 5 H 3 N - 6 - M e ) L } 2 ( T M E D A ) ] ( 8 )

C o ( l ^ N ( l ) 2.258(4) N(2)-C(5). 1.359(5)

Co ( l ) -N (2 ) 2.007(4) N(3>-C(17) 1.369(5)

Co( l>-N(3) 2.355(3) N(4>-C(17) 1.362(5)

Co ( l ) -N (4 ) 1.998(3) S i ( l ) -N(2 ) 1.725(4)

Co ( l ) -N (5 ) 2.176(4) Si(l>~N(4) 1.735(3)

N( l> -C(5 ) 1.354(6)

N ( 2 ^ C o ( l > - N ( 4 ) 120.5(1) C ( 5 ) - N ( 2 ^ C o ( l ) 96.8(3)

N ( 2 ^ Co ( 1 > " N ( 5 ) 112.6(1) C(5 ) -N(2>-S i ( l ) 127.8(3)

N(4>-Co( l ) -N(5) 126.7 ⑴ Co( l> -N(2) -S i ( l ) 135.0 ⑴

N ( l > - C o ( l ) - N ( 2 ) 63.8(1) C(17) -N(4) -Co( l ) 99.6(2)

N ( l ^ C o ( l ) - N ( 3 ) 172.6(1) C(17>-N(4)-Si(2) 125,8(3)

N(3H:o(1>-N (4 ) 62.7(1) Co( l ) -N(4>-Si(2) 133.0 ⑴

44



shown in Figure 2-6. Selected bond distances (A) and angles (。）are listed in Table 2-8.

Compound 9 crystallizes in a monoclinic crystal system with space group Pll/c,

The iron(n) center is bound by two monodentate Ar^ 'O ligands and one chelating

T M E D A molecule, resulting in a distorted tetxahedral geometry around the metal center.

The Fe -0 bond distances of 1.887(3) and 1.890(2) A in compound 9 are

marginally longer than that of 1.853(1) A in compound 6 and those of 1.822(5)-1.822(6)

A reported for the terminal Fe -0 bond distances in the dimeric [Fe(OMes*)2]2.55 They

are similar to that of 1.883(1) A in the monomelic [Fe(OCPh3)2(THF)2].55 The longer

Fe-O bond distances in our current complex may be ascribed to a more crowded four-

coordinate environment around the metal centers.

The bond angle 0(1)-Fe( 1 ^ 0 ( 2 ) between the two Ar^ 'O ligands, v/z. 125.6(1)。

is large due to steric repulsion between the two aryloxide ligands.

45

C紧

I 上

C(2

6)

C{1

8)(

^ I

cm

) C(

31|

C(9)

Figu

re 2

-6.

Mol

ecul

ar s

truc

ture

of

[Fe(

OC

6H,-2

,6-'B

u2-4

Me)

i(TM

ED

A)]

(9)

.


[FE(OC6H2-2,6-^II2-4-ME)2(TMEDA)] (9)

C ( l H X l ) 1.348(4) Fe( l>-N(2) 2.317(3)

C(16)-0(2) 1.350(4) F e ( l H X l ) [890(2) F e ( l ) - N ( l ) 2.295(4) Fe( l> -0(2) 1.887(3)

N ( l ) -Fe ( l > -N (2 ) 78.9(1) N ( 2 ) - F e ( l > - 0 ( 2 ) 101.6(1)

N ( l ) - F e ( l ) - 0 ( 1 ) 97.8(1) 0(1>-Fe( 1 ^ 0 ( 2 ) 125.6(1)

N ( l > - F e ( l ) - 0 ( 2 ) 121.3(1) C ( l ) - 0 ( 1 ) - F e ( l ) 159.1(2)

N ( 2 ) - F e ( l ) - 0 ( 1 ) 123.5(1) C ( 1 6 ) - 0 ( 2 > - F e ( l ) 170.3(2)

47



shown in Figure 2-7. Selected bond distances (A) and angles ( , are listed in Table 2-9.

Compound 10 crystallizes in a monoclinic crystal system with space group P21/c.

The metal center o f compound 10 is bound by two monodentate A i ^ 'O ligands and a

chelating T M E D A molecule, resulting in a distorted tetrahedral N 从 coordination

geometry.

The average Co-O bond distance o f 1.90 A in 10 is comparable to that o f

1.872(2) A in the mononuclear four-coordinate complex [Co(OCPli3)2(THF)2], and

those o f 1.887(3)-1.890(2) A for the F e - 0 bond distances in compound 9. They are

somewhat longer than those of 1.84 A (av.) and 1.85 A (av.) in the ionic cobalt(n)

complexes [Co(Cl)(OC 它 113)2 • Li(THF)3] and [Li(THF)4.5] [Co(a)(OCBu3)2]，

respectively.^^ In comparison wi th other neutral cobalt(n) aryloxide complexes, the Co-

O bond distances in our current complex are much longer than the terminal Co-O bond

distances of 1.78 A (av.) in the binuclear complex [Co{OC(QHn)3}2]2, 1.81 A (av.) in

[Co(OCPh3)2L, and 1.85 A (av.) in [Co(OSiPli3)2(THF)]2，57 where the metal centers in

these latter complexes exhibit a nearly trigonal planar geometry.

The bond angles N ( l ) - C o ( l > - 0 ( l ) and N(2>-Co(l>-0(2) of 122.8(1)-134.2(1)°

are large.

48

—身

36

,

气參

）

C(3

7l

Figu

re 2

-7.

Mol

ecul

ar s

truc

ture

of [

Co(

OQ

Hr2

,6-'B

u,-4

-Me)

,(TM

ED

A)]

(10

).

I


[Co(OC6H2-2,6-它 i v 4 - M e ) 2 ( T M E D A ) ] ( 10 )

C ( l H X l ) 1.341(5) Co( l>-N(2) 2.183(4)

C ( 1 9 H X 2 ) 1.349(5) C o ( l ) - 0 ( l ) 1.907(3)

C o ( l > - N ( l ) 2.223⑷ Co( l> -0(2) 1.893(3)

N ( l > -Co ( l ) -N (2 ) 8 3 . 0 ( 1 ) N ( 2 > - C O ( 1 K ) ( 2 ) 1 2 2 . 8 �

N ( l ) - C o ( l ) - 0 ( l ) 134.2(1) 0 ( l > -Co ( l> -0 (2 ) 108.1(1)

N ( l ^ C o ( l > - 0 ( 2 ) 104.5(1) C ( l K ) ( l ^ C o ( l ) 133.1(3)

N (2>-Co( l> -0 ( l ) 104.6(1) C ( 1 9 H X 2 ^ C o ( 1 ) 138.1(3)

50



shown in Figure 2-8. Selected bond distances (A) and angles are listed in Table 2-10.

Compound 13 crystallizes in an orthorhombic crystal system with space group

Pna2{\). The iron(II) center in compound 13 is bound by two monodentate thiolato

ligands ArS and a bidentate TMEDA molecule, resulting in a distorted tetrahedral N名2

coordination environment around the metal center.

The Fe-S bond distances

[Fe( l ) -S( l ) and Fe(l)-S(2)] of 2.321(9)-2.327(1) A in

compound 13 are longer than the terminal Fe-S bond distance of 2.256(3) A in

[Fe(SC6H2-2,4,6-它U3)2]2,52 and 2.275(2)-2.277(2) A in [ V c i S C , T h e

two latter complexes consist of three-coordinate and two-coordinate iron(n) centers,

respectively. The longer Fe-S bond distances in our current complex may be ascribed to

a more crowded tetrahedral coordination environment around the metal center.

The inter-ligand angle S( l ) -Fe( l ) -S(2) , viz. 119.1(4)。is large mainly due to

steric repulsion between the two bulky ArS ligands.

51

广;

CO

O)

C(2

8)

斤>

Oc

(2

9l

广广

\

®

� 7)

4

C(3

8)

Ci9

)

Figu

re 2

-8.

Mol

ecul

ar s

truc

ture

of

[Fe(

SQH

2-2A

6“'B

ii3)2

(TM

EDA

)l (1

3).

Table 2 - 9 . Selected bond distances (A) and angles (。) for compound 10.

