Syntheses And Structures Of Transition Metal Coordination Compounds Based On Carboxylic Acids And Pyridine Derivatives

Metal organic coordination polymer has flexible and tunable architecture and potential application in the fields of gas adsorption and separation, catalysis, photochemical areas and magnetics. In this thesis, based on ditopic carboxylatic acids and pyridine derivatives as organic linker(from single to mixed ligands, from linear to V-shaped ligands), transitional metal ions as nodes, series of coordination compounds were synthesized. The relationships between reaction conditions(temperature, concentration, solvents and heating rate) and crystal structures are studied. Through analyses of 21 novel crystal structures, hydrogen bonds and π-π stacking are researched how influence the structure.Based on single chelating ligand 1,10-phenanthroline and Co2+, four novel zero dimension supramolecular compounds, [Co(phen)2Cl2]?4DMF(1, M-4DMF), [Co(phen)2Cl2]?1.5DMF(2, M-1.5DMF), [Co(phen)2Cl2]?DMF(3, M-1DMF-II), [Co(phen)2Cl2](4, M-II), [Co(phen)2Cl2]?DMF(5, M-1DMF-I) and [Co(phen)2Cl2](6, M-I)(phen = 1,10-phenanthroline, DMF = dimethyl formamide, M = [Co(phen)2Cl2], form I and II in the order of their discovery) have been synthesized from DMF solvent. Temperature, concentration and heating rate are main influence factors of rystallization conditions. The desolvation process was studied from the crystal structures and intermolecular interaction energies. DMF molecules in the structures are removed from [Co(phen)2Cl2] molecules step by step along with the increase of temperature, finally thermodynamically stable crystal form is abtained. This result provides experimental basis for studying the desolvation process of coordination polymers from solvents.Based on 4,4’-bipyridine and linear ditopic carboxylic acids as mixed ligands,(4, 4’-H2bipy)[Cu(ox)2](7),(4, 4’-H2bipy)[Na H(ox)2](8),(4,4’-H2bipy)[H2(ox)2](9) and(4,4’-H2bipy)(adc)(10)(ox2- = oxalate, adc2- = acetylenedicarboxylate) were synthesized through changing different anions. Unit cell parameters of the 4 compounds are very close, so they are isostructural. Comparing intermolecular interactions of the four structures, we speculate that the supermolecular isostructurality is ascribed to the cooperative effect of the multiple N-H···O, C-H···O, and π-π interactions. Meanwhile, crystal environment plays a decisive role when the proton transferred ftom acid to basis in(4,4’-H2bipy)(adc).Based on a novel ligand 2,2-bis(4,4’-biphenyl-carboxylic acid)hexafluoropropane(H2L, 11) and phen as mixed ligands, Co2+ and Cu2+ as metal nodes, five novel coordination polymers [Co(L)(phen)]?3DMF(12), [Co(L)(phen)]?DMF(13), [Cu(L)(phen)]?0.5H2O(14), [Cu(L)(phen)]?0.25H2O(15) and [Cu(L)(phen)]?0.5H2O?0.5DMF(16) have been synthesized and characterized by single crystal X-ray diffraction. Structures 12 and 13 are 1D chains and supramolecular isomers to each other. The [Co N2O4] clusters in 12 and 13 have a different arrangement, isotactic for 12 and syndiotactic for 13, which is rare in crystal engineering. Compounds 14-16 with different colors are synthesized in one pot. Reaction temperature and DMF/H2 O ratio are the main factors of crystallization conditions. Single crystal X-ray diffraction results show that the coordination modes of Cu(II) in three compounds are different, distorted octahedron for 14, square-plan for 15 and distorted square-plan for 16, and structures 14-16 are supramolecular isomers to each other. The visible light adsorption test shows that the relation of crystal field splitting energy is 15 > 16 >14, which agrees with the structural characters.Based on another novel ligand 2,2-bis(4,4’-biphenyl-carboxylic acid)ethane(H2L’, 17) and chelating pyridine derivatives as mixed ligands, Co2+ and Zn2+ as metal nodes, eight 1D compounds [M(L’)2(H2O)4]?2(C2H6NH2) [M = Co(18), Zn(19)], [M(L’)(2,2’-bipy)]?2(CH3NH2)?(C3H7NO) [M = Co(20), Zn(21)], [M(L’)(phen)]?(CH3NH2)?0.75(C3H7NO) [M = Co(22), Zn(23)], [M(L’)(tbubipy)] [M=Co(24), Zn(25)](2,2’-bipy = 2,2’-bipyridine, tbubipy = 4,4’-di-tert-butyl-2,2’-dipyridyl), have been synthesized and characterized by single crystal X-ray diffraction. The appearence and disappearence of pores are controlled successfully through changing the coordinated H2 O to 2,2’-bipy and phen with ability to form π-π stacking and changing 2,2’-bipy and phen to tbubipy with poor ability to form π-π stacking. BET and powder XRD tests show that the pores are not stable, and easy to collapse, but it makes sense for designing porous materials.