Syntheses, Crystal Structures and Antimicrobial Activity of Copper(II) and Zinc(II) Complexes with Aroylhydrazones

A pair of structurally similar dinuclear copper(II) and zinc(II) complexes, Cu-2(L-1)(2) (1) and [Zn-2(L-2)(2) (CH3OH)(2)] (2), where L-1 and L-2 are the dianionic form of 2-bromo-N'-(2-hydroxy-5- methylbenzylidene)benzohydrazide (H2L1) and 2-chloro-N'-(2-hydroxy-5-methylbenzylidene)benzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared spectra and single-crystal X-ray diffraction. Complex 1 crystallizes in the triclinic space group P (1) over bar, with unit cell parameters: a=0.914 11(6) nm, b=1.180 04(7) nm, c=1.359 36(9) nm, alpha=101.928(2)degrees, beta=91.399(2)degrees, gamma=107.873(2)degrees, V=1.359 3(2) nm(3), Z=2, R-1=0.054 0, wR(2)=0.118 9, GOF=0.970. Complex 2 crystallizes as the monoclinic space group P2(1)/c, with unit cell parameters: a=1.216 97(9) nm, b=1.214 96(9) nm, c=1.212 83(9) nm, beta=110.939(1)degrees, V=1.674 8(2) nm(3), Z=2, R-1=0.034 1, wR(2)=0.068 9, GOF=1.024. X-ray analysis indicates that the complexes are centrosymmetric dinuclear species, with the Cu atoms in 1 in square planar coordination, and with the Zn atoms in 2 in square pyramidal coordination. The complexes were evaluated for their antibacterial (B. subtilis, S. aureus, E. coli and P. aeruginosa) and antifungal (C. albicans and A. niger) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. CCDC: 1447054, 1; 1447056, 2.