[Fe(SQIV2，4,6-Bu3)2(TMEDA)] (13)

C ( l ) - S ( l ) 1.801(3) Fe(l>-N(2) 2.198(3)

C(21)-S(2) 1.798(3) F e ( l ^ S ( l ) 2.327(1)

F e ( l ) - N ( l ) 2.200(3) Fe(l)-S(2) 2.321(9)

N ( l ) -Fe ( l ) -N (2 ) . 82.1(1) N(2)-Fe( l ) -S(2) 109.5⑷

N ( l ^ F e ( l ^ S ( l ) 116.3(9) S(l>-Fe(l)-S(2) 119.1(4)

N( l ) -Fe ( l ) -S (2 ) 110.7(9) C(l)-S(l>-Fe(l) 113.0(1)

N(2>-Fe(l>-S(l) 113.2(9) C(21>-S(2V-Fe(l) 114.4(1)

I

53



shown in Figure 2-9. Selected bond distances (A) and angles (°) are listed in Table 2-11.

Compound 14 crystallizes in the same crystal system as that of compound 13:

Pna2{\). The mononuclear dithiolate complex 14 exhibits a distorted tetrahedral

geometry around the metal center.

The Co-S bond distances of 2.276(3) A in 14 are slightly shorter than those of

2.33 A (av.) for the anionic [Co(SPh)4]2-严糾 and 2.321(9>-2.327(1) A in compound 13.

The small discrepancy in the bond distances may be a consequence of the anionic charge

on the latter complex. The Co-S bond distance in 14 is marginally longer than those of

2.228(1) A (av.) and 2.260(1) A (av.) of the mononuclear four-coordinate

[Co(dppp)(SPh)2] and [Co(bdpp)(SPh)2] (dppp 二 l,3-bis(diphenylphosphino)propane;

bdpp = bis(2-phenylphosphinoethyl)phenylphosphine), respectively.^^ It is also slightly

longer than the terminal Co-S bond distance of 2.222(2) A in the neutral binuclear

complex [CO(SQH2-2,4,6-它 113)2]2,52 and 2.191(5)-2.215(5) A in the anionic [Co^CSCA-

2，4,6- >『3)5]一.51

The inter-ligand angle S(l>-Co(l)-S(2), viz, 119.5(1)。is large. This is ascribed

to the steric repulsion between the two bulky ArS ligands.

54

11

1

Figu

re 2

-9‘

Mol

ecul

ar s

truc

ture

of

tCo(

SC6l

V2，

4，6-

T8ii3

)2(T

MED

A)�

(14)

.

Table 2 - 9 . Selected bond distances (A) and angles (。) for compound 10.

[Co(SC6H2-2，4，6-TBu3)2(TMEDA)] (14)

C(1^S(1) 1.833(5) Co( l>-N(2) 2.151(9)

S(2>-C(19) 1.826(5) C o ( l ) - S ( l ) 2.276(3)

C o ( l ) - N ( l ) 2.138(8) C o ( l ^ S ( 2 ) 2.276(3)

N ( l > - C o ( l ) - N ( 2 ) 85.9(4) N(2>-CG(1)-S(2) 111.1(3)

N ( l ^ C o ( l ^ S ( l ) 112.5(2) S ( 1 H : o ( 1 ^ S ( 2 ) 119.5 ⑴

N ( l > - C o ( l ^ S ( 2 ) 106.7(2) C ( l ^ S ( l > - C o ( l ) 116.9(2)

N ( 2 ^ C o ( l ) - S ( l ) 115.9(3) C(19>-S(2)-Co(l) 116.8(2)

56

2.3 EXPERIMENTALS FOR CHAPTER 2

Materials:

Anhydrous F e C l�， C0CI2, 2-amino-6-picoline, 邸卵

tetramethylethylenediamine, 2,6-泡 i^A-Me-QHsOH and 2-MeCH(4,6-它u^QHsOH):

were purchased from Aldrich. Anhydrous FeCl�，C0CI2 and 2-amino-6-picoline were

used as received. -tetramethylethylenediamine was distillated over sodium

before use. 2,6-它u^W-MeCsHsOH and 2-MeCH(4,6-它u^QH�。!!)： were purified by

recrystallization from hexane. and the lithium reagents

[L i (L) (TMEDA)] (2) and L i L (3)，were prepared according to the literature procedures.

Synthesis of compounds:

Synthesis of [Fe{N(Si$iiMe2)(2-C5H3N-6-Me)}J (4). To a solution of FeCl: (0.36 g,

2.80 mmol) in diethyl ether (10 mL) at 0。C was slowly added a solution of compound 3

(1.28 g, 5.60 mmol) in diethyl ether (20 mL). The reaction was stirred for a further 8

hours at room temperature and all the volatiles were then removed in vacuo. Diethyl

ether (20 mL) was added to extract the residue and the solution was then filtered. The

filtrate was concentrated to ca. 3 mL. Crystallization at ambient temperature afforded

compound 4 as olive-green crystals. The product was washed three times with hexane

and dried in vacuo (0.81 g, 1.62 mmol, 58 %). Crystals suitable for X-ray diffraction

studies were obtained by recrystallization from toluene. M.p.: 107-110。C. MS (E. I. 70

eV): miz (%) 500 (21) _+，443 (40) [M-它u]+，221 (9) [L]+，165 (100) [L-它u]. , 57 (30)

57

[TBu]+. /Zeff. = 4.87 /zb. Anal. Found: C, 57.10; H, 8.74; N, 11.49 %. Calc. for

C24H42FeN4Si2： C, 57.81; H, 8.49; N, 11.23 %.

Synthesis of [Co{N(SiTBuMe2)(2-C5H3N-6-Me)}{N(SiTBuMe2)(2-C5H3N-6-CH2)} •

Li(THF)]2 (5). To a solution of CoCl: (0.47 g, 3.62 mmol) in THF (10 mL) at 0。C was

added a solution of compound 3 (1.65 g, 7.23 mmol) in THF (20 mL). The resulting

mixture was further stirred at room temperature for 8 hours and all the volatiles were

then removed in vacuo. Hexane (30 mL) ^ s added to extract the residue. The solution

was then filtered through Celite and the filtrate was concentrated to ca. 3 mL.

Compound 5 was obtained as greenish brown crystals upon standing at ambient

temperature. The product was washed three times wi th hexane and dried in vacuo (0.23

g, 0.20 mmol, 11 %). M.p.: 163-165。C. MS (E. 1. 70 eV): mlz (%) 501 (4) [Co(L)(L,)]+,

445 (17) [Co(L)(L，)一它uf，221 (4) [ L ] ^ 165 (100) [L-TBuT, 57 (15) ["Buf. /Zeff. = 4.20

/ZB per Co. A n a l Found: C, 57.78; H, 8.68; N，9.84 %, Calc. for CssH^sCo^I^NsOsSi*:

C，58.01; H，8.52; N , 9 . 6 6 %，

Synthesis of [Fe{N(SiTBuMe2)(2-CsH3N-6-Me)} {0<：6珏2-2，6-18112_4-

Me}{NH(SfBiiMe2)(2-C5H3N-6-Me)}] (6). A solution of 4 (0.89 g, 1.78 mmol) in

hexane (30 mL) was slowly added to a solution of 2 , 6 -它 i ^ ^ - M e Q H p H (0.39 g, 1.78

mmol) in the same solvent (10 mL) at 0°C. The reaction mixture was stirred at room

temperature for 8 hours and then filtered. The filtrate was concentrated to ca. 2 mL,

Compound 6 was obtained as pale green crystals upon standing at ambient temperature.

The solid was washed three times wi th hexane and dried in vacuo (0.96 g，1.34 mmol,

58

75 %). Crystals suitable for X-ray diffraction studies were obtained by recrystallization

from toluene. M.p.: 155-158。C (dec.). MS (E. I. 70 eV): miz (%) 496 (29)

[Fe(L)(LH)]% 481 (7) [Fe(L) (LH)-Me]^ 439 (36) [ F e ( L ) ( L H ) - ^ u ] ^ 222 (10) [ L ] \ 220

(15) 205 (37) [AI^^Ô-ME]^ 165 (91) [L—TBU]+, 57 (100)[它11]+. = 4.97 A

B. Anal. Found: C, 65.50; H，9.32; N, 7.85 %. Calc. for C39H,6FeN40Si2： C, 65.15; H,

9.25; N , 7.79%.

