N(4)-tolyl-2-benzoylpyridine thiosemicarbazones and their copper(II) complexes with significant antifungal activity.: Crystal structure of N(4)-para-tolyl-2-benzoylpyridine thiosemicarbazone

Three new copper complexes of general formula [Cu(HL)Cl-2] have been obtained with N(4)-ortho (H(2)Bz4oT, HL1), N(4)-meta (H(2)Bz4mT, HL2) and N(4)-para-tolyl-2-benzoylpyridine thiosemicarbazone (H(2)Bz4pT, HL3), in which the thiosemicarbazone attaches to the metal through the N-py-N-S chelating system. H(2)Bz(4)pT (HL3) crystallizes in the P (1) over bar space group, with a = 9.509(3) angstrom, b = 9.807(4) angstrom, c = 11.564(4) angstrom; alpha = 100.76(2), alpha = 105.99(2). = 114.59(2). The thiosemicarbazones and their copper(II) complexes exhibit high antifungal activities against Candida albicans with low values of minimum inhibitory concentration ( MIC), in the 8-0.3 mu g mL(-1) (23 - 0.7 mu mol L-1) range for the free bases and in the 1-0.1 mu g mL(-1) (2 - 0.3 mu mol L-1) range for the complexes. Our results suggest that coordination to copper( II) could be an interesting strategy for dose reduction.