The isolation from diethyl ether of ionic [(Me2N)3PI]I and [(CH2CHCH2)2PhPI]I, and the crystallographically characterised molecular ‘spoke’ structure PhMe2PI2

Abstract

Ten new compounds of stoichiometry R₃PI₂[R₃=(o-MeOC₆H₄)₃, (o-MeOC₆H₄)₂Ph, (o-MeOC₆H₄)Ph₂, (p-FC₆H₄)₂Ph, (p-FC₆H₄)Ph₂, (p-CH₂CHC₆H₄)Ph₂, (CH₂CHCH₂)₂Ph, (C₆H₁₁)Ph₂, (PhCH₂CH₂)₃ or (Me₂N)₃] have been prepared by the direct reaction of PR₃ and I₂ in diethyl ether solution. The compounds have been characterised by Raman and solid-state ³¹P-{H} magic angle spinning (MAS) and solution NMR spectroscopy. Solid-state ³¹P-{H} MAS NMR studies indicate that the predominant solid-state species is the molecular ‘spoke’ structure R₃P–I–I; however, in some cases a minor peak was also assignable to the ionic species, [R₃PI]I. Additionally, solid-state ³¹P-{H} MAS NMR studies of (Me₂N)₃PI₂ and (CH₂CHCH₂)₂PhPI₂ indicate that, in contrast to all other compounds of stoichiometry R₃PI₂ prepared in diethyl ether, they are exclusively ionic, [R₃PI]I. The crystal structure of PhMe₂PI₂ shows it to have the molecular ‘spoke’ geometry, PhMe₂P–I–I, d(I–I)= 3.408 Å, previously observed for Ph₃PI₂, in agreement with solid-state ³¹P-{H} MAS NMR results.