Synthesis of [{Fe[N(SiûMe.J(2-QH3N-6-Me)],}2(TMEDA)] (7). Method A. To a

suspension o f FeCl^ (0.27 g, 2.13 mmol) in diethyl ether (10 mL) at 0。C was slowly

added a solution o f compound 2 (1.47 g, 4.27 mmol) in the same solvent (20 mL). The

reaction mixture was slowly warmed to room temperature and stirred for a further period

o f 8 hours. The pale green suspension was filtered through Celite and the filtrate was

concentrated to ca. 2 mL under a reduced pressure to give compound 7 as pale green

crystals. I t was washed twice wi th hexane and dried in vacuo (0.70 g，0.63 mmol, 59 %).

M,p.: 55-58。C. MS (E. I 70 eV): mIz (%) 499 (53) [FeLJ% 443 (100) [ F e L ^ - ^ u f , 221

(12) \ L ] \ 165 (81) [L-它u]+，117 (6) [TMEDA]+，57 (48) pBu]+. fi 说二 4.86 … p e r Fe.

Anal. Found: C, 57.78; H, 9.30; N , 12.71 %. Calc. for CÛ.ooPQ^îoÛ- C, 58.25; H,

9.05; N , 12.57%.

Method R To a solution o f compound 4 (0.75 g, 1.50 mmol) in diethyl ether (15 mL) at

0。C was added T M E D A (0.11 mL，0.73 mmol). The resulting mixture was stirred for 6

hours at room temperature and the solution was filtered through Celite. The filtrate was

concentrated to ca. 2 mL under a reduced pressure to give the title compound (0.42 g,

0.38 mmol, 52 %).

59

Synthesis of [{CopVfSiTBuMe^Xl-CsByV-G-MejljWTMEDA)] (8). Method A A

solution of compound 2 (2.18 g, 6.33 mmol) in diethyl ether (20 mL) was added to a

suspension of CoCl: (0.41 g, 3.16 mmol) in diethyl ether (10 mL) at 0。C. The reaction

mixture was slowly warmed to room temperature and stirred for a further period of 8

hours. The green suspension was filtered through Celite and the filtrate was

concentrated to ccl 3 mL under a reduced pressure. Compound 8 was isolated as green

crystals. I t was washed twice with hexane, and dried in vacuo (1.20 g, 1.07 mmol, 68

%). M.P.: 66—69。C. MS (E. 1. 70 eV): miz (%) 502 (11) [CoL^]", 445 (35) [CoL^-'Bu]^

223 (5) [ L f , 165 (100) [L-它u]+，57 (13)[它u]+. //eff. 二 5.31 n丑 per Co. Anal. Found: C，

57.93; H，9.00; N，12.51 %. Calc. for C54HiooCo2NioSi4: C，58.25; H, 9.05; N, 12.57 %.

Method B. To a solution of C0CI2 (0.54 g, 4.16 mmol) in diethyl ether (10 mL) at O^C

was slowly added a solution of compound 3 (1,90 g, 8.32 mmol) in diethyl ether (20

mL). The reaction was stirred for a further 8 hours at room temperature and all the

volatiles were then removed in vacuo. Diethyl ether (20 mL) was added to extract the

. residue and the solution was then filtered. A l l the volatiles in the filtrate was removed in

vacuo to give a dark greenish yellow intractable oil. Diethyl ether (15 mL) was added to

the dark greenish yellow intractable oil followed by an excess TMEDA (1.0 mL) at 0。C.

The resulting mixture was further stirred at room temperature for 6 hours and all the

volatiles were then removed in vacuo. Diethyl ether (30 mL) was added to extract the

residue and the solution was then filtered through Celite. The filtrate was concentrated

under a reduced pressure to ca. 2 mL. Compound 8 was obtained as green crystals (1.26

g, 1.12 mmol, 54 %).

60

Synthesis of [Fe(OC,H2-2,6-TBu2-4-Me)2(TMEDA)] (9). To a solution of 2,6-TBIV4-

MeCgHsOH (0.81 g, 3,69 mmol) in hexane (10 mL) at 0。C was slowly added a solution

o f compound 7 (1.03 g，0.92 mmol) in hexane (30 mL). The resulting mixture was

stirred at room temperature for 8 hours. A l l the volatiles were then removed in vacuo.

The residue was extracted with toluene (20 mL) and the solution was filtered. The

filtrate was concentrated to ca‘ 3 mL to give compound 9 as white crystals. The product

was washed wi th hexane for three times and dried in vacuo (0.28 g, 0.45 mmol, 49 %).

M . P . : 212-214。C (dec.). M S (E. 1. 70 e V ) : miz ( % ) 220 (35 ) [ A 严 0 ] + , 205 (100)

[Ar^Ô-Me]", 115 (5) [TMEDA]+，57 (24) [lBu]+. "ef i 二《83 "b . Anal. Found: C,

70.13; H, 10.06; N, 4.55 %. Calc. for CssH^-FeNp:: C, 70.80; H，10.23; N，4.58 %.

Synthesis of [Co(OC6H2-2，6-它iv4-Me)2(TMEDA)] (10). To a solution of 2,6-它

M e Q H p H (0.85 g, 3.85 mmol) in hexane (10 mL) at 0。C was slowly added a solution

of compound 8 (1.08 g, 0.96 mmol) in hexane (30 mL). The resulting mixture was

stirred at room temperature for 8 hours. A l l volatiles were removed in vacuo and the

residue was extracted with toluene (20 mL). The solution was filtered and the filtrate

was concentrated to ca. 3 mL to give compound 10 as green crystals. The product was

washed three times with hexane and dried in vacuo (0.27 g, 0.44 mmol, 46 %), M.p.:

227-230。C (dec.). MS (E. L 70 eV): m/z (%) 498 (17) 220 (33) [Ar^Ô]^

205 (100) [Ar^Ô-Me]", 117 (9) [TMEDA]^ 59 (90) ["Buy. n说二 3.64 /ZB- Anal.

Found: C, 70.55; H，10.06; N, 4.68 %. Calc. for Cs^HâCoNÔ^： C，70.33; H, 10.33; N,

4.55 %.

61

Synthesis of [Fe{(OC6H2-4,6-'Bu2)2(2-CHMe)}(TMEDA)] (11). To a solution of 2-

MeCH(4,6-它U2C6H20H)2 (1.03 g, 2.34 mmol) in hexane (20 mL) at 0。C was added a

solution of compound 7 (1.30 g, 1.17 mmol) in hexane (30 mL). The resulting mixture

was further stirred at room temperature for a further period of 8 hours and all volatiles

were removed in vacuo. Toluene (30 mL) was added to extract the residue and the

solution was filtered. The filtrate was concentrated in vacuo to ca 3 mL to give

compound 11 as white crystals. The product was washed three times with hexane and

dried in vacuo (0.32 g, 0.53 mmol, 45 %). M.p.: 270-273。C (dec.). MS (E. 1. 70 eV):

m/z (%) 608 (90) [M]+, 593 (7) [M-Me]% 551 (1) [M-它u]+，403 (4) [M—Ar,0]+，117 (62)

[ T M E D A r , 57 (100) pBuT 近=4.92 Ub- Anal. Found: C, 71.63; H, 9.81; N, 4.54 %.

Calc. for CsAoFeN.O^： Q 71.03; H, 9.93; N, 4.60 %.

Synthesis of [Co{ (OQH,-4 ,6 .^u ,M2.CHMe)} (TMEDA) ] (12). To a solution of 2-

MeCH(4,6-它UzQHtOH), (1.18 g, 2.69 mmol) in hexane (20 mL) at 0。C was added a

solution of compound 8 (1.50 g, 1.34 mmol) in hexane (30 mL). The resulting mixture

was further stirred at room temperature for 8 hours and all volatiles were removed in

yacuo. Toluene (30 mL) was added to extract the residue and the solution was filtered.

The filtrate was concentrated in vacuo to ca 3 mL to give compound 12 as bluish green

crystals. The product was washed three times with hexane and dried in vacuo (0.40 g，

0.66 mmol, 49 %). M.p.: 305-308X. MS (E. 1. 70 eV): m/z (%) 611 (57) [M\\ 596 (5)

[ M - M E R , 5 5 4 ( 2 ) [ M - ^ U F , 4 0 6 ( 5 ) [ M - A R ’ 0]+，1 1 7 ( 5 8 ) [ T M E D A F , 5 7 ( 1 0 0 ) [ W -

乂eff 二 4.46 /Zb. Anal. Found: C，71.17; H, 9.56; N，4.37 %. Calc. for C 3 凡 C o N A : C，

70.67; H, 9.88; N, 4.58%.

