Photochemically Induced Reactions of Ozone with 1,2-Dibromoethene and 1,2-Dichloroethene: An FT-IR Matrix Isolation Study

Matrix isolation study of the early intermediates in the ozonolysis of selected vinyl ethers

The Criegee mechanism of the ozonolysis reaction of vinyl ethers has been observed by matrix isolation FTIR spectroscopy.

A matrix isolation study of the photochemically induced reactions of nitrogen dioxide with 1,2-dibromoethene and 1,2-dichloroethene using Fourier transform infrared spectroscopy

Photolyses of matrices of either BrCHCHBr/NO2/Ar or ClCHCHCl/NO2/Ar using quartz-filtered radiation (lambda>240 nm) led to the appearance of infrared bands attributable to carbonyl, carbon monoxide, and ketene species; no bands belonging to a precursor complex NO2cdots, three dots, centeredXCHCHX (where X=Br or Cl) were observed upon matrix deposition. The possible reaction pathway is discussed.

Ozonolysis of Fluoroethene: Theoretical Study of Unimolecular Decomposition Paths of Primary and Secondary Fluorozonide

A theoretical investigation into unimolecular decomposition paths of primary (POZF) and secondary (SOZF) fluorozonide was carried out by utilizing the multiconfigurational CASSCF/cc-pVTZ level in optimizations of the stationary points and calculations of the harmonic vibrational frequencies. The dynamical electron correlation was accounted for via the multireference CASPT2/cc-pVTZ treatment based on the zeroth-order CASSCF/cc-pVTZ reference. The CASPT2 was substituted with the CCSD(T)/6-311G(2d,2p) correction whenever the former resulted in negative activation barriers. The most favorable decomposition route of POZF is a concerted cleavage to carbonyl oxide (CO) and formyl fluoride (FF) with fragments in the anti conformation, with regard to the orientation of the terminal oxygen in the carbonyl oxide and the flourine atom of the carbonyl compound. The ratio of unimolecular rate constants calculated within the RRKM formalism suggests that the CO-FF channel of cleavage amounts to 98%, which agrees well with the upper bound of experimental esimates. The SOZF decomposition most readily takes place in a stepwise manner initiated by the O-O bond rupture. Two conformational minima are exhibited by SOZF, the O-O and H(2)C-O half-chairs. The calculated rotational constants and scaled frequencies for the O-O half-chair are in good agreement with the experimental values.