A series of novel lanthanide complexes with 2-bromine-5-methoxybenzoic acid and 2,2′-bipyridine: Syntheses, crystal structures, and luminescent properties.

Six new lanthanide complexes [Ln(2-Br-5-MOBA) 3 (2,2′-DIPY)] 2 (Ln = Nd( 1 ), Eu( 2 ), Gd( 3 ), Tb( 4 ), Ho( 5 ), Er( 6 ); 2-Br-5-MOBA = 2-bromine-5-methoxybenzoate; 2,2′-DIPY = 2,2′-bipyridine) have been successfully synthesized and characterized. The complexes 1 – 5 are isostructural and nine-coordinated by the single-crystal X-ray diffraction analyses, while the complex 6 is eight-coordinated. The difference of crystal structure may be the result of the lanthanide contraction effect. The binuclear units were further assembled into 1D, 2D, 3D supramolecular structures by the π-π stacking and C H⋯O hydrogen bonding interactions. The thermal decomposition mechanism of complexes 1 – 6 was studied by TG analysis and further authenticated by TG/DSC-FTIR techniques. The solid-state luminescence properties of complexes 2 and 4 were investigated at room temperature. The results indicate that complexes 2 and 4 show characteristic emission of Eu 3+ ion and Tb 3+ ion, respectively. What's more, the title complexes have good antibacterial activities against Candida albicans . [ABSTRACT FROM AUTHOR]