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 wi th broad-band UV-visible radiat ion (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 dif ferent paral lel 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 *Cl -N orbital of ClNCO was proposed. On the other hand, FSO2NCO remains almost photostable when exposed to similar conditions, with the only formation of FNCO and CO in very small proportions.