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 NH(2) 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.

Synthesis, characterization and antimicrobial activity of Co(II), Zn(II) and Cd(II) complexes with N-benzyloxycarbonyl-S-phenylalanine.

In this paper the first complexes of M(2+) ions (M(2+) = Zn(2+), Cd(2+) and Co(2+)) with N-benzyloxycarbonyl-S-phenylalaninato ligand (1-3) are described. The new complexes were characterized by means of elemental analysis, IR and UV-vis spectroscopy, molar conductivity measurements and (1)H, (13)C and (15)N NMR spectroscopy (1D and 2D). The Co(II) complex adopts an octahedral geometry, and the Zn(II) and Cd(II) complexes adopt a tetrahedral one. For the first time, the antimicrobial activity of N-benzyloxycarbonyl-S-phenylalaninato ligand (N-Boc-S-phe) and the complexes 1-3 was investigated against gram-positive: Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Bacillus subtilis and gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and two strains of the yeast Candida albicans. It was shown that the complexes were effective against most strains. The best activity was detected against the yeast C. albicans.

Mixed cobalt(III) complexes with aromatic amino acids and diamines. III. Absolute structure of Lambda-trans(O)-(1,2-diaminoethane-kappa(2)N,N)bis(S-tyrosinato)cobalt(III) chloride tetrahydrate.

The title compound, [Co(C(9)H(10)NO(3))(2)(C(2)H(8)N(2))]Cl.4H(2)O, is one of six possible diastereomers of the (1,2-diaminoethane)bis(S-tyrosinato)cobalt(III) complex. The cobalt(III) ion has an octahedral coordination, with three five-membered chelate rings which have deformed coordination angles and coordinated O atoms in trans positions. In comparison with the previously reported crystal structure of the Delta-C(1)-cis(O) diastereomer [Miodragovic et al. (2001). Enantiomer, 6, 299-308], the compound presented in this paper has more planar five-membered aminocarboxylate rings. Complex cations, chloride anions and water molecules of crystallization are linked together by a network of hydrogen bonds. The chloride anions lie approximately between two Co atoms and form hydrogen bonds with all coordinated NH(2) groups. In the crystal structure, there is a weak intermolecular pi...pi interaction between the phenyl rings.