Synthesis, Structure, and Reactivity of Group 14 Bis(thiophosphinoyl) Metal Complexes

Bis(thiophosphinoyl)methane, CH2(PPh2S)2, and its monolithium salt [Li{(SPPh2)2CH}(THF)(Et2O)] (1) have been used to prepare a series of low-valent group 14 metal complexes. The reaction of lithium salt [Li{(SPPh2)2CH}(THF)(Et2O)] (1) with 1 equiv of MCl2 (M = Ge, Sn) in diethyl ether afforded monomeric organometal(II) chlorides [MCl{CH(PPh2S)2}] (M = Ge (2), Sn (3)). Treatment of CH2(PPh2S)2 with equimolar M{N(SiMe3)2}2 (M = Sn, Pb) afforded 1,3-dimetallacyclobutanes [M{μ2-C(Ph2PS)2}]2 (M = Sn (4), Pb (5)), which are believed to be formed by the dimerization of the metallavinylidene intermediate. Compounds 2 and 5 further reacted with elemental chalcogens (S and Se) to give trans-dithiadigermetane [GeCl{CH(PPh2S)2}(μ-S)]2 (6) and lead(II) chalcogenates [PbE{C(PPh2S)2}] (E = S (7), Se (8)), respectively. Compounds 2−8 have been determined by X-ray crystallography.