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)(2)CH}- (THF)(Et2O)1 (1) have been used to prepare a series of low-valent group 14 metal complexes. The reaction of lithium salt [Li{(S=PPh2)(2)CH}(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{mu(2)-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)}(mu-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.