Physical Methods

BY J. C. TEBBY

The abbreviations PIII, PIV, and PV refer to the co-ordination number of phosphorus, and the compounds mentioned in each subsection are usually dealt with in this order. A number of relevant theoretical and inorganic studies are included in this chapter. In the formulae, the letter R represents hydrogen, alkyl, or aryl; X repre- sents electronegative substituents ; Ch represents chalcogen (usually oxygen or sulphur); and Y and 2 are used to indicate a wide variety of substituents.

1 Nuclear Magnetic Resonance Spectroscopy

Biological Applications.-Phosphorus-3 1 n.m.r. spectroscopy is becoming a valuable biological probe2 In addition to its use in the assay of phosphorus metabolites in living tissue,2 such as heart and other ~nuscle,~ it has revealed the presence of phos- phorus compounds that were not previously known to be in muscle t i~sue .~ The sig- nal produced by inorganic phosphate appears to consist of numerous overlapping components, each depending on the unique environment of a phosphorus nucleus.6 The signals of ATP in normal and diseased muscle differ,$ and the 31P spin relaxa- tion times are significantly longer in malignant than in normal tissue.' Nucleotide equilibria in tumour cells have been studied.8 Attention has also been focused on the phosphorus-containing components of bloods and on the binding of phosphate to haemoglobin.1° Phospholipids have been the subject of numerous reports, the ma-

1 R. E. Richards, Endeavour, 1975, 34, 118; s. J. Kohler, Diss. Abs. Internat (B), 1976, 37, 251. J. Dawson, D. G. Gadian, and D. R. Wilkie, J. Physiol., l976,258,82P; C. T. Burt, T. Glonek and M. Barany, Science. 1977, 195. 145. D. G. Gadian,- D. I. Hoult, GI K. Radda, P. J. Seeley, B. Chance, and C. Barlow, Proc. Nut. Acad. Sci. U.S.A., 1976,73, 4446; P. B. Garlick, G. K. Radda, P. J. Seeley, and B. Chance, Biochem. Biophys. Res. Comm., 1977, 74, 1256. C. T. Burt, T. Glonek, and M. Barany, Biochemistry, 1976, 15, 4850. P. J. Seeley, S. J. W. Busby, D. G. Gadian, G. K. Radda, and R. E. Richards, Biochem. SOC. Trans., 1976,4, 62. C. T. Burt, T. Glonek, and M. Barany, J. Biol. Chem., 1976,251, 2584. K. S. Zaner and R. Damadian, Science, 1975,189, 729. G. Navon, S. Ogawa, R. G. Shulman, and T. Yamane, Proc. Nut. Acad. Sci. U.S.A., 1977, 74, 87. R. J. Labotka, T. Glonek, M. A. Hruby, and G. R. Honig, Biochem. Med., 1976, 15, 311. E. T. Fossel and A. K. Solomon, Biochim. Biophys. Acta, 1976, 436, 505; B. Benko and S. Vuk-Pavlovic, Biochem. Biophys. Res. Comm., 1976, 71, 1303; W. E. Marshall, A. J. R. Costello, T. 0. Henderson, and A. 0. Machi, Biochim. Biophys. Acta, 1977, 490, 290.

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23 8 Organophosphorus Chemistry

jority concerning 31P chemical shift anisotropy l1 or praseodymium shift reagents.12 Complete resolution of the 13C n.m.r. spectra of enriched phosphatidylcholine has been achieved, using an ytterbium shift reagent.13 Carbon-13 and proton relaxation times have also been usef~1.l~ Several 31P n.m.r. studies of nucleotides and related compounds have appeared, mainly t o determine their conformat i~n~~ and the de- pendence of conformation on pH,le but in one study, signals for two diastereo- isomers were detected1' (see section on Non-equivalence; p. 248). The 13C spectra of AMP have also been analysed.l*

Chemical Shifts and Shielding Effects.-Phosphorus-31. The sign convention used for expressing shifts in this Report is not the same as was used in earlier volumes. Positive chemical shifts are now downfield from 85 % phosphoric acid, and are given without the appellation p.p.m. Since both conventions are in use, it remains neces- sary to state the sign convention used in each paper published. B P of PI1 Compounds. A number of compounds of general formula X-P=Y have been prepared whose chemical shifts are very sensitive to the nature of the directly bonded atoms. Replacement of the carbon atoms in (l)lS by nitrogen caused an increase in values of dp from 150 k 30 for (1) to 218 f 14 for (2),20 and to 326 for (3),21 whereas replacement of carbon by phosphorus [as in (4)] gave a value of 8 , of -218.22

,OSiMe, /

RP=C\ CMe,

t 0 IR I1

R,NP=NR R,P=P-P(OE t);

11 M. C. Uhing, Chem. and Phys. Lipids, 1975, 14, 303; J. Seelig and H. U. Gally, Biochemistry, 1976, 15, 5199; P. R. Cullis and B. De Kruyff, Biochim. Biophys. Acta, 1976, 436, 523; W. Niederberger and J. Seelig, J. Amer. Chem. SOC., 1976, 98, 3704; S. J. Kohler and M. P. Klein, Biochemistry, 1977, 16, 519.

12 K. Arnold, W. Gruender, R. Goeldner, and A. Hofmann, Z. phys. Chem. (Leipzig), 1975, 256, 522; A. Chrzeszczyk, A. Wishnia, and C. Springer, Chem. Abs., 1976, 86, 1374; P. W. Nolden and T. Ackermann, Biophys. Chem., 1976,4, 297; L. 0. Sillerud and R. E. Barnett, Biochim. Biophys. Acta, 1977, 465, 466.

l3 B. Sears, W. C. Hutton, and T. E. Thompson, Biochemistry, 1976,15, 1635. 14 P. A. Kroon, M. Kainosho, and S. I. Chan, Biochim. Biophys. Ada, 1976, 433, 282; A. A.

Ribeiro and E. A. Dennis, J. Colloid Interface Sci., 1976, 55, 94. 15 C. H. Lee, F. E. Evans, and R. H. Sarma, F.E.B.S. Letters, 1975,51,73; S . V. Zenin, Doklady

Akad. Nauk S.S.S.R., 1975, 221, 1219; N. S. Kondon, F. Ezra, and S . S. Danyluk, F.E.B.S. Letters, 1975, 53, 213; F. E. Evans and R. H. Sarma, J. Amer. Chem. SOC., 1975, 97, 3215; C.-H. Lee, F. E. Evans, and R. H. Sarma, J. Biol. Chem., 1975,250, 1290.

1 6 K. Akasaka, A. Yamada, and H. Hatano, F.E.B.S. Letters, 1975,53, 339; P . J. Cozzone and 0. Jardetzky, Biochemistry, 1976,15,4853,4860; R. J. Labotka, T. Glonek, and T. C. Myers, J. Amer. Chem. SOC., 1976,98, 3699.

1 7 A. V. Lebedev and A. I. Rezvukhin, Izuest. sibirsk. Otdel. Akad. Nauk S.S.S.R., Ser. khim. Nauk, 1975, 149.

18 M. Morr, M.-R. Kula, and L. Ernst, Tetrahedron, 1975, 31, 1619. 19 G. Baker, 2. anorg. Chem., 1976,423,242. 20 J. Luber and A. Schmidpeter, Angew. Chem. Internat. Edn., 1976, 15, 111. 21 E. Niecke and R. Kroeher, Angew. Chem. Internat. Edn., 1976,15, 692. 22 D. Weber and E. Fluck, Z. anorg. Chem., 1976,424, 103.

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Physical Methods 239

BP ofPII1 Compounds. Theoretical estimates of SP by CNDO/2 calculations required the inclusion of phosphorus d-orbitals and an adjustable parameter Zzif, which de- pends on the type of compound, e.g. phosphine or p h ~ s p h i t e . ~ ~ The chemical shifts of a series of cyano-compounds ( 5 ; X, Y = ha1 or CN) agree with those predicted by Letcher and van Wazer’s quantum-mechanical interpretation. 24 The sensitivity of BP to stereochemical changes often leads to quite large differences of chemical shift between various conformers or isomers, e.g. the axial conformer (6) has BP upfield

of the equatorial conformer,26 and there is a difference of 10p.p.m. between the cis- and trans-isomers of the phosphine (7).26 Such differences can be used diag- nostically. Thus the phosphorus resonances of the cis-isomers of the dioxaphos- pholan (8) appear downfield of those of the trans-isomer~.~~ However, there is an opposite trend for dioxaphosphorinans, which clearly shows the danger inherent in extrapolating an effect from one ring system to another. This particular difference is probably the result of a y-effect.28s 29 The nature of the P-substituents can also be important ; thus, whilst the cis-isomers of the diazadiphosphetidines (9; Y = OR) give signals downfield of those of the trans-isomers,so the trend is reversed for the di-t-butyl compounds (9; Y = The dependence of BP on bond angles enables the ring size of cyclopolyphosphines to be identified.32 The chemical shift anisotro-

R

\ IPr Pr

Pr /p-p\ Pr

/OH

‘Y RP

23 M. Rajzmann and J. C. Simon, Org. Magn. Resonance, 1975, 7 , 334. 24 K. B. Dillon, M. G. C. Dillon, and T. C. Waddington, J. Inorg. Nuclear Chem., 1976, 38,

25 S. I. Featherman and L. D. Quin, J. Amer. Chem. SOC., 1975, 97, 4349. 26 K. Issleib, H. Winkelmann, and H. P. Abicht, Z. anorg. Chem., 1976,424,97. 27 W. G. Bentrude and H.-W. Tan, J. Amer. Chem. Soc., 1976,98, 1850. 28 H.-W. Tan and W. G. Bentrude, Tetrahedron Letters, 1975, 619. 29 L. D. Quin, M. D. Gordon, and S. 0. Lee, Org. Magn. Resonance, 1974,6, 503. 30 T. Kawashima and N. Inamoto, Bull. Chem. SOC. Japan, 1976, 49, 1924. 31 0. J. Scherer and G. Schnabl, Angew. Chem. Internat. Edn., 1976, 15, 772. 32 M. Baudler, B. Carlsohn, W. Boehm, and G. Reuschenbach, Z. Nrrturforsch., 1976,31b, 558;

M. Baudler, J. Hahn, H. Dietsch, and G. Furstenberg, ibid., p. 1305; L. R. Smith and J. L. Mills, J. Amer. Chem. SOC., 1976, 98, 3852.

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240 Organophosphorus Chemistry

pies of the tetraphosphines (10; R=But or CF,) have also been determined.8s Changes in temperature can sometimes dramatically alter equilibria of tautomers or conformers. When this occurs, quite large changes of 6~ may occur. Thus the phos- phorus nucleus of the diphosphine (1 1) is shielded by 10.5 p.p.m. as the temperature is increased from - 50 to + 40 0C,34 and in the ester and amide derivatives of phos- phonous acids (12; Y=OR or NR2) the nuclei are deshielded by 0.6 p.p.m. for each 10 "C rise.3s SP ofPIV Compounds. Phosphorus chemical shifts are generally insensitive to changes in solvent; however, the phosphorus nucleus of the oxide (13) is deshielded by 5-7 p.p.m. when the solvent is changed from chloroform to water.86 The alkyl hypo- phosphites and thiono-analogues

0 I 1

E t, PH

(13)

(14) have SP values of 15-18 and 4 1 4 2 , re-

spect i~ely.~~ The phosphorus-conjugated acetylenic bond consistently shifts C ~ P up- field by 5-20 p.p.m.,38 and the inclusion of the phosphorus atom in a five-membered ring has the opposite effect.39 There can be little doubt that the latter effect is the cause of the signals' being at exceptionally low field, SP being 105-110 for the phospholen sulphides (15).40 On the other hand, very small rings, as in the phos- phirans (16), produce a shielding effect.41 A quantum-mechanical interpretation of the n.m.r. parameters of 3- and 4-fluoro- or -chloro-phenylphosphines (17) and their

Ch

/ \

R

Z-NR

(16) (1 7)

chalcogenides indicates that n-bonding is largely responsible for the downfield shift of the chalcogenides, and that this is greater for the sulphides and ~elenides .~~ The n-bonding concept contrasts with conclusions drawn from other theoretical studies

33 J. P. Albrand, A. Cogne, D. Gagnaire, and J. B. Robert, Mol. Phys., 1976, 31, 1021. 34 S. Aime, R. K. Harris, E. M. McVicker, and M. Fild, J.C.S. Dalton, 1976, 2144. 35 M. D. Gordon and L. D. Quin, J. Magn. Resonance, 1976,22, 149. 38 L. D. Quin and C. E. Roser, J. Org. Chem., 1974, 39, 3423. 37 N. B. Karlstedt, M. V. Proskurnina, and I. F. Lutsenko, J. Cen. Chem. (U.S.S.R.), 1976,

46, 1942. 38 H. J. Bestmann and W. Kloeters, Angew. Chem. Internat. Edn., 1977, 16,45; E. Fluck and W.

Kazenwadel, 2. anorg. Chem., 1976, 424, 198; 2. Naturforsch., 1976, 31b, 172. 39 F. Ramirez, J. F. Marecek, and H. Okazaki, J. Amer. Chem. SOC., 1976,98,5310; F. Ramirez,

J. F. Marecek, and H. Tsuboi, Phosphorus, 1976, 6, 215; W. Winter, Tetrahedron Letters, 1975, 3913; M. A. Pudovik and A. N. Pudovik, Bull Acad. Sci. U.S.S.R., 1975, 24,880; M. El-Deek, G. D. MacDonell, S. D. Venkataramu, and K. D. Berlin, J. Org. Chem., 1976, 41, 1403; W. R. Purdum and K. D. Berlin, ibid., 1975, 40, 2801.

40 K. Moedritzer, 2. Naturforsch., 1976, 31b, 709. 4 1 H. Quast, M. Heuschmann, and M. 0. Abdel-Rahman, Angew. Clzem. Internat. Edn., 1975,

42 R. F. De Ketelaere and G. P. van der Kelen, J . Mol. Structure, 1975, 27, 25, 363. 15, 486; E. Niecke and W. Flick, Angew. Chem., 1975,87, 363.

