title: Generation and spectroscopic identification of ClCNS, ClNCS and NCCNS.
abstract: The photolysis of four chloro-substituted thiadiazoles (3,4-dichloro-, 3-chloro- and 3-chloro-4-fluoro-1,2,5-thiadiazole; 3,5-dichloro-1,2,4-thiadiazole) and 3,4-dicyano-1,2,5-thiadiazole was investigated in inert solid-argon matrices at cryogenic temperatures by means of UV irradiation at selected wavelengths of 254 and 280 nm. The photolysis products were identified by mid-IR and UV spectroscopy. Evidence for the existence of three novel pseudohalides, namely, chloronitrile sulfide (ClCNS), chlorine isothiocyanate (ClNCS) and cyanogen N-sulfide (NCCNS), was provided by direct spectroscopic methods supported by quantum chemical calculations. Ground-state geometries, vibrational frequencies, IR intensities, and UV excitation energies of ClCNS, ClNCS and NCCNS were obtained from calculations using the B3LYP, CCSD(T) and SAC-CI methods and the aug-cc-pV(T+d)Z basis set.
authors.affiliation: Institute of Chemistry, Eötvös University, P.O. Box 32, 1518 Budapest 112 (Hungary), Fax: (+36) 1-372-2909.
authors.forename: Melinda
authors.initials: M
authors.lastname: Krebsz
authors.forename: György
authors.initials: G
authors.lastname: Tarczay
authors.forename: Tibor
authors.initials: T
authors.lastname: Pasinszki
keywords: IR spectroscopy; UV/Vis spectroscopy; heterocycles; matrix isolation; photochemistry