High-resolution infrared and theoretical study of gaseous 1,2,5-selenadiazole in the 600–1400cm−1 range

High-resolution infrared and theoretical study of the fundamental bands ν2, ν4 and ν9 and the c-Coriolis interacting dyad ν5, ν14 of 1,3,4-thiadiazole

“…Four fundamental bands in the ringand CH-deformation region 800-1000 cm À1 and one band near 1400 cm À1 of 1,3,4-thiadiazole are dealt with in the present work. The appearance of these bands is very similar to those analysed previously in [1,2].…”

“…The a-inertial axis coincides with the C 2 -axis, as in Eq. (1). The 15 normal vibrations of the molecule are classified by symmetry as: m 1 -m 6 (A 1 ), m 7 -m 8 (A 2 ), m 9 -m 10 (B 1 ), m 11 -m 15 (B 2 ).…”

“…We have described in detail [1,2,7] our methods of both assigning and fitting of a-, b-, and c-type bands of asymmetric tops, with the same range of asymmetry as 1,3,4-thiadiazole, and where j is numerically small. The Reader is therefore referred to these papers for these details.…”

“…In recent papers, we studied the unsaturated five-membered heterocyclic sulphur-containing compounds 1,2,5-thiadiazole, C 2 H 2 N 2 S [1] and the parent ring system thiophene, C 4 H 4 S, [2]. The present Note deals with 1,3,4-thiadiazole, (1).…”

Improved synthesis and characterisation of 1,3,4-oxadiazole

“…In the context of recent experimental and computational studies on the high resolution vibrational spectra of some fundamental heterocyclic compounds, [1][2][3][4][5][6] we needed to prepare 1,3,4-oxadiazole 1. 7 Although this simple compound was first reported in 1965, 8 only one method has ever been described for its preparation, 9 and this involves thermal elimination of ethanol from compound 2, itself formed by reaction of N-formylhydrazine with triethyl orthoformate (Scheme 1).…”