Structure and stability of cyano-derivatives of organochlorophosphate(V) ions
Abstract
The organochlorophosphate(V) ions [PRCl5]–(R = Et, C6F5, or CCl3) react with excess AgCN to form [PEt(CN)5]–, [P(C6F5)Cl(CN)4]–(one isomer), and [P(CCl3)Cl2(CN)3]–(all three isomers) respectively; salts containing these ions have been isolated and characterised. Several intermediate chlorocyanophosphates have been detected by 31P n.m.r. spectroscopy and isomeric configurations have been assigned by the method of pairwise interactions. A possible rationalisation of the degree of substitution by cyanide into these and other organochlorophosphates is proposed, based on the relative stabilities of the six-co-ordinate anions and the five-co-ordinate phosphoranes from which they are derived.