Heterocyclo-Substituted Sulfa Drugs: Part XII. Mercapto-S-Azo-Benzothiazol Dyes and Their Metal Complexes.

New azo sulfadrugs of 2-mercapto-S-azo ( p ′-heterocyclo-substituted benzene-sulfonyl) benzothiazole derivatives (L 1 and L 2 ) were synthesized by coupling of p ′-heterocyclo-substituted-benzene-sulphonyl diazonium salts with 2-mercapto-benzothiazole in acid medium. The corresponding iron(III), cobalt(II), nickel(II), copper(II), and mercury(II) chelates were prepared in a 1:1 metal to ligand molar ratio. The ligands and their chelates were characterized on the basis of microanalysis, UV, IR, and H 1 -NMR spectrometry. Thermal decomposition of the complexes was studied in static air. On the basis of the thermogravimetric curves some decomposition steps could be correlated with the proper decomposition products. The photochemical behavior of the ligands and their complexes were investigated. The photosensitivity shown by the complexes was attributed to the photoreactivity of their free ligands. The ligands and their chelates were screened in vitro for their antimicrobial activities (antibacterial and antifungal). The complexes induce a remarkable increase in the antimicrobial activity compared to the corresponding ligands. [ABSTRACT FROM AUTHOR]