Interleaved and entangled divalent metal thiophenedicarboxylate coordination polymers with an extremely long-spanning and flexible dipyridylamide ligand

•Divalent metal coordination polymers with 2,5-thiophenedicarboxylic acid (H2tdc).•Inclusion of very long spanning dipyridylamide ligand 4-ppbp.•Copper derivative has slab topology with pairs of interleaved (4,4) layer motifs.•Cobalt derivative has tubular structure with rare 1D + 1D → 2D parallel polycatenation.•Nickel derivative has unprecedented system of interpenetrated (4,4)IIb layers.

Hydrothermal reaction of metal nitrates, 2,5-thiophenedicarboxylic acid (H2tdc) and the conformationally flexible and very long spanning dipyridylamide ligand propane-1,3-diylbis(piperidine-4,1-diyl)bis(pyridin-4-ylmethanone) (4-ppbp) produced three new coordination polymers which were structurally characterized by single-crystal X-ray diffraction. [Cu(tdc)(4-ppbp)(H2O)]·2H2O}n (1) manifests a slab topology with pairs of interleaved (4,4) layer motifs. [Co(tdc)(4-ppbp)(H2O)]n (2) shows a 2,4-connected 1-D tubular structure that engages in very rare 1D + 1D → 2D parallel polycatenation. [Ni(tdc)(4-ppbp)2(H2O)]n (3) possesses a unique system of 2D + 2D → 2D interpenetrated 2,6-connected layers, derived from the edge-crossed SP 2-periodic (4,4)IIb net, when O–H⋯N hydrogen bonding patterns are taken into account. The conformational flexibility of the 4-ppbp ligand affords the requisite loops for the unique polycatenation patterns in 2 and 3. Thermal decomposition properties of these three new materials are discussed.

Graphical abstractHydrothermal reaction of metal nitrates, 2,5-thiophenedicarboxylic acid (H2tdc) and the conformationally flexible dipyridylamide ligand propane-1,3-diylbis(piperidine-4,1-diyl)bis(pyridin-4-ylmethanone) (4-ppbp) produced three interleaved or entangled coordination polymers. [Co(tdc)(4-ppbp)(H2O)]n (pictured) shows a 2,4-connected 1-D tubular structure that engages in very rare 1D + 1D → 2D parallel polycatenation. The nickel congener represents the first example of interpenetration of 2,6-connected looped-ligand layers derived from an edge-crossed SP 2-periodic (4,4)IIb net. Figure optionsDownload full-size imageDownload as PowerPoint slide