Electron spin resonance studies of cation radicals of some alkylphosphines

Abstract

The effect of alkyl substitution on the geometry of the phosphine cation radical has been investigated by e.s.r. spectroscopy. It is shown by the use of Huheey's electronegativity parameters that the geometry of the alkylphosphine cation radicals is related to the electronegativity of the alkyl groups as in other trigonal radicals. The effects of methyl substitution on the geometry of AlH^–₃ and SiH₃ are also discussed in terms of Huheey's electronegativity parameters. It is shown, further, that there is a correlation between the ³¹P hyperfine coupling constants of the alkylphosphine cation radicals and ³¹P n.m.r. chemical shifts for the respective neutral molecules.