Hydrothermal self-organization of two 2,2′-bipyridine-3,3′-dicarboxylate bridged polymers of Tb III and Ni II involving in situ ligand synthesis

Abstract

Two organic–inorganic hybrid polymers, {[Tb(μ 2-bp3dc)(NO 3)(H 2O) 4] · 2H 2O} n ( 1) and {[Ni(μ 2-η 2-bp3dc)(H 2O) 3] · H 2O} n ( 2) (bp3dc = 2,2′-bipyridine-3,3′-dicarboxylate) have been hydrothermally synthesized from 2,2′-bipyridine-3,3′-diformylhydrazide (bp3dh) and characterized by the elemental analyses, IR spectrum, TG analysis and the single crystal X-ray diffraction. Polymer 1 shows a 1D linear chain structure, in which extensive hydrogen bonding between the deprotonated carboxylates, nitrate ions, and coordinated water molecules result in a 3D network which also contains face-to-face π–π interactions between adjacent bp3dc ligands. Polymer 2 is a 1D helical chain, and the interchain hydrogen bonding interactions also contribute to the final 3D network. The bridging bp3dc ligands in 1 adopt the anti-bridging bidentate mode, while that in 2 adopt the chelating bridging tridentate mode. The solid-state magnetic properties of the Tb and Ni complexes demonstrated the presence of weak antiferromagnetic exchange interactions, caused by interaction between the neighbouring ions along the 2,2′-bipyridine-3,3′-dicarboxylate bridged chain.