Synthesis, spectroscopic, theoretical and structural studies of new trihalomethyl sulphenyl derivatives of 5‐methyl‐1,3,4‐thiadiazole‐2‐thiol

Abstract

Although 2-mercapto-5-methyl-1,3,4-thiadiazole (mmtd) is commonly thought of as a thione tautomer, electrophilic substitution occurs on the thiol moiety. The tautomeric ability of mmtd allows a substitution reaction to take place at the sulphur; this is shown by reaction with Cl 3Àn F n CSCI compounds (n = 0-2) to give perhalomethyldithio thiadiazole derivatives. Three novel perhalomethylsulphenyl compounds, which exhibit a wide range of potentially interesting applications, were obtained and characterized by x-ray crystal diffraction, mass spectrometry, IR and Raman spectroscopy and density functional theory calculations.

Raman, infrared and NMR spectral analysis, normal coordinate analysis and theoretical calculations of 5-(methylthio)-1,3,4-thiadiazole-2(3H)-thione and its thiol tautomer

“…The tautomeric equilibria of mercapto thiadiazoles has been a source of controversy for many authors [1118] since the thione form is proposed to be the prevailing species according to vibrational spectroscopy [1115], whereas the existence of the thiol form has also been suggested [1618]. Moreover, the occurrence of thiolthione tautomerism was reported [9,19,20] where the thione tautomer was favoured for 4-thiazoline-2-thiones [9] and a signature of the thione tautomer was also observed in the FT-IR spectrum of 1,3,4-thiadiazol-2-thione derivatives in an Ar-matrix [19]. In addition, a thione tautomer is verified for 1,3,4-thiadiazole/thione and the derivatives of 5-methyl-1,3,4-thiadiazole-2-thiol [20].…”

Thiadiazoles

“…More recently, fragmentation studies of several trihalomethylsulfenyl derivatives of 5-methyl-1,3,4-thiadiazole-2-thiols 540 and 541 have been reported [274]. The diagnostic fragments are characterized by the loss of the halogenated substituents, and in all cases cleavage via fragmentation a (Figure 14.6 …”

Crystal structure of poly-bis(1,3,4-thiadiazolium-2-thiolato)lead(II), Pb(C2HN*S2)2

“…One of the scientific most important features concerning high performance for lead removal is the coordination behavior of Pb ion [1][2][3]. Furthermore, thiadiazoles have attracted increasing attention because of their potential applications in coordination and polymer chemistry [4][5][6]. Recently, we synthesized a versatile bifunctional ligand based on 1,3,4-thiadiazole [7].…”