Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: A supramolecular structure

Two new cadmium(II) complexes with the formula of CdL2(NCS)(2) and CdL2(N-3)(2) (in which L is 2,2-dimethyl-N,N'-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV-Visible, H-1 and C-13 NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N-2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd-N-imine bond distances are found in the range of 2.363(2)-2.427(2) angstrom while the Cd-N-isothiocyanate bond distances are 2.287(2) angstrom and 2310(2) angstrom. The existence of C-H center dot center dot center dot pi and C-H center dot center dot center dot S interactions in the CdL2(NCS)(2) crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated. (C) 2014 Elsevier B.V. All rights reserved.