Flash vacuum thermolysis of 3,4-dimethyl-1-germacyclopent-3-enes: UV photoelectron spectroscopic characterization of GeH2 and GeMe 2
Résumé
Gas-phase UV photoelectron spectra of germylene (GeH2) and its dimethyl analogue (GeMe2) have been recorded, using flash vacuum thermolysis of 3,4-dimethyl- and 1,1,3,4-tetramethyl-germacyclopent-3-ene to generate these reactive species in the inlet of the photoelectron spectrometer. The lowest vertical ionization bands for GeH2 (9.4 eV) and GeMe 2 (8.2 and 10.0 eV) have been located with the aid of time-dependent density functional theory calculations carried out at the B3LYP/6-311G(d,p) level of theory. Similar experiments carried out with 3,4-dimethyl-1,1- diphenylgermacyclopent-3-ene, in an attempt to record the photoelectron spectrum of diphenylgermylene (GePh2), were less conclusive, but are consistent with the theoretically predicted lowest lonization potential of 8.0-8.2 eV for GePh2. Photoelectron spectra of the three germacyclopentene derivatives are also reported. Copyright © 2004 John Wiley & Sons, Ltd.