Preparation and Coordination Chemistry of Bidentate Benzimidazoline-2-germylenes

Bridged bis(benzimidazoline-2-germylene)s have been prepared in good yield by the reaction of N,N‘,N,‘ ‘N‘ ‘‘-tetralithiated tetraamines with GeCl2·1,4-dioxane or by the direct transamination reaction between tetraamines and Ge[N(SiMe3)2]2. Four bis(benzimidazoline-2-germylene)s with different bridging groups between the benzimidazoline-2-germylene groups have been shown by X-ray diffraction analysis to exhibit different types of weak intermolecular interactions, but no significant Ge···Ge interaction was observed in the solid state. One of the bisgermylenes disproportionates in solution at ambient temperature to yield a Ge(IV) spiro compound and elemental germanium. The bisgermylenes can act as chelate ligands replacing norbornadiene in [Mo(nbd)(CO)4] with formation of complexes of the type [Mo(η2-bisgermylene)(CO)4], which have been investigated by 1H NMR and vibrational spectroscopy and X-ray diffraction analysis.