Cryosynthesis, structure, and spectroscopic properties of aluminum chloride—cobalt(ii) chloride complexes: experiment and calculations

Abstract

Products of co-condensation of aluminum chloride and cobalt(ii) chloride vapors were studied by low-temperature (80—200 K) IR spectroscopy. In addition to 2 : 1 complexes, previously unknown equimolar associates were found and their IR spectra were investigated. Quantum-mechanical calculations were carried out including electron correlation with the use of the B3LYP and PBE density functionals. The geometric structures were optimized and harmonic vibrational frequencies of the molecules of aluminum chloride, cobalt chloride, and their complexes with different compositions were calculated. Under conditions of limited molecular mobility, the (AlCl3)2·CoCl2 complexes can be stabilized in structures containing the Co atom in a tetrahedral or distorted octahedral environment. Their thermal stability limits were determined. It was found that labile ionic species are generated in the reactions of aluminum chloride complexes with cobalt chloride with different compositions at 120—170 K.