title: Pyridine substituted N-heterocyclic carbene ligands as supports for Au(I)-Ag(I) interactions: formation of a chiral coordination polymer.
abstract: Reaction of 1,3-bis(2-pyridinylmethyl)-1H-imidazolium tetrafluoroborate, [H(pyCH(2))(2)im]BF(4), with silver oxide in dichloromethane readily yields [Ag((pyCH(2))(2)im)(2)]BF(4), 1.BF(4)(). 1.BF(4) is converted to the analogous Au(I)-containing species, [Au((pyCH(2))(2)im)(2)]BF(4), 3, by a simple carbene transfer reaction in dichloromethane. Further treatment with two equivalents of AgBF(4) produces the trimetallic species [AuAg(2)((pyCH(2))(2)im)(2)(NCCH(3))(2)](BF(4))(3), 4, which contains two silver ions each coordinated to the pyridine moieties on one carbene ligand and to an acetonitrile molecule in a T-shaped fashion. Monometallic [Ag((py)(2)im)(2)]BF(4), 5, and [Au((py)(2)im)(2)]BF(4), 6, are made analogously to 1.BF(4) and 3 starting from 1,3-bis(2-pyridyl)-imidazol-2-ylidene tetrafluoroborate, [H(py)(2)im]BF(4). Addition of excess AgBF(4) to 6 yields the helical mixed-metal polymer, ([AuAg((py)(2)im)(2)(NCCH(3))](BF(4))(2))(n), 7 which contains an extended Au(I)-Ag(I) chain with short metal-metal separations of 2.8359(4) and 2.9042(4) A. Colorless, monometallic [Hg((pyCH(2))(2)im)(2)](BF(4))(2), 8, is easily produced by refluxing [H(pyCH(2))(2)im)]BF(4) with Hg(OAc)(2) in acetonitrile. The related quinolyl-substituted imidazole, [H(quinCH(2))(2)im]PF(6), is produced analogously to [H(pyCH(2))(2)im]BF(4). [Hg((quinCH(2))(2)im)(2)](PF(6))(2), 9, is isolated in good yield as a white solid from the reaction of Hg(OAc)(2) and [H(quinCH(2))(2)im]PF(6). The reaction of [H(quinCH(2))(2)im]PF(6) with excess Ag(2)O produces the triangulo-cluster [Ag(3)((quinCH(2))(2)im)(3)](PF(6))(3), 11. All of these complexes were studied by (1)H NMR spectroscopy, and complexes 3-9 were additionally characterized by X-ray crystallography. These complexes are photoluminescent in the solid state and in solution with spectra that closely resemble those of the ligand precursor.
authors.affiliation: Department of Chemistry, University of Nevada, Reno, NV 89557, USA.
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Catalano
authors.forename: Mark A
authors.initials: MA
authors.lastname: Malwitz
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Etogo
mesh_terms: D018360:Crystallography, X-Ray; D006046:Gold / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D006838:Hydrocarbons; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D019216:Metals, Heavy / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D012834:Silver / Q000737:chemistry
chemical_list: D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D008024:Ligands; D019216:Metals, Heavy; D009942:Organometallic Compounds; D011108:Polymers; D011725:Pyridines; C030011:carbene; D012834:Silver; D006046:Gold; D008697:Methane