Copper aromatic dicarboxylate complexes with a very long conformationally flexible dipyridyl ligand: Coordination polymers and a supramolecular nanotube

Abstract

Hydrothermal reaction of copper nitrate and aromatic dicarboxylate precursors with the conformationally flexible and very long-spanning dipyridylamide ligand propane-1,3-diylbis(piperidine-4,1-diyl)bis(pyridin-4-ylmethanone) (4-ppbp) has generated three coordination polymers and a threaded-loop supramolecular complex. {[Cu(tere)(4-ppbp)(H2O)]·1.5H2O}n (1, tere=terephthalate) and {[Cu(iph)(4-ppbp)(H2O)]·2H2O}n (2, iph=isophthalate) both display slab motifs built from interdigitated (4,4) grid layers. {[Cu2(phda)(phdaH)2(4-ppbp)2]·6H2O}n (3, phda=1,4-phenylenediacetate) possesses a 4-connected 658 cds network with self-penetration of 8-membered circuits. {[Cu2(phtH)2(4-ppbp)2(H2O)4](NO3)2·H2O}n (4, pht=phthalate) manifests ring-like dinuclear coordination complex cations with anionic phtH ligands projecting into supramolecular tubes with an inner diameter of approximately 12Å. Dehydration and thermal degradation properties of these new materials are discussed. We also report the crystal structure of the recrystallized dipyridylamide, 4-ppbp·2H2O.