62

Synthesis of [Fe(SC6H2-2，4，6-$U3)2(TMEDA)] (13). A solution of 2,4,6-^U3QH2SH

(1.31 g, 4.69 mmol) in hexane (10 mL) was treated wi th a solution of 7 (1.31 g，1.17

mmol) in the same solvent (30 mL) at 0°C. The resulting mixture was stirred at ambient

temperature for a further period of 8 hours. The mixture was filtered through Celite and

the filtrate was concentrated in vacuo to ca. 2 mL. Crystallization at ambient

temperature afforded compound 13 as yellowish brown crystals. I t was then washed

twice wi th hexane and dried in vacuo (0.41 g，0.56 mmol, 48 %). M.p.: 197-200°C

(dec.). MS (E. 1. 70 eV): miz (%) 278 (14) [ArS]^ 263 (10) [ArS-Me]+, 245 (9) [Ar ]^

231 (17) [ A r - M e n 221 (8) [ A r S - ^ u ] ^ 117 (9) [TMEDA]^ 57 (100)[它11]+. n 逊.二 4.96

A n a l Found: C, 57.93; H, 9.00; N, 12.51 %. Calc. for C42H74FeN2S2: C，58.25; H,

9.05; N , 12.570/0,

Synthesis of [Co(SC6H2-2，4，6-TBu3)2(TMEDA)] (14). A solution of compound 8 (1.32

g, 1.18 mmol) in hexane (30 mL) was added to a solution of 2,4,6-它UsQHsSH (1.32 g,

4.73 mmol) in hexane (10 mL) at 0。C‘ The reaction mixture was stirred at room

temperature for 8 hours and was then filtered. The filtrate was concentrated to ca. 3 mL

to give compound 14 as reddish brown crystals. The product was washed twice with

hexane and dried in vacuo (0.38 g, 0.52 mmol, 44 %). M.p.: 197-202。C (dec.). MS (E.

L 70 eV): mIz (%) 278 (26) [ArS]+，263 (3S) [ArS-Me]+，244 (18) [Ar]% 229 (56)

[Ar—Me]+，221 (5) [ArS-它u]+, 115 (7) [TMEDA].，57 ( 1 0 0 ) [ 它 u ] 十 . = 3.78 讼

Anal. Found: C, 68.56; H, 10.10; N，3.77 %. Calc. for C42H74C0N2S2: C, 69.09; H，10.22;

N，3.84%.

63


1. Bryndza, H. R ; Tarn, W. Chem. Rev. 1988, 88,1163.

2. Roundhill, D. M Chem. Rev. 1992, 92, 1.

3. Holm, R. H.; Keimeppohl, R; Solomon, E. L Chem. Rev. 1996, 96, 2239. 4. Casalnuovo, A. L.; Calabrese, J. Q ; Milstein, D. J. Am. Chem Soc. 1988,110,

6738. 5. Cowan, R. L.; Trogler, W. C. Organometallics 1987, 6, 2451.

6. Klein, D. P.; Hayes, J. C.; Bergman, R. G. J. Am. Chem. Soc. 1988, 110,

3704. 7. Cowan, R. L.; Trogler，W. C. J. Am. Chem. Soc. 1989, 111, 4750.

8. Glueck, D. S.; Winslow, L. J.; Bergman, R. G. Organometallics 1991, W,

1462.

9. Hartwig, J. R; Bergman, R. G.; Andersen, R. A. J. Am. Chem. Soc. 1991，113,

6499.

10. Villanueva, L. A.; Abboud, K. A.; Boncella, J. M. Organometallics 1992，11,

2963. 11. Seligson, A. L.; Trogler, W. C. Organometallics 1993，12, 744. 12. Boncella, J. M.; Villanueva, L. A. J. Organomet. Chem. 1994, 465, 297.

13. Villanueva, L. A,; Abboud, K. A.; Boncella, J. M. Organometallics 1994, 13,

3921.

14. VanderLende, D. D.; Abboud, K. A.; Boncella, J. M. Inorg. Chem. 1995，34,

5319. 15. -Driver, M. S.; Hartwig, J. F. J. Am. Chem. Soc. 1996,118, 7217.

16. Widenhoefer, R. A.; Buchwald, S. L. Organometallics 1996,15, 2755.

17. Dorta, R.; Egli, P.; Ziircher, E ; Togni, A. J. Am. Chem. Soc. 1997’ 119’

10857.

18. Wolfe, J. P.; Buchwald，S. L. X Am. Chem, Soc. 1997，119, 6054. 19. Burger, H.; Wannagat, U. Monatsh. Chem. 1963，94, 1007, 20. Murray, B. D.; Power, P. R Inorg. Chem. 1984，23, 4584. 21. Andersen, R. A.； Faegri, K.； Green, J. C ; Haaland, A.； Lappert，M‘ F.； Leung,

W.-R; Rypdal，K. Inorg. Chem, 1988，27, 1782. 22. Bradley, D. C.; Hursthouse, M. B.; Smallwood, R. J.; Welch, A. J. J. Chem.

Soc” Chem. Commun. 1972, 872. 23. Brito，V; Frohlich H. O.; Muller, B. Z Chem. 1979，19, 28.

24. Hope，H.; Olmstead, M. M.; Murray, B. D.; Power, R P. J. Am. Chem. Soc.

1985,107, 712. 25. Bartlett, R. A.; Power, P. P. J. Am. Chem. Soc. 1987，109, 7563. 丨

64

26. Bartlett, R. A.; Feng, X. ; Olmstead, M . M. ; Power, R R; Weese, K. J. J. Am.

Chem. Soc. 1 9 8 7 , 1 0 9 , 4851.

27. Chen, H.; Bartlett, R. A.; Olmstead, M . M. ; Power, R P.; Shoner, S. C. J. Am.

Chem. Soc. 1990,112, 1048.

28. Olmstead, M. M. ; Power, P. P. Shoner, S. C‘ Inorg. Chem. 1991, 30, 2547.

29. Siemeling, U.; Vorfeld, U.; Neumann, B.; Stammler, H.-G. Inorg, Chem.

2000, 59,5159.

30. Putzer, M. A.; Neumiiller, B.; Dehnicke，K.; Magul l , J. Chem. Ber. 1996，129,

715. 31. Yang, E.-C.; Cheng, M , C ; Tsai, M.-S. Peng, S.-M. J. Chem. Soc., Chem.

Commun. 1994, 2377. 32. Cotton, F. A.; Daniels, L. M ; Jordan, G. T., IV ; Mur i l lo , C‘ A. 1 Am. Chem.

Soa 1997,119, 10377.

33. Clerac, R.; Cotton, F. A.; Dunbax, K . R.; Lu, T.; Mur i l lo , C. A.; Wang, X. J.

Am. Chem Soc. 2000,122, 2272. 34. Clerac, R.; Cotton, E A.; Dunbar, K. R.; Lu, T ; Mur i l lo , C. A.; Wang, X.

Inorg. Chem. 2000, 39, 3065. 35. Cotton, F. A.; Daniels, L. M ; Maloney, D. J.; Mur i l lo , C A. Inorg. Chim.

Acta 1996, 249, 9. 36. Cotton, F. A.; Daniels, L. M. ; Favello, L. R.; Matonic, J, H.; Mur i l lo , C. A.

Inorg. Chim. Acta 1997，256, 269.

37. Cotton, F. A.; Daniels, L. M. ; Matonic, J. H.; Mur i l lo , C. A. Inorg. Chim.

Acta 1997, 256, 277.

38. Cotton, F. A.; Daniels, L. M. ; Maloney, D. I ; Matonic, J. H.; Murillo，C. A.

Inorg. Chim. Acta 1997，256, 283 ‘ 39. Blower, P. J.; Dilworth，J. R. Coord Chem. Rev. 1978, 76, 121.

40. Dance, I G. Polyhedron 1986, 5, 1037. 41. Krebs, B.; Henkel, G. in Roeskyu, H. (Ed)： Rings, Clusters and Polymers of

Main Group and Transition Elements, Elsevier, Amsterdam 1989, 439. 42. Hagen, K. S.; Holm, R. H. J. Am. Chem. Soc. 1982,104, 5496.

