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

Abstract

Reactions of lithium salts of the bulky guanidinate ligands, [ArNC(NR₂)NAr]⁻ (NR₂ = N(C₆H₁₁)₂ (Giso⁻) and cis-NC₅H₈Me₂-2,6 (Pipiso⁻); Ar = C₆H₃Prⁱ₂-2,6), with GeCl₂·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(Bu^t)NAr]⁻, Priso⁻ = [ArNC(NPrⁱ₂)NAr]⁻) has been investigated. Salt elimination reactions have yielded the new monomeric complexes, [(Piso)Ge(NPrⁱ₂)] 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 GaCl₃ has given the structurally characterised contact ion pair, [(Priso)Ge][GaCl₄]. In addition, the inconclusive outcome of a number of attempts to reduce the germanium halide complexes are discussed.