Matrix isolation and theoretical investigation of the photochemical reaction of CrCl2O2 with benzenes substituted with electron withdrawing groups

The matrix isolation technique, combined with infrared spectroscopy and theoretical calculations, has been used to characterize the products of the photochemical reactions of chlorobenzene, α,α,α-trifluorotoluene, benzonitrile, and nitrobenzene with CrCl2O2. While initial twin jet deposition of the reagents led to no visible changes in the recorded spectra, 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 the corresponding cyclic ketone derivatives and CrCl2O. With benzonitrile, cyanophenol complexed to CrCl2O was also observed. This latter result arises from C-H bond activation and oxygen atom insertion into a C-H bond. The identification of the complexes were further supported by density functional calculations at the B3LYP/6-311G++(d, 2p) level. Product distributions were rationalized by an analysis of the electron density distribution.