Construction of six novel lanthanide complexes supported by 2,4-difluorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine: Structures, spectroscopies and thermochemical properties

Abstract The reaction of 2,4-difluorobenzoic acid (2,4-DFBA) and 5,5′-dimethyl-2,2′-bipyridine (5,5’-DM-2,2’-bipy) with Ln(NO3)3·6H2O by via slow evaporation generated a series of new binuclear lanthanide complexes, namely, [Ln(2,4-DFBA)3(5,5’-DM-2,2’-bipy)(H2O)]2 (Ln = La (1), Pr (2), Nd (3)) and [Ln(2,4-DFBA)3(5,5’-DM-2,2’-bipy)]2•2H2O (Ln = Sm (4), Eu (5), Gd (6)), had been characterized by elemental analysis, IR spectra, Raman spectra and single-crystal X-ray diffraction. Structural determinations demonstrated that all complexes crystallized in Pī space group, triclinic crystal system. The series consisted of two structural types: complexes 1-3 and 4-6 were isostructural, respectively. The TG/DSC-FTIR technique was employed in order to study thermal decomposition of the complexes. Beyond that, the luminescent property and fluorescence lifetime of complex 5 containing Eu(III) had been investigated in detail.