Metal–organic frameworks based on the [1,1′:3′,1′′-terphenyl]-3,3′′,5,5′′-tetracarboxylic acid ligand: syntheses, structures and magnetic properties†
Abstract
The solvothermal reactions of [1,1′:3′,1′′-terphenyl]-3,3′′,5,5′′-tetracarboxylic acid (H4TPTA) with transition metal cations afforded five novel coordination polymers in the presence of three pyridine ligands (4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine and phen = 1,10-phenanthroline), namely [M(TPTA)0.5(4,4′-bpy)0.5(H2O)2]n (M = Co for (1), Ni for (2)), {[Mn2(TPTA)(2,2′-bpy)H2O]·1.5H2O}n (3), and [M(H2TPTA)(phen)]n (M = Mn for (4), Co for (5)). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Polymers 1 and 2 are isomorphous and exhibit 3D 4-fold interpenetrated networks with the point Schläfli symbol of (42·104) (4·102). Polymer 3 shows a 2D layer framework. Polymers 4 and 5 are also isomorphous and each displays a one-dimensional (1D) chain, which further forms a 2D supramolecular architecture via inter-chain π⋯π interactions. Moreover, variable-temperature magnetic susceptibilities of polymers 3–5 exhibit overall weak antiferromagnetic coupling between the adjacent M(II) ions.