Gas-phase characterization by photoelectron spectroscopy of unhindered, low-coordinate germanium compounds: Germaimines, germylenes, and germaisonitriles

Low-coordinate, unhindered germanium compounds, germaimines, germylenes, an d germaisonitriles, have been generated and characterized by the combinatio n of flash vacuum thermolysis (FVT) of appropriately substituted germacyclo pentenes and ultraviolet photoelectron spectroscopy (UV-PES). These product s have characteristic ionization potentials (IPs) at low energy consistent with their great kinetic instability and their high reactivity. The ionizat ion potentials associated with the ejection of an electron from the pi(Ge-N ) orbital for germaimines and the n(Ge) lone pair for germylenes are useful fingerprints of these compounds. At higher temperature these transient spe cies lead to the formation of germaisonitriles that show two characteristic IPs associated with the pi(Ge-N) and the n(Ge) orbital ionizations. Charac terization of these three unhindered species is supported by ab initio calc ulations of the geometrical and electronic structures by using the B3LYP de nsity functional hybrid with LANL2DZ(d) and 6-311G(d) basis sets.