Anion-Dependent Silver(I) Coordination Polymers of the Tridentate Pyridylphosphonite: PPh(3-OCH2C5H4N)2

Abstract

Three new multidimensional coordination polymers have been constructed from the reaction of AgX, where X = OTf-, BF4-, or tfa-, with the novel phosphonite PhP(3-OCH2C5H4N)2, PCP-32, 1. It is seen that regardless of the ratio of reactants mixed, polymeric growth of the compounds always reveals a ligand-to-metal ratio of 1:2 for PCP-32AgOTf, 2, 1:1 for PCP-32AgBF4, 3, and 1:2 for PCP-32Ag(tfa), 4. The coordination number, metal environment, ligand conformation, and polymer dimensionality are found to vary greatly from 2 to 4 and are dependent upon the anion present. Coordination numbers from 2 to 4, representing linear, trigonal, and distorted tetrahedral environments are displayed. PCP-32AgOTf polymerizes as a linear chain containing both two- and four-coordinate silvers, PCP-32AgBF4 repeats a single trigonal motif throughout its structure, and PCP-32Ag(tfa) shows two unique distorted tetrahedral silver centers. Ligand flexibility allows for cross-ligand Ag-Ag distances to range from 3.1918(8) to 14.015(2) A. The coordination polymers have been characterized by elemental analysis, variable-temperature multinuclear NMR spectroscopy, single-crystal X-ray diffraction, and fluorometric studies.