Formation of XNCO species (X = F, Cl) through matrix -isolation photochemistry of XSO2NCO molecules

NORMA LIS ROBLES; ANDREA FLORES ANTOGNINI; ROSANA MARIEL ROMANO

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2011 vol. 223 p. 194 - 201

1010-6030

The photochemistries of the molecules ClSO2NCO and FSO2NCO isolated in solid argon matrices at 10 K have been investigated. After photolysis of the matrices with broad-band UV-visible radiation (200-800 nm) the products were identified by their IR spectra. ClSO2NCO decomposes in two steps. In the first place, the photolysis gives a 1:1 molecular complex between SO2 and ClNCO. In the second step, ClNCO decomposes in different parallel photochemical channels to give ClNO, NO, CO and the ClCO· radical , while SO2 , transformed from a complexed to an uncomplexed form, remains stable on photolysis. The SO2 :ClNCO molecular complex was theoretically investigated by ab initio and DFT methods. Based on the comparison with the experimental findings, a structure in which the lone pair of one of the oxygen atoms of the SO2 unit interacts with the unoccupied sigma*Cl-N orbital of ClNCO was proposed. On the other hand, FSO2NCO remains almost photostable whenexposed to similar conditions, with the only formation of FNCO and CO in very small proportions.