Coordination chemistry of bithiazole ligands: a comparative study of the 2,2’ and 4,4’ isomers

Abstract

The bithiazole ring system consists of two thiazole (C3NS) aromatic rings. There are many regioisomers but two of potential interest for coordination chemistry are the 2,2’-bis(1,3-thiazole) and the 4,4’-bis(1,3-thiazole), because in the syn orientation they have a bipyridyl-like core that could lead to chelating behaviour. Very few single-crystal structures are known to contain bithiazole ligands and those that are known, are mostly of the 4,4’-isomer. This thesis presents work on new ligands using the bithiazole core, reporting the synthesis and coordination chemistry of 2,2’-dichloro-4,4’-bithiazole, 5,5’-dibromo-2,2’-dimethyl-4,4’-bithiazole, and 5,5’-dibromo-2,2’-diamino-4,4’ bithiazole. In solution, the bithiazole ligands are weaker ligands than bipyridyl ligands, but when used in large-scale, and high concentration reactions, a coordination complex can be isolated. UV-vis and combustion analysis evidence are reported to support the formation of the coordination complex. In the case of coordination compounds between silver(I) and a 5,5’-dicyano-2,2’-bithiazoles core, thermogravimetric analysis, differential scanning calorimetry, and X-ray powder diffraction are used to characterize the thermal stability of the known single-crystal structures.