Aluminum halide—cobalt halide polynuclear complexes active in low-temperature conversion of alkanes: formation,molecular structures,and IR spectra

Low-temperature FT-IR studies of products of co-condensation of aluminum chloride and cobalt chloride in hydrocarbon matrices were carried out in the temperature range 80–250 K. DFT quantum mechanical calculations of the geometry and vibrational frequencies of aluminum chloride/cobalt chloride polynuclear molecular and ionic complexes of different compositon were carried out. Isomeric labile complexes Al₂Cl₆·CoCl₂ were detected under partial matrix isolation conditions and their behavior was monitored. The interaction of the 1: 1 and 2: 1 aluminum halide/cobalt halide molecular complexes at 120–170 K produces catalytically active species in low-temperature conversion of alkanes. According to the data of in situ spectral studies and to the results of quantum chemical calculations, these species represent ionic associates which simultaneously contain Co and Al atoms in both cationic and anionic fragments.