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Physical Methods 241

(see section on Carbon-13; p. 243) but it is in agreement with perturbation calcula- tions based on reactivity studies.43 The electronic distribution and conformation of iminotriphenylphosphoranes and hydrazino-analogues (1 8) have been discussed in the context of their 31P and 13C n.m.r. parameters and relevant CND0/2 M.O. calculation^.^^ The chemical shifts of the iminophosphoranes (19)46 and of the adducts (20)46 correlate with Hammett substituent constants, and dp of the phos- phonic esters (21) and phosphonyl fluorides (22) can be correlated with the log of the

Ar,P=N-N-CR, ArN=PCl$CI,

(1.8) (19)

S -

+ I Bu,P-C=-NR

0 II

YZPF

(20) (21) (22)

sum of Taft substituent constants. The trends have been discussed in terms of vary- ing d,-p interaction^.^' Mesomeric and inductive effects have been studied through the n.m.r. spectra of vinylphosphonates. 48 The phosphonyl difluorides (23) have 6p and SF values which are shifted upfield as the electron-withdrawing power of Y increases. In this case also, SP correlates with substituent parameters of Y.49 Steric effects on SP are often consistent within a given structural series. Thus, in a number of dioxaphosphorin chalcogenides, SP appears further downfield when the phos- phoryl oxygen or sulphur atom occupies an axial orientation, as shown in (24).60*

Ch 0

Y D". I I Se

II 1 (RO),PSeR

(23) (24) (25)

The shielding effects of the trichloromethyl group have been compared with those of alkyl and aryl groups,62 and the shielding effects of the dimethylamino-groups in tetra-azaphosphorines have been compared with those of phenoxy-gro~ps.~~ Replace- ment of oxygen atoms by sulphur atoms generally causes dp of PIV compounds to shift downfield. Replacement of sulphur by selenium does not appear to cause a further shift; cf. B P 85-86 for the diselenophosphates (25)64 and SP 94-99 for dithiophosphates.

43 B. Klabuhn, Tetrahedron, 1976, 32, 609. 44 T. A. Albright, W. J. Freeman, and E. E. Schweizer, J. Org. Chem., 1976,41, 2716. 45 E. S. Kozlov, S. N. Gaidamaka, and R. Kh. Sadykov, J. Gen. Chem. (U.S.S.R.), 1976,46,547. 46 K. Akiba, T. Yoneyama, H. Hamada, and N. Inamoto, Bull. Chem. Soc. Japan, 1976,49,1970. 47 E. T. Gainullina and M. K. Baranaev, Zhur. 8.z. Khim, 1976, 50, 1951. 48 A. I. Razumov, S. V. Yalymova, and Yu. Yu. Samitov, Chem. Abs., 1975, 83, 96 170. 49 L. L. Szafraniec, Org. Mugn. Resonance, 1974, 6, 565. 50 M. Mikolajczyk, J. Krzywanski, and B. Ziemnicka, J. Org. Chem., 1977,42,190; R. D. Adam-

5 1 D. Bouchu and J. Dreux, Tetrahedron Letters, 1976, 3151. 52 F. M. Kharrasova and V. D. Efimova, J. Gen. Chem. (U.S.S.R.), 1976,46,2150. 63 J. P. Majoral, R. Kraemer, J. Navech, and F. Mathis, Tetrahedron Letters, 1975, 1481. 54 N. I. Zemlyanskii, L. M. Dzikovskaya, V. V. Turkevich, and A. P. Vas'kiv, J . Gen. Chem.

cik, L. L. Chang, and D. B. Denney, J.C.S. Chenz. Comm., 1974, 986.

(U.S.S.R.), 1976, 46, 1447.

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242 Organophosphorus Chemistry

QP of Pv Compounds. The chemical shifts of pentaco-ordinated phosphoranes, in general, vary remarkably little with variation of the atoms (if they are members of the first two Periods) which are bound to phosphorus.S6~ It was therefore of par- ticular interest to find that the tricyclic phosphorane (26) has QP 31.6, far downfield of the usual region for P V compounds, and in the region for salts and It appears, therefore, that steric effects may have to be taken into account even when quite small structural changes are made. The presence of one five-membered ring

O+X X OAr

d / \ Et 0

( 2 6 ) X = CF, (27) (28)

does not usually cause excessive shifts, yet it is claimed that the hydroxyphosphor- anes (27) are responsible for resonances at 6p 58-75, which is very close to those of the phospholen oxides (28).68 The chemical shifts of the oxyphosphoranes (29) are relatively insensitive to changes in electron-donor power of the aryl substituents. Thus, changing Y from halogen to methyl shifts 8p downfield by 1.4 p.p.m.66 A

Ph \

(2% (30)

transitory signal at dr -59.5 that was observed during the reaction of a phospho- nium ylide with a phosphite-ozone adduct was attributed to the Wittig-intermediate

66 G. G. Furin, T. V. Terent'eva, A. I. Rezvukhin, and G. G. Yakobson, J. Gen. Chem. (U.S.S.R.), 1975, 45, 1441; R. Appel and I. Ruppert, Chem. Ber., 1975, 108, 919; M. Fild, W. S. Sheldrick, and T. Stankiewicz, 2. anorg. Chem., 1975, 415, 43; J. V. Weiss and R. Schmutzler, J.C.S. Chem. Comm., 1976, 16, 643; H. B. Stegmann, H. V. Dumm, and K. B. Ulmsschneider, Tetrahedron Letters, 1976, 2007; M. F. Chasle-Pommeret, A. Foucaud, M. Leduc, and M. Hassairi, Tetrahedron, 1975, 31, 2775; T. Kh. Gazizov, Yu. I. Sudarev, and E. I. Gol'dfarb, J. Gen. Chem. (U.S.S.R.), 1976,46, 920; F. Ramirez, M. Nowakowski, and J. F. Marecek, J. Amer. Chem. SOC., 1976, 98, 4330; A. Skowronska, J. Mikolajczak, and J. Michalski, J.C.S. Chem. Comm., 1975,986; I. L. Knunyants, U. Utebaev, and E. M. Rokhlin, Bull. Acad. Sci U.S.S.R., 1976, 25, 853; M. Wilson, R. Burgada, and F. Mathis, Compt. rend., 1975, 280, C, 225; W. Stec, B. Uznanski, D. Houalla, and R. Wolf, ibid., 1975, 281, C, 727; W. Zeiss, Angew. Chem. Internat. Edn., 1976, 15, 555.

56 V. V. Vasil'ev, V. B. Lebedev, and N. A. Razumova, J. Gen. Chem. (U.S.S.R.), 1976,46,1690. 57 H. A. E. Aly, J. H. Barlow, D. R. Russell, D. J. H. Smith, M. Swindles, and S. Trippett,

58 N. A. Kurshakova, N. A. Razurnova, and A. A. Petrov, J. Gen. Chem. (U.S.S.R.), 1976,46, J.C.S. Chem. Comm., 1976,449.

1693; N. A. Kurshakova and N. A. Razumova, ibid., p. 1023.

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Physical Methods 243

oxaphosphetan (30).69 The chemical shifts of the related four-, five-, and six-co- ordinated species (3 1)-(33) showed regular upfield shifts.6o

+ Me,PF, Me,PF, Me, FF,

(31) (32) (33)

Carbon-13. The a-carbon resonance of phosphabenzene (34) appears at low field, possibly due to the diamagnetic anisotropy of the phosphorus atom.60 The stereo- chemistry of the cyclohexylphosphine (35) was confidently assigned from its C-13

Ph

(34) (35) ( 3 6 )

chemical shifts in combination with its proton spectra.61 Quite pronounced differ- ences in 6c are observed for the cis- and trans-isomers of heterocycles such as (36). As found for Q P , ~ ~ discussed above, the trends may be opposite in direction for five- and six-membered rings.62 The trend may also be reversed if there is a change in the axial or equatorial orientation of the substituents.28 The shielding effects of phos- phorus groups on the a-carbons of alkyl chains are quite large (15-30p.p.m.), although @-effects are quite small (0-3 p.p.m.).29$ 63 The y-effects are also small (0.2-1.6 p.p.m.) along an aliphatic chain, e.g. (37),29 but they are larger for diphos- phine di~ulphides.~~ The deshielding @-effect by the PH2 group in the cyclohexyl compound (38; Y=H) is the largest (8.3 p.p.m.) of any phosphorus group so far

(37) (38) (3 9)

examined, although its a-effect is negligible.64 Carbon-13 n.m.r. spectroscopy has been applied by a number of workers to the study of phosphonium ylides (39). The values of the chemical shift of the ylidic carbon atom (3.2-78 p.p.m.) are in the same region, but with a wider range than those of the corresponding s a l t ~ . ~ ~ - ~ ' However, for P-aryl compounds, the aryl C-1 atom is deshielded by 14 f 2 p.p.m. in the ylides compared to the salts.66 The 13C n.m.r. spectra of the allylidenephosphor- ane (40) and its methyl derivatives have been recorded. Within the complex of peaks

59 H. J. Bestmann and L. Kisielowski, Angew. Chem. Internat. Edn., 1976, 15, 298. 60 M. Brownstein and R. Schmutzler, J.C.S. Chem. Comm., 1975, 278; A. J. Ashe, R. R. Sharp,

61 A. M. Aguiar, C. J. Morrow, J. D. Morrison, R. E. Burnett, W. F. Masler, and N. C. Bhacca,

62 J. Martin and J. B. Robert, Org. Magn. Resonance, 1975, 7 , 76. 63 R. B. King and J. C. Cloyd, jun., J.C.S. Perkin 11, 1975, 938. 64 M. D. Gordon and L. D. Quin, J. Org. Chem., 1976,41, 1690. 6s T. A. Albright. M. D. Gordon, W. J. Freeman, and E. E. Schweizer, J. Amer. Chem. Soc.,

and J. W. Tolan, J . Amer Chem. SOC., 1976,98, 5451.

J. Org. Chem., 1976, 41, 1545.

1976,98, 6%9: 66 M. Seno, S. Tsuchiya, H. Kise, and T. Asahara, Bull. Chem. SOC. Japan, 1975,48,2001. 67 K . A. Ostoja Starzewski, and H. Tom Dieck, Phosphorus, 1976, 6, 177.

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244 0 rganop hosp horus Chemistry

associated with the spz-hybridized carbons, the a-signal is at highest field, followed by the y-signal and the almost normal /?-signal. The shifts correlate with the CNDO computed partial charges on carbon, with a slope of 240 p.p.m. per unit charge.gs Thus it appears that the charge on carbon and the related l / r 3 dependence on the paramagnetic term (i.e. the radius of the p,-orbital) are responsible for the shifts. It is interesting to note that ~JCH for the ylidic carbon of several ylides varied little as

H /

the phenyl groups on phosphorus were replaced by methyl groups; 69 the 150 Hz coupling corresponds to sp2 hybridization. Further, the inclusion of d-sets in ab initiu calculations based on the ylide (41) had no dramatic effect on the carbonp- orbital, which is distorted far into the bonding region of the phosphorus atom.7o Thus the effect of the d-orbitals appears to be one of polarization rather than the formation of a n-bond.71 The shorter P-C bond is attributed to coulombic forces and to the deformation of the H.O.M.O. into the bonding region.70 The aryl sub- stituent effects on 6c-a of benzoyl-stabilized ylides (42) correlate with orn in the sense that electron-withdrawing substituents cause deshielding. The carbonyl carbon atoms correlate in the reverse manner, and the extent of the shift is twice that of the ylidic carbon and greater than in the corresponding acetophenone. 7 2 The deshielding of the axial methyl resonance in the phosphorinol sulphide (43) has been attributed to steric compre~sion,~~ whereas the deshielding of the p-carbon in the phospholen sul- phides (44) has been attributed to polarization of the n-electrons towards the phos-

Ch

(43) (44) (45 1

phorus atom. 74 Carbon-13 n.m.r. studies of methylene-bridged phosphonyl com- pounds 76 and aryl-substituted fluorophosphazenes 76 have also been reported.

Fluorine-19. Further work on the use of 6~ for estimating electronic effects has been reported. Both fluorophenylphosphines and their chalcogenides (45) gave positive

68 K. A. Ostoja Starzewski, H. Tom Dieck, and H. Bock, J. Amer. Chem. SOC., 1976,98, 8486. 139 K. A. Ostoja Starzewski and M. Feigel, J, Organometallic Chem., 1975, 93, C20. 7 O H. Lischka, J. Amer. Chem. SOC., 1977, 99, 353. 7 1 D. A. Bochvar, N. P. Gambaryan, and L. M. Epshtein, Uspekhi Khim., 1976, 45, 1316. 7 2 P. Froeyen and D. G. Morris, Acta Chem. Scand. (B) , 1976,30, 790. 7 3 L. D. Quiii, A. T. McPhail, S. 0. Lee, and K. D. Onan, Tetrahedron Letters, 1974, 3473. 74 C. Symes, jun., and L. D. Quin, J. Org. Chem., 1976, 41, 1548. 75 W. Althoff, M. Fild, and H. P. Rieck, 2. Naturforsch., 1976, 31b, 153. 76 C. W. Allen, J. Organometallic Chem., 1977, 125, 215.

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Physical Methods 245

01 values for the phosphorus groups. The phosphoryl groups had mesomeric accept- ing properties which increased in the order PSe < PS < PO.77 The resonance and inductive interactions of the phosphinimino-group have been similarly investigated. 78

Oxygen-I7 and Nitrogen-15. The pulsed Fourier-transform n.m.r. technique is pro- viding a probe into the changes of environment of oxygen and nitrogen nuclei. For phosphoryl and PN compounds in particular, the data promise to provide informa- tion which will help clarify the information obtained from other nuclei.79

Hydrogen-I. Proton chemical shifts and kinetic evidence indicate that there is a P. - -0 interaction in ortho-anisyl-phosphines (46).80 The downfield shift of NH or OH resonances when they are hydrogen-bonded is frequently used to identify isomers such as (47).81 However, when hydrogen-bonding is present in both isomers,

Me

(46) (47) (48)

and the magnetic anisotropies of the basic sites differ, the most strongly hydrogen- bonded isomer does not always give a proton signal at lowest field; thus although the trans-enol (48) has OH 14.6, compared to 13.3 for the cis-enol, the latter pre- dominates in most

Equilibria and Shift Reagents.-Tautomeric mixtures have been observed in phos- phorus n.m.r. spectra. The thiophosphonite (49) contains 40 % of the phosphite tautomer (50),83 and a sample of the anhydride (51) contains the phosphoryl com-

pound (52).84 It has also been shown that the j3-formyl salt (53), in chloroform solu- tion, contains both cis- and trans-enol t a u t o m e r ~ , ~ ~ and that the dihydrazides (54)

77 R. F. De Ketelaere and G. P. van der Kelen, J. Mol. Structure, 1975, 27, 33. 78 S. Yolles and J. H. R. Woodland, J. Organometallic Chem., 1975, 93, 297. 79 G. A. Gray and T. A. Albright, J. Amer. Chem. SOC., 1976, 98, 3857; G. Grossmann, M.

