The Syntheses,Structures And Properties Of Coordination Complexes Based On Mult-carboxylic Acid And Nitrogen Heterocycle Ligands

Over the past decades,the construction of coordination complexes owning intriguing structural architectures and potential applications have caused the extensive interest in chemistry and material science fields.To design and synthesis coordination complexes bearing new structure and excellent performance constructed from oxygen carboxylic acids,nitrogen heterocycles and nitrogen-oxygen mixed ligands have been became a hot topic of coordination chemistry.But it is still a great challenge to achieve target coordination complexes which are designed in advance,because many factors such as temperature,pH,solvent,organic ligands,metal ions,metal/ligand ratio etc.,can significantly influence the final structures of complexes.Among them,rational design of organic ligand is the most important key in the self-assembly of coordination complexes.Based on the above,in this paper we designed and synthesized azobenzene-3,3',5,5'-tetracarboxylic acid?H₄abtc?and 1,3-[?8-hydroxy-5-quinolinato?azo]-phthalic acid?H₃qapc?through hydrothermal and solvothermal synthesis.A series of rare earth metal coordination complexes have been constructed by employing H₄ abtc ligand and H₃ qapc ligand.Complexes have been characterized by single crystal X-ray diffraction analyses,elemental analysis,IR spectroscopy,UV spectroscopy,thermal stability analysis,and magnetic and fluorescent analysis for partial complexes.In order to study the application value of complexes by our group,we study the magnetic of four complexes based on 1-?benzotriazole-1-methyl?-2-propylimidazole?bpmi?,[Cu?bpmi?2?Ac?2]·H₂O?9?,[Cu?bpmi?2?H₂O?2]·2NO3·2H₂O?10?,[Cu?bpmi??N3?2]?11?,and [Cu3?bpmi?2?SCN?4?DMF?]?12?.The main contents are as follows:1.Five novel complexes based on H₄ abtc,[Dy?Habtc??H₂O?₃]·2H₂O?1?,[Eu?H₃abtc?2?DMF?₃?H₂O?]·2H₂O?2?,[Nd3?abtc?2.5?H₂O?6.5]?3?,[La3?abtc?2.5?H₂O?6.5]?4?and [Y?abtc??H₂O?]?5?have been synthesized.Single crystal X-ray diffraction analyses reveal that complexes 1 and 5 are 3D structure owing two kinds of 1D channel,complex 2is a 1D line structure,and complexes 3 and 4 are 2D structure owing 1D channel bearing the same structure.It is worth noting that the degree of protonation of multi-carboxylic acids have an important impact on the structure of coordination complexes in self-assembly process.The weak p-p conjugate and hydrogen bond exist in the structure of complexes 2-4.2.Three novel complexes based on H₃ qapc,[Dy?qapc??H₂O?2]·2H₂O?6?,[Y?qapc??H₂O?2]·2H₂O?7?and [Nd2?H₂qapc?2?Hqapc?2?H₂O?10]·6H₂O?8?have been synthesized.Single crystal X-ray diffraction analyses reveal that complexes 6 and 7 are 3D structure owing 1D channel bearing the same structure,complex 8 are 0D structure.The weak hydrogen bond exist in the structure of complex 8.3.Fluorescence measurement on the condition of room temperature for H₄ abtc,H₃qapc,and complexes 1,3-8 indicate that rare earth ions have varying degrees of influence of the fluorescence of ligands.4.Magnetic susceptibility measurement on the condition of 2-300 K and 1000 Oe for 6 indicates that complex 6 exhibits an antiferromagnetic coupling between adjacent rare earth ions.5.Thermal stability of complexes 1-8 have been studied.6.Magnetic susceptibility measurement on the condition of 2-300 K and 1000 Oe for 9-12 indicate that complex 1 exhibits an antiferromagnetic coupling between adjacent Cu2+ ions.