Matrix isolation of HGaX2 (X = Cl or Br): IR spectroscopy and ab initio calculations

Abstract

High-vacuum thermolyses of the intramolecularly co-ordinated gallanes Me₂N(CH₂)₃GaX₂ with X = Cl 1 or Br 2 were investigated with matrix isolation techniques. Among the products, which have been identified with IR spectroscopy, ab initio calculations, and known literature data, are monomeric HGaCl₂ and HGaBr₂. The experimental vibrational frequencies of these hydrides are compared with calculated harmonic frequencies at the MP2(fc)/6-311+G(2d,p) and B3LYP/6-311+G(2d,p) level of theory. Beside monomeric HGaX₂, the argon matrices of the thermolyses experiments contained CH₄, HCN, H₂CCH₂, H₂CNMe, [H₂CCHCH₂]˙, H₂CCHCH₃, HX, and GaX (X = Cl or Br). In the case of GaBr the difference between the known gas-phase value and the measured IR frequency in argon matrices is discussed and explained with the help of SCRF-B3LYP calculations.