Antimicrobial effect of oligomeric copper(ii) derivatives of bis(pyrimidin-2-ylthio)- and bis(4,6-dimethylpyrimidin-2 ylthio)alkanes

Abstract

A novel series of copper(II) derivatives of bis(pyrimidin-2-ylthio)- and bis(4,6-dimethylpyrimidin-2-ylthio)alkane of general formula [Cu x Cl y (L) z ] n {x = 1, y = 2, z = 1, L = ptm (1), pte (2), dptm (4), dpte (5), dpth (6); x = 2, y = 4, z = 3, L = pth (3)} were tested for antimicrobial activity. These complexes were characterized by elemental analysis, infrared spectroscopy (IR) and gel permeation chromatography (GPC). Complex-4, 5 and 6 have the metal at the center of a square planar geometry, and in complex-1, 2 and 3 the metal is at the center of a square pyramidal geometry. The structure of complex-4, determined by X-ray diffraction analysis, shows this compound as an oligomer with one-dimensional chain in zigzag conformation. The high average molecular weight (Mw) of these copper(II) complexes confirms their oligomeric character. Although the free ligands were inactive against the microorganisms tested, the copper(II) derivatives showed good antifungal and antibacterial inhibition against C. albicans, C. tropicalis, S. aureus and E. coli, more effective than Nystatin and Norfloxacin.