Divergent topologies in divalent metal furandicarboxylate or thiophenedicarboxylate coordination polymers with bis(4-pyridylformyl)piperazine coligands

Abstract

Hydrothermal reaction of a metal nitrate, 2,5-furandicarboxylic acid (H2fdc), and the long-spanning dipyridylamide ligand bis(4-pyridylformyl)piperazine (bpfp) produced three coordination polymers which were structurally characterized by single-crystal X-ray diffraction. {[Cd2(fdc)2(bpfp)(H2O)4]·10H2O}n (1) possesses 1D 3-connected coordination polymer ladders co-crystallized with decameric water molecule clusters. {[Cu(fdc)(bpfp)(H2O)2]·2H2O}n (2) exhibits (4,4) grid coordination polymer layers stacked in an unusual parallel ABCD pattern. {[Ni(fdc)(bpfp)(H2O)2]·4H2O}n (3) also manifests (4,4) grid coordination polymer layers, but these engage in 2D+2D→3D mutually inclined interpenetration. Hydrothermal reaction of metal nitrates, 2,5-thiophenedicarboxylic acid (H2tdc), bpfp afforded {[Zn(tdc)(bpfp)(H2O)]·2H2O}n (4), {[Cd(tdc)(bpfp)(H2O)]·2H2O}n (5), {[Ni2(tdc)2(bpfp)2(H2O)4]·3H2O}n (6), and {[Cu(tdc)(bpfp)(H2O)2]·3H2O}n (7). Compounds 4 and 5 exhibit (4,4) sawtooth coordination polymer layer motifs that engage in relatively uncommon 2D+2D→3D parallel interpenetration. Compounds 6 and 7 both showed 2D+2D→3D mutually inclined interpenetration of parallel sets of (4,4) grid layer motifs, but with different orientations of the heterocycles within their respective metal/tdc chain submotifs. Thermal properties of all new materials were also investigated. The luminescent cadmium and zinc derivatives 1, 4, and 5 were assayed as potential detectors for nitrobenzene in methanol suspension.