Supramolecular of Lanthanide-2,6-Dimethylbenzoic -2,2′:6′,2″-Terpyridine Materials: Crystal Structures, Luminescent Property, and Thermochemical Behaviour

Abstract

Three mononuclear complexes [Ln (2,6-DMBA)3(terpy)](Ln=Dy(1),Ho(2),Er(3); 2,6-DMBA = 2,6-dimethylbenzoic; terpy = 2,2′:6′,2′′- terpyridine) were synthesized via conventional solution method and characterized by elemental analysis, IR spectra, thermal analysis and single X-ray diffraction techniques. The single-crystal X-ray structures of complex 1-3 are described here, and the complexes are isomorphous and crystallize in the orthorhombic crystal system Pbcn space group. Each Ln(III) is nine-coordinated by six O atoms from three 2,6-DMBA ligands and three N atoms from a terpy molecule, which is defined as a distorted monocapped square anti-prismatic geometry. Each adjacent Ln(III) structural unit forms a 2D supramolecular structure through C-H···O intermolecular hydrogen bonding interaction. The thermal decomposition mechanism of complexes 1-3 were analyzed by TG/DSC-FTIR. The luminescence spectra of Dy (III) complex were studied and the characteristic emission peaks of Dy (III) ion were observed.

Keywords: lanthanide complexes, aromatic carboxylic acids, crystal structure