A Coordination Compound of Ge0 Stabilized by a Diiminopyridine Ligand

Reduction of the cationic Ge-II complex [dimpyrGeCl][GeCl3] (dimpyr=2,6-(ArN=CMe)(2)NC5H3, Ar=2,6-iPr(2)C(6)H(3)) with potassium graphite in benzene affords an air sensitive, dark green compound of Ge-0, [dimpyrGe], which is stabilized by a bis(imino)pyridine platform. This compound is the first example of a complex of a zero-valent Group14 element that does not contain a carbene or carbenoid ligand. This species has a singlet ground state. DFT studies revealed partial delocalization of one of the Ge lone pairs over the *(CN) orbitals of the imines. This delocalization results in a partial multiple-bond character between the Ge atom and imine nitrogen atoms, a fact supported by the X-ray crystallography and IR spectroscopy data.