THE PREPARATION, CHARACTERIZATION, CRYSTAL-STRUCTURE AND BIOLOGICAL-ACTIVITIES OF SOME COPPER(II) COMPLEXES OF THE 2-BENZOYLPYRIDINE SCHIFF-BASES OF S-METHYLDITHIOCARBAZATE AND S-BENZYLDITHIOCARBAZATE

The complexes [Cu(NNS)X] (HNNS represents the 2-benzoylpyridine Schiff bases of S-methyl- or S-benzyldithiocarbazate; X = Cl, Br, NO3) have been prepared and characterized by a variety of physico-chemical techn iques. Magnetic and spectral evidence support a square-planar structur e for the [Cu(Bp-SR)X] (Bp-SR=the benzoylpyridine Schiff bases; R = CH 3, CH2C6H5; X = Cl, Br) and [Cu(Bp-SMe)NO3] complexes and a five-coord inate distorted square-pyramidal structure for the [Cu(Bp-SBz)NO3] com plex. The crystal structures of [Cu(Bp-SMe)NO3] and [Cu(Bp-SBz)NO3] ha ve been determined by X-ray diffraction studies. The complex [Cu(Bp-SM e)NO3] crystallizes in the triclinic space group P1 with a = 7.600(3), b = 10.5346(2), c = 11.564(3) Angstrom, alpha = 116.0033(14), beta = 103.91(3), gamma = 91.55(3)degrees, V = 798.3(4) Angstrom(3) and Z = 2 . The complex has a distorted square-planar geometry with the copper i on lying in an approximate plane of four coordinating atoms, three of which come from the 2-benzoylpyridine Schiff base of S-methyldithiocar bazate while the fourth coordination site is occupied by an oxygen fro m the nitrate ligand. The complex, [Cu(Bp-SBz)NO3] crystallizes in the monoclinic space group P2(1)/a with a = 9.0124(19), b = 18.501(5), c = 13.0642(24) Angstrom, beta = 106.377(15)degrees, V = 2089.9(9) Angst rom(3) and Z = 4. The coordination environment around the copper(II) i on is a distorted square-pyramid with three donor atoms (NNS) coming f rom the 2-benzoylpyridine Schiff base and the fourth and fifth atoms ( oxygen) coming from the bidentate NO3- ion. The antifungal and antibac terial properties of the copper(II) complexes have been evaluated agai nst three pathogenic fungi and two bacteria. The Schiff bases and copp er (II) complexes display moderate antifungal activities but their act ivities are less than that of the commercially important antifungal ag ent nystatin.