Copper(II) Compounds of 4-Nitrobenzohydrazide with Different Anions (ClO4 - , NO3 - and Br- ): Synthesis, Characterization, DFT Calculations, DNA Interactions and Cytotoxic Properties.

Copper complexes containing 4-nitrobenzohydrazide (4-NH), [Cu(4-NH)2 (ClO4 )2 ] (1), [Cu(4-NH)2 (NO3 )2 ] (2) and [Cu(4-NH)2 Br2 ] (3), were synthesized and characterized by various spectroscopy. DFT calculations have revealed a distorted octahedral for 1, 2 and 3. DNA interactions of 1-3 toward calf-thymus DNA were investigated by absorption titration, viscosity, fluorescence spectroscopy and gel electrophoresis. All complexes bind to DNA via intercalation mode. The Kb values have shown the binding ability in the order of 3>2>1. The in vitro cytotoxicity of 1-3 was tested against two human cancer cells (HeLa and MCF-7) and normal Vero cells by MTT assay. All complexes show anticancer ability upon increasing time, but the ligand is inactive. Complex 3 with the Br- anion gives the lowest IC50 values of 19.26±2.43 µg/mL toward MCF-7. Moreover, all complexes were not arrested at any cell cycle phases. However, the sub-G1 populations were enhanced upon increasing the complex concentration. Therefore, they may induce apoptotic cell death for both cancer cells. The antibacterial activity of 1-3 was tested against E. coli, Salmonella and Campylobacter. Complex 3 gives the best activity toward Campylobacter (0.156×103  µg/mL).

Methanol[1-(methoxymethanimidoyl)-2-(pyridin-2-ylmethyl)guanidine]bis(perchlorato)copper(II).

The title complex, [Cu(ClO(4))(2)(C(9)H(13)N(5)O)(CH(3)OH)], was synthesized from a methanolysis reaction of N-(methylpyridin-2-yl)cyanoguanidine (L(3)) and copper(II) perchlorate hexahydrate in a 1:1 molar ratio. The Cu(II) ion is six-coordinated by an N(3)O(3) donor set which confers a highly distorted and asymmetric octahedral geometry. Three N-donor atoms from the chelating 1-(methoxymethanimidoyl)-2-(pyridin-2-ylmethyl)guanidine (L(3m)) ligand and one O atom from the methanol molecule define the equatorial plane, with two perchlorate O atoms in the apical sites, one of which has a long Cu-O bond of 2.9074 (19) Å. The dihedral angle between the five- and six-membered chelate rings is 8.21 (8)°. Two molecules are associated into a dimeric unit by intermolecular N-H...O(perchlorate) hydrogen bonds. Additionally, the weakly coordinated perchlorate anions also link adjacent [Cu(ClO(4))(2)(L(3m))(CH(3)OH)] dimers by hydrogen-bonding interactions, resulting in a two-dimensional layer in the (100) plane. Further C-H...O hydrogen bonds link the two-dimensional layers along [100] to generate a three-dimensional network.

Bis(1-carbamimidoyl-2-ethyl-isourea)copper(II) bis-(perchlorate).

The title complex, [Cu(C(4)H(10)N(4)O)(2)](ClO(4))(2) or [Cu(L(1e))(2)](ClO(4))(2), where L(1e) is 1-carbamimidoyl-2-ethyl-isourea, was obtained from the ethano-lysis reaction of 2-cyano-guanidine and copper(II) perchlorate hexa-hydrate in a 2:1 molar ratio. The two bidentate L(1e) ligands are coordinated to the Cu(II) center through N-donor atoms, leading to the CuN(4) chromophore. The Cu(II) environment is slightly distorted square-planar, with a dihedral angle of 5.17 (6)° between the two six-membered chelate rings. One of the ClO(4) (-) anions is disordered over two positions in a 0.6:0.4 ratio.

Bis(1-carbamimidoyl-2-ethyl-isourea)copper(II) dinitrate.

The copper(II) complex, [Cu(C(4)H(10)N(4)O)(2)](NO(3))(2) or [Cu(L(1e))(2)](NO(3))(2), where L(1e) is 1-carbamimidoyl-2-ethyl-isourea, was obtained from a 1:2 molar ratio of copper(II) nitrate hemipenta-hydrate with 2-cyano-guanidine in ethanol. The crystal structure consists of the centrosymmetric [Cu(L(1e))(2)](2+) cation and two NO(3) (-) counter-anions. The cation exhibits four-coordinate bonding of the two N,N-bidentate ligands and the Cu(II) atom through the N-donor atoms, yielding a square-planar CuN(4) geometry. Inter-molecular N-H⋯O hydrogen bonds link between the cation and and counter-anion, forming a two-dimentional layered structure extending parallel to (01).