A Bis(silylenyl)pyridine Zero-Valent Germanium Complex and Its Remarkable Reactivity.

The synthesis, reactivity, and electronic structure of the unique germylone iron carbonyl complex [SiNSi]Ge →Fe(CO) is reported. The compound was obtained in 49 % yield from the reaction of the bis(N-heterocyclic silylenyl)pyridine pincer ligand SiNSi (1,6-C NH -[EtNSi(N Bu) CPh] ) with GeCl ⋅(dioxane) to give the corresponding chlorogermyliumylidene chloride precursor [SiNSi]Ge Cl  Cl , which was further reduced with K Fe(CO) . Single-crystal X-ray diffraction analysis of [SiNSi]Ge→Fe(CO) revealed that the Ge center adopts a trigonal-pyramidal geometry with a Si-Ge-Si angle of 95.66(2)°. Remarkably, one of the Si donor atoms in the complex is five-coordinated because of additional (pyridine)N→Si coordination. Unexpectedly, the reaction of [SiNSi]Ge→Fe(CO) with GeCl ⋅(dioxane) (one molar equivalent) yielded the first push-pull germylone-germylene donor-acceptor complex, [SiNSi]Ge→GeCl →Fe(CO) through the insertion of GeCl into the dative Ge →Fe bond. The electronic features of the new compounds were investigated by DFT calculations.