Self-assembly of {Ag2N4}-core-containing coordination polymers from AgX (X=NO3-, ClO4-, and PF6-) and oxadiazole-bridged 4,4′- and 3,3′-biphenylamine Ligands

The coordination chemistry of the oxadiazole-bridged 4,4'- and 3,3'-biphenylamine ligands, namely, 2,5-bis(4-aminophenyl)-1,3,4-oxadi.azole (L3) and 2,5-bis(3-aminophenyl)-1,3,4-oxadiazole (L4), with inorganic Ag(l) salts has been investigated. Four new coordination polymers (1-4) were synthesized from solution reactions of L3-L4 with corresponding inorganic Ag(I) salts, respectively. Compound [Ag-4(L-3)(4)(NO3)(2)](NO3)(2)center dot CH2Cl2 (1) (triclinic, P (1) over bar, a = 7.5566(5) angstrom, b = 13.290303)angstrom, c = 17.7449(11)angstrom, alpha = 70.1790(10)degrees, beta = 81.7940(10)degrees,gamma = 83.4780(10)degrees, Z = 4) was obtained from L3 and AgNO3 in a CH2Cl2/CH3OH mixed solvent system. In 1, cationic [Ag-4(L3)(4)(NO3)(2)](2+) units are connected to each other by a long Ag-O bond into one-dimensional chains, which are further linked together by eight N-H...O hydrogen-bonding systems into a three-dimensional H-bonded porous network with channels along the crystallographic a axis. [Ag(L3)]CIO4 (2) (monoclinic, I2/m, a = 8.035(2) angstrom, b = 17.395(5) angstrom, c = 11.531(4) angstrom, 103.807(4)degrees, Z = 4) was generated from L3 and AgClO4 in a MeOH/H2O mixed solvent system. It adopts a novel three-dimensional structural motif in the solid state with big rhombic channels (ca. 14 x 8 angstrom). [Ag(L4)](NO3)center dot 0.5H(2)O (3) (orthorhombic, Ccca, a = 11.8508(6) angstrom, b = 15.8958(9) angstrom, c = 15.9963(9) angstrom, Z = 8) and Ag(L4)PF6 (4) (orthorhombic, Ccca, a = 13.225(2,1 angstrom, b = 15.998(3) angstrom, c = 16.049(3) angstrom, Z = 8) are isostructural and feature a novel two-dimensional zeolite-like net. All four new polymeric complexes contain the {Ag2N4} cluster moiety, and Ag... Ag separations are in the range of 3.36-3.83 angstrom.