Synthesis, characterisation and reactivity of germanium(II) amidinate and guanidinate complexes

Reactions of lithium salts of the bulky guanidinate ligands, [ArNC(NR(2))NAr](-) (NR(2) = N(C(6)H(11))(2) (Giso(-)) and cis-NC(5)H(8)Me(2)-2,6 (Pipiso(-)); Ar = C(6)H(3)Pr(2)(i)-2,6), with GeCl(2) . dioxane afforded the heteroleptic germylenes, [(Giso)GeCl] and [(Pipiso)GeCl], the former of which was structurally characterised. The further reactivity of these and the related complexes, [(Piso)GeCl] and [(Priso)GeCl] (Piso(-) = [ArNC(But)NAr](-), Priso(-) = [ArNC(NPr(2)(i)) NAr](-)) has been investigated. Salt elimination reactions have yielded the new monomeric complexes, [(Piso)Ge(NPr(2)(i))] and [(Piso)GeFeCp(CO)(2)], whilst a ligand displacement reaction afforded the heterometallic species, [(Piso)Ge(Cl){W(CO)(5)}]. Chloride abstraction from [(Priso)GeCl] with GaCl(3) has given the structurally characterised contact ion pair, [(Priso)Ge][GaCl(4)]. In addition, the inconclusive outcome of a number of attempts to reduce the germanium halide complexes are discussed.