Lanthanide complexes with 2,6-dimethylbenzoic acid and 2,2′:6′,2′′-terpyridine: Crystal structures, thermochemical property and luminescent behavior

Abstract

Four 2D lanthanide complexes [Ln(2,6-DMBA)2(terpy)(NO3)]2·4(terpy) (Ln = Sm(1), Eu(2), Gd(3), Tb(4)); 2,6-DMBA = 2,6-dimethylbenzoate; terpy = 2,2′:6′,2′′-terpyridine) were obtained via conventional solution method at room temperature. The crystal structures are characterized by IR, X-ray single crystal diffraction and elemental analysis. The results show that the four complexes are isomorphic, and the coordination number of each metal center is nine, showing a distorted monocapped square anti-prismatic geometry. The complexes 1-4 form a 2D supramolecular framework structure by CH⋯O hydrogen bond interactions. The thermal decomposition mechanism of complexes 1-4 were investigated by the technology TG/DSC-FTIR. The luminescence studies show that the crystal complexes 1, 2 and 4 have good luminescent properties and show good potential as fluorescent materials. The luminescence lifetimes of the Eu(III) and Tb(III) complexes are 1.03 ms and 1.24 ms, respectively.