80 W. E. McEwan, J. E. Fountaine, D. N. Schulz, and W. I. Shiau, J. Org. Chem., 1976,41, 1684. 81 G. Baccolini and P. E. Todesco, Tetrahedron Letters, 1976, 1891 ; J. Y . Merour, T. T. Nguyen,

82 A. N. Pudovik and R. D. Gareev, J. Gen. Chem. (U.S.S.R.), 1976, 46, 456. 83 E, E. Nifant’ev, A. I. Zavalisbina, and S. F. Sorokina, J. Gen. Chem. (U.S.S.R.), 1976,46,469. 84 V. L. Foss, Yu. A. Veits, N. V. Lukashev, and I. F. Lutsenko, J . Organometallic Chem.,

85 N. A. Nesmeyanov, S. T. Berman, and 0. A. Reutov, Bull. Acac!. Sci. U.S .S .R. , 1976, 25, 223.

Gruner, and G. Seifert, 2. Chem., 1976, 16, 362.

and P. Chabrier, Compt. rend., 1975, 280, C , 473.

1976,121, C27.

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246 Organophosphorus Chemistry

are extensively in the iminol form.8s The change of 8~ upon addition of sulphuric acid to phosphoryl and thiophosphoryl compounds gave titration curves which showed a good correlation of basicity constant with substituent constants if the

0 Me ll I

P I ~ , ~ H , C H O x- RP(CH,CONHNHJ, (RO),P=O,H,O Y,P

(5 3) (54) (55 ) S--H . * * S

(56)

compounds were considered in two groups; (a) oxides and thiolic compounds, and (6) compounds possessing POR and POH groups.87 Equilibria involving hydrates (55) 88 and dimers (56) 89 have been followed, using 8H20 and BSH, respectively.

A study of the shifts produced by europium and praseodymium reagents on a series of ethoxy and ethyl phosphinous and phosphoryl compounds showed that the phosphorus shifts of the phosphines and phosphoryl compounds differed from the proton and carbon shifts in that they were dominated by contact interactions. Large pseudocontact phosphorus shifts for triethyl phosphite indicate that there is little direct P - .La interaction.OO Shift reagents have been used in the stereochemical assignments of some bicyclic oxides such as (57) O1 and the conformational analysis of dioxaphosphorinans (58) O 2 and dithiaphosphorinans (59). ss The conformational

equilibria of the former were sometimes altered by the presence of the lanthanide. Shift reagents have been used to detect diastereotopic groups in a-aminophosphonic esters 94 and to assist studies of phosphatidyl~holines.~~

Pseudorotation.-Ab initio calculations on the hypothetical phosphorane (60) indi- cated that the relative tendency of ligand Y to occupy an apical site is OR> R> 0-,

86 A. I. Razumov, T. V. Zykova, R. L. Yafarova, R. K. Ismagilov, and N. A. Zhikhareva, J.

8 7 N. K. Skvortsov, G. F. Tereshchenko, B. I. Ionin, and A. A. Petrov, J. Gen. Chem. (U.S.S.R.),

8 8 G. P. Savoskina and E. N. Sventitskii, Zhur. strukt. Khim., 1975, 16, 306. 89 V. K. Pogorelyi, I. I. Kukhtenko, and T. F. Divnich, Teor. i eksp. Khim., 1975, 11, 242.

T. A. Gerken and W. M. Ritchey, J. Magn. Resonance, 1976,24, 155. 91 Y. Kashman and 0. Awerbouch, Tetrahedron, 1975, 31, 45, 53; 0. Awerbouch and Y .

Kashman, ibid., p. 33. 92 P. Finocchiaro, A. Recca, and W. G. Bentrude, Chimicae Industria, 1976,58,45 1 ; P. Finocchiaro,

A. Recca, W. G. Bentrude, H. W. Tan, and K. C. Yee, J. Amer. Chem. SOC., 1976,98,3537; L. L. Chang and D. B. Denney, J. Org. Chem., 1977,42,782; A. J. Dale, Acta Chem. Scand. (R) , 1976,30,255.

93 B. E. Maryanoff and R. 0. Hutchins, J. Org. Chem., 1977, 42, 1022. 94 V. A. Bidzilya, N. K. Davidenko, and L. P. Golovkova, Ukrain. khim. Zhu. , 1976,42, 1150. 95 B. Dekrui-iff, P. R. Cullis, and G. K. Radda, Biuchim. Biuphys. Acta, 1975, 406, 6 ; K. K.

Gen. Chem. (U.S.S.R.), 1976, 46, 1687.

1976, 46, 518.

Yabusaki and M. A. Wells. Biochemistry, 1975, 14, 162.

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Physical Methods 247

and that the phosphoryl oxygen’s apical preference is not altered by the presence of bulky substi tuent~.~~ Experimental measurements on the phosphoranes (61) showed

Z c:, ’ 1 /OMe

“-pH I \OAr I OMe H OAr OMe

H OAr I ,OAr

Me-P I

(6 0) (61) (6 2)

that intense steric crowding, as in (61 ; Ar = 2,6-dimethylphenyl), slows ligand re- organization. 97 Variable-temperature n.m.r. spectra of some trimethoxyphosphor- anes (62) exhibit some remarkable differences of Tc. g8 Pseudorotation barriers of some bicyclic oxyphosphoranes 99 and caged polycyclic phosphoranes, e.g. (63),loo have been reported. In the caged compounds, the presence of one or more five- membered rings inhibited pseudorotation. Pseudorotation of a number of di- and

F3cMcF3 s s

B ‘P’

F

tri-fluorophosphoranes has also been investigated.l0lP lo2 When an amino-substituent was present, as in (64), 13C n.m.r. showed that P-N bond rotation was not an important factor.lo2 Restricted Rotation.-The PN compounds (65), in which the phosphorus atom bears electronegative substituents (X= ha1 or CF,) and the nitrogen atom bulky groups (Y = But or SiMe,), exhibit rotational hindrance about the P-N bond at room tem- perature.lo3 Four-co-ordinate compounds (66) and (67) exhibit lower barrier~.~*41 lo5

The possibility that n-u* directional z-bonding also contributes to restricted rota- tion has been discussed.lo4 Cyclophosphamide has been studied,lo6 and evidence for

96 C. A. Deakyne and L. C. Allen, J. Amer. Chem. Sac., 1976,98,4076. 97 I. Szele, S. J. Kubisen, jun., and F. H. Westheimer, J. Amer. Chem. SOC., 1976, 98, 3533. 98 B. A. Arbuzov, A. A. Musina, A. V. Aganov, R. M. Aminova, N. A. Polezhaeva, and Yu. Yu.

99 G. Buono and J. R. Llinas, Tetrahedron Letters, 1976, 749; R. Boigegrain and B. Castro,

100 B. S. Campbell, N. J. De’ath, D. B. Denney, D. Z. Denney, I. S. Kipnis, and T. B. Min,

101 J. A. Gibson, G. V. Roeschenthaler, and R. Schmutzler, J.C.S. Dalton, 1975,918; J. G. Riess

102 J. A. Gibson and G. V. Roeschenthaler, J.C.S. Dalton, 1976, 1440. 103 0. J. Scherer and N. Kuhn, Chem. Ber., 1975, 108, 2478; R. H. Neilson, R. C.-Y. Lee, and

104 J. Burdon, J. C. Hotchkiss, and W. B. Jennings, J.C.S. Perkin IZ, 1976, 1052. 105 J. Martin and J. B. Robert, Tetrahedron Letters, 1976, 2475. 106 W. Egan and G. Zon, Tetrahedron Letters, 1976, 813.

Samitov, Doklady Akud. Nauk S.S.S.R., 1976,228, 865.

Tetrahedron, 1976, 32, 1283; D. Bernard and R. Burgada, ibid., 1975,31, 797.

J. Amer. Chem. SOC., 1976,90, 2924.

and D. U. Robert, Bull. SOC. chim. France, 1975, 425.

A. H. Cowley, J, Amer. Chem. SOC., 1975,97, 5302.

9*

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248 Organophosphorus Chemistry

restricted rotation about the P-0 bond in steroidal phosphorofluoridates (68) has been presented.lo

Non-equivalence, Configuration, and Medium Effects.-Extensive studies of the n.m.r. spectra of epimers in solution have been published by the Moscow chemists. Follow- ing observations on compounds such as the valine derivative (69), that the signals

0 \\ s COVat

/ Me-P’ \I EtO

obtained from a mixture of enantiomers are at different positions from those of separate enantiomers at the same concentration,loB the role of hydrogen-bonding and the interaction of the two chiral centres was recognized.loB More recently, the concept of Statistically Controlled Associate Diastereomerism has been developed to explain the phenomenon.11o The effect can be observed in compounds containing only one asymmetric centre if strongly hydrogen-bonded associates are present; thus the lH n.m.r. spectrum of the optically active but optically impure amides (70; Y=Ph, CGH4NO2, or H) shows distinct signals for the P-methyl groups in the (A)-

OY 0-

(70) (71)

and (9-enantiomers even without the addition of any optically active substanCes.111 The 31P spectra of trisubstituted pyrophosphates (71) appear as two AB spin systems

107 G. H. Cooper and R. A. Chittenden, Org. Magn. Resonance, 1974, 6, 563. 108 M. I. Kabachnik, T. A. Mastryukova, E. I. Fedin, A. E. Shipov, M. S. Vaisberg, P. V.

Petrovskii, and L. L. Morozov, Bull. Acad. Sci. U.S.S.R., 1975, 24, 537, 1418; E. I. Fedin, L. L. Morozov, P. V. Petrovskii, M. S. Vaisberg, A. E. Shipov, T. A. Mastryukova, and M. I. Kabachnik, Doklady Akad. Nauk S.S.S.R., 1974,219, 1181.

109 M. I. Kabachnik, T. A. Mastryukova, E. I. Fedin, A. E. Fedin, A. E. Shipov, M. S. Vaisberg, P. V. Petrovskii, and L. L. Morozov, Bull. Acad. Sci. U.S.S.R., 1975, 24, 537.

110 M. I. Kabachnik, E. I. Fedin, L. L. Morozov, M. S. Vaisberg, P. V. Petrovskii, A. E. Shipov, and T. A. Mastryukova, Bull. Acad. Sci. U.S.S.R., 1976, 25, 58; M. I. Kabachnik, T. A. Mastryukova, E. I. Fedin, M. S. Vaisberg, L. L. Morozov, P. V. Petrovskii, and A. E. Shipov, Tetrahedron, 1976,32, 1719.

111 M. J. P. Harger, J.C.S. Chem. Comm., 1976, 555.

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Physical Methods 249

when one of the groups bound to phosphorus is optically active.l12 The apical fluorine atoms in fluorophosphoranes (72) can become non-equivalent not only by restricted rotation about a P-NHR bond113 but also by the presence of a chiral

( 7 3 (73)

group, as in (73).11* The effects can be combined, to give four apical fluorine reso- nances.l16 The diastereomers of the oxyphosphorane (74) 116 and of the diphospho- nate (75)117 were observed directly in their 31P n.m.r. spectra. They were unequally

0 0 /I I I

Me-P- As-P-Me I l l

M e 0 Ph OMe

populated for the oxyphosphorane. The chiral structure of the tris-chelate complex (76) was reflected in the presence of two sharp methyl doublets in its lH n.m.r. spect r um. l1

\ /Ph

/p-p\

Ph

H H

A chiral solvent, (+)- or (-)-1-phenylethanolamine, was used in order to distin- guish the dl- and meso-forms of the diphosphine (77). The high-field signal was split into two resonances, showing it to be due to the dZ-form.llS The non-equivalence of the methoxy protons in chlorophos in various solvents and at different temperatures

112 V. F. Zarytova, D. G. Knorre, A. V. Lebedev, A. S. Levina, and A. I. Rezvakhin, Izuest.

113 A. V. Fokin, G. I. Drozd, and M. A. Landau, Zhur. strukt. Khim., 1976, 17, 385. 114 D. U. Robert, D. J. Costa, and J. G. Rims, J.C.S. Chem. Comm., 1975, 29; Org. Magn.

115 M. Sanchez and A. H. Cowley, J.C.S. Chem. Comm., 1976, 690. 116 J. I. G. Cadogan, R. S. Strathdee, and N. J. Tweddle, J.C.S. Chem. Comm., 1976, 891. 117 K. M. Abraham and J. R. van Wazer, J. Organometallic Chem., 1976, 113, 265, 118 D. Hellwinkel and W. Krapp, Phosphorus, 1976, 6, 91. 119 J. P. Albrand and J. B, Robert, J.C.S. Chem. Comm., 1976, 876.

sibirsk. Otdel. Akad. Nauk S.S.S.R., Ser. khim. Nauk, 1975, 139.

Resonance, 1975,7, 291.

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250 Organophosphorus Chemistry

has been studied.lZO However, the appearance of extra methylene resonances for hydroxymethyl compounds in carboxylic acid solvents such as TFAA was due to ester formation.121

Phosphorus-3 1 chemical shift anisotropies for trimethylphosphine, its oxide, and its sulphide were & 6, + 210, and + 127 p.p.m., respectively. n-Bonding will provide a cylindrical mobile electron cloud which can circulate freely when the C,, symmetry axis is parallel to the magnetic field, but which is hindered when it is perpendicular. Thus olI- oI should be positive, as is observed for the oxide and sulphide, and the smaller value for the sulphide compared to the oxide could reflect reduced n- bonding.

Spin-Spin Coupling.-Relationships have been derived between the PC bond length of vinylphosphorus compounds and J(HC=CH)c$s or trans.123

JPP and JPM. The larger negative value of ~JPP (-214 Hz) for the df-diphosphine (78) compared to the meso-form (79) (- 135.2 Hz), although differences in chemical shift are small, has been attributed to the preferential population of the conformers shown in (78) and (79),124 and, as previously to J becoming more

(78) (79)

negative as the lone-pairs are eclipsed. The PIII-PIII coupling constants are usually temperature-sensitive. This is especially noticeable for the very high vicinal coupling constant (80 Hz at 30 "C and 167 Hz at - 50 "C) for a quasi-cyclic tetraphosphine.lZ6 There have been further examples of configurational assignments, e.g. for the dioxa- phosphorinan (80), which are based on the magnitude of lJpse.12' The PSe couplings (ca. 230 Hz) for a number of selenophosphites (81) have also been recorded.lZ8 The extremely wide range of the values of PNP coupling constants (- 35 to + 446 Hz)

120 K. V. Nikonorov, E. A. Gurylev, T. A. Zyablikova, and I. D. Temyachev, Bull. Acad. Sci.

121 J. C. Tebby, Phosphorus, 1976, 6, 253. 122 J. D. Kennedy and W. McFarlane, J.C.S. Chem. Comm., 1976, 666. 123 S. V. Yalymova, Yu. Yu. Samitov, and A. Sh. Agishev, Zhur. strukt. Khim., 1975, 16, 991. 124 J. P. Albrand, J. B. Robert, and H. Goldwhite, Tetrahedron Letters, 1976, 949. 1 2 5 'Organophosphorus Chemistry', ed. S. Trippett (Specialist Periodical Reports), The Chemical

Society, London; (a) Vol. 8, Ch. 12; (b) Vol. 7, Ch. 12. 126 M. Baudler and D. Koch, Z. anorg. Chem., 1976,425,227. 127 A. Okruszek and W. J. Stec, Z . Naturforsch., 1976, 31b, 354; W. J. Stec, R. Kinas, and A.

