Pyridine Benzimidazole Coordination Polymer Synthesis, Structural Characterization And Nature Of The Study

In recent years, metal-organic polymer has obtained widely attention and became the main research direction of coordination chemistry because its diverse structure and topology as well as its potential application in many fields such as optical, electrical, magnetic, ion exchange and separation, catalytic and gas storage. Crystal engineering based on coordination polymer is an efficient strategy for designing and synthesizing metal-organic frameworks (MOFs) with elegant topologies and potential applications. The structural geometry can be controlled and modulated by selecting the coordination geometry of metal ions and the chemical nature of the terminal and bridging ligands. The common process to control the structures of the coordination polymers is using N-heterocyclic ligands and poly-carboxylate. Sixteen coordination polymers were synthesized under hydrothermal conditions based on n-PyHBIm (n= 2,3,4) and a series of carboxylate ligands. The compounds were characterized by single crystal X-ray diffraction, IR, and thermogravimetric and elemental analyses in order to find out their potential application.Paper structure is divided into three parts:In Chapter 1, Preface. The development of coordination chemistry, crystal engineering, synthetise and structures of coordination polymers are simply introduced. And the search development of complexes containing 2-(n-Pyridyl)benzimidazole ligands was also summarized.Eight new coordination polymers, namely [Zn(2-PyHBIm)(oba)]_n (1), [Cd(2-PyHBIm)(oba)]_n (2), [Zn(3-PyHBIm)(oba)H₂O]_n (3), [Cd(3-PyHBIm)(oba)H₂O]_n (4) {[Ni(3-PyHBIm)(oba)H₂O]·3H₂O}n (5), [Zn(4-PyBIm)(oba)]_n (6), {[Cd(4-PyHBIm)2(oba)]·H₂O}n (7),{[Co(4-PyHBIm)2(oba)]·H₂O}n (8), were synthesized under hydrothermal conditions based on 2-(n-Pyridyl)benzimidazole (n-PyHBIm) and 4,4'-oxybis-(benzoate) (oba) ligands. Compounds 1 and 2 contain 1D meso-helical chain. Compounds 3 and 4 contain simple 1D polymeric chains assembled into a 3D network through aromaticπ-πstacking interactions and hydrogen bonding interactions. Compound 5 contains 1D polymeric chains with side arms which assembled into a 2D network with channels and further assembled into a 3D network though C-H...πinteractions. Compounds 6 and 7 form 1D molecular ladder coordination polymers. Compound 8 consists of 2D coordination networks with 2-fold interpenetration.Eight new coordination polymers{[Zn3(2-PyBIm)3(2-PyHBIm)2(tma)(H₂O)]·H₂O}n (9), [Co(2-PyHBIm)2(H2tma)]+(H2tma)-(10), [Ni(2-PyHBIm)2(H2tma)]+(H2tma)- (11), {[Zn(IPA)(3-PyHBIm)]·3H₂O}n (12),{[Cd(IPA)(3-PyHBIm)(H₂O)2]·2H₂O}n (13), {[Zn(5-NIPA)(3-PyHBIm)(H₂O)]·H₂O}n (14), [Zn(5-OIPA)(3-PyHBIm)]_n (15), {[ZnNa(5-SIPA)(3-PyHBIm)2]}n(16), were synthesized under hydrothermal conditions based on 2-(n-Pyridyl)benzimidazole (n-PyHBIm), trimesic acid, isophthalic acid, 5-hydroxyisophthalic acid,5-nitroisophthalic acid, and 5-sulfoisophthalic acid sodium salt. Compound 9 contains 1D helical chain with trinal-nucleus unit. Compounds 10 and 11 form 3D supermolecule structures. Compounds 12 and 13 form 1D line chain structures. Compound 14 contains 1D zigzag chain. Compounds 15 and 16 form 2D layer structures.