Structure and Luminescence of Carboxylic Acid Samarium and Europium Complexes

Two crystals, [Sm(Hcpna)(cpna)center dot 3H2O](n) (1) and [Eu(Hcpna)(cpna)center dot 2H(2)O](n) (2), have been synthesized by solvothermal method based on Sm3+ and Eu3+ with multiple acid ligands 5-(4-carboxyphenoxy)nicotinic acid (H2cpna), 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 1D chain structure. It crystallizes in the triclinic system, space group P (1) over bar with a = 5.9738(11), b = 12.528(2), c = 18.021(4) angstrom, alpha = 93.156(3), beta = 98.067(3)degrees, gamma = 92.692(3)degrees, V = 1331.3(4) A3, Z = 2, S = 1.069, F(000) = 702, R = 0.0277 and wR = 0.0688 (I > 2 sigma(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) angstrom, beta = 93.881(2), V= 2621.4(7) angstrom(3), Z = 4, S = 1.110, F(000) = 1372, R = 0.0302 and wR = 0.0811 (I > 2 sigma(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.