Iz8 L. Maier, Helu. Clrim. Acta, 1976, 59, 252.

U.S.S.R., 1976, 25, 1341.

Okruszek, ibid, p. 393.

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Physical Methods 25 1

for diphosphinoamines has been attributed to changes of conformation; the geo- metry (82) is believed to produce large positive values.12e When one or more of the phosphorus atoms is tetraco-ordinated, the PNP coupling constant is usually less than 85 H d 3 * The phosphinimine (83) is an exception, and has J p ~ p 110 Hz.131 The trends for cyclic P-N-P compounds have also been discussed.132

JPF, JPO, and JPN. The apical trifluoromethyl groups of fluorophosphoranes exhibit relatively small 2 J p ~ ~ values (34-88 Hz) compared to equatorial groups (108-134 H z ) . ~ ~ ~ Several P-15N coupling constants have been determined, and found to change in sign upon co-ordinati~n.~~, 134 Some PJ4N and P--170 couplings 7 9 y 136 have also been recorded.

JPC. The direct P-C coupling constant to the methylene carbon of the phosphiran (84; n = 1) was much larger (- 39.7 Hz) than those (+ 0.6 to - 17 Hz) for the phos- phines (84; n = 3-6) with larger rings; note the rare positive sign for a PII1 com- pound. However, the direct P-C(pheny1) couplings were all in the region -12 to - 39 Hz. The corresponding salts all had ~JPC in the region 46-53 H Z . ~ ~ ~ The cis-

and trans-phosphines (85) and (86) also possess ~JPC values which, although smaller, show a greater stereodependence than those of the corresponding 0 ~ i d e s . l ~ ~ It has been found that ~JPC can be quite large, e.g. 169 Hz for diethyl phosphonates (87),13$ and even 220 Hz for dimethyl diazophosphonates (88).139 The effect of sub- stituting chlorine groups on phosphorus is usually to increase the coupling constants; however, ~JPC is only + 75 and + 104 Hz for the methylphosphonyl dichlorides (89;

0 0 Ch I1

(87) (88) (8 9)

MePC& I1

(M eO),PCN, II

(E tO),PCHY Z. R

129 R. J. Cross, T. H. Green, and R. Keat, J.C.S. Dulton, 1976, 1424. 130 W. Wolfsberger and W. Hager, Z . anorg. Chem., 1976, 425, 169; M. A. Pudovik and A. N.

Pudovik, J. Gen. Chem. (U.S.S.R.), 1976, 46, 219; N. P. Grechkin, 1. A. Nuretdinov, and L. K. Nikonorova, ibid., p. 1703.

131 W. Wolfsberger and W. Hager, J. Organometallic Cliem., 1976, 118, C65. 132 R. K. Harris and M. I. M. Wazeer, J.C.S. Dalton, 1976, 302; 0. J. Scherer and G. Schnabl,

2. Naturforsch., 1976, 31b, 1462; R. Keat, R. A, Shaw, and M. Woods, J.C.S. Dalton, 1976, 1582; M . Biddlestone, R. Keat, H. Rose, D. S. Rycroft, and R. A. Shaw, Z. Naturforsch., 1976, 31b, 1001 ; G . Bulloch and R. Keat, J.C.S. Dalton, 1976, 1 1 13.

133 K. I . The and R. G. Cavell, Znorg. Chem., 1976, 15, 2518. 134 D. E. J. Arnold and D. W. H. Rankin, J.C.S. Dalton, 1976, 1130. 135 W. J. Stec, A. Konopka, and B. Uznanski, J.C.S. Chem. Comm., 1974, 923. 136 G. A. Gray, S. E. Cremer, and K. L. Marsi, J. Amer. Chem. SOC., 1976, 98, 2109. 137 C. Symmes, jun., and L. D. Quin, Tetrahedron Letters, 1976, 1853; J. Org. Chem., 1976, 41,

138 N. Gakis, H. Heimgartner, and H. Schrnid, Helu. Chim. Acta, 1975, 58, 748; V. E. Bel'skii,

139 P. A. Bartlett and K. P. Long, J. Amer. Chem. SOC., 1977, 99, 1267.

238.

L. A. Kudryavtseva, and A. M. Kurguzova, Bull. Acad. Sci. U.S.S.R., 1975,24, 958.

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252 Organophosphorus Chemistry

Ch=S) and (89; Ch=0).l4O Coupling constants have also been reported for a variety of ylides and phosphonium derivatives.141 The spectra of some polycyclic phosphine sulphides showed that 2 J ~ ~ increases with an increase in ring Strong steric control of the vicinal coupling constants was observed for the cyclo- hexylphosphine (38 ; Y = H), 3.fPH being 9 Hz for the brans-isomer shown but only 2 Hz for the cis-isomer, in which the phosphino-group is axial.s4 The difference was even larger for the dithiaphosphorinan (go), Jpscc(av) being 23.5 Hz when R is equatorial and 0.5 Hz when R is a ~ i a 1 . l ~ ~ A further example is the different PNCC

(90) (91)

coupling constants involving the non-equivalent methyl groups in the phosphine (91).144 The variation of JPCCC according to the Karplus relationship has been used to determine the stereochemistry of the oxides (92)145 and (93).146

0 II

Ph,PCHRCHRCOR

(9 2)

Y

(93)

JPH. The n.m.r. parameters of protons directly bonded to phosphorus in 550 com- pounds have been classified according to ~JPH, the lowest being 122 Hz for F2PH and the highest 11 15 Hz for F4PH.14' The almost doubled magnitude (642 Hz) of ~JPH fother diprotonated diphosphine (94) compared to other protonated triarylphos-

140 V. 1. Zakharov, Yu. V. Belov, Yu. L. Kleiman, N. V. Morkovin, and B. I. lonin, J. Gen. Chem. (U.S.S.R.), 1976,46, 1391.

141 R. Appel, F. Knoll, and H. Veltmann, Angew. Chem. Internat. Edn., 1976, 15, 315; R. Appel and W. Morbach, ibid., 1977, 16, 180; H. Schmidbaur, J. Eberlein, and W. Richter, Chem. Ber., 1977, 110, 677; H. Schmidbaur, H. J. Fueller, and F. H. Koehler, J. Organometallic Chem., 1975, 99, 353; M. S. Hussain and H. Schmidbaur, 2. Naturforsch., 1976, 31b, 721.

142 Y. Kashman, I. Wagenstein, and A. Rudi, Tetrahedron, 1976, 32, 2427. 143 J. Martin, J. B. Robert, and C, Taieb, J. Phys. Chent., 1976, 80, 2417. 144 A. H. Cowley, M. Cushner, M. Fild, and J. A. Gibson, Znorg. Chem., 1975, 14, 1851. 145 C. A. Kingsbury and D. Thoennes, Tetrahedron Letters, 1976, 3037. 146 Y. Kashman and A. Rudi, Tetrahedron Letters, 1976, 2819. 147 J. F. Brazier, D. Houalla, M. Koenig. and R. Wolf, Topics Phosphorus Chem., 1976, 8, 99.

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Physical Methods 253

phines has been attributed to the increase in positive charge brought about by the second protonated On the other hand, JPH decreases for protonated phos- phites (95) as alkoxy-groups are replaced by thioalkyl groups.149

JPC,H. The spectra of the phosphinates (96) can be rationalized in terms of JPCH being the least negative when the proton is trans to the phosphoryl group,lK0 as predicted by M.O. LCAO calculations for phosphorus acids and 126 The coupling constants for a number of phosphorins lK2 and substituted vinyl com- poundslK3 have been recorded. The geminal coupling to the vinyl a-proton has not been used for stereochemical assignments ; in fact the vicinal coupling constants of

(97)

1,2-vinylene compounds (97 ; R = H), and hence their stereochemistries, have been estimated, using the assumption that JPCH remained in the range of values 20+4 H Z . ' ~ ~ Evidence for this assumption was obtained from the unsymmetrical com- pounds. However, the geminal coupling constant can vary more widely than this, e.g. 11 Hz for the cis-phosphonate (98) but 20.5 Hz for the 2,4dinitrophenylhydra- zide of its truns-i~omer.~~~ The PCH couplings for a number of P V phosphoranes were in the range 12-26

The stereochemical dependence of the vicinal P-H coupling constant across a double bond also applies to P V phosphoranes; the oxyphosphorane (99) has J(trans)

No Ha\ 0 C\O,Me ,COW

,c=c (HO),P \ /c-Hb

\ CH,-C 'H

0-P,

03 CO,H

(99) (1 00)

148 L. J. Van de Griend, J. G. Verkade, C. Jongsma, and F. Bickelhaupt, Phosphorus, 1976,6,13 1. 149 G. A. Olah and C. W. McFarland, J. Org. Chem., 1975,40,2582. 150 R. D. Gareev, Yu. Yu. Samitov, and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1976,46, 1881. 161 R. K. Safiullin, R. M. Aminova, and Yu. Yu. Samitov, Zhur. strukt. Khini., 1975, 16, 42. 152 A. Naaktgeboren, J. Meijer, P. Vermeer, and L. Brandsma, Rec. Trav. cliim., 1975, 94, 92;

153 G. Haegele, W. Kuchen, and H. Keck, 2. Naturforsch., 1976, 31b, 1326; D. Gloyna, K. G.

154 H. Christol, H. J. Cristau, and J. P. Joubert, Bull. SOC. chim. France, 1974, 2975; A. N.

155 A. J. Rudinskas and T. L. Hullar, J. Org. Chem., 1976, 41, 2411. 156 W. Althoff, M. Fild, H. Koop, and R. Schmutzler, J.C.S. Chem. Comm., 1975, 468; H.

Germa and R. Burgada, BuZl. SOC. chim. France, 1975, 2607; C. Laurenco and R. Burgada. Tetrahedron, 1976,32,2089; V. V. Vasil'ev, N. A. Razumova, and L. V. Dogadaeva, J. Gen. Chem. (U.S.S.R.), 1976, 46, 461; P. Savignac, B. Richard, Y. Leroux, and R. Burgada, J. Organometallic Chem., 1975, 93, 331; D. J. Scharf, J. Org. Chem., 1976, 41, 28; A. Schmid- peter and J. Luber, C k m . Ber., 1975, 108, 820.

M. S . Chattha, Chem. and Ind., 1976, 484.

Berndt, H. Koeppal, and H. G. Henning, J. prakt. Chem., 1976, 318, 327.

Pudovik and G. E. Vershinina, J. Gen. Chem. (U.S.S.R.), 1976, 46, 2385.

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254 Organophosphorus Chemistry

45.9 Hz and its cis-isomer has J(cis) 22 Hz.15' The stereochemistry of the acrylic derivative (100) was assigned from the vicinal 13C-H coupling constant, and the cis-coupling 4JPHa was larger than the trans-coupling 4JPHb.15s This trend, which is the same as that deduced earlier,169 has been used for stereochemical assignments; thus the isomeric dichlorides which possessed values of *JPCH3 of 2.9-8.3 Hz were assigned the (E) geometry (101), whilst those showing 4JPCH3 of 0-2.5 Hz were assigned the (2) geometry.lsO The PNNCH coupling constants of the phosphinimine (102) were assigned in the opposite manner because the authors worked on the basis

that Ha resonates to low field of Hb.lal In contrast, the four-bond couplings through saturated bonds are usually largest when the bonds possess a W configuration.la2

JPXCH and JPCXH. The vicinal couplings such as JPOCH continue to find use in the conformational analysis of The spectra of the oxathiaphospholans (103) showed that JPSCH varies with steric change to a greater magnitude than JPOCH.1a4 Values of cis- and trans-PCNH couplings of 3 and 19 Hz were observed

in the 14N spin-decoupled spectra of the thiaformamides (104) in chloroform solu- tion.la5 Long-range couplings ( 6 J ~ ~ 1.3-2.3 Hz) for iminothiazolines (105) have been described.ls6 Relaxation, C.I.D.N.P., and N.q.r. Studies.-The spin-lattice relaxation of diphos- phines and diphosphine sulphides occurs by competing dipolar and spin-rotation

157 R. Burgada, Compt. rend., 1976,282, C, 849. 15s R. M. Davidson and G. L. Kenyon, J. Org. Chem., 1977,42, 1030. 159 D. Danien and R. Carrie, Bull. Sac. chim. France, 1972, 1130. 160 V. V. Moskva, T. Sh. Sitdikova, A. I. Razumov, T. V. Zykova, and R. A. Salakhutdinov,

161 A. N. Pudovik and R. D. Gareev, J. Gen. Chem. (U.S.S. R.), 1976, 46, 946. 162 G. A. Dilbeck, D. L. Morris, and K. D. Berlin, J. Org. Chem., 1975, 40, 1150. 163 K. L. Marsi, J. Org. Chem., 1975,40, 1779; A. Hassner and J. E. Galle, ibid., 1976,41, 2273;

R. Arshinova, R. Kraemer, J. P. Majoral, and J. Navech, Org. Magn. Resonance, 1975, 7 , 309; E. N. Ofitserov, T. A. Zyablikova, E. S. Batyeva, and A. N. Pudovik, Bull. Acad. Sci. U.S.S.R., 1976, 25, 1325; A. C. Guimaraes and J. B. Robert, Tetrahedron Letters, 1976,473; M. Revel, J. Roussel, J. Navech, and F. Mathis, Org. Mugn. Resonance, 1976, 8, 399; C. Roca, R. Kraemer, J. P. Majoral, and J. Navech, ibid., 1976, 8, 407.

164 S. Nakayama, M. Yoshifuji, R. 0. Kazaki, and N. Inamoto, Bull. Chem. SOC. Japan, 1975, 48,3733.

165 0. Dahl and S. A. Laursen, Org. Magn. Resonance, 1976, 8, 1 . 166 C. K. Tseng and A. Mihailovski, Org. Magn. Resonance, 1974, 6, 494.

J. Gen. Chem. (U.S.S.R.), 1976, 46, 1938.

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Physical Methods 255

mechanisms, the relative importance depending on temperature and size of the sub- stituents on phosphorus.ls7 Some lH and 13C relaxation parameters and deuterium quadrupole splittings have been used to study phosphatidy1cholines.Iss Further C.I.D.N.P. studies of the oxidation of phosphites have been based on 31P n.m.r. spectra.ls9

N.q.r. spectroscopy, which is one of the most sensitive methods for investigating molecular dynamics in crystals, has been used to study the phosphinimines (106; Y = C3C15 or Poc&&) and chlorophosphoranes (1O7).l7O Structural studies by 36Cl

n.q.r. spectroscopy on the phosphazene (1O8)l7l and on chlorophosphorane-phos- phonium salt equilibria172 have also been reported.