43. Hagen, K. S.; Waston, A. D.; Holm，R. H. J. Am. Chem. Soc. 1983, 105, 3905.

44. Lane, R. W.; Ibers, J. A.; Frankel, R. B.; Papaefthymiou, G. C ; Holm, R. H. J.

Am, Chem. Soc. 1977，99, 84. 45. Hagen, K. S.; Holm, R. H. Inorg. Chem. 1984，23，418.

46. Hagen, K. S.; Berg, J. M. ; Holm, R. H. Inorg. Chim. Acta 1980, 45, L17.

47. Hagen, K. S.; Reynolds, J. G.; Holm, R. H. J. Am. Chem. Soc. 1981，102,

4054.

65

48. Hagen, K. S.; Stephan, D. W.; Holm, R. H. Inorg. Chem. 1982，21, 3928,

49. Dance, I G.; Calabrese, J. C. J. Chem. Soc., Chem. Commun. 1975, 762. 50. Dance, 1. G. J. Am. Chem. Soc. 1979,101, 6264.

51. Ruhlandt-Senge, K.; Power, R R J. Chem. Soc., Dalton Trans. 1993, 649. 52. Power, P. P.; Shoner, S. C. Angew. Chem. Int. Ed. Engl. 1991，30, 330. 53. Ellison, J, J.; Ruhlandt-Senge, K.; Power, R P. Angew. Chem. Int. Ed. Engl

1994，15，1178.

54. Bradley, D. C ; Mehrotra, R. C.; Gaur, D. P. Metal Alkoxides; Academic: New

York, 1978.

55. Barlett, R. A.; Ellison, J. J.; Power, P. R; Shoner, S. C. Inorg. Chem. 1991，30,

2888.

56. Bochmann, M.; Wilkinson, G.; Young, G. B.; Hursthouse, M. B.; Malik, K.

M. A. J. Chem, Soc., Dalton Trans. 1980, 901.

57. Bochmann, M.; Wilkinson, G.; Young, G. B.; Hursthouse, M. B.; Malik, K.

M. A, J. Chem. Soc” Dalton Trans, 1980，1863.

58. Olmstead, M. M.; Sigel, G.; Hope, R ; Xu, X.; Power, P. P. J�Am. Chem. Soc.

1985,107, 8087. 59. Olmstead, M. M.; Power, P. R; Sigel, G. Inorg. Chem. 1986，25, 1027. 60. Sigel, G.; Barlett, R. A.; Decker, D.; Olmstead, M. M.; Power, P. R Inorg.

Chem 1987, 26，1773.

61. Peng, Y. M Phil Thesis, The Chinese University of Hong Kong, 1999. 62. Evans, D. F. J. Chem. Soc. 1959, 2005.

63. Lappert, M. R; Power, R R; Sanger, A. R‘； Srivastava, R. C. Metal and

Metalloid Amides; Ellis Horwood: Chichester, 1980. 64. Fryzuk, M D.; MacNeil, R A. J. Am. Chem. Soc. 1981，102, 3592.

65. Fryzuk, M. D.; MacNeil, P. A.; Rettig, S. I ; Secco, A. S.; Trotter, J.

Organometallics 1982, 7,918. 66. Fryzuk, M. D.; Montgomery, C. D. Coord. Chem. Rev. 1989，95, 1. 67. Engelhardt, L. M ; Junk, P. C ; Patalinghug, W. C ; Sue, R. E.; Raston，C. L.;

Skelton, A. H. J. Chem. Soc” Chem. Commun. 1991, 930.

68. Ruhlandt-Senge, K.; Power, P. R J. Chem. Soc” Dalton Trans. 1993，649. 69. VanderLende, D. D.; Boncella, J. M. ; Abboud, K. A. Acta Cryst 1995, C51,

591.

70. Penney, J.; VanderLende, D. D.; Boncella, J. M. ; Abboud, K. A. Acta Cryst

1995，C51’ 2269. 71. Soderquist, J. A.; Hwang-Lee, S.-J.; Barnes, C. L. Tett Lett 1988，29, 3385. 72. Palenik, G. J. Acta. Cryst. 1964,17, 1753. 73. Goebel, D. W., Jr.; Hencher, J. L.; Olive, J. R Organometallics 1983, 2, 746.

66

74. Gardiner, M. G.; Raston, C. L. Organometallics 1993, 72, 81.

75. Hallock; R. B.; Hunter, W. E.; Atwood, J. L.; Beachley,〇 .T.，Jr.

Organometallics 1985, 4, 547. 76. O'Hare, D.; Foord，J. S.; Page, T. C. M.; Whitaker, T. J. J. Chem. Soa, Chem.

Commun. 1991, 1445. 77. Atwood，J. L.; Bott, S. G.; Elms, F. M.; Jones, C.; Raston, C. L. Inorg. Chem.

1991，30, 3793.

78. Byers, J. J.; Pennington, W. T.; Robinson, G. H. Acta. Cryst. 1992，C48,

2023.

79. Burford, N.; Losier, P.; Bakshi, P. K.; Cameron，T. S‘ Chem. Commun. 1996,

307. 80. Lobkovskii, E. B.; Soloveichik, G. L. J. Organomet Chem. 1984, 265’ 167. 81. Kerby, M. Q ; Eichhom, B. W.; Creighton, J. A.; Vollhardt, K. R C. Inorg.

Chem. 1990，29，1319.

82. Mal ik, M. A.; Motevalli, M.; O'Brien, P.; Walsh, J. R. Inorg. Chem. 1997，36,

1263.

83. Swenson, D.; Baenziger, N. Q ; Coucouvanis, D. J. Am. Chem. Soc. 1978,

100,1932. 84. Coucouvanis, D‘； Swenson, D.; Baenziger, N. C ; Murphy, C.; Holah，D. G.;

Sfamas, N.; Simopoulos, A.; Kostikas, A. J. Am. Chem. Soc. 1981, 103, 3350.

85. Wei, G.; Hong, M.; Huang, Z.; Liu, H. J. Chem. Soc” Dalton Trans. 1991，

3145. 86. Rundel, W. Chem, Ben 1968,101, 2956.

67

CHAPTER 3. SYNTHESIS AND STRUCTURES OF MANGANESE(II) AMIDES

3.1 INTRODUCTION

The first manganese(n) amide, namely Mn[N(SiMe3)2L，was synthesized by

Wannagat and Bradley. 口 The compound was later proved to be the dimeric

[Mn{N(SiMe3)2}2]2 in the solid state] and monomeric Mn[N(SiMe3)2]2 m the gas phase.

This amido complex forms adducts wi th Lewis bases such as THF to give

[Mn{N(SiMe3)2}2(THF)]5’6 and [Mn{N(S iMe3 )2 }2 ( ^ )2 ] ' respectively.

Power and co-workers have reported the homoleptic tris(silylamide) of

manganese, namely [Mn{N(SiMe3)2}3 • L i (THF)] . ' The same research group have also

employed the sterically demanding borylamide [ N ( R ) ( B R y ] " (R and R’ = Ph, Mes or ‘ I

Xy l ) and silylamide [NCSiMePh�)�]— and prepared the two-coordinate manganese(n)

amides [Mn{N(Mes)(BMes2)}2]' ' ' and [MiH^KSiMePh〗):}〗].】。These compounds have

been characterized by X-ray crystallography and proven to be monomeric in the solid

state. In 1991, two bulky bidentate amido ligands [(NMes)2SiMeJ- and

pippNCH2CH2N(H)Dipp]~ (Dipp 二 2,6-^>r2QH3) were prepared and shown to be

capable o f stabilizing the corresponding manganese(n) amides

[Li{Mn[(NMes)2SiMe2]}2{N(SiMe3)2}] and [Mn{N(Dipp)CH2CH2N(H)Dipp}2] ”

Dehnicke and co-workers have employed the strongly basic [N(SiMe3)2] ligand

to prepare the anionic amido compound [Mn{N(SiMe3)2}3]

A few representative examples o f manganese(n) amides were depicted in

Scheme 3-1.

