Thermal behaviour and characterisation of new biologically active Cu(II) complexes with benzimidazole as main ligand

• Published in: Journal of thermal analysis and calorimetry Vol. 118; no. 2; pp. 1119 - 1133
• Main Authors: Badea, Mihaela, Vlaicu, Ioana Dorina, Olar, Rodica, Constand, Madalina, Bleotu, Coralia, Chifiriuc, Mariana Carmen, Marutescu, Luminita, Lazar, Veronica, Grecu, Maria Nicoleta, Marinescu, Dana
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2014; Springer
• Subjects: Analysis; Analytical Chemistry; Bacteria; Bridges (structures); Calorimetry; Chemistry; Chemistry and Materials Science; Coordination compounds; Copper compounds; Decomposition; Electronics; Inorganic Chemistry; Ligands; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences; Thermal analysis; Copper(II) complex; Antimicrobial activity; Thermal behaviour; Acrylate; Benzimidazole
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-014-3745-z

Four coordination compounds of copper(II) were synthesised and characterised in solid state by elemental analysis, infrared, electronic and EPR spectroscopy, as well as by thermal analysis (TG/DTA). The complexes were formulated on the basis of experimental data as: [Cu(BzIm) 2 (H 2 O)]·H 2 O ( 1 ), [Cu 2 (Acr) 4 (HBzIm) 2 ] ( 2 ), [Cu(Acr) 2 (HBzIm) 2 ] ( 3 ) and [Cu(Acr) 2 (HBzIm) 2 (H 2 O)]·H 2 O ( 4 ). IR data are in accordance with the unidentate nature of benzimidazole, in complexes ( 2 ), ( 3 ) and ( 4 ), and bridge bidentate nature of benzimidazole, in complex ( 1 ), while acrylato acts as uni- or bridge/chelate ligand. The electronic spectra display the characteristic pattern of square planar, square pyramidal, or octahedral stereochemistry, also confirmed by EPR spectra. Thermal decomposition evidenced several well-defined steps as dehydration of complexes ( 1 ) and ( 4 ), benzimidazole molecule releases for all complexes and acrylate decomposition in carbonate for complexes ( 3 ) and ( 4 ). In all four cases, the final residue after thermal treatment in air flow is copper(II) oxide, formed during the decomposition steps for complexes ( 3 ) and ( 4 ), and, respectively, after the oxidation of the metallic copper for complexes ( 1 ) and ( 2 ). Antimicrobial activities of the complexes have been determined by in vitro assays, against various Gram-negative and Gram-positive bacterial and fungal strains. Copper(II) complexes were also evaluated for their cytotoxicity on eukaryotic cells.