Activation of CO 2 , CS 2 , and COS by α-Diimine-Stabilized Gallylenes

Several gallylenes [L GaM(THF) ] stabilized by an α-diimine ligand (L =[(2,6-iPr C H )NC(Ph)] ; M=Li, n=3, 3-Li; M=Na, n=4, 3-Na; M=K, n=1, 3-K) were prepared, which display diverse reactivities toward carbon dioxide and its sulfurized analogues. The reaction of 3 with CO yielded a trimeric carbonate complex [{L Ga(CO ) } {μ-K (THF) }] (4) and a dinuclear oxo-carbonate complex [K (THF) ][L Ga(μ-CO )(μ-O)GaL ] (5) in one pot through reductive disproportionation of CO . For CS , two ethenetetrathiolate gallium complexes, [M (Solv) ][L Ga(μ-C S )GaL ] (M=Na, Solv=THF, 6; M=K, Solv=DME, 7), were obtained via reductive coupling of CS . In the case of COS, disproportionation gave a disulfide-bridged complex [K (THF) ] [L Ga(μ-S) GaL ] (8) at room temperature, but a dithiocarbonate [Na (THF) ][L Ga(S CO)] (9) at low temperature, the latter being the first example of dithiocarbonates of p-block elements.