Amidinatogermylene Metal Complexes as Homogeneous Catalysts in Alcoholic Media
A series of transition metal complexes containing the bulky amidinatogermylene Ge(tBu2bzam)tBu (1; tBu2bzam N,N' bis(tert butyl)benzamidinate) as a ligand have been prepared and characterized. While the hydrolytic degradation of the germylene ligand of the square planar complexes [MCl(e4 cod){Ge(tBu2bzam)tBu} (M Rh (2) Ir (3) cod 1,5 cyclooctadiene) and [PdCl(e3 metallyl){Ge(tBu2bzam)tBu} (4; metallyl 2 methylallyl) is slow but clearly evident in carefully dried aprotic solvents, the octahedral complexes [RuCl2(e6 cym){Ge(tBu2bzam)tBu} (5; cym p cymene) and [IrCl2(e5 Cp*{Ge(tBu2bzam)tBu} (6; Cp* pentamethylcyclopentadienyl) have proven to be stable even in alcoholic solvents. These latter complexes have been tested as catalyst precursors of reactions involving alcohols as substrates and/or solvents, and remarkably, they have been found to be active in the transfer hydrogenation of cyclohexanone with isopropyl alcohol (5 and 6) the N alkylation of aniline with benzyl alcohol (5 and 6)