Investigation of half-sandwich platinum group metal complexes featuring benzamide derived ligands and their diazido derivatives: Synthesis, molecular structures and biological studies

Abstract

Benzamide derivative ligands L1 and L2 were synthesized and reactions of these ligands with metal dimers [Ru(p-cymene)Cl2]2 and [Cp*MCl2]2 (M = Rh/Ir) yielded a series of “piano-stool”-type neutral mononuclear metal-arene-benzamide complexes (1, 2, 3, 4, 5 and 6) of the general formula [(arene)M(κ1(N)L)Cl2] (where arene = p-cymene and Cp*, M = Ru, Rh and Ir and L = L1 and L2). Further treatment of the neutral complexes 1-6 with sodium azide in methanol resulted in the formation of diazido complexes 7, 8, 9 and 10. Crystallographic studies of the complexes 2, 5, 7 and 8 revealed the ligands coordinated to the metal centers through the nitrogen atom of thiazole/thiadiazole ring in a monodentate fashion. The complexes were characterized by NMR, FTIR, UV-Vis spectroscopy and ESI-mass spectrometry. All the ligands and metal complexes were screened for their antibacterial and antioxidant activities. Interestingly, it was observed that only the diazido complexes were active towards the Gram-positive Staphylococcus aureus bacterial strains, with activities more than the standard. Antioxidant study revealed that the compounds possess insignificant activities.