Antimicrobial Activity of Anionic Bis(-Heterocyclic Carbene) Silver Complexes.

The antimicrobial properties of a series of anionic bis(carbene) silver complexes Na[Ag(NHC)] were investigated (- and , where NHC is a 2,2'-(imidazol-2-ylidene)dicarboxylate-type -heterocyclic carbene). The complexes were synthesized by the interaction of imidazolium dicarboxylate compounds with silver oxide in the presence of aqueous sodium hydroxide. Complexes , were characterized analytically and spectroscopically, and the ligand precursor and complexes and were structurally identified by X-ray diffraction methods.

Chirality influence on the cytotoxic properties of anionic chiral bis(N-heterocyclic carbene)silver complexes.

Complexes Na[Ag(NHC)], 2a-e and 2b'-c', where NHC is a N-heterocyclic carbene of the 2,2'-(1H-2λ,3λ-imidazole-1,3-diyl)dicarboxylate type, were prepared by treatment of compounds HL, 1a-e and 1b'-c' (2-(1-(carboxyalkyl)-1H-imidazol-3-ium-3-yl)carboxylate), with silver oxide in the presence of aqueous sodium hydroxide. They were characterized by analytical, spectroscopic (infrared, IR, H and C nuclear magnetic resonance, NMR, and circular dichroism) and X-ray methods (2a). In the solid state, the anionic part of complex 2a, [Ag(NHC)], shows a linear disposition of C-Ag-C atoms and an eclipsed conformation of the two NHC ligands.

Antimicrobial Properties of Amino-Acid-Derived N-Heterocyclic Carbene Silver Complexes.

Complexes {Ag[NHC]} (R = H, ; Me, and ; Pr, ; Bu, ), were prepared by treatment of imidazolium precursor compounds [Im] (2-(3-mesityl-1-imidazol-3-ium-1-yl)acetate, , ()-2-(3-mesityl-1-imidazol-3-ium-1-yl)acetate, -, and ()-2-methyl(3-mesityl-1-imidazol-3-ium-1-yl)acetate, , with AgO under appropriate conditions. They were characterised by analytical, spectroscopic (IR, H, and C NMR and polarimetry), and X-ray methods (). In the solid state, is a one-dimensional coordination polymer, in which the silver(I) cation is bonded to the carbene ligand and to the carboxylate group of a symmetry-related Ag[NHC] moiety.

Homochiral imidazolium-based dicarboxylate silver(I) compounds: synthesis, characterisation and antimicrobial properties.

Complexes [Ag(L)], 2 (L = 2,2'-(imidazolium-1,3-diyl)di(2-acetate)), were prepared by treatment of compounds HL, 1, with AgO. They were characterised by analytical, spectroscopic (IR, H and C NMR and polarimetry) and X-ray methods (2c, 2c' and 2e). In the solid state, these compounds are novel one-dimensional or two-dimensional coordination polymers in which silver(I) cations are connected the chiral [L] anion with unprecedented coordination modes.

Molybdenum-Catalyzed Enantioselective Sulfoxidation Controlled by a Nonclassical Hydrogen Bond between Coordinated Chiral Imidazolium-Based Dicarboxylate and Peroxido Ligands.

Chiral alkyl aryl sulfoxides were obtained by molybdenum-catalyzed oxidation of alkyl aryl sulfides with hydrogen peroxide as oxidant in mild conditions with high yields and moderate enantioselectivities. The asymmetry is generated by the use of imidazolium-based dicarboxylic compounds, HL. The in-situ-generated catalyst, a mixture of aqueous [Mo(O)(O₂)₂(H₂O)] with HL as chirality inductors, in the presence of [PPh₄]Br, was identified as the anionic binuclear complex [PPh₄]{[Mo(O)(O₂)₂(H₂O)]₂(μ-L)}, according to spectroscopic data and Density Functional Theory (DFT) calculations.

Oxidoperoxidomolybdenum(vi) complexes with acylpyrazolonate ligands: synthesis, structure and catalytic properties.

Oxidoperoxido-molybdenum(vi) complexes containing acylpyrazolonate ligands were obtained by reaction of [Mo(O)(O)(HO)] with the corresponding acylpyrazolone compounds HQ. Complexes PhP[Mo(O)(O)(Q)] (R = neopentyl, 1; perfluoroethyl, 2; hexyl, 3; phenyl, 4; naphthyl, 5; methyl, 6; cyclohexyl, 7; ethylcyclopentyl, 8) were obtained if the reaction was carried out with one equivalent of HQ in the presence of PhPCl. Alternatively, neutral complexes [Mo(O)(O)(Q)] (R = neopentyl, 9; hexyl, 10; cyclohexyl, 11) were formed when two equivalents of HQ were used in the reaction.

Experimental and theoretical insights into the oxodiperoxomolybdenum-catalysed sulphide oxidation using hydrogen peroxide in ionic liquids.

The oxidation of organic sulphides with aqueous hydrogen peroxide in ionic liquids (ILs) catalysed by oxodiperoxomolybdenum complexes was investigated. The selective formation of several sulfones was achieved using the 1 : 3 ratio of sulphide : H2O2 in [C4mim][PF6] (C4mim = 1-butyl-3-methylimidazolium) in a reaction catalysed by the [Mo(O)(O2)2(H2O)n] complex. Conversely, sulfoxides were produced with good selectivities using a 1 : 1 ratio in the same solvent in a 1 h reaction with [Mo(O)(O2)2(Mepz)2] (Mepz = methylpyrazol).