A unique 3-D 3d–4f heterometallic coordination polymer with double betaine ligand: Crystal structure and magnetic properties

Abstract

A unique 3d–4f heterometallic coordination polymer with double betaine ligand, [GdCu 2(L 1) 4(H 2O) 2](ClO 4) 7 · 6H 2O 1 (L 1 = 1,3-bis(pyridinio-4-carboxylato)-propane), has been synthesized by the self-assembly of Cu(ClO 4) 2 and Gd(ClO 4) 3 with flexible double betaine ligand L 1, and structurally characterized by single-crystal X-ray diffraction. The structure of 1 can be regarded as being constructed by the cross-linkage of the vertex-sharing double-paddle-wheel-like trinuclear [Cu(COO) 4Gd(COO) 4Cu] units and L 1 ligands to produce an interesting cationic NaCl-like framework with a 4 126 3 topology, which is counter-balanced by the perchlorate ions located in the interspaces of the framework. Variable-temperature magnetic susceptibilities of 1 show there is no magnetic interaction between the Cu(II) and Gd(III) ions.