Construction of lanthanide ternary complexes based on 2,4-difluorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine: Crystal structures, thermoanalysis and luminescence properties

The reactions of 2,4-difluombenzoic acid, 5,5'-dimethyl-2,2'-bipyridine with Ln(NO3)(3)center dot 6H(2)O resulted in the formation of two isostructural binuclear complexes Ln(2,4-DFBA)(3)(5,5'-DM-2,2'-bipy)](2)(H2O)(2) (2,4-DFBA = 2,4-difluorobenzoate, 5,5'-DM-2,2'-bipy = 5,5'dimethyl-2,2'-bipyridine, Ln = Tb (1), Dy (2)). Their structures were first detected by single crystal X-ray diffraction and further characterized by elemental analysis and TG/DSC-FTIR techniques. The X-Ray crystal structures confirmed that each metal ion resided in distorted triangular prism geometry and both of them had triclinic characteristics with P (1) over bar space group. Besides, the complexes also existed as one dimensional chain which was further assembled into two-dimensional supramolecular framework via extensive hydrogen bonds (C-H center dot center dot center dot F). Heat capacities of the complexes were measured by a DSC instrument over the temperature range from T = 262.15-349.15 K. Additionally, the luminescence spectra and lifetime of complex 1 were evaluated.

Automated summary

The reactions of 2,4-difluombenzoic acid, 5,5'-dimethyl-2,2'-bipyridine with Ln(NO3)(3)center dot 6H(2)O resulted in the formation of two isostructural binuclear complexes. The X-Ray crystal structures confirmed that each metal ion resided in distorted triangular prism geometry and both of them had triclinic characteristics with P (1) over bar space group. The complexes existed as one dimensional chain which was further assembled into two-dimensional supramolecular framework via hydrogen bonds.