68

Me.Si SiMeg fiMeg ^ \ ^ /

Me^Si、 .N* .SMe^ Me.Si^^s, - Z \ - 3 Mn—O N - M n Mn-N M e ^ S i 、 / — V ^

Me^Si/ ^N \siMe3 \ “ / SiMeg MegSi SiMeg ^

Mes I Mes

P ^ M e S i \ / SiMePh^ Mes 一日 ^ 门 ― / N — M n - N MesZ ^ ^ M e s

PhsMes/ \siMePh2 / ivies

一 SiMeg

Me3SizN\ /SiMe3 3 M n - N

MegSi、， \siMe3 \

_ SiMeg _

Scheme 3-1

69

3.2 RESULTS AND DISCUSSION

3.2.1 Synthesis of Manganese(n) Amide

Attempts to synthesize the neutral homoleptic manganese(n) amide of the type

M n L J by the reaction of one equivalent o f manganese(n) chloride with two equivalents

o f compound 2 in diethyl ether or THF were unsuccessful (Scheme 3-2). Only an air-

sensitive intractable oil was obtained in both cases.

，厂 <

EtoO or THF MnCU + 2 f \ Intractable oil .

2

Scheme 3-2

Attempted reactions of one equivalent of manganese(n) chloride with two

equivalents of compound 3 in diethyl ether or toluene were also unsuccessful (Scheme

3-3). Again, only an air-sensitive intractable oi l was obtained.

Et:。or toluene MnClj + 2 LilN(Si®uMe2)(2-C5H3N-6-Me)] Intractable oit

r.t., 8 h 3

Scheme 3-3

70

On the other hand, treating one equivalent of manganese(n) chloride with three

equivalents of compound 3 in THF, an ionic manganese(II) amide was synthesized

(Scheme 3-4).

X ^ N N sreuMe。

, M THF \

MnCU + 3 Li[N(Si BuMe2){2-C5H3N-6-Me)] ^ ^ H F — L i Mn V - A r.t.’ 8 h 个 \ \ N 》 60% V-N \ W

3 r v \ 厂 SiSuMea

Scheme 3-4

Compound 15 was obtained as yellow crystals in 60 % yield by treating one

equivalent of manganese(n) chloride wi th three equivalents o f compound 3 in THF. I t is

an extremely air sensitive compound, giving an uncharacterizable black substance upon

exposure to trace amount of oxygen and moisture.

The formation of compound 15 is proposed as follows. As illustrated in Scheme

3-5, the neutral mononuclear manganese(n) amido complex first formed from the

metathetical exchange reaction between one equivalent of manganese(n) chloride and

two equivalents of compound 3. This intermediate further reacts with the excess

compound 3 followed by THF coordination to the l ithium center, resulting in the

formation of compound 15.

71

\ /

+ 2 Li[N(SiSuMe2)(2-C5H3N-6-Me)] ^ 丫 \SiBuMe2

《zSifBuMe〕

/ ^ N SieuMej

SKBuMe:

- - .

y ^ N Si'BuMe。

I

V v \ / SKBuMe。

15

Scheme 3-5

3.2.1 Physical Characterization of Compound 15

Compound 15 has been characterized by melting point determination, magnetic

moment measurement, elemental analysis and X-ray diffraction studies. Table 3-1 lists

some physical properties of compound 15.

72

Table 3-1. Some physical properties of compound 15.

Compound Yield (%) Color M.p. (。C)

1 5 60 Yellow crystals 100-105

The magnetic moment of compound 15 was found to be 5.91 // b at 298 K by the

Evans method^^ which is consistent with a high-spin cf electronic configuration.

Elemental analysis on compound 15 was correct and consistent with its empirical

formula.

3.2.2 Molecular Structure of Compound 15


depicted in Figure 3-1. Selected bond lengths (A) and angles (。）are listed in Table 3-2.

Compound 15 crystallizes in a triclinic crystal system with space group Pi

Compound 15 is an ionic metal complex that consists of one anionic

tris(amido)manganese(n) unit and a THF-coordinated lithium cation. One of the amido

ligand L binds to the manganese(n) center in a iV,?/^chelating fashion and the remaining

two ligands bridge between the manganese(n) center and the lithium ion in a N,N'-

bridging mode. The manganese(n) center exhibits a distorted tetrahedral geometry with

a7V4 coordination environment. A distorted tetrahedral N f i environment is observed for

the lithium center.,

The Mn-N^do bond distances in 15 [Mn(l>-N(2) 2.109(3) A, Mn(l>-N(4)

2.129(3) A，Mn(l)-N(6) 2.142(3) A ] are longer than those of compounds 4, 7 and 8 [4:

73

M = Fe 2.010(3) A, 7: M 二 Fe 2.025(5>-2.051(5) A，8: M 二 Co 2.007(4^1.998(3) A].

The bond distances Mn(l>-N(2) and Mn( l ) -N(4 ) of 2.109(3)-2.129(3) A in 15 are

longer than those of 2.023(3) A in [Mn{N(SiMe3)2}3 • Li(THF)], ' and 1.997(3^1.999(3)

A in the dimeric [MtU^SiMe])�}�]�？ They are also longer than those of 1.988(3>-

1.9g9(3) A in [Mn{N(SiMePli2)2}2].i�The longer Mn-N^ido m our current complex may

be ascribed to a more crowded four-coordinate environment around the metal centers.

The Mn( l ) -N (6 ) bond distance of 2.142(3) A is similar to that of 2.143(2) A in

[Mn{N(SiMe3)2}3 • Li(THF)].' The Mn—Li distance of 2.906(7) A in 15 is longer than

that of 2.718(6) A in [Mn{N(SiMe3)2}3 • Li(THF)],^ and 2.640(7) A in

[Li{Mn[N(SiMe3)2] CBu^CO)�}]/" The Li—O bond distance of 1.999(7) A in compound

15 is slightly longer than that of 1.939(6) A in [Mn{N(SiMe3)2} 3 • Li(THF)].^

A trend of the Mn-N細d。bond distances in 15, viz. Mn(l>-N(6) 2.142(3) A >

Mn( l ) -N (4 ) 2.129(3) A > Mn( l ) -N(2) 2.109(3) A is observed. As N(6) is bridging

between two metal centers but N(2) and N(4) are not, Mn( l ) -N(6 ) should be the longest

among the three distances. Mn( l ) -N(4) is longer than Mn( l } -N(2) because of the

highly strained four-member metallacycle ring.

The observed Si -N bond distances in 15 [1.724(3>~1,736(3) A] are similar to the

S i -N distances found in other silylamido complexes.'' Delocalization of the lone-pair

electrons onto the pyridyl ring is evidenced by the short Cpyidyi-Namido distances of

1.342(4)-1.382(5) A in 15. They are close to the observed C咖matk—Nannd。distances in

other metal arylamido complexes, in which delocalization of electron density onto the

aromatic substituents have been suggested/'"'' Apparently, ligand L behaves as a weak

21 -acceptor in complex 15 and this may account for the stability of the complex.

74

As expected，the amido nitrogen centers [N(2) and N(4)] exhibit a nearly trigonal

planar geometry [sum of bond angles == 359.8。（av.)]，which is consistent wi th sp、

hybridized nitrogen atoms. On the other hand, the sum of bond angles around the amido

nitrogen N(6)，viz. 350.4。，deviates slightly f rom that o f planarity. This evidence，

together wi th the short L i ( l>-N(6) bond distance [2.283(7) A ] , suggest a substantial

L i ( l ) — N ( 6 ) bonding interaction. The N謹fM—Np^^dyi ( M = M n or L i ) bite angles

[N(3>-Mn( l ) -N(4) = 62.3(1)。，N(5>-Li(l)-N(6) 二 64.1(2)。] are small due to the highly

strained four-member metallacycle rings.

75

C(3)

Figu

re 3

-1.

Mol

ecul

ar s

truc

ture

of

[{M

n[N

(Si'B

uMe2

)(2-C

5H3N

-6-M

e)l3

} • L

i(TH

F)]

(15)

.


[{Mn[N(SiTBuMe2)(2-C5H3N-6-Me)]3} • Li(THF)] (15)

Mn( l ) -N (2 ) 2.109(3) N(3)-C(21) 1.370(5)

Mn( l ) -N (3 ) 2 . 2 5 4 ( 3 ) N(4^C(21) 1.342(4)

Mn( l ) -N (4 ) 2.129(3) N(5^C(41) 1.363(5)

Mn( l>-N(6) 2.142(3) N(6>-C(41) 1.382(5)

L i ( l > - N ( l ) 2.106(8) Si( l ) -N(2) 1.734(3)

L i ( l ^ N ( 2 ) 2.691(8) Si(2>-N(4) 1.724(3)

L i ( l ^ N ( 5 ) 2.063(8) Si(3)-N(6) 1.736(3)

L i ( l>-N(6) 2.283(7) Mn( l> -L i ( l ) 2.906(7)

NCIK：⑴ 1.353(5) L i ( l H X l ) 1.999(7)

N(2 ) -C( l ) 1.378(5)

N ( l ) - L i ( l ) - N ( 5 ) 153.2(4) C ( l > -N (2^Mn( l ) 108.0(2)

N( l>-L i ( l>-N(6) 103.4(3) C( l>-N(2)-Si( l ) 125.7(3)

N(l)~Li( lHXl) 95.4(3) Mn(l>-N(2>-Si(l) 125.9(1)

N(5>-Li( l>-N(6) 64.1(2) C(21>-N(4^Mn( l ) 94.2(2)

- N(5>-L i ( l ) -0(1) 105.8(4) C(21>-N(4>-Si(2) 128.4(3)

0(1) -L i ( l>-N(6) 151.9(4) Mn(l>-N(4>-Si(2) 137.3(1)

N(2>-Mn(l) -N(3) 128.8(1) C(41>-N(6)-Li( l) 85.6(3)

N(2>-Mn(l>-N(4) 121.1(1) C(41>-N(6>-Mn(l) 110.6(2)

N(2>-Mi i ( l ) -N(6) 111.9(1) C(41)-N(6)-Si(3) 121.0(2)

N(3>-Mn(l) -N(4) 62.3(1) L i ( l>-N(6>-Mn( l ) 82.0(2)

N(3) -Mn( l ) -N(6) 102.1 ⑴ Li(l>^N(6)^Si(3) 129.7(3)

N(4) -Mn( l ) -N(6) 121.7(1) Mn(l)-N(6>-Si(3) 118.8(1)

77

I I I !)

3.3 EXPERIMENTALS FOR CHAPTER 3

Materials:

Anhydrous MnCl! was purchased from Aldrich and was dried at 120。C under

vacuum for 4 hours before use. L i L (3) was prepared according to the literature

procedure. 23

Synthesis of compound:

Synthesis of [{Mn[N(Si它uMe^XZ-CsByV-G-Me)]，} • Li(THF)] (15). To a suspension

o f MnCl^ (0.316 g，2.51 mmol) in THF (10 mL) at 0°C was added a solution of

compound 3 (1.72 g, 7.53 mmol) in THF (30 mL). The reaction mixture was slowly

warmed to room temperature and stirred for a further period of 8 hours. A l l the volatiles

was then removed in vacuo and the residue was extracted with hexane to give compound

15 as yellow crystals. The product was washed twice with hexane and dried in vacuo

(1.20 g, 1.50 mmol，60%). Crystals suitable for X-ray crystallographic studies were

obtained by recrystallization from toluene. M.p.: 100-105°C. //进• = 5.91 "b. Anal.

Found: C, 59.11; H, 9.07; N，10.52 %. Calc. for C^oH^.LiMnN^OSia： C, 60.19; H, 8.97;

N , 10.52%.

78


1. Burger, R ; Wamiagat, U. Monatsh. Chem. 1964, 95, 1099.

2. Bradley, D. C.; Hursthouse, M . B.; Mal ik , K. M. A. ; Moseler, R. Transition

Met, Chem. {Weinheim, Ger) 1978, 5, 253. 3. Murray, B. D,; Power, P. R Inorg. Chem. 1984, 22, 4 5 8 4 . 4. Andersen, R. A.; Faegri, K. ; Green, J. C.; Haaland, A. ; Lappert, M . R; Leung,

W.-P.; Rypdal, K. Inorg. Chem. 1988, 27，1782. 5. Bradley, D. C. Adv. Inorg. Chem. Radiochem. 1972,15, 259.

6. Eller, R G.; Bradley, D. C ; Hursthouse, M . B.; Meek, D. W. Coord Chem.

Rev. 1977, 24, 1.

7. Bradley, D. C ; Hursthouse, M . B.; Ibrahim, A. A.; Mal ik , K. M . A.;

Moteval l i , M. ; Moseler, R.; Powell, R ; Ruimacles, J. D.; Sullivan, A. C.

Polyhedron 1990, 9, 2959. 8. Bartlett, R. A.; Feng, X. ; Olmstead，M. M. ; Power, R R; Weese, K. J. J. Am.

Chem. Soa 1987，7 卯 , 4 8 5 1 .

9. Chen, H.; Bartlett, R. A.; Olmstead，M. M. ; Power, R R; Shoner, S. C. J. Am.

Chem. Soc. 1990,112,1048. 10. Chen, H.; Bartlett, R. A.; Bias, H. V. R.; Olmstead, M . M. ; Power, R R J. Am.

Chem. Soc. 1989, 111, 4338. 11. Chen, R ; Bartlett, R. A.; Bias, H. Y R.; Olmstead, M . M. ; Power, R R Inorg.

Chem. 1991，20, 2487. 12. Putzer, M. A.; Neumiiller, B.; Dehnicke, K. ; Magul l , J. Chem. Ber. 1996,129,

715.

13. Evans, D. F. J. Chem. Soa 1959, 2005.

14. Murray, B. D.; Power, P. R J, Am. Chem. Soc. 1984,106, 7011.

15. Lappert, M . R; Power, P. P.; Sanger, A. R.; Srivastava, R. C. Metal and

Metalloid Amides; Ellis Horwood: Chichester, 1980. 16. Fryzuk, M. D.; MacNeil，P. A. J. Am. Chem. Soc. 1981，103, 3592.

17. Fryzuk, M. D.; MacNeil, R A. ; Rettig, S. J.; Secco, A. S.; Trotter, J. Organometallics 1982, 7,918.

18. Fryzuk, M. D.; Montgomery, C. D. Coord. Chem. Rev. 1989, 95,1.

19. Engelhardt, L M ; Junk, P. C.; Patalinghug, W. C.; Sue, R. R ; Raston, C. L.;

Skelton, A. H. J. Chem. Soc., Chem. Commun, 1991, 930. 20. Ruhlandt-Senge, K.; Power, P. P. J, Chem. Soa, Dalton Trans, 1993，649.

21. VanderLende, D. D.; Boncella, J. M . ; Abboud, K. A. Acta Cryst. 1995，C51，

591.

79

22. Penney, J.; VanderLende, D. D.; Boncella, J. M. ; Abboud, K. A. Acta Cryst.

1995, C51, 2269. 23. Peng, Y. M. Phil Thesis, The Chinese University of Hong Kong, 1999.

80

APPENDIX 1

General Procedures, Physical Measurements and X-ray Structure Analysis

A l l manipulations were carried out under a purified nitrogen atmosphere using

modified Schlenk techniques or in a Braun M B 150-M drybox. Solvents were dried

over sodium wires and freshly distilled under nitrogen from calcium hydride (hexane)

and sodium benzophenone (Etp，THF, toluene)，and degassed thrice by freeze-thaw

cycles prior to use.

Mass spectra were obtained on a Hewlett-Packard 5989B Mass Engine

spectrometer (E. 1. 70 eV). Magnetic moments were measured by the Evans

method in toluene solution at 298 K using a JOEL 60 MHz N M R Spectrometer.

Melt ing points were recorded on an Electrothermal melting-point apparatus and were

uncorrected. Elemental analysis (C, H, N) were performed by MEDAC Ltd.,

Brunei University, UK.

Single-crystals of compounds 4-10 and 13-15 suitable for crystallographic

studies were mounted in glass capillaries and sealed under nitrogen. Data were

collected on a Rigaku RAXIS-IIC diffractometer at 294 K using graphite-

monochromatized Mo K a radiation (X 二 0.71073 A) by taking oscillation photos.

The structures were solved by direct phase determination using the computer

program SHELX-97 on a PC 486 computer and refined by fii l l-matrix least squares

81

wi th anisotropic thermal parameters for the non-hydrogen atoms.口 Hydrogen atoms

were introduced in their idealized positions and included in structure factor

calculations wi th assigned isotropic temperature factors.

a Sheldrick, G. M. SHELX-97; Package for Crystal Structure Solution and Refinement, University of

Gottingen: Gottingen, Germany, 1997.

82

APPENDIX 2

Table A-1, Selected crystallographic data for compounds 4-^.

Table A-2. Selected crystallographic data for compounds 7-10.

Table A-3. Selected crystallographic data for compounds 13-15.

83

Tabl

e A

-1,

Sele

cted

cry

stal

logr

aphi

c da

ta f

or c

ompo

unds

10-

12.

- 4

5 6

Mol

ecul

ar F

orm

ula

C^^

H.^

FeN

^Si,

C36

H,,C

o,Li

,N30

,Si4

Q

A^F

eN^O

Si^

M

olec

ular

wei

ght,

g m

ol"^

49

8.70

11

59.5

2 C

olor

and

hab

it O

live-

gree

n bl

ock

Gre

enis

h br

ov^

p at

es

Pa e

gre

en p

rism

C

ryst

al s

ize,

mm

0.

35 x

030

x 0

.10

0.43

x 0

.34

x 0.

31

0.48

><

0.32

x 0

.30

Cry

stal

sys

tem

M

onoc

linic

M

onoc

linic

Tn

ciin

ic

Snac

e gr

oup

C2c

P2^/

n P\

a

t 18

.404

(4)

13.436(2)

9.40

6(2)

B

A

7

.80

82

(16

) 1

7.3

01

(3)

12

.86

2(3

)

；A

21

.105

(4)

15.2

41(2

) 17

.933

(4)

�d

eg

106.

20(3

) 11

0.21

6(3)

10

1.51

6�

t v/人

3 29

12.3

(10)

33

24.8

(8)

2121

.5(8

) Z

4 2

2 D

ensi

ty, g

cm-3

1.

274

1.15

8 丄.二

A

bs.c

oeff

s.,m

m-^

0.625

0.61

3 0A

44

Tran

smis

sion

fac

tors

0.

815-

1.12

2,

0.81

45-1

.000

0 0.

7896

-1.0

000

2 0

max,

deg.

83

.6

99.4

97

.3

No.

ofre

flns

. col

lect

ed

3398

22

059

^445

7 N

o. o

f uni

que

data

mea

sd.

2140

79

85

^005

6 N

o. o

f var

iabl

es, p

14

3 33

5 Fi

nal R

indi

ces

[I>2

a (1

)]“

R1

= 0.

0564

R

1 二

0.0

533

R1 二

0.0

548

wR

2 二

0 1

512

二 0

.139

2 0.

1126

R

ind

ices

(al

l dat

a/

R1

= 0.

0649

R

1 =

0.12

37

0.^

59

0.15

81

= 0.

1654

0.

1355

“ R1 二

EIIF

J -

IFJI

/EIF

J; w

R2

= -

Tabl

e A

-2,

Sele

cted

cry

stal

logr

aphi

c da

ta f

or c

ompo

unds

10-

12.

7 8

9 10

Mol

ecul

ar F

orm

ula

QdH

iooF

eaN

ioSi

^ Q

Aoo

Cos

Nio

Si^

C

36H

,,F

eNA

QA

^C

oN

A M

olec

ular

wei

ght,

g m

ol-i

1113

.50

1119

.66

610.

73

Col

or a

nd h

abit

Pale

gre

en b

lock

G

reen

blo

ck

Whi

te p

rism

G

rcon

pla

tes

Crys

tal s

ize

mm

0.

32 x

0.2

2 x

0.20

0.

40 x

0.4

0 x

0.30

0.

50 x 0.30

x 0.

18

0.30

x 0

.25

x 0.

22

Cry

stal

sys

tem

Tr

iclin

ic

Tric

linic

M

onoc

linic

M

onoc

limc

Spac

e gr

oup

M

P飞

舰

a A

12.0

40(2

) 12

.046

(2)

11.8

39(1

) 18

.196

(4)

3 A

12.3

19(2

) 12

.286

(3)

15.1

25(1

) 14

.902

(3)

；A

12 3

53(5

) 12

.291

(3)

20.7

61(2

) 13

.428

(3)

》，

deg.

73

.26⑵

72

.65(

3)

99.4

76(2

) 90

.00(

3)

V A

' 16

77.4

(8)

1660

.8(6

) 36

66.8

(7)

3641

.1(1

3)

1 1

1 4

4 D

ensi

ty, g

cm

"^

1.10

2 U

19

1.10

6 h

UO

A

bs. c

oeffs

.，

mm

-i 0.

542

0.61

0 0.

441

0.50

2 Tr

ansm

issi

on fa

ctor

s 0.

843-

0.94

1 0.

854-

1.14

1 0.

635-

1.22

2 0.

807-

1.13

6 2

0_

de

g.

99.5

77

.6

83.7

二么

No.

of r

efln

s. c

olle

cted

58

92

4809

93

81

8169

N

o. o

f uni

que

data

mea

sd.

5892

48

09

5402

51

29

No.

of v

aria

bles

,;?

317

317

371

371

Fina

l R in

dice

s [I>

2 o (1

)]“

R1

= 0.

0767

R

1 二

0.0

643

R1

- 0.

0764

R

1 -

0.07

84

wR

2 二

0.1

133

= 0.

1779

=

0.19

80

wR

2 =

0.16

83

R in

dice

s (a

ll da

ta)"

R1 二

0.2

125

R1

- 0.

0733

R

1 =

0.08

78

R1

= 0.

1202

w

R2 二

0.1

553

WR

2-0.

1875

wR

2 =

0.2

084

wR

2 =

0.18

92

«R1

= E

ll/g

- IF

JI/Z

IFJ;

wR

2 =

{S[w

(F。

2- /

。2)2

]/对狄(厂

。2)2

]广2

Tabl

e A

-3,

Sele

cted

cry

stal

logr

aphi

c da

ta f

or c

ompo

unds

10-

12.

13

14

15

Mol

ecul

ar F

orm

ula

C4A

4FeN

2S,

C42H

74C0

N2S2

Q

oH^^

LiM

nN^O

Sis

M

olec

ular

wei

ght,

g m

ol"^

72

7.00

73

0.08

79

8.18

C

olor

and

hab

it Y

ello

wis

h br

own

bloc

k R

eddi

sh b

row

n bl

ock

Yel

low

pris

m

Cry

stal

size

，m

m

0.56

x 0

.48

x 0.

44

0.40

x 0

.25

x 0.

20

0.82

x 0

.75

x 0.

47

Cry

stal

sys

tem

O

rtho

rhom

bic

Ort

horh

ombi

c Tr

iclin

ic

Spac

e gr

oup

Pna2

(\)

Pna2

(\)

P\

a A

23

.239

(3)

23.1

77(5

) 10

.199

3(10

) b

k 11

.010

(2)

11.0

56(2

) 12

.557

0(12

) c

k 17

.398

(3)

17.2

63⑷

19

.540

1(19

) y^，

cieg.

90

90

86

.362

(2)

- V

A^

4451

(1)

4423

.6(1

5)

2374

.3⑷

Z 4

4 4

Den

sity

, g c

m''

1.08

5 1.

096

U1

6 A

bs. c

oeffs

., m

m-i

0.46

0 0.

510

0.38

8 Tr

ansm

issi

on fa

ctor

s 0.

7177

-1.0

000

0.75

1-1.

263

0.53

99-1

.000

0 2

e_

de

g.

99.7

89

.3

99.4

N

o. o

f ref

lns.

col

lect

ed

2871

8 10

495

1223

6 N

o. o

f uni

que

data

mea

sd.

8482

38

57

7420

N

o. o

f va

ri

ab

le

s,

42

5 40

0 47

0 Fi

nal R

indi

ces

[I>2

a (I)

]"

R1 二

0.0

396

R1 二

0.0

879

R1

= 0.

0582

w

R2

= 0.

0787

w

R2

- 0.

2436

二

0.1

475

R i

ndic

es (

all d

ata/

R

1 =

0.10

30

R1 二

0.1

075

= 0.

0917

wR

2 =

0.0

966

wR2

- 0.

2635

w

R2

= 0.

1624

^Rl-

Ell

FJ

- IF

JI/E

IFJ;

wR2

=

{E

[vK斤

-F^y

ynH

KW

• .... / -

： • -

. ‘ _

- ‘ 、 ‘

‘ / -•:: - . . . . •

. . . •. • •, .... . . . . . . . . . . . . . . . . ： -

,• • •厂

CUHK L i b r a r i e s

圓••llillllll 0D3fi71S3b

reactivities of low-valen latt e transition meta amidel s4,6-^u2c6h2), the bulky thiophenol arsh (ar...

Documents