Syntheses, crystal structures and properties of two unusual pillared-layer 3 d–4 f Ln–Cu heterometallic coordination polymers

Abstract

Two unusual pillared-layer 3 d–4 f Ln–Cu heterometallic coordination polymers, {[ Ln 2Cu 5Br 4(IN) 7(H 2O) 6]·H 2O} n ( Ln=Eu ( 1) and Gd ( 2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. The structure determination reveals that 1 and 2 are isostructural and feature a novel three-dimensional pillared-layer hetrometallic structure built upon the linkages of one-dimensional (1D) linear Ln–carboxylate chains, zero-dimensional (0D) Ln–carboxylate Ln 2(IN) 8 dimers, rare 1D zigzag [Cu 5Br 4] n inorganic chains and IN − pillars. In both 3D structures, there are Ln–carboxylate layers resulted from the connections of 1D Ln–carboxylate chains and 0D Ln 2(IN) 8 dimers through O–H⋯O hydrogen bondings. The luminescent properties of 1 have been investigated. The magnetic properties of 1 and 2 have also been studied.