Lewis-Base Adducts of Group 11 Metal(I) Compounds. LIV. Synthesis and Structural Characterization of Binuclear μ,μ′-Dichloro-, Dibromo- and Diiodo-bis[(pyridine)(triphenylphosphine)silver(I)] Pyridine Solvate Complexes

Mixed base pyridine (py)/triphenylphosphine adducts of the silver(I) halides, AgX (X = Cl, Br, I), have been synthesized for 1 : 1 : 1 stoichiometry. The three complexes are isomorphous and isostructural, being monoclinic, P21/c, a ≈ 11.2, b ≈ 16.8, c ≈ 16.5 � , β ≈ 122 � ; the complexes are centrosymmetric �, �?- dihalo -bridged dimers , [(PPh3)( py )AgX2Ag( py )(PPh3)1 (Z = 2 dimers ). Although the stoichiometry of the complex itself is as above, an additional unit of pyridine per silver atom is found as solvent in the lattice, implying the unlikelihood of the existence of an independent 1 : 2 : 1 AgX : py : PPh3 molecular series. In addition, the iodide has been isolated as a different C2/m (?) disordered polymorph.