Microwave spectra of isotopic thiazoles. Molecular structure and 14N quadrupole coupling constants of thiazole

Abstract

Microwave spectra of thiazole and the eight monosubstituted isotopic species have been investigated. For the parent and four substituted species the 14N hyperfine structure was analyzed and the nuclear quadrupole coupling constants determined. These coupling constants were used to derive center frequencies for all except the 15N species. The rotational constants were computed by least squares in the rigid rotor approximation. The substitution structure of thiazole is given and discussed. Except for the N,C(4) bond and its nearest angles, the thiazole molecule is very well described as a 1:1 composition of thiophene and 1,3,4-thiadiazole.