Raman, FT-IR, NMR spectroscopic data and antimicrobial activity of bis[mu(2)-(benzimidazol-2-yl)-2-ethanethiolato-N,S,S-chloro-palladium(II)] dimer, [(mu(2)-CH2CH2NHNCC6H4)PdCl](2)center dot C2H5OH complex

Abstract

The 1,6-bis(benzimidazol-2-yl)-3,4-dithiahexane (1) ligand and its palladium(H) chloride complex [(mu(2)-SCH2CH2NHNCC6H4)PdCl](2) center dot C2H5 OH (2) have been synthesised and characterised by spectroscopical methods. The crystal structure of the triclinic title compound (P-1 (no. 2), a = 879.6(l) pm, b = 984.4(l) pm, c = 1471.8(2) pm; a = 94.330(6)degrees, beta = 98.546(6)degrees, gamma = 99.258(7)degrees, Z = 2) was solved from X-ray single crystal diffraction data. In the binuclear complex, each palladium atom is coordinated in a slightly distorted square-planar arrangement by one nitrogen, two bridging sulphurs and one terminal chlorine atom. Molar conductivity, FT-Raman, FT-IR (mid-i.r., far-i.r.), H-1 and C-13 NMR spectra of the complex (2) have been recorded and show a good accordance with the square-planar geometry. The antimicrobial and antifungal activities of palladium(II) chloride, free ligand, its hydrochloride salt and the complex were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) the dilution method, against 10 bacteria and five yeast cultures. The results for the antibacterial from the disk diffusion method were assessed in side-by-side comparison with those for penicillin-g, ampicillin, cefotaxime, vancomycin, ofloxacin and tetracycline. Antifungal activities were referenced with nystatin, ketaconazole, and clotrimazole, commercial antifungal agents. The data from the dilution procedure were compared with gentamycin as antibacterial and nystatin as antifungal agent, respectively. In most cases, the compounds tested showed broad-spectrum (Gram positive and Gram negative) activities that were comparatively more active, or as potent as referenced pharmaceutical agents. The palladium complex has the potential to generate new kind of metabolites by displaying high affinities for most of the receptors compared with palladium chloride, free ligand and its hydrochloride salt.