Research On Coordination Assembly, Crystal Structure And Properties Of Nitrogen-containing Heterocycles, Organic Carboxylates And Transition Metals

Metal Organic Frameworks?MOFs?are a new type of porous crystal materials constructed by self-assembling metal ions/clusters with multifunctional organic ligands.So far,MOFs have been widespread utilized for many potential applications such as gas separation/adsorption,catalyst,optics,chemical sensing,and so on due to their high porosity,diverse structure and adjustable pores.Because the structure of the MOFs is much more complex and diverse than the traditional porous materials,the design and synthesis of function-oriented MOFs is still a challenge.The exploration of the structure-property relationships can provide a rich theoretical basis for the practical application of MOFs.In this master dissertation,thirteen new coordination polymers have been hydrothermally synthesized by using flexible N-heterocyclic ligands of bbi,m-bix,btx?bbi=1,1?-?1,4-butanediyl?bis?imidazole?;m-bix=1,3-bis?1H-imidazolyl?-methyl?benzene;btx=1,4-bis?1,2,4-triazol-1-ylmethyl?benzene)as main ligands,and organic carboxylic acids of 4,4-oxybisbenzoic acid,5-hydroxyisophthalic acid,1,4-naphthalenedicarboxylic acid as auxiliary ligands,coordinated assembly with transition metal ions of Co?II?,Zn?II?,Ni?II?,Mn?II?,Cd?II?.Their structures were characterized by techniques of single-crystal X-ray diffraction analysis,elemental analysis,infrared spectra and thermogravimetric analysis.The arrangement mode of cooperation unit in the complexes and the interaction between coordination units were further elucidated and analyzed by using the structural analysis software of Diamond,Olex and Topos.Moreover,the magnetic and fluorescence properties of the complexes were investigated by variable temperature magnetic susceptibility,fluorescence excitation spectra/emission,fluorescence lifetime and quantum yield.The specific findings of the works are summarized as follows:?1?A series of transition metal complexes with novel structures of{[Zn₅??₃-OH?₂?bbi??OBA?₄]·2H₂O·2MeCN}_n?1?;{[Co₂?bbi?₂?OBA?₂]·H₂O}_n?2?;{[Mn₂?bbi?₂?OBA?₂]·H₂O}_n?3?were synthesized by using bbi as the main ligand and4,4-oxybisbenzoic acid as an auxiliary ligand.Complex 1 is a 3D interlocking framework based on the pentanuclearmetal clusters of[Zn₅??₃-OH?₂?COO?₆]as secondary building units.And the structures of complexes 2 and 3 are three-dimensional network structures.Complex 1 has a longer fluorescence lifetime than other transition metal complexes of 2 and 3.?2?Three novel transition metal complexes,[Ni?HIP??m-bix??H₂O?]_n?4?;{[Co₂?oba?₂?m-bix?₂]·H₂O}_n?5?;{[Cd?m-bix?₂]·Cl₂}_n?6?,were synthesized by using m-bix as the main ligand.Both the complexes 4 and 5 are extended into 3D supramolecular structures by intralayer hydrogen-bonding interactions.And complex6 shows a one-dimensional chain structure with ring shapes connected to the central metal ions via m-bix ligands.The temperature-dependent magnetic study suggest that the complex 4 exhibits a spin canting weak ferromagnetic coupling,while the complex 5 displays an antiferromagnetic interaction in the temperature range of 55 K-300 K.?3?Four transition metal complexes of[Co₅?btx?₂?NDC?₄??₃-OH?₂?H₂O?₂]·H₂O}_n?7?;[Co?btx??IP?]_n?8?;[Mn?btx??NIP??H₂O?]_n?9?;{[Zn?btx?₂?H₂O?₂]·2NO₃·2H₂O}_n?10?,were synthesized by using btx as the main ligand.Complex 7 is a self-penetrating 10-connected three-dimensional ile framework formed by pentanuclear[Co₅??₃-OH?₂?COO?₈]SBUs and btx ligands.Complex 8 is a 2D layer structure with binuclear[Co₂O₄]as SBUs.Complex 9 features a 3-fold interpenetrating 3D supramolecular network structure.In addition,complex 10 forms a two-dimensional architecture via the abundant hydrogen bonding.The magnetic studies suggest that the complex 7 exhibits antiferromagnetic interaction.Unlike complex 7,the complexes of 8 and 9 both show weak ferromagnetic interaction.Furthermore,upon excitation at 402 nm,the complex 10 displays a maximum luminescent emission intensity at 431 nm.?4?Three new transition metal complexes of{[Co₁₆?btca?₈?H₂O?₄₀]·16H₂O}_n?11?;[Mn?OBA?₂?H₂O?₂]_n?12?;{[Zn₄?trz?₄?Hnip?₂?nip?]·2H₂O}_n?13?,were synthesized by using 1,2,3,4-butanetetracarboxylic acid,4,4-oxybisbenzoic acid and 5-nitroisophthalic acid as organic carboxylic ligands.Both complexes 11 and 12 are further extended a 2D/3D supramolecular network via extensive intermolecular hydrogen bonding interactions.The complex 13 is 3D framework with[Zn₂?trz?₂]²⁺as SBUs.The magnetic studies suggest that both complexes of 11 and 12 exhibit strong antiferromagnetic interactions between two adjacent transition metal ions.The strong fluorescence emissions of the complex 13 indicate that it may be an excellent candidate for photoluminescent materials.