2 Electron Spin Resonance Spectroscopy

The e.s.r. spectra of ts and n radicals and radical ions that had been reported up to 1974 have been reviewed.173 The similarity of a(P) of the PI1 amide radical (109) with values for other phosphino radicals indicated that they might have comparable

asi=(yJ N /

(TmaN),+ Me M e

(109) (110)

structures, with the odd electron in a 3p,-orbital and bond angles of 95-100 O.I7*

On the other hand, the phosphacyanine (110) had a very high a(P), 63.8 G, which

167 R. K. Harris and E. M. McVicker, J.C.S. Faradaj, ZI, 1976, 72, 12. 168 R. M. Riddle, T. J. Williams, T. A. Bryson, R. B. Dunlap, R. R. Fisher, and P. D. Ellis,

J. Amer. Chem. Soc., 1976,98,4286; A. A. Ribeiro and E. A. Dennis, Biochemistry, 1975,14, 3746; R. E. London, C. E. Hildebrand, E. S. Olson, and N. A. Matwiyoff, ibid., 1976, 15, 5480; B. Sears, W. C. Hutton, and T. E. Thompson, Biochem. Biophys. Res. Comm., 1974, 60, 1141; G. W. Stockton and I. C. P. Smith, Chem. and Phys. Lipids, 1976, 17, 251.

169 D. G. Pobedimskii, V. A. Kurbatov, E. P. Gol’dfarb, and A. L. Buchachenko, Bull. Acad. Sci. U.S.S.R., 1976,25,981; A. D. Pershin, D. G. Pobedimskii, V. A. Kurbatov, and A. L. Buchachenko, ibid., 1975,24, 506; D. G. Pobedimskii, A. D. Pershin, Sh. A. Nasybullin, and A. L. Buchachenko, ibid., 1976, 25, 68.

170 V. A. Mokeeva, I. A. Kyun’tsel, and G. B. Soifer, Zhur. strukr. Khim., 1976, 17, 366; V. A. Mokeeva, I. A. Kyun’tsel, and G. B. Soifer, Zhur. fir. Khim., 1975, 49, 1020; V .A. Mokeeva, I. V. Izmest’ev, I. A. Kyun’tsel, and G. B. Soifer, V. sb. Radiospektroskopiya, 1975, 52, 59, (Chem. Abs., 1977, 86, 24 144, 24 145).

171 P. P. Kornuta, L. I. Derii, A. I. Kalenskaya, and V. 1. Shevchenko, J. Gen. Chem. (U.S.S.R.), 1976,46, 1453.

172 K. B. Dillon, R. J. Lynch, R. N. Reeve, and T. C. Waddington, J.C.S. Dalton, 1976, 1243. 173 P. Schipper, E. H. J. M. Jansen, and H. M. Buck, Topics Phosphorus Chem., 1977, 9, 407. 1 7 4 M. J. S. Gyane, A. Hudson, M. F. Lappert, P. P. Power, and H. Goldwhite, J.C.S. Chem

Comm., 1976, 623.

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256 Organophosphorus Chemistry

may be due to twisting of the The spectra of radical ions (111)176 and (1 12)177 have been reported. Nucleotide phosphates have been studied by e.s.r. after either irradiation with X-rays,178 co-ordination with Mn2+,179 or spin labelling with

But

(1 11) (112) (113)

nitroxide.ls0 A number of other nitroxide spin-labelled compounds have also been studied.lE1 The thiyl radicals (113) gave no detectable e m . signals, possibly due to relaxation broadening, but their presence was established by trapping with nitro- methane aci-anion.la2 The fact that cyclization of unsaturated phosphoranyl radicals (114), for which a(P)= 860-900 G, to give the phosphetan (115) had occurred was

0-CH, 0-CH, RO,I ! RO,I 1

,Po CH-CH, ,P-CH-eH, X I X I

OR OR

(1 14) (115) established by showing that a(P) had decreased to 180-200 G.le3 y-Irradiation of cyclic phosphazenes gave radical ions in which the odd electron is confined to a single phosphorus atom possessing a t.b.p. configurat i~n.~~~ E.s.r. spectroscopy has shown that X-ray irradiation of methylenediphosphonic acid produces a wide range of ~adica1s.l~~ The wide difference in pseudorotational barriers between PV phosphor- anes and related phosphoranyl radicals has produced a burst of interest in variable- temperature e.s.r. spectra. Lineshape analysis of the spectra of the radical (116) showed equivalent methyl groups above -30 "C, whether R was ethyl, t-butyl, or t-penty1.lE6 The aminophosphoranyl radicals (1 17) have amino-groups which are

OR NMe, z (116) (117) (118)

175 H. Oehling, F. Baer, and K. Dimroth, Tetrahedron Letters, 1976, 1329. 176 D. Griller, K. Dimroth, T. M. Fyles, and K. U. Ingold, J . Amer. Chem. SOC., 1975,97, 5526. 177 A. G. Evans, J. C. Evans, and D. Sheppard, J.C.S. Perkin ZZ, 1976, 1 166. 178 J. N. Herak, D. Krilov, and C. A. McDowell, J . Magn. Resonance, 1976, 23, 1. 179 J. M. Backer and I. A. Slepneva, Analyt. Biochem., 1977, 77, 413. 180 E. M. Gause and J. R. Rowlands, Spectroscopy Letters, 1976, 9, 237. 181 A. V. Il'yasov, Ya. A. Levin, A. Sh. Mukhtarov, and M. S. Skorobogatova, Bull. Acacl. Sci.

U.S.S.R., 1975, 24, 1545; A. Sh. Mukhtarov, A. V. Il'yasov, and Ya. A. Levin, Teor. i eksp. Khim., 1976, 12, 831; G. Sosnovsky and G. Karas, Phosphorus, 1976, 6, 123. G. Brunton, B. C. Gilbert, and R. J. Mawby, J.C.S. Perkin I I , 1976, 6 , 650.

183 A. G. Davies and M. J. Parrott, J.C.S. Perkin ZZ, 1976, 9, 1066. 184 S. P. Mishra and M. C. R. Symons, J.C.S. Dalton, 1976, 1622. 185 M. Geoffroy, L. Ginet, and E. A. Lucken, Mol. Phys., 1976, 31, 745. 186 J. W. Cooper and B. P. Roberts, J.C.S. Perkin II , 1976, 808.

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Physical Methods 257

characterized by high a(N) values (ca. 12.6 G) when they occupy apical sites, and which have similar apicophilicities to a lkoxy-gro~ps.~~~ On the other hand, the phosphate group appears to be more apicophilic than alkoxy-groups.ls8 It has also been found that five- and six-membered rings which incorporate two P-N bonds, e.g. (1 18), resemble dioxaphospholan rings in that they bridge apical-equatorial positions and that the barrier to pseudorotation is higher for endocyclic ligands than for acyclic ligands.lE7 Several ethoxyfluorophosphoranyl radicals (1 19) were found to undergo rapid pseudorotat i~n.~~~ Unrestricted Hartree-Fock calculations on fluorophosphoranyl radicals F4P - , FBHP -, and FzHzP - indicated large spin densi- ties solely for the 3p,-orbitals of apical fluorine atoms, and also indicated that barriers to pseudorotation are higher by > 13 kcal mol-l than in the corresponding phos- phoranes.lso Similar calculations were used to determine the factors which control the stereochemical change from t.b.p. to tetrahedral when oxygen functions are re-

€3. H

placed by phenyl groups,1Q1 and to show that d-orbitals must be included in order to calculate accurately the spin densities of n-ligand complexes of PIV compounds.1D2 Certain monohalogeno-radicals arealso believed to have a tetrahedral a on figuration.^^^ Changes in a(P) and a(N) of the tetrahedral nitrotetra-aryl radicals (120) have been attributed to a variation of conjugation.lg4 The PH radical (121) has a(H)= 182 G, which is very large and corresponds to a 1s spin density of O.36.lg5 The anion radicals produced by electrochemical reduction of p-nitrophenylphosphonic acid and its esters have been studied.lg6 The factors which control the hyperfine splitting con- stants of H2P-, FzP-, HIP., and F4P. have been estimated by the ab initio U.H.F. method.

3 Vibrational and Rotational Spectroscopy

Band Assignments and Structure Elucidation.-The conjugated A 2-phospholens can be distinguished from A3-phospholens by the low frequency (ca. 2225 cm-l) of their P-H stretching vibrations.198 The i.r. and Raman spectra of the chloride (122)

R. W. Dennis and B. P. Roberts, J.C.S. Perkin 11, 1975, 140. lE8 A. G. Davies, M. J. Parrott, B. P. Roberts, and A. Skowronska, J.C.S. Perkin ZI, 1976, 1154. 189 1. H. Elson, M. J . Parrott, and B. P. Roberts, J.C.S. Chem. Comm., 1975, 586. lQo J. M. Howell and J. F. Olsen, J. Amer. Chem. Soc., 1976, 98, 7119. Igl V. V. Pen’kovskii, Chem. Abs., 1976, 85, 192 037. 1g2 3. M. F. van Dijk, J . F. M. Pennings, and H. M. Buck, J. Amer. Chem. Soc., 1975,97, 4836. lg3 M. C. R. Symons, Chem. Phys. Letters, 1976,40, 226. l g 4 R. D. Rieke, C. K. White, and C. M. Milliren, J. Amer. Chem. Suc., 1976, 98, 6872. lg5 K. Nishikida and F. Williams, J. Amer. Chem. Soc., 1975, 97, 5462. Ig6 A. Sh. Mukhtarov, A. V. Il’yasov, Ya. A. Levin, A. A. Vafina, and S. S. Krokhina, Zhur.

197 A. Hudson and R. F. Treweek, Chem. Phys. Letters, 1976, 39, 248. 198 A. 0. Vizel, V. K. Krupnov, L. I. Zyryanova, and B. A. Arbuzov, J. Gen. Chem. (U.S.S.R.),

strukt. Khim., 1976, 17, 76.

1976,46, 1536.

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258 Organophosphorus Chemistry

indicate the presence of a non-centrosymmetric dimer in the crystalline state.lg9 Corrections have been made to the Raman low-frequency assignments of tris(tri-

0

(122) (123) (124)

fluoromethy1)phosphine. 2oo The final locations of le0 labels in the phosphorinan (123) and amidophosphate (124) were established by the shift by 30-40 cm-1 of the appropriate PO band to lower frequency.201,z0a The phosphoryl bands in the Raman spectra have been used as a mechanistic probe to follow the transfer of phos- phate from ATP in a model The vibrational spectra of dioxaphospholans (125) have been assigned.204 The site of methylation of the thioamide (126) was

(125) (126) (127)

followed by the change in Y(PS).~O~ The v(PN) band of the aminotriphenylphospho- nium azide (127) and its deuterium analogues appeared in the region 889-938 cm-l, and at 1153 [v(PNH)] and 1036 cm-l [v(PND)] for the corresponding iminophos- phoranes. 206

Stereochemistry.-The multiplicity of bands which arise from conformational effects have been analysed and correlated with those obtained by other spectroscopic tech- n i q u e ~ . ~ ~ ' Raman spectra and torsional barriers at 14 and 190 K have been reported for trimethylphosphine (128), its chalcogenides, and the deuterium analogues. 208

Rotational barriers have been calculated from the microwave and vibrational spectra of the difluoride (129).z09 Restricted rotation about the P-N bonds of aminophos-

0

Me,P MePF, R,PNMe, Me,CHPH, II

(128) (129) (130) (131)

199 J. R. Durig and J. E. Saunders, J. Mol. Structure, 1975, 27, 403. 200 C. J. Marsden and L. S. Bartell, Znorg. Chem., 1976, 15, 2713. 201 Zh. M. Ivanova, E. A. Suvalova, and I. E. Boldeskul, J. Gen. Chem. (U.S.S.R.), 1976,46,1647. 202 Yu. G. Gololobov, I. E. Boldeskul, and T. I. Sarana, J. Gen. Chem. (U.S.S.R.), 1976,46, 1248. 203 A. Lewis, N. Nelson, and E. Racker, Biochemistry, 1975, 14, 1532. 204 K. R. Shagidullin, I. Kh. Shakirov, A. Kh. Plyamovatyi, L. I. Gurarii, and E. T. Mukmenev,

205 J. Boedeker and P. Koeckritz, J. Organometallic Chem., 1976, 111, 65. 206 W. Buder and A. Schmidt, Spectrochim. Acta, 1976, 32A, 457. 207 J. Goubeau, Pure Appl. Chem., 1975,44, 393. 208 H. Rojhantalab, J. W. Nibler, and G. J. Wilkins, Spectrochim. A m , 1976, 32A, 519.

J. R. Durig, K. S. Kalasinsky, and V. F. Kalasinsky, J. Mol. Structure, 1976,34,9.

J. Gen. Chem. (U.S.S.R.), 1976, 46, 1017.

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Physical Methods 259

phines (1 30; R = Et or Ph) and their chalcogenides has also been studied.21o Analyses of the v(PH) region of isopropylphosphine (131) and its deuterium analogue showed the presence of both gauche and trans conformers in the fluid phases.211 Variable- temperature vibrational spectroscopy has also been used for the conformational analysis of various PI11 chlorides.212 The conformational equilibria of thio- and seleno-pho~phinates,~~~ methylpho~phonates,~~~~ phosphonamidate~,~~~ phos- phonth ioa te~ ,~~~ dioxaphosphorinans,216 and trialkyl phosphates 217 have also been tackled by vibrational spectroscopy.

Bonding.-The intramolecular interactions in di-para-substituted arylphosphines (132) were estimated from the intensities of the y s ring-stretching band near 1600 cm-l. The PH, and PR2 groups appear to be weak electron donors, whereas PAr,, PC&, and P(OEt), are electron acceptors. 218 Force constants have been calculated for dimethylsilylphosphine 219 and aminomethylphosphonic acid.220 There is still a keen interest in the study of hydrogen-bonding. Phosphoryl compounds are the most commonly studied,221 substituent effects and correlations with Taft constants being the main area of interest.222 Basicities of phosphazene~,~~~ the sites of protona-

0

2Lo A. N. Pudovik, 1. Ya. Kuramshin, N. R. Safiullina, A. A. Muratova, N. P. Morozova, and

211 J. R. Durig and A. W. Cox, jun., J. Phys. Chem., 1976, 80, 2493. 212 A. I. Fishman, A. B. Remisov, 1. Ya. Kuramshin, and I. S. Pominov, Spectruchim. Acfa,

1976, 32A, 651 ; D. F. Fazliev, R. R. Shagidullin, N. A. Chadaeva, N. A. Makarova, and E. T. Mukmenev, J. Gen. Chem. (U.S.S.R.), 1976, 46, 1776; R. R. Shagidullin, D. F. Fazliev, L. I. Gurarii, and E. T. Mukmenev, ibid., 1975, 45, 1235.

