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The synthesis and structural characterization of an electron poor Au(III) trication bearing 2 imidazole and 2 acetonitrile ligands is described. The new complex is capable of aryl C–H metalation with the formation of a monomesitylene complex and also demonstrated to be highly oxidizing in the rapid room temperature conversion of cyclohexene to benzene. [ABSTRACT FROM AUTHOR]

A series of nine luminescent iridium(III) complexes with pH-responsive imidazole and benzimidazole ligands have been prepared and characterized. The first series of complexes were of the form [Ir(ppy)2(N^N)]+ or [Ir(ppy)2(C^N)]+ (where ppy is 2-phenylpyridine and N^N is 2-(2-pyridyl)imidazole or 2-(2-pyridyl)benzimidazole and C^N represents a pyridyl-triazolylidene-based N-heterocyclic carbene ligand). For these complexes, the benzimidazole group was either unsubstituted or substituted with electron-withdrawing (Cl) or electron-donating (Me) groups. The second series of complexes were of the form [Ir(phbim)2(N^N)]+ or [Ir(phbim)2(C^N)]+ (where phbim is 2-phenylbenzimidazole and N^N is either 2,2′-bipyridine or 1,10-phenanthroline and C^N is either a pyridyl-imidazolylidene or pyridyl-triazolylidene N-heterocyclic carbene ligand). UV-visible and photoluminescence pH titration studies showed that changing the protonation state of these complexes results in significant changes in the photoluminescence emission properties. The pKa values of prepared complexes were estimated from the spectroscopic pH titration data and these values show that the nature of the pH-sensitive ligands (either main or ancillary ligands) resulted in a significant capacity to modulate the pKa values for these compounds with values ranging from 5.19–11.22. Theoretical investigations into the nature of the electronic transitions for the different protonation states of compounds were performed and the results were consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The monoanion of 1,3-bis(carboxymethyl)imidazolium (H2imdc+) combines with Cu(ii) to produce an undulating 2D coordination polymer of composition [Cu2(imdc)2(CH3OH)2](BF4)2·(CH3OH)(H2O) (1) in which copper acetate-like dimers, linked by imdc− ligands, act as 4-connecting centres. Cationic sheets stack on top of each other in an A, B, A, B… fashion and produce a structure that contains channels running parallel to the plane of network. Tetrafluoroborate anions are located in channels between sheets. Upon removal of coordinated and non-coordinated solvent molecules a single crystal-to-single crystal transformation occurs to yield a similar compound but with BF4− anions now coordinated. CO2 isotherms measured at 258 and 273 K show only modest uptake of CO2 but provide an indication that the sheets move apart at elevated pressures in order to accommodate the guest molecules. A compound of composition [Cu3(OH)2(imdc)2]·SiF6·2H2O·2MeOH (3), which possesses a 3D network, is formed by the combination of copper(ii) acetate, copper(ii) hexafluorosilicate and Himdc. In this structure infinite parallel Cu3(OH)2 chains are linked by bridging imdc− ligands to form channels that have an approximately triangular cross-section. These channels are occupied by SiF62− anions in addition to solvent molecules. When copper(ii) acetate is combined with Himdc in the appropriate ratio, a 1D coordination polymer of composition Cu(imdc)2 (4) is formed in which pairs of imdc− anions bridge Cu(ii) centres. When the reaction is performed in the presence of NaBF4 a minor crystalline product with tetragonal symmetry is isolated in addition to the 1D coordination polymer. This compound of composition Cu2(imdc)4NaBF4·7H2O (5) consists of 2D Cu(imdc)2 networks and features an unusual mode of interpenetration. [ABSTRACT FROM AUTHOR]