Tetranuclear Cu(II) complex with octaazamacrocycle and bridging bicyclic dicarboxylato ligands

A new tetranuclear copper(II) complex of the formula [Cu4L(tpmc)2](ClO4)6·4NaClO4 (tpmc = N,N,N,N-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane; L = endo-bicyclo[2.2.1]-hept-5-en-2,3-cis-dicarboxylate dianion) has been isolated. The complex was characterized by elemental analysis, magnetic and conductometric measurements, electronic and IR spectroscopy and cyclic voltammetry (CV). This is one of the rare cases when a tetranuclear complex with tpmc is formed, with the bulky bicyclic dicarboxylate as the bridging ligand between two tpmc units in which two copper(II) ions are coordinated in the exo position

Interesting coordination abilities of antiulcer drug famotidine and antimicrobial activity of drug and its cobalt(III) complex

Crystal structure of a novel cobalt(III) complex with antiulcer drug famotidine and ethylenediamine was determined. This is the second structure of a transition metal complex with famotidine resolved by a single crystal X-ray analysis, in which famotidine shows different mode of coordination than that observed in the other cases. Drug molecule is coordinated to metal ion as a tetradentate ligand through guanidine N6, thiazole N4, thioether S2 and terminal N3 atom. Two NH2 groups (N3H(2) and N6H(2)) are deprotonated and drug coordinates as dianion. In the asymmetric unit, one chloride anion and one water molecule were found to complete the complex stoichiometry. The structure of the complex is abundant in atoms, which can be involved in hydrogen bond formation either as hydrogen acceptors or hydrogen donors. Because of that, a great number of hydrogen bonds dominates the crystal packing. Beside the hydrogen bonds, there are two interesting noncovalent interactions: CH...pi and NH...pi within the famotidine anion, which stabilize the complex structure. The pi...pi stacking interactions between neighboring complex cations are also observed. Antibacterial and antifungal activity of famotidine and its newly synthesized complex against representative bacteria: Escherichia coli, Staphilococcus aureus and Micrococcus lysodeikticus and fungi: Aspergillus niger and Candida albicans were examined. The results indicate a higher selectivity of the famotidine-Co(III) complex, as well as better growth inhibitory activity (lower MIC values (MIC, minimal inhibitory concentration)) in comparison with the drug alone. (c) 2006 Elsevier Inc. All rights reserved

Synthesis, structure and magnetic properties of the first copper(II) complex with an (E)-4-aryl-4-oxo-2-butenoato ligand

A new binuclear Cu(II) complex with an (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato ligand (L) was successfully synthesized and characterized by elemental analysis and IR-spectroscopy. The structures of (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoic acid (HL), and the corresponding (tetrakis)-mu-[(E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato]-bis(ethanol)-copper(II) complex, [Cu2L4(C2H5OH)(2)], were determined by single crystal X-ray analyses and are preliminarily discussed. This is the first complex of a transition metal with ligand L. as well as the first determined crystal structure of a metal complex with this type of ligand. Analysis of the magnetic susceptibility measurements of the isolated [Cu2L4(C2H5OH)(2)]center dot H2O complex shows the existence of a strong anti-ferromagnetic intra-dimer coupling, with an exchange integral value 2J of -260 cm(-1). (C) 2006 Elsevier B.V. All rights reserved