2 1 3 I . I. Vandyukova, R. R. Shagidullin, and I. A. Nuretdinov, Zzwst. Akad. Nauk. S.S.S.R., 1976, 1390.

214 P. M. Zavlin, L. A. Ashkinazi, B. I. Ionin, and Ya. L. Iganatovich, J. Gen. Chem. (U.S.S.R.), 1976, 46, 2503; L. A. Ashkinazi, P. M. Zavlin, V. hl. Shek, and B. I. Ionin, ibid., p. 1015.

a15 L. A. Ashkinazi, P. M. Zavlin, and B. I. Ionin, J. Gen. Chern. (U.S.S.R.), 1976, 46, 921. 216 E. I. Matrosov, A. A. Kryuchkov, and E. E. Nifant’ev. Bull. Acad. Sci. U.S.S.R., 1975, 24,

2473. 217 0. A. Kaevskii, A. N. Vereshchagin, Yu. A. Donskaya, A. G. Abul’khanov, and Ya. A. Levin,

Bull. Acad. Sci. U.S.S.R., 1976, 25, 1889. M. I . Kabachnik, I. G. Malakhov, E. N. Tsvetkov, K. F. Johnson, A. R. Katritzky, A. J. Sparrow, and R. D. Topsom, Austral. J. Chem., 1975, 28, 755.

E. G. Yarkova, J. Gen. Chem. (U.S.S.R.), 1976,46, 764.

219 R. Demuth, 2. anorg. Chem., 1976,424, 13. 220 C. Garrigou-Lagrange and C. Destrade, Compt. rend., 1975, 280, C, 969. z21 E. I. Matrosov and M. I. Kabachnik, Doklady Akad. Nauk. S.S.S.R., 1977, 232, 89; C .

Madic, J. C. Saey, and L. Mangane-Le Desert, J. Inorg. Nuclear Chem., 1975,37, 1599; N. M. Turkevich, D. D. Lutsevich, and A. F. Mynka, Izoest. V.U.Z. Khim. i khim. Tekhnol., 1976, 19, 396.

222 A. A. Shvets, E. G. Amarskii, 0. A. Osipov, and L. V. Goncharova, J. Gen. Chem. (U.S.S.R.), 1976, 46, 1654; R. R. Shagidullin, L. Kh. Ashrafullina, and V. E. Bel’skii, Bull. Acad. Sci. U.S.S.R., 1976, 25, 778; I . P. Lipatova, Z. Z. Kurzhunova, and F. M. Kharrasova, J. Gen. Chem. (U.S.S.R.), 1976, 46, 1251; V. E. Bel’skii, R. F. Bakeeva, L. A. Kudryavtseva, A. M. Kurguzova, and B. E. Ivanov, ibid., 1975,45, 2568.

223 V. Prons, N. B. Zaitsev, M. P. Grinblat, and A. L. Klebanskii, J. Gen. Chem. (U.S.S.R.), 1976,46, 434.

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260 Organophosphorus Chemistry

tion of triphenyl phosphite 224 and aminobenzylphosphonates,225 and the keto-enol equilibria of P-keto-phosphonates (133) 226 have also been studied. The difference in basicity between axial and equatorial phosphoryl groups, which controls the site of alkylation of cyclic has been investigated, using i.r. studies of hydro- gen-bonded associates of the dioxaphosphorinans (1 34). 228

4 Electronic Spectroscopy

Absorption.-It has been argued that U.V. evidence for p,, conjugation in arylphos- p h i n e ~ l ~ ~ ~ is invalid because the Kerr data show that the aryl rings do not have the required c ~ n f o r m a t i o n . ~ ~ ~ The U.V. absorption maxima of some cyclic arylphosphines (135; R=Me or Ph) and their oxides have been compared with their ionization potentials. 230 The spectra of o-anisylphosphines (1 36) contain extra solvent-indepen-

Me I

dent bands at 284 and 287.5 nni which are absent from those of the para-orientated isomers. The bands are part of the evidence for an intramolecular interaction between the oxygen atom and the phosphorus d - ~ r b i t a l s . ~ ~ ~ There have been several reports on the spectra of conjugated ylides and phosphinimines, 232 and some highly coloured compounds have been obtained. 233 Theoretical M.O. calculations have been used to predict absorption frequencies of merocyanins and phosphocyanins. 234 Intensely coloured compounds have also been produced by the diazotization of arylphosphine

The U.V. spectra of spirocyclic phosphonium salts have been compared with those of the corresponding nitrogen and arsenic

224 I. S. Akhmetzhanov, J. Gen. Chem. (U.S.S.R.), 1976, 46, 575. 225 G. Zuchi, G. Morait, and F. Chiraleu, Rev. Chim. (Rounzania), 1976, 27, 791. 226 A. 1. Razumov, V. V. Moskva, M. P. Sokolov, and Z. Ya. Sazonova, J. Gen. Chem. (U.S.S.R.),

227 A. P. Hong, J. B. Lee, and J. G. Verkade, J. Amer. Chem. SOC., 1976, 98, 6547. 228 E. I. Matrosov, E. E. Nifant’ev, A. A. Kryuchkov, and M. I. Kabachnik, Bull. Acad. Sci.

229 I. P. Romin and E. N. Gur’yanova, J. Gen. Chem. (U.S.S.R.), 1976, 46, 445. 230 A. N. Smirnov, L. A. Yagodina, V. M. Orlov, A. 1. Bokanov, and B. I. Stepanov, f. Gen.

Chem. (U.S.S.R.), 1976, 46, 435. 231 W. E. McEwen, W.-I. Shiau, Y.-I. Yeh, D. N. Schulz, R. U. Pagilagan, J. B. Levy, C. Symrnes,

G. 0. Nelson, and I. Granoth, J. Amer. Chem. SOC., 1975, 97, 1787. 232 R. D. Gareev and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1976,46, 1424; R. I. Yurchenko,

0. M. Voitsekhovskaya, I. N. Zhmurova, and V. G. Yurchenko, ibid., p. 251 ; I . N. Zhmurova, 0. M. Voitsekhovskaya, R. I. Yurchenko, and A. V. Kirsanov, ibid., p. 229.

23s I. V. Megera and M. I. Shevchuk, J. Gen. Chem. (U.S.S.R.), 1976, 46, 2135. 234 N. Mishra, L. N. Patnaik, and M. K. Rout, Indian J. Chem., 1976, 14A, 56, 334. 235 W. Kormachev, T. V. Vasil’eva, B. I. Bryantsev, and V. A. Kuktin, J . Gen. Chem. (U.S.S.R.),

1976, 46, 1244; K. A. Petrov, V. A. Chauzov, T. S. Erokhina, and L. P. Chernobrovkina, ibid., p. 491.

1976,46, 1936.

U.S.S.R., 1976, 25, 512.

236 D. Hellwinkel and H.-J. Wilfinger, Phosphorus, 1976, 6, 151.

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Physical Methods 261

Photoelectron.-New information on the binding energies of phosphorus has been The orbital sequence and angular dependence of the band intensities

for phospliabenzene (137)238 and the nature of the lone pair of electrons of 2- phosphanaphthalene (138) 239 have been studied. The p.e. spectra of phosphines and

(137) (138)

the effects of substituents have been reviewed. 240 The spectra of trifluoromethyl- phosphines 241 and of vinyl-, allyl, phenyl-, and benzyl-phosphines 242 indicate the presence of P-C n-hyperconjugation. The ionization potentials of aryldicyclohexyl- p h o s p h i n e ~ , ~ ~ ~ pyrrylphosphines (139), and their oxides 244 have been measured, and that of phosphole (140) has been ca lc~la ted .~~~7 246 It has been concluded that the

(139) (140)

p.e. data in phospholes can be interpreted in terms of an aromatic ring, and that the non-planarity is due to 0 The nature of the bonding in the phos- phorins (141),247 in a wide range of reactive and stabilized phosphonium ylides (142)y~ 6S, z48 and also in various chalcogenides 249 has been studied, and there has

Ph OHl 0 I

237

238

239

240

3 4 1

242

213 214

2 15

2.16

“47

2 18

249

I Y R,P==CHY 0-

(141) (142) (143) W. C . Lineberger, I.E.E.E. Truns. h‘urleur Sci., 1976, NS23, 934 (Chem. Abs., 1976, 84, 169 934). A. J . Ashe, F. Burger, M. Y. El-Sheik, E. Heilbronner, J. P. Maier, and J. F. Muller, Helo. Chiin. Acta, 1976, 59, 1944; M . H. Palmer, R. H. Findlay, W. Moyes, and A. J. Gaskell, J.C.S. Perkin ZZ, 1975, 841. W. Schaefer, A. Schweig, H. Vermeer, F. Bickelhaupt, and H. D. Graaf, J. Electron Spec- troscopy Reloted Phenomena, 1975, 6, 9 I . H. Bock, Pure Appl. Chem., 1975, 44, 343. S. Elbel, H. Tom Dieck, and R. Demuth, Z. Nolur/brsch., 1976, 31b, 1472. H. Schmidt, A. Schweig, F. Mathey, and G. Mueller, Tctralzcdron, 1975, 31, 1287. H. Goetz, F. Marschner, 14. Juds, and H. Pohle, Phospirorus, 1976, 6, 137. F. Marschner, H. Kessel, and H. Goetz, Phosphorus, 1976, 6, 135. W. Von Niessen, L. S. Cederbaum, and G. H. F. Diercksen, J. Anier. Chem. Soc., 1976, 98, 2056. N. D. Epiotis and W. Cherry, J. Anicr. Clrrni. Soc., 1976, 98, 4365. W. Schaefer, A. Schweig, K. Dimroth, and €4. Kanter, J . Amcr. Chenz. SOC., 1976, 98, 4410. K. 51. A. Ostoja Starzewski and W. Richter, Chem. Ber., 1976, 109, 473; A. J. Dale, Phos- phorus, 1976, 6 , 8 1. E. Fluck and D. Weber, Piire Appl. Cliem., 1975,44, 373; S . Elbel and H. tom Dieck, J.C.S. Drdton, 1976, 1762; W. B. Perry, T. F. Schaaf, and W. L. Jolly, J. Ampr. Chem. SOC., 1975,97, 4899; V. V. Zverev, F. 1. Vilesov, V. 1. Vovna, S. N. Lopatin, and Yu. P. Kitaev, Bid/. Acud. Sci. U.S.S.R., 1975, 24,961.

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262 Organophosphorus Chemistry

been a theoretical study of the electronic structures of phosphorinone (143) and its isomers. 250

5 Rotation

The optically active triarylphosphine ( l a ) , [a]436= - 6.36 0,251 and the phospholan (145), [o(]D= +22.53 0 ,252 have been prepared. Nucleoside phosphates have been studied by ~ . d . ~ ~ ~

de 9 Ph-P

lP*- Ph

(145)

Dco2H (144)

6 Diffraction

X-Ray.-A crystallographic study has shown that the phosphimine (146) has a NPN bond angle of 104.9 0 . 2 5 4 This remarkable feature indicates that the P-N bonds retain a large proportion of p-character, as in phosphines, with the lone-pair of

electrons being highins-character. It has been shown that steric hindrance in the phos- phine (147) increases the CPC bond angles to 107-111 O, compared to 103 O for triphenylphosphine. 2 5 5 The molecular structures of two tryptycene-type phosphines (148) and (149) 256 and of the phenoxaphosphine (150) 257 have been determined. The heterocyclic ring of the latter compound has a slightly boat-shaped conforma- tion. The PNC and PCC bond angles of ylides and iminophosphoranes have been rationalized in terms of non-bonding interactions. The deformation of the endocyclic bond angle a of the phenyl ring in (151) has been found to depend on the a-electron- withdrawing or -releasing properties of the group Y and on the extent of conjugation

250 E. V. Borisov and E;. A. Kornienko, Zhur. .fiz. Khim., 1976, 50, 1566. 251 R. Luckenbach, 2. Naturforsch., 1976, 31b, 1 1 35. 252 K. L. Marsi and H. Tuinstra, J . Org. Clzem., 1975, 40, 1843. 253 L. V. Karabashyan, A. M. Kritsyn, S. N. Mikhailov, and V. L. Florent'ev, Mol. Biol. (Mos-

cow). 1976, 10, 367; J. Lavayre, M. Ptak, and M. Leng, Biochem. Biophys. Res. Comm., 1975, 65, 1355; M. Boublik, D. Grunberger, and Y. Lapidot, ibid., 1975, 62, 883.

254 S. Pohl, Angew. Chem. Internat. Edn., 1976, 15, 687. 255 A. N. Sobolev, L. A. Chetkina, I. P. Romm, and E. N. Gur'yanova, Zhur. strukt. Khim.,

256 D. Schomburg and W. S. Sheldrick, Act0 Cryst, 1976, B32, 1021 ; 1975, B31,2427. 257 F. G. Mann, I. T. Millar, H. M. Powell, and D. J. Watkin, J.C.S. Perkin ZI, 1976, 1383.

1976, 17, 103.

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Physical Methods 263

ph\

of Y with the phenyl ring. The relationship oc=3.33~+ 111.4 has been derived.a58 The mean values of o! are 118.5 O for PII1 compounds, 119.8 O for phosphonium salts, and 119.4 O for phosphonium ylides, which gives electronegativity values k) of 2.5 for the salts and 2.4 for the y l i d e ~ . ~ ~ ~ Structures have been established of a mercuric complex of an ylide,260 of the thiolate betaine (152),2s1 of triphenylphosphine oxide,262 of the phosphocin (153),263 and of the oxides (154),264 (155), and (156).266 The phosphinamide (157) was found to possess a short P-N bond and a distorted c-- NO

s- (1 52) (153)

Me Me I /

258 G. Glidewell, J . fnorg. Nitclear Chem., 1976, 38, 669. 259 A. Domenicano, A. Vaciago, and C. A. Coulson, Acta Cryst., 1975, B31, 1630. 260 N. L. Holy, N. C. Baenziger, R . M. Flynn, and D. C. Swenson, J . Amer. C h ~ m . SOC., 1976,

261 G. Bombieri, E. Forsellini, U. Chiacchio, P. Fiandaca, G. Purrello, E. Foresti, and R. Graziani,

262 G. Ruban and V. Zabel, Cryst. Struct. Cumm., 1976, 5, 671. 263 W. Winter, Z. Naturfursch., 1976, 31b, 1 1 16. 264 W. J. Seifert, 0. Schaffer, and K. Dimroth, Angew. Chem. fnternat. Edn., 1976, 15, 238. 26s F. Allen, 0. Kennard, L. Nassimbeni, R . Shepherd, and S. Warren, J.C.S. Perkin ZI, 1974,

98,7823.

