Synthesis, Structural and Biochemical Activity of Pyridine Substituted Pyrrole Ligands and Their Mononuclear Cu(II), Ni(II) and Co(II) Complexes

Abstract

Monomeric copper(II), nickel(II) and Co(II) complexes of 6-(2,5-dimethyl-1H-pyrrol-1- yl)pyridin-2-amine (dmpypr) and 2,6-bis(2,5-dimethyl-1H-pyrrol-1-yl)pyridine (tmpypr) were prepared and characterized by elemental analyses, magnetic moments, 1H and ¹³C NMR, IR, mass spectral studies. The mononuclear metal complexes of dmpypr and tmpypr were found to have a 1:2 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of metal complexes indicated that the metal ions were coordinated to the -NH₂ and C=N group nitrogen atoms. All of the data obtained from spectral studies supported the structural properties of ligands and their metal complexes. The free ligands and their metal complexes showed antimicrobial activity against S. aureus but no antifungal activity was observed against yeast like fungi. Among them, copper complexes and free ligands showed a narrow range of inhibitory activity against Mycobacterium smegmatis. Free ligands (2, 3), were found to have activity against Saccharomyces cerevisiae (Sc).