Luminescent coordination polymers with extended Au(I)-Ag(I) interactions supported by a pyridyl-substituted NHC ligand

Reaction of [Ag(CH(3)impy)(2)]PF6, 1, with Au(tht)Cl produces the monometallic Au(I)-species [Au(CH(3)impy)(2)]PF6, 2. Treatment of 2 with excess AgBF4 in acetonitrile, benzonitrile or benzylnitrile produces the polymeric species {[AuAg(CH(3)impy)(2)(L)](BF4)(2)}(n), (L = CH3CN,3; L = C6H5CN, 4; L = C6H5CH2CN, 5) where the Au(I) centers remain bound to two carbene moieties while the Ag(I) centers are coordinated to two alternating pyridyl groups and a solvent molecule (L). Reaction of 2 with AgNO3 in acetonitrile produces the zig-zag mixed-metal polymer {[AuAg(CH(3)impy)(2)(NO3)]NO3}(n), 6, that contains a coordinated nitrate ion in place of the coordinated solvent species. All of these polymeric materials are dynamic in solution and dissociate into their respective monometallic components. Compounds 2-6 are intensely luminescent in the solid-state and in frozen solution. All of these complexes were characterized by H-1, C-13 NMR, electronic absorption and emission spectroscopy and elemental analysis. (c) 2005 Elsevier B.V. All rights reserved.