Synthesis, structure, and reactivity of a µ-bis(dialkylphosphido)-dilithium [Li(µ-PR2)]2[R = CH(SiMe3)2]

Abstract

Reaction of lithium shot with PClR₂[R = CH(siMe₃)₂] in OEt₂ at 25 °C affords the title phosphide [Li(µ-PR₂)]₂, (1), which in c₆D₆ shows a triplet ⁷Li n.m.r. signal, and reacts as (a) a Lewis acid to afford the monomeric Li(PR₂)(NMe₂[CH₂]₂NMe₂), (2), (which in C₆H₆ shows a doublet ⁷Li n.m.r. signal), (b) a R₂ transfer agent to yield PR₂X (X = H or Me) with XCl, or (c) a reducing agent to furnish P·R₂with Bu^tCl or Sncl₂; compound (1) has a planar Li₂P₂ ring with average Li–P and P–C distances of 2.473(10) and 1.892(7)Å, and mean LiPLi, PliP, and CPC angles of 72.2(3), 107.8(3), and 102.0(5)°.