Syntheses, Crystal Structures And Properties Of Coordination Polymers Based On S-containing Nictinic Acid Ligands

In recent years, the molecular aggregates constructed by small molecule ligands and metal ions, have become a general interest in coordination chemistry, supramolecular chemistry and material chemistry owing to their potential applications in many fields. Yet, how to design and select the building blocks is of critical importance for constructing a new functional coordination complex. In this thesis, we choose mercaptonictinic acid or its derivatives as ligands, fifiteen coordination polymers with novel structures and telephonic, photogenic or biological properties have been studieded. The main results are as follows:1. Based on 2-mercaptonanicotinic acid (2-H2MN), five new lanthanide complexes [Ln2(DTDN)4(phen)4]·7H2O·2H3O+(Ln=Nd (1), Sm (2), Eu (3), Tb (4), Dy (5)) have been synthezised, in which 2,2'-dithiodinicotinic acid (H2DTDN) ligand was generated in situ. Single-crystal X-ray diffraction analysis revealed that all crystals are isostructural and crystallize in monoclinic system with space group C2/c. The structures can be considered as two-dimensional (2D) structures and further linked by hydrogen bonds into the final trinodal 4-connected network. Photoluminescence studies revealed that complexes 2-5 exhibit the characteristic peaks of the lanthanide metals.2. Based on 6-mercaptonanicotinic acid (6-H2MN), three complexes 6-8 have been solvothermally synthesized. By in situ oxidation of 6-H2MN, the new ligand H2TDN or H2DTDN was generated in complexes 7,8. Complexes 6,7 can be considered as 2D layered structures, and further linked into a 3D supramolecular architecture by hydrogen bonds in complex 7. Complex 8 shows a two-fold interpenetrating six-connected hxg topology nework. Photoluminescence studies revealed that complexes 6,7 exhibit strong fluorescent than 6-H2MN. The electrochemical behavior of complex 8 was studied by cyclic voltammetry, indicating that the electron transfers in the electrode reaction are irreversible.3. A new multicarboxylate ligand,2-carboxymethylsulfanyl nicotinic acid (2-H2CMSN), has been designed, and seven novel complexes 9-15 of transition metals based on 2-H2CMSN have been sinthzised by hydro(solvo)thermal or solution. Complex 9 is a 2D layered architecture, and further linked into a 3D supramolecular architecture by hydrogen bonds. Complexes 10-13 have been constructed by changing the ancillary ligands. Complexes 10-12 are 1D chain structures, in which 2,2'-bipy or phen modified on both sides. Complex 13 is expanded by bpp to form a (3,6) layered structure. Complex 14 is 2D structure and further linked by hydrogen bonds into the final 3D supramolecular network. From the topological perspective, complex 15 can be considered as a two-fold interpenetrating dia topology network. The luminescent, electrochemical properties and biological activities have been studied and discussed.