Chlorine-35 nuclear quadrupole resonance studies of some chlorine-containing phosphorus–nitrogen compounds

Abstract

The ³⁵Cl n.q.r. spectra of a series of chlorine-containing phosphorus–nitrogen compounds including [Cl(X)PNR]₂(X = lone pair, R = Bu^t; X = O, R = Bu^t or Me), PCl₂(NBu^tH)O, Cl₂P·NBu^t·PCl₂, Cl₂P·NMe·P(O)Cl₂, Cl₂(X)P·NMe·P(X)Cl₂(X = O or S), Cl₂(O)P·NR·P(S)Cl₂(R = Me or Ph), the heterocycle C₁₇H₂₀ClN₂OP (see Table 1), and Cl₂(O)P·N:PPh₃ have been recorded at ambient temperatures and/or 77 K. The results are discussed in terms of the structures, where known, and a linear correlation between P–Cl bond lengths and n.q.r. frequencies has been deduced for phosphoryl compounds : this is different from the correlation previously deduced for cyclophosphazenes. Data for Cl₂(O)PCH₂P(O)Cl₂ are also included. The n.q.r. results enable some comparisons to be made of the relative electron supply of some common substituents encountered in phosphorus chemistry.