Miscellaneous Physical and Structural Aspects

Extensive 13C and 81P n.m.r. studies have been reported for phosphine oxides and selenides, and the inversion-recovery technique has been used to establish 2J and ZJ values for 18C-31P coupling.52 Shift reagents have been used to establish alkene geometry in the oxides (61).53 Coupling and shift data have been published for the arylphosphine derivatives (62).54 

Torsional barriers for trimethylphosphine derivatives (63) have been obtained from Raman spectra.56 Vibrational spectra for the uranyl nitrate complex of (63a) have been published.66 Complexes of triarylphosphine derivatives (64) with iodine,67 and of (64b) with metal halides,68 have been the subject of thermodynamic67 and spectroscopic67 68 study. 

X-Ray data have been published for A -phospholen 1-oxide (65),69 tri-o-tolyl-phosphine derivatives (66),60 and various halogeno-alkylphosphine oxides.61 

Further study has been made of the ionization of the phosphinoyl-substituted acids (67), and the substituent at phosphorus has been found to be important in influencing acidity.62 Evidence for cyclic solvates was found for (67 n = l).62 The 

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Miscellaneous Physical and Structural Aspects Ab initio M.O. calculations have been carried out on the phosphorane (61), formed by hypothetical addition of hydride ion to phosphine oxide. A number of different geometries were examined and a slightly distorted trigonal bipyramid was found to be the most stable, provided that the phosphoryl oxygen is placed in an equatorial site. 

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