J.C.S. Perkin If, 1976, 1404.

1530.

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264 Organophosphorus Chemistry

trigonal arrangement of groups about the nitrogen atom. 266 The hydrogen-bonded dimeric structure (158) is forced to be out of plane by the t-butyl groups.267 Inter-

(157) (158) (159 )

molecular hydrogen-bonding causes phenylphosphonic acid to crystallize in puck- ered layers.268 Strain in the bicyclic phosphonate (159) produces some very short C-C bonds and a torsional angle around one double bond of 29°.2G9 The eight- membered ring of the phosphonate (160) assumes the crown symmetry

0

(160)

The crystal structures of glycylaminomethylphosphonic and of methane-, ethane-, and propane-diphosphonic have been determined. The unit cell of the last acid contains two molecules, with different conformations. The molecular structures of the constrained phosphite (161), the phosphate (162), and the thio- phosphate (163) have been The nitrogen in the last compound is very nearly trigonal planar, and the large P--N distance (313 pm) shows that there is little P. .N interaction. The phosphazene (164) adopts a novel conformation,274

0

266 Mazhar-U1-Haque and C. N. Caughlan, J.C.S. Perkin I f , 1976, 1101. 267 M. E. Druyan, A. H. Reis, jun., E. Gebert, S. W. Peterson, G. W. Mason, and D. F. Peppard,

268 T. J. R. Weakley, Acta Cryst., 1976, E32, 2889. 269 R. Hoge and G. Maas, Acta Cryst., 1976, B32, 3339. 270 A. E. Kalinin, V. G. Andrianov, and Yu. T. Struchkov, Z h r . strukt. Khim., 1975, 16, 1041. 271 M. Cotrait, M. Avignon, J. Prigent, and C. Garrigon-Lagrange, J. Mo!. Structure, 1976,

32, 45. 273 S. W. Peterson, E. Gebert, A. H. Reis, jun., M. E. Druyan, G. W. Mason, and D. F. Peppard,

J. Phys. Chem., 1977, 81, 466; E. Gebert, A. H. Reis, jun., M. E. Druyan, S. W. Peterson, G. W. Mason, and D. F. Peppard, ibid., p. 471.

273 J. C. Clardy, D. S. Milbrath, and J. G. Verkade, J. Amer. Chem. SOC., 1977, 99, 631; D. S. Milbrath, J. P. Springer, J. C. Clardy, and J. G. Verkade, ibid., 1976, 98, 4593.

274 Y. S. Babu, T. S. Cameron, S. S. Krishnamurphy, H. Manohar, and R. A. Shaw, Z. Natur- forsch., 1976, 31b, 999.

J. Ainer. Chem. Soc., 1976, 98, 4801.

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Physical Methods 265

c1

Ph,P O + -

(164) (165)

and each ring of the pyrophosphate (165) has a flattened chair conformation, with the phosphoryl oxygen occupying an equatorial position.275 On the other hand, the thione (166) has an open envelope conformation.276 The molecular structures of

(166)

the insecticides bromophos (167) 2 7 7 and azinphos-methyl (168),278 of the antitumour drug (169),279 and of a number of nucleotides 280 have also been reported.

OOH n Cl

Cl

(167) (168) (169)

The molecular electrostatic potential of dimethyl phosphate has been investi- gated by the ab initiu method.281 The stereochemistry of the polycyclic oxyphos- phoranes (170) 282 and (171) 283 has been established and the crystallographic data of cyclic enediol and acyl phosphoryl derivatives have been reviewed. 284

2 i 5

2 7 6

277

2 7 8

279

280

281 182

283

284

D. S. Cook and R. F. M. White, J.C.S. Dalton, 1976, 2212. M. W. Wieczorek and J. Karolak-Wojciechowska, Cryst. Struct. Comm., 1976, 5, 739. R. G. Baughman and R. A. Jacobson, J. Agric. Food Chem., 1976,24, 1036. W. J. Rohrbaugh, E. K. Meyers, and R. A. Jacobson, J. Agric. Food Chem., 1976, 24, 713. A. Camerman, H. W. Smith, and N. Camerman, Biochem. Biophys. Res. Comm., 1975, 65, 828. 9. M. Rosenberg, N. C . Seeman, R. 0. Day, and A. Rich, Biochem. Biophys. Res. Comm., 1976, 69, 979; S. B. Zimmerman, J. Mol. Biol., 1976, 106, 663; S. Neidle, W. KuehIbrandt, and A. Achari, Actu Cryst., 1976, B32, 1850; H. Sternglanz, E. Subramanian, J. C. Lacey, and C . E. Bugg, Biochemistry, 1976, 15, 4797; M. E. Druyan, M. Sparagana, and S . W. Peterson, J. Cyclic Nucleotide Res., 1976, 2, 373; D. W. Young, P. Tollin, and H. R. Wilson, Naturvz, 1974, 248, 513. H. Berthod and A. Pullman, Chem. Phys. Letters, 1975, 32, 233. T. Saegusa, S . Kobayashi, and Y . Kimura, J.C.S. Chem. Comm., 1976,443. A. Schmidpeter, D. Schomburg, W. S. Sheldrick, and J. El. Weinmaier, Angew. Chem. Internat. Edn., 1976, 15, 781. F. Ramirez and 1. Ugi, Phosphorus and Sulphur, 1976, 213, 231.

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266 Organophosphorus Chemistry

0 (1 70)

Electron.-Electron diffraction has shown that the acylphosphine (172) has larger bond angles than trimetliylphosphine. 285 Chloromethylphosphonyl dichloride (1 73 ;

\ / O 0 0 M e

I l (CH,=CH),PCl

I/ M e RPCl,

M e /p-c\

(172) (173) (174)

R= CH2Cl) adopts two conformations in the vapour phase,286 whereas the vinyl compounds (173; R=vinyl) and (174) have P-0 and C--C bonds close to cis- geometry in the principal conformers of both The spectra of the dichlorides (175) and (176) are in best agreement with [gauche] : [transoid] conformer

F

S

I I MeOPCL, MeSPCI, - F

(175) (176) (177)

ratios of 4: 1 288 and 3 : 7,289 respectively. The amino-groups of the difluorophos- phorane (177) have been estimated to have a torsional angle of 70.1 The effects of temperature, hydration, and surface pressure on the structure of phos- pholipid single bi-layers have also been studied. 291

7 Dipole Moments, Conductance, and Vultammetry

The dipole moment of the lone pair on phosphorus has been calculated to be 0.54 D, which is based on the effective charges in PH3 and PF3.292 This figure is nearly half that of an earlier estimate based on data for t h i o p h ~ s p h i t e . ~ ~ ~ ~ The partial moment of the lone pair is found to dominate the dipole moment of triarylphosphines (178).

285 L. S. Khaikin, L. G. Andrutskaya, and L. V. Vilkov, Vestnik. Moskov. Univ., Khim., 1976,

286 E. Vanja, M. Kolonits, I. Hargittai, and S. Szoke, J. Mol. Structure, 1976, 35, 235. 287 V. A. Naumov and S. A. Shaidulin, Zhur. strukt. Khim., 1976, 17, 304. 288 V. M. Bezzubov and V. A. Naumov, Zfiur. strukt. Khim., 1976,17, 98. 289 V. A. Naumov and V. M. Bezzubov, Doklady Akad. Nauk S.S.S.R., 1976, 228, 888. 290 H. Oberhammer and R. Schmutzler, J.C.S. Dalton, 1976, 1454. 291 S. W. Hui, M. Cowden, D. Papahadjopoulos, and D. F. Parsons, Biochim. Biophys. Acta,

1975, 382,265. 292 L. Maiis and G . N. Fainshtein. Latv. P.S.R. Zinat. Akad. Vrstis. Kim. Ser.. 1976. 364.

17, 123.

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Physical Methods 267

As the CPC bond angles increase from go", the negative contribution from the ligands slowly decreases, whilst the positive contribution from the lone pair rapidly increases, reaching a maximum at 101.5" that corresponds to sp hybridization of the lone pair.293 The calculated dipole moments for phosphabenzene (1.87 D on an sp basis and 0.99 D on an spd basis) are above and below the experimental value of

OAr I

(178) (179) (180)

1.5 D. The calculations confirm that the negative end of the dipole is towards phos- p h o r ~ ~ . ~ ~ ~ ~ 125a The calculated dipole moments of phosphole (1.9 D) and pyrrole (2.0 D) are similar, and, unlike furan, the positive ends of the dipoles are towards the h e t e r o a t o m ~ . ~ ~ ~ Dipole moments have been used, in combination with results from other methods of study, to estimate the preferred conformations of the dichlo- ride (179),294 of the phosphites (180),295 and of triarylphosphine The use of dipole moments to aid stereochemical studies of PIV compounds has been re- viewed. 297 Additive polarizability parameters should not be used in the calculations, and it has been recommended that data should be obtained from model compounds containing identical environments for the phosphorus atoms. 298 The sensitivity of bond moments to structural changes has been studied; perfluoroalkyl groups lower the phosphoryl bond moment, and the P-N bond moment is very sensitive to the valence state of the phosphorus atom.299 The conformational analyses of phospho- nates,300 phosph~namides,~~~ silyl phosphates,302 and a number of dioxaphosphori- nans (181) 3 0 s 9 304 have been reported. The P-Se bond moment has been estimated to be 1.24D.304 The zwitterionic structure (182) was identified by its high dipole

293 M. P. Warchol, E. N. Dicarlo, C. A. Maryanoff, and K. Mislow, Tetrahedron Letters, 1975,

294 R. P. Arshinova, J. Faucher, M. Graffeuil, J. F. Labarre, and C . Leibovici, Acta Chim. Acad.

295 R. P. Arshinova, S. G. Vul'fson, S. D. Ibragimova, E. T. Mukmenev, and B. A.Arbuzov,

296 S. B. Bulgarevich, E. G. Amarskii, A. A. Shvets, and 0. A. Osipov, J. Gen. Chem. (U.S.S.R.),

297 B. A. Arbuzov, R. P. Arshinova, and 0. A. Raevskii, Chern. Abs., 1975, 83, 77 843. 298 B. A. Arbuzov and R. P. Arshinova, Doklady Akad. Nairk S.S.S.R., 1976, 227, 1361. 29Q S. I. Vdovenko, V. Ya. Semenii, Yu. P. Egorov, Yu. Ya. Borovikov, and V. N. Zavatskii,

J. Gen. Chem. (U.S.S.R.), 1976, 46, 2491. 30° E. A. Ishmaeva, A. N. Vereshchagin, and F. M. Kharrasova, J. Gen. Chem. (U.S.S.R.), 1976,

46, 278; 0. A. Samarina, E. A. Ishmaeva, and N. G. Khusainova, ibid., p. 1708. 301 L. A. Ashkinazi, P. hf. Zavlin, V, M. Shek, B. I. Ionin, and Ya. L. Ignatovich, J. Gen. Chem.

(U.S.S.R.), 1976, 46, 1699. 302 Yu. V. Kolodyazhnyi, V. G. Tkalenko, A. P. Sadiinenko, N. A. Kardanov, and 0. A. Osipov,

J. Gen. Chem. (U.S.S.R.), 1975, 45, 738. a03 E. A. Ishmaeva, V. V. Ovchinnikov, R. A. Cherkasov, and A. B. Remizov, J. Gen. Chem.

(U.S.S.R.), 1975,45,931; E. A. Ishmaeva, V. V. Ovchinnikov, R. A. Cherkasov, A. B. Remi- zov, A. N. Pudovik, and A. A. Musina, Chem. Abs., 1976, 85, 93 679; K. Faegri, jun., T. Gramstad, and K. Tjessem, J. Mol. Structure, 1976, 32, 37.

504 E. A. Ishmaeva, M. Mikolajczyk, A. B. Remizov, and A. N. Pudovik, Dokludy Akad. Nauk S.S.S.R., 1975, 223, 351.

11, 917.

Sci. Hung., 1976, 90, 207.

Bull. Acad. Sci. U.S.S.R., 1976, 25, 1202.

1976, 46, 1661.

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268 Organophosphorus Chemistry

moment,305 and the trends observed for a series of phosphoryl compounds and their di- and tri-thia-analogues were interpreted in terms of a pdn interaction which de- creases in the order RO > RNH > RS.306

and reduction potentials 308 of salts, and on the electrochemical oxidation of triarylphosphines 309 and diphosphonic acids.31e

Reports have been published on

8 Mass Spectrometry

Mass spectral studies of organophosphorus compounds, published up to 1973, have been reviewed,311 as have the problems involved in the use of mass spectral data for the detection of phosphinidene~.~~~ However, peaks corresponding to the phosphini- dene (183) were the most intense peaks in the spectra of the phenylenediamine com- pounds (1 84) and their sulphides. 31 A considerable amount of work has been carried

M e Me

Me Me

M e Me

(183) (184)

out on a wide variety of phosphines, including acylpho~phines.~~~ Bridged ions, such as (185) from o-tolylphosphines, are believed to be formed when the aryl rings bear ortho-substit~ents.~~~, 315 The presence of a second functional group may also produce some unusual migrations. Migrations of oxygen, hydroxy-groups, and di- phosphino-groups have been postulated in order to explain the spectra of acyL316 and o-anisyl-diphenylphosphines. 231 Also, migration of phenyl from oxygen to

305

306

307

308 809

ti0

a12

311

313

314

a15

816

L. Maijs and 0. Lukevics, Latv. P.S.R. Zinat. Akad. Vestis, Kim. Ser., 1976, 590. P. M. Zavlin, V. M. Shek, A. N. D’yakonov, and V. M. Al’bitskaya, Chem. Abs., 1976, 85, 123 123. V. M. Tsentovskii, V. P. Barabanov, V. S. Tsentovskaya, and L. I. Kashirskaya, J. Gcn. Chem. (U.S.S.R.), 1976, 46, 1472. L. Horner and J. Roeder, Phosphorus, 1976, 6, 147; Y. Nagao and L. Horner, ibid., p. 139. Yu. M. Kargin, E. V. Nikitin, G. V. Romanov, 0. V. Parakin, B. S. Mironov, and A. N. Pudovik, Doklady Akad. Nauk S.S.S.R., 1976,226, 1101. J. H. Wagenknecht, J. Electrochem. SOC., 1976, 123, 620. I. Granoth, Topics Phosphorus Cheivt., 1976, 8, 41. U. Schmidt, Angew. Cfiem. Internat. Edn., 1975, 87, 523. 0. S. Anisimova, A. I. Bokanov, E. N. Karpova, and B. I. Stepanov, J. Gen. Chem. (U.S.S.R.), 1976, 46, 807. R. G. Kostyanovsky, A. P. Pleshkova, V. N. Voznesensky, and Yu. I. Elnatanov, Org. Mass Spectrometry, 1976, 11, 237; K. Henrick, M. Mickiewicz, N. Roberts, E. Shewchuk, and S. B. Wild, Austral. J. Chem., 1975, 28, 1473; D. H. Lemmon and J. A. Jackson, J. Fluoriae Chem., 1976, 8, 23. K. Henrick, M. Mickiewicz, and S. B. Wild, Austral. J. Chem., 1975, 28, 1455. J. Martens, K. Praefcke, H. Schwarz, and H. Simon, Phosphorus, 1976, 6, 247.

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Physical Methods 269

carbon has been postulated in order to explain the spectra of the phosphonyl- stabilized ylide (1 8Q317 The hydrogen rearrangements of cyclic phosphine oxides 318 and cyclic have been studied by deuterium labelling. The mass spectra of unsymmetrical d i s u l ~ h i d e s , ~ ~ ~ dialkylphosphonyl a z i d e ~ , ~ ~ ~ phosphinyl and unsaturated phosphonates 323 have also been studied. Further details have been published of the spectra of steroidal phosphinic esters. 324 G.c.-mass spectral analysis has been applied to cyclophosphamide 3 2 5 and other pesticides,32s and, after deriva- tization, to aminoalkylphosphonic acids 3 2 7 and pho~phazenes .~~~

Field desorption mass spectrometry has been successfully applied to mono- and bis-alkyl- and -alkenyl-triphenylphosphonium salts (1 87). The phosphonium cation gave rise to the base peaks.32g

There has been keen interest in ion-molecule reactions. Cyclotron resonance spectroscopy showed that methylpho~phines,~~~ the fluorides (188; ie = 1 or 2),331

Ph,{R X- Me,PF3-, Me,P=CH,

(187) (188) (18%

and the ylide (189) 332 give ions which contain two or three phosphorus atoms. The formation of phosphonium ions in a field source from PI11 compounds and alkylat- ing agents has been de~cribed.”~ The chemical ionization spectra of triphenylphos- phine with isobutane showed M+ 1, M+C4H9, and M-Ph peaks.334

317 L. Toekes and G. H. Jones, Org. Mass Spcctronietry, 1975, 10, 241. sl* G. L. Kenyon, D. H. Eargle, jun., and C. W. Koch, J. Org. Chem., 1976, 41, 2417. 319 A. Murai and M. Kainosho, Org. Mass Spectrometry, 1976, 11, 175. Z 2 O J . Koketsu, K. Ohashi, and Y. Ishii, Chubu Kogyo Daigaku Kiyo, 1975, 11A, 85. 321 H. F. Schroeder and J. Mueller, Z. anorg. Chem., 1975,418,247. 522 B. N. Laskorin, V. V. Yakshin, and L. I. Sokal’skaya, J. Gen. Chem. (U.S.S.R.), 1976, 46,

323 G. Peiffer and E. M. Gaydou, Org. Mass Spectrometry, 1975, 10, 122. 324 K. Jacob, W. Vogt, M. Knedel, and W. Schaefer, Biomed. Mass Spectrometry, 1976, 3, 64. 325 C. Pantarotto, A. Martini, G. Belvedere, M. G. Donelli, and A. Frigerio, Cancer Treat. Rep.,

1976,60, 493. 326 H. J. Stan, B. Abraham, L. Behla, and M. Kellert, Mitteilrtngsbl. G.D.C.H.-Pachgruppe

Lebensmittelchem. Gerichtl. Chem., 1976, 30, 146. 327 M. L. Reuppel, L. A. Suba, and J. T. Marvel, Biomed. Mass Spectrometry, 1976, 3, 28. 328 R. Vilceanu and P. Schulz, Phosphorus, 1976, 6, 231. 329 G. W. Wood, J. M. Mclntosh, and P.-Y. Lau, J. Org. Chem., 1975, 40, 636. 330 K. P. Wanczek, 2. Naturforsch., 1975, 30a, 329; K. P. Wanczek and Z. C. Profous, Internat.

331 K. P. Wanczek and G. V. Roeschenthaler, Dynamics Mass Spectrometry, 1976, 4, 163. 339 0. R. Hartmann, K. P. Wanczek, and H. Hartmann, 2. Nuturforsch., 1976, 31a, 630. 333 V. B. Labintsev, Yu. K. Gusev, N. N. Grishin, V. N. Chistokletov, and A. A. Petrov, Zhur.

334 F. Kober, Chem.-Ztg., 1976, 100, 235.

2434.

J. Mass Spectrometry Zon Phys., 1975, 17, 23.

org. Khim., 1976, 12, 1597.

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270 Organophosphorus Chemistry

9 PKa and Thermochemical Studies

The PKa values of phosphine oxides have been Their deviation from Hammett base b e h a ~ i o u r , ~ ~ ~ their HO dependencies,336 and their sites of protona- tion 337 have been studied. The acidifying effects of p h o ~ p h o r y l , ~ ~ ~ p h o ~ p h i n y l , ~ ~ ~ and thiophosphinyl groups 340 have been studied. Ionization constants have been used to examine substituent effects in alkanephosphonic acids 341 and phosphinyl- carboxylic structural correlations in various phosphorus and sol- vent effects on the properties of thiophosphorus The linear free-energy relationships, which are based mainly on PKa data, have been analysed and rt-

Thermogravimetric analysis has been used to study the thermolysis of phosphine the phosphinylimine (190),347 and the anhydrides of some phosphonic

and to follow the formation of pyropho~phates ,~~~ other mixed anhy- d r i d e ~ , ~ ~ ~ and indolylpho~phonates.~~~ Triphenylphosphine oxide (heat of combus- tion = - 35 796.6 k 14.3 J g-l) has been recommended as a reference substance for organophosphorus compounds. 352

335 E. I. Matrosov, E. N. Tsvetkov, Z. N. Mironova, R. A. Malevannaya, and M. I. Kabachnik,

336 A. Piekos-Maron and T. A. Modro, Phosphorus, 1976, 6, 129. 337 M. I. Kabachnik, E. I. Matrosov, T. Ya. Medved, and N. P. Nesterova, Doklady Akad.

338 E. S . Petrov, E. N. Tsvetkov, M. I. Terekhova, R. A. Malevannaya, A. 1. Shatenshtein, and

339 E. S. Petrov, E. N. Tsvetkov, S. P. Mesyants, A. N. Shatenshtein, and M. I. Kabachnik, Bull.

340 J. Boedeker and H. Zaertner, J. prakt. Chem., 1976, 318, 149. 341 A. J. Kresge and Y. C. Tang, J. Org. Chem., 1977,42,757; P. C . Schulz and A. L. M. LeLong,

343 E. N. Tsvetkov, R. A. Malevannaya, and M. I. Kabachnik, J. Gen. Chem. (U.S.S.R.), 1975,

343 V. A. Baranskii, B. I. Istomin, and A. V. Kalabina, Reakts. spos. org. Soedinenii, 1976,13,263. 344 A. G. Kozachenko, A. B. Uryupin, L. L. Spivak, A. Grigor'eva, E. I. Matrosov, M. I. Kabach-

nik, and T. A. Mastryukova, Bull. Acad. Sci. U.S.S.R., 1976, 25, 1561. 345 B. I. Istomin, V. A. Baranskii, A. D. Lobanov, and E. F. Grechkin, Reakts. spos. org. Socdin-

cnii, 1975, 12, 69; V. A. Baranskii and B. I. Istomin, ibid., p. 83; M. I. Kabachnik, Khim. Primen. Fosfororg. Soedinenii, 1974, 257, (Chem. Abs., 1975, 83, 77 844).

Bull. Acad. Sci. U.S.S.R., 1975, 24, 1231.

Nauk S.S.S.R., 1976, 230, 1347.

M. I. Kabachnik Bull. Acad. Sci. U.S.S.R., 1976, 25, 517.

Acad, Sci. U.S.S.R., 1976,25, 762.

Rev. Latinoamer. Quim., 1976, 7 , 9.

45, 706.

346 K. Moedritzer, Thermochim. Acra, 1976, 16, 173. 347 E. Kameyama, S. Inokuma, and T. Kawamura, Bull. Chem. SOC. Japan, 1976, 49, 1439. 348 0. N. Grishina, N. A. Andreev, and E. E. Sidorova, J. Gen. Chem. (U.S.S.R.), 1976,46, 1458. 3*9 M. A. Ruveda, E. N. Zerba, R. Podesta, and S. A. de Licastro, Tetrahedron, 1975, 31, 885. 35@ V. N. Eliseenkov, N. A. Samatova, and N. P. Anoshina, J. Gen. Chem. (U.S.S.R.), 1976,

351 A. 1. Razumov, P. A. Gurevich, R. I. Tarasova, and S. Yu. Baigil'dina, J. Gat. Ckrm.

3J2 A. J. Head and D. Harrop, Con$ Int. Thermodyn. Chim., 1975, 19.

46, 23.

(U.S.S.R.), 1976,46, 33.

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Physical Methods 27 1

10 Chromatography

G.1.c.-Most reports have concerned the analysis of pesticides353 and efforts to in- crease the sensitivity and selectivity of The gas-chromatographic physical behaviour of bis(2-ethylhexyl) phosphate has also been

T.1.c.-The separation of phosphonic acid derivatives has been Reports on the application of t.1.c. to the analysis and separation of nucleotides 357 and other biologically important phosphates 3 5 8 abound. Enzymatic reagents have been used to develop chromatograms of phosphate esters which inhibit cholinesterase. Clean, sharp-edged spots against a dark background are obtained. 359

Paper Chromatography.-Solvent systems have been developed for the separation of trichloromethyl- phenyl-, and pentafluorophenyl-phosphonic and -phosphinic

Phosphoramidates and their hydrolysis products have been chromato- graphed, using triethylamine as a Silica gel on glass-fibre sheets may be used to separate inositol from its phosphate 3 6 2 and to analyse phosphatide glyceryl ethers.

H.p.1.c.-Methods have been devised for the separation of deoxyribonucleoside tri- of phosphatidylcholine from ~ph ingomye l in ,~~~ and of phospho-

lipids. 366

0 II

(EtO), PSC€I,CH, SEt

(191)

Column Chromatography.-Thiophosphates such as (191) have been purified on

353 Y. Aoki, M. Takeda, and M. Uchiyama, Eisei Kugaku, 1976, 22, 81; T. Lipowska, S. J. Kubacki, and H. GOSZCZ, Pr. Inst. Lab. Badaw. Przem. Spozyw., 1975, 25, 395; G. F. Ernst and M. J. P. T. Anderegg, J. Assoc. Ofic . Analyt. Chemists, 1976, 59, 1185; W. Krijgsman and C. G . Van de Kamp, Mcded. Fac. Landbouwwet., Rijksuniv. Gent, 1976,41, 1423.

354 S. Hasinski, Chem. analit. (Warsaw), 1975, 20, 1135; Y. Takimoto and J. Miyamoto, Nippon Noyaku Gakkaishi, 1976, 1, 193; N. Mellor, J. Chromatog., 1976. 123, 396; R. B. Dehew, Chem. Abs., 1976, 85, 86 799; V. V. Brazhnikov and E. B. Shmidel, J. Chromatog., 1976, 122, 527.

355 L. L. Borin and V. I. Serov, Zhur. Jir. Khim., 1975, 49, 8 10. 456 R. J. Maile, jun. and G. J. Fischesser, J. Chromatog., 1977, 132, 366. 357 W. Kreis, A. Greenspan, T. Woodcock, and C. Gordon, J. Chromatog. Sci., 1976, 14, 33 1 ;

E. R. Sargent and P. F. Agris, J. Chromatog., 1976, 123, 490; A. A. White, ibid., 1975, 104, 184; G. Volckaert, W. Min Jou, and W. Fiers, Anal-vt. Biochem., 1976,72,433; R. C . Gupta, E. Randerath, and K. Randerath, Nucleic Acids Res., 1976, 3, 2915.

558 J. Zadrozinska, Rocz. Panstw. Zakl. Hig., 1976,27, 391 ; R. D. Petukhov, Veterinariya (Mos- cow), 1976, 101 ; C. K. Hong and I. Yamane, Nippon Dojo-Hiryogaky Zasshi, 1976,47, 122; N. Salen, jun., L. G. Abood, and W. Hoss, Analyt. Biochem., 1976,76,407; J. H. M. Poorthuis, P. J. Yazaki, and K. Y. Hostetler, J. Lipid Res., 1976, 17, 433; A. Di Muccio and M. Delise, Riv. SOC. Ital. Sci. Aliment., 1976, 5, 77.

356 P. Ambrosetti, A. Bolla, and B. Chialo, Chromatographia, 1976, 9, 633; H. Dumitrescu, Z. Barduta, and D. Dumitrescu, Chem. Abs., 1976, 85, 121 884.

360 A. N. Bogushevskii and N. I. Gabov, Zhur. analit. Khim., 1976, 31, 582. 361 H. Kuehne, H. A. Lehmann, and W. Toepelmann, Z. Chem., 1976,16,23. 362 M. Hokin-Neaverson and K. Sadeghian, J. Chromatog., 1976, 120, 502. 363 M. H. Hack and F. M. Helmy, J. Chromatog., 1975, 107, 155. a64 H. J. Breter and R. K. Zahn, Z. Naturforsch., 1976,31c, 551.

a66 R. H. McCluer and F. B. Jungalwala, Adu. Exp. Med. Biol., 1976, 68. F. B. Jungalwala, J. E. Evans, and R. H. McCluer, Biochem. J., 1976, 155, 55.

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272 Organophosphorus Chemistry

silica gel,367 and condensed phosphates separated using ion-exchange resin.368 The analysis of a range of biologically important phosphates has been achieved,369 using affinity micelle formation,371 and microcolumn

367 J. Jarv and A. Aaviksaar, Chern. Abs., 1975, 85, 77 559. 368 D. Lucansky, Chem. prumysl., 1976,26, 514. 3159 H. Jensen, F. Habault, A. M. Lacoste, and A. Cassaigne, J. Chromatog., 1977, 132, 556;

J. X. Khym, ibid., 1976, 124, 415; I. M. Koshkina, L. A. Remizova, and I. A. Favorskaya, Vestnik. Leningrad Uniu., Fiz., Khim., 1976, 2, 135; S. T. Thompson, R. Cass, and E. Stell- wagen, Analyt. Biochem., 1976,72, 293.

370 A. K. Sinha and R. W. Colman, European J. Biochem., 1977, 73, 367. a71 A. K. Sen Gupta, Fette, Seifen, Anstrichm., 1976, 78, 1 1 1. 371 V. P. Demushkin, Yu. G. Plyashkevich, and N. M. Shalina, Bioorg. Khim., 1975, 1, 1728.

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