Matrix isolation study of the photochemical reaction of cyclohexane and cyclohexene with CrCl2O2

The matrix isolation technique, combined with infrared spectroscopy, has been used to characterize the products of the photochemical reactions of cyclohexane and cyclohexene with CrCl2O2. While initial twin jet deposition of the reagents led to no visible changes in the recorded spectra, strong product bands were noted following irradiation with light of λ > 300 nm. The irradiation was shown to lead to oxygen atom transfer, forming complexes between cyclic alcohol derivatives and CrCl2O, although complexes between ring expansion products and CrCl2O could not be ruled out. This latter result could arise from C–C bond activation and oxygen atom insertion into a C–C bond. For the cyclohexene system, the cyclohexanone–CrCl2O complex was also observed. The identification of the complexes was further supported by isotopic labeling (2H) and by density functional calculations at the B3LYP/6-311G++(d,2p) level.