“Honeycomb” (6, 3) network constructed from 14-membered ring [Ag2(μ-dppb)2]: Synthesis, characterization and crystal structures of two silver(I) complexes of bis(diphenylphosphino)butane

Coordination Assemblies of Acetylenic Dithioether Ligands on Silver(I) Salts: Crystal Structure, Antibacterial and Cytotoxicity Activities

Coordination polymers (CPs) and metal-organic frameworks (MOFs) constitute a new class of antibacterial materials. Interest in them stems from their wide range of topology, dimensionality, and secondary building units that can be tuned by an appropriate choice of metal ions and ligands. In particular, silver-based species feature good antibacterial properties. In this study, we explored the coordination of three acetylenic dithioether RSCH2C≡CCH2SR [R = phenyl (LPh), cyclohexyl (LCy), or tert-butyl (LtBu)] ligands on several silver salts (silver tosylate, silver triflate, and silver trifluoroacetate). The crystallographic characterization evidenced the formation of a molecular macrocycle and six CPs with different dimensionalities, ranging from one to two dimensions. In most cases, they are composed of four-coordinated silver atoms in a tetrahedral environment. Their antibacterial activity was investigated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. All CPs present good antibacterial properties against the tested bacteria with minimal inhibitory concentrations ranging from 5 to 40 μg of Ag/mL. Interestingly, we found that these values could not be correlated to their architecture or morphology or to the amount of silver released. The cytotoxicity of these compounds was also evaluated on normal human dermal fibroblasts, and three of these CPs were found to be biocompatible.

Syntheses and Structures of d10 Coinage Metal Complexes of Electron-Accepting Phosphine Ligands Featuring a 3,3,4,4,5,5-Hexafluorocyclopentene Framework

Cu(I), Ag(I), and Au(I) complexes of monophosphine or bisphosphine ligands based on the 3,3,4,4,5,5-hexafluorocyclopentene skeleton were synthesized and structurally characterized by X-ray crystallographic analysis. The electron-withdrawing nature of these polyfluorinated phosphines was experimentally revealed via UV/vis absorption studies and crystal structure analysis. Successful catalytic application of the Au(I) complex for alkyne hydration reactions was investigated.

A versatile diphosphine ligand: cis and trans chelation or bridging, with self association through hydrogen bonding

The diphosphine ligand, N,N'-bis(2-diphenylphosphinoethyl)isophthalamide, dpipa, contains two amide groups and can form cis or trans chelate complexes or cis,cis or trans,trans bridged complexes. The amide groups are likely to be involved in intramolecular or intermolecular hydrogen bonding. This combination of properties of the ligand dpipa leads to very unusual structural properties of its complexes, which often exist as mixtures of monomers and dimers in solution. In the complex [Au2(μ-dpipa)2]Cl2, the ligands adopt the trans,trans bridging mode, with linear gold(I) centers, and the amide groups hydrogen bond to the chloride anions. In [Pt2Cl4(μ-dpipa)2], the ligands adopt the cis,cis bridging mode, with square planar platinum(II) centers, and the amide groups form intermolecular hydrogen bonds to the chloride ligands to form a supramolecular one-dimensional polymer. Both the monomeric and dimeric complexes [PtMe2(dpipa)] and [Pt2Me4(μ-dpipa)2] have cis-PtMe2 units with cis chelating or cis,cis bridging dpipa ligands respectively; each forms a supramolecular dimer through hydrogen bonding between amide groups and each contains an unusual NH···Pt interaction. An attempted oxidative addition reaction with methyl iodide gave the complex [PtIMe(dpipa)], which contains trans chelating dpipa, while a reaction with bromine gave a disordered complex with approximate composition [Pt2Me3Br5(μ-dpipa)2], which contains trans,trans bridging dpipa ligands.