Matrix isolation investigation of the photochemical reaction of benzene with CrCl2O2 and OVCl3

Matrix isolation studies of photochemical and thermal reactions of 3- and 5-membered cyclic hydrocarbons with CrCl2O2

The matrix isolation technique has been combined with infrared spectroscopy and theoretical calculations to characterize the products of the photochemical and thermal reactions of cyclopentadiene, cyclopentene, cyclopentane, and cyclopropane with CrCl 2O 2. While initial twin jet deposition of the reagents led to no visible changes in the recorded spectra, product bands were observed following irradiation with light of lambda > 300 nm. The irradiation was shown to lead to oxygen atom transfer to the five-membered rings, forming complexes between cyclic alcohol derivatives and CrCl 2O. For the cyclopentadiene and cyclopentene systems, complexes between cyclic ketone derivatives and CrCl 2O were also observed. For cyclopropane, a ring-opening oxidation reaction followed by fragmentation was observed for the first time, forming the H 2COCrCl 2O complex and C 2H 4. In the room temperature thermal (merged jet) reactions between CrCl 2O 2 and cyclopentadiene, cyclopent-3-enone was observed. At the higher temperatures, 150 and 200 degrees C, 1,3-cyclopentanedione was also observed as well. No product bands were detected in the merged jet experiments for the other three systems. These conclusions were supported by isotopic labeling ((2)H) and by B3LYP/6-311G++(d,2p) density functional calculations.

Matrix isolation investigation of the photochemical reaction of methyl-substituted benzenes with CrCl2O2

The matrix isolation technique, combined with infrared spectroscopy, has been used to characterize the products of the photochemical reactions of toluene, m-, o-, and p-xylene, mesitylene, and hexamethylbenzene 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 lambda > 300 nm. The irradiation was shown to lead to oxygen atom transfer, forming complexes between methylcyclohexadienone derivatives and CrCl2O. With the xylenes and mesitylene, di- and trimethylphenols, complexed to CrCl2O, were also observed, respectively. This latter result arises from C-H bond activation and oxygen atom insertion into a C-H bond. 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. Product distributions were rationalized by an analysis of the electron density distribution.

Infrared matrix isolation study of the oxidation of H2S by CrCl2O2

The thermal and photochemical reactions between CrO2Cl2 and H2S have been investigated using matrix isolation infrared spectroscopy. Twin-jet co-deposition of the two reagents into argon matrices at 14 K followed by irradiation with light of lambda > 300 nm led to the growth of a number of new bands. These have been assigned to the HSOH-CrCl2O complex, and to SO2. These assignments were supported by deuterium isotopic substitution and high level density functional calculations. Merged-jet deposition with the reaction zone at temperatures above 125 degrees C led to substantial yields of SO2 and HCl, as well as the complex of HCl with excess parent H2S. The evidence suggests that the thermal and photochemical reactions may follow different pathways.