Gas phase characterization by photoelectron spectroscopy of unhindered α-heterosubstituted germylenes

Two unhindered α-heterosubstituted (O and S) cyclic germylenes have been generated and characterized by the combination of flash vacuum thermolysis of stable germacyclopentenes and ultraviolet photoelectron spectroscopy. This coupling associated with ab initio calculations with the hybrid functional B3LYP and the 6-311G(d) basis set allows to predict the electronic properties of the generated germylenes. The thermodynamic stabilization of these reactive molecules by electronic delocalization of the heteroatom π lone pairs within the 4π orbitals of the germanium atom is clearly shown.