Synthesis and characterization of two tetranuclear heterometallic Tb(III)–Zn(II) complexes

Abstract

Tetranuclear heterometallic complexes, [Tb2Zn2(Bzo)10(phen)2] (1) and [Tb2Zn2(TPA)10(phen)2] (2) ( , phen = 1,10-phenanthroline), were synthesized by the rheological phase reaction method and characterized by elemental analysis, IR and X-ray crystallography. Both complexes are tetrameric and the carboxylate ligands display three coordination modes, bidentate bridging, bidentate chelating and tridentate chelating-bridging. The Zn atoms in complexes 1 and 2 are coordinated by two nitrogen atoms from one phen ligand, four oxygen atoms from two bidentate bridging and a tridentate chelating-bridging carboxylate group. However the coordination spheres around the Tb atoms are different. The Tb atom in 1 is eight-coordinate, while the Tb atom in 2 is seven-coordinate. Both complexes 1 and 2 exhibit green luminescence when irradiated by UV light. Compared with binary terbium benzoate, the introduction of the Zn2+ ion and phen enhances the luminescence intensity dramatically.