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.
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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^^OH (Ar^^ = 2,6-^u^"4-MeQH2) and 2-MeCH(Ar'OH)2 (Ar' 二
4,6-^U2C6H2), 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(Si^uMe2)(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^^OH gave the novel mononuclear mixed-ligand
iron(n) complex [Fe {N(SffiiiMe2)(2-C5H3N-6-Me)} {OQH2-2,6-^U2-4-
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(0Ar^e)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 2-4. Selected bond distances (A) and angles (。)for compound 6. 30
Table 2-5. Some physical properties of compounds 7-14. 37
Table 2-6. Selected bond distances (A) and angles (。)for compound 7. 41
Table 2-7. Selected bond distances (A) and angles (。)for compound 8. 44
Table 2-8. Selected bond distances (A) and angles (。)for compound 9. 47
Table 2-9. Selected bond distances (A) and angles (。)for compound 10. 50
Table 2-10. Selected bond distances (A) and angles (。)for compound 13. 53
Table 2-11. Selected bond distances (A) and angles (。) for compound 14. 56
Table 3-1. Some physical properties o f compound 15. 73
Table 3-2. Selected bond distances (A) and angles (。)for compound 15. 77
Table A-1. Selected crystallographic data for compounds 4-6. 84
xii
Table A-2. Selected crystallographic data for compounds 7-10. 85
Table A-3. Selected crystallographic data for compounds 13-15. 86
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
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Amides; Ellis Horwood: Chichester, 1980.
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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.
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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
2. Molecular Structure of Compound 5
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 i^uMe2) (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>^o ( 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(4K^o( 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(4H^i( 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
3. Molecular Structure of Compound 6
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
).
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[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^^O-Me]^ (205,100 %), [TMEDA]+ (115,5 %) and [它u]+ (57, 24 %). A similar
pattern, viz. (498, 17 %), [Ar^^O]^ (220, 33 %), [Ar^^O-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
1. Molecular Structure of Compound 7
The molecular structure of compound 7 with the atom numbering scheme is
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
).
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[{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
2. Molecular Structure of Compound 8
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
).
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[ { 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
3. Molecular Structure of Compound 9
The molecular structure of compound 9 wi th the atom numbering scheme is
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)
.
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[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
4. Molecular Structure of Compound 10
The molecular structure of compound 10 wi th the atom numbering scheme is
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
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[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
5. Molecular Structure of Compound 13
The molecular structure of compound 13 wi th the atom numbering scheme is
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
6. Molecular Structure of Compound 14
The molecular structure of compound 14 with the atom numbering scheme is
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^^^O-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(Si^uMe.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 C^U.ooPQ^^io^U- 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^^O-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^^O]^
205 (100) [Ar^^O-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^H^aCoN^O^: 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
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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
The molecular structure of compound 15 with the atom numbering scheme is
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)
.
Table 2-9. Selected bond distances (A) and angles ( � ) for compound 10.
[{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
3.4 REFERENCES FOR CHAPTER 3
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