A coordination compound of Ge0 stabilized by a diiminopyridine ligand

Abstract

Reduction of the cationic GeII complex [dimpyrGeCl][GeCl 3] (dimpyr=2,6-(ArN=CMe)2NC5H3, Ar=2,6-iPr2C6H3) with potassium graphite in benzene affords an air sensitive, dark green compound of Ge0, [dimpyrGe], which is stabilized by a bis(imino)pyridine platform. This compound is the first example of a complex of a zero-valent Group 14 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 π*(Cï£N) 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. Putting the e back into Ge: A cationic GeII complex was reduced to give a complex composed of a neutral germanium atom with a tridentate diiminopyridinate ligand. The Ge0 complex was found to have a singlet ground state and partial multiple-bond character between the Ge atom and the imine nitrogen atoms according to NMR, IR, and EPR spectroscopy, as well as X-ray analysis and DFT calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.