Synthesis, Crystal Structures and Luminescence of Organic-Lanthanide Complexes with Nicotinic Acid and Adipic Acid Ligands

Two new lanthanide coordination polymers, [Sm-2(nic)(3)(ad)(0.5)(H2O)(mu(3)-O)(2)] (1), [Pr(nic)(ad)]center dot 2H(2)O (2) (nic = nicotinic acid, ad = adipic acid) have been synthesized hydrothermally from the self-assembly of the lanthanide ions (Ln(3+)) with rigid nicotinic acid and the flexible adipic acid. They were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Structural analyses reveal that both of the complexes crystallize in triclinic, space group P-1 and have different framework characterization. Because of different coordination modes of nicotinate, complexes 1 and 2 exhibit 2D and 3D framework structure, respectively. In 1, the Sm1 and Sm2 atoms and their corresponding centrosymmetric atoms are connected by bridging oxygen atoms to form a 1D Sm-2(mu(3) -O)(2) polymeric chain along [010] direction. The photoluminescent properties of 1 and thermogravimetric analysis of 1 and 2 are discussed in detail.