Synthesis and crystal structure of rare earth complexes with o-nitrobenzoic acid and N,N-dimethylformamide

The rare-earth compound [Ce0.5Sm0.5(o-NBA)3(DMF)2]2 (where o-NBA = o-nitrobenzoic acid, DMF = N,N-dimethylformamide) has been synthesized and structurally characterized. The crystal structure of the compound is characterized by Fourier transfer infrared spectroscopy (FT-IR), fluorescent emission spectroscopy (FES) and single-crystal X-ray diffraction. The results show that the compound crystallizes in a triclinic system, space group P-1 with a = 11.8284 (6) Å, b = 12.5082 (7) Å, c = 13.0203 (7) Å, α = 63.9650 (10)°, β = 66.3900 (10)°, γ = 71.7380 (10)°, V = 1563.7 (14) Å3, Dc = 1.677 g/cm3, Z = 1, F(0 0 0) = 790. Each Ln (III) atom is bridged by four o-nitro-benzoates and chelated by one o-nitrobenzoate. The Ln (III) atom is eight-coordinated by six oxygen atoms from five o-nitro-benzoates and two oxygen atoms from two DMF molecules. Hydrogen bonds and aromatic π⋯π stacking interactions assemble the compound into a three-dimensional network. Luminescence measurement shows that the compound emits fluorescence.