Structure and Luminescence of Carboxylic Acid Samarium and Europium Complexes

Two crystals, [Sm(Hcpna)(cpna)·3 H_2O]n(1) and [Eu(Hcpna)(cpna)·2 H_2O]n(2),have been synthesized by solvothermal method based on Sm3+ and Eu3+ with multiple acid ligands5-(4-carboxyphenoxy)nicotinic acid(H_2cpna), and the new complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric analysis and fluorescence analysis. Complex 1 exhibits a 1 D chain structure. It crystallizes in the triclinic system, space group P1 with a = 5.9738(11), b = 12.528(2), c = 18.021(4) ?, α = 93.156(3)o, β =98.067(3)o, γ = 92.692(3)o, V = 1331.3(4) ?3, Z = 2, S = 1.069, F(000) = 702, R = 0.0277 and wR =0.0688(I 2σ(I)). Complex 2 shows a two-dimensional network structure, which crystallizes in monoclinic system, space group C2/c with a = 13.6733(19), b = 18.422(3), c = 10.4307(15) ?, β =93.881(2)o, V= 2621.4(7) ?3, Z = 4, S = 1.110, F(000) = 1372, R = 0.0302 and wR = 0.0811(I 2σ(I)). The solid-state fluorescent test results show tcomplex 1 has weaker fluorescence intensity than the ligand. However, complex 2 has excellent fluorescence properties, and can emit bright red light under the irradiation of ultraviolet lamp.