Preparation,Structure And Properties Of Complexes From Pyridimium Salts Flexible Carboxylic Acid Ligands

In recent years,metal organic coordination polymers have become the topic of deep discussion among researchers,and more and more complex frameworks have been reported.Many literatures have shown that flexible pyridinium salt carboxylic acid organic ligands construct more complex and variable structures with their flexible coordination modes and metal ions when synthesizing complexes.Different structures lead to different properties,so the pyridinium salt carboxylic acid complexes have more potential and potential to be explored in the fields of adsorption,optics,magnetism and catalysis.In this dissertation,two flexible pyridinium carboxylate ligands were designed and synthesized.They are the 4-carboxy-1-?4-carboxybenzyl?pyridine-1-indole salt with the molecular configuration of V type,which are called ligands.H2?L2?Br];The molecular configuration is similar to that of windmilled 1,1',1"-??benzene-1,3,5-tris?methylene??tricarboxy?-pyridyl bromide salt,known as[H3?L3?Br].Through the use of different transition metal or rare earth ions and their self-assembly,10 of coordination polymers have been successfully constructed.The main contents are as follows:Through the self-assembly of H2?L2?Br synthesized with transition metals and rare earth ions,four metal organic complexes were obtained.[Cd?L2?₂]�2H20 C₃H60?1?,[Cd?L2?2]�5H20?2?,[Pb?N03?2?L2?]?3?,[Eu?L2?2?H20?2]�Cl?4?.The structures of complexes 1 and 2 were all different from each other by X-ray single crystal diffraction.Thermal stability analysis showed that complex 2 was more stable than the framework structure of complex 1.Complex 3 is a two-dimensional network structure bridged by nitrate ions.It contains pore structures of different sizes in the orthogonal axial direction.This complex has unique advantages in adsorption and separation.Interestingly,the ligands in complex 4 were self-assembled with metal ions using two coordination modes to construct complexes containing cage-like structures.The guest molecules were contained in each cage.Using the space groups and structural differences of complexes 1 and 2,we performed second-order nonlinear optical properties on complex 1 to show the superior optical properties of the Fdd2 space group.Through the thermal stability analysis,the presence of guest water molecules in Complex 2 led to the study of changes in fluorescence.Based on the ligand H3?L3?Br,six new structures of coordination compounds were obtained with the transition metal ions in diffusion and hydrothermal conditions.[CdBr4]?L3?�H2O?5??[Cd3 L3)2?H20?4Br6]�4H20?6??[Zn3?L3?2?H20?4Br6]�4H2O?7??[Pb?L3??H20?Br2]�4H20?8??[Cd2?L3??H20?Br]�H2O?9??[Cd5?L3?4Brg?H2O?8]?ClO4?2�6H2O?10?.The complexes 6 and 7 are pseudopolymorphism with each other,and the complex 8 shows the interpenetration of the frame.Complexes 6,9 and 10 are cadmium complexes,and the coordination pattern of cadmium in 9 is very similar to that of complex 6,but the coordination atoms are different.Surprisingly,they are controlled by different anion salts of metal cadmium,and therefore it is known that in the process of building complexes,different anions in the solvent have an inseparable relationship with the structure of the complex.Among them,complex 10 is a complex with five different coordinating configurations of cