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.

Dissociation pathways for the molecular cation of 3,4‐dichloro‐1,2,5‐thiadiazole: A time‐of‐flight mass spectrometry and computational study

“…The photochemistry of the parent and substituted 1,2,5‐thiadiazole in the gas phase has been studied mostly for the production and characterization of various nitrile N ‐sulfides (R‐CNS). Pasinszki and co‐workers have generated various R‐CNS such as ClCNS, CH 3 CNS, ClNCS and NCCNS in the matrix by 254 nm UV irradiation of the parent and various substituted 1,2,5‐thiadiazoles . In a similar context, electron ionization studies of 1,2,5‐thiadiazole have been undertaken for the generation of ions related to various nitrile N ‐sulfides such as, NCCNS, H 2 NCNS, H 3 CSCNS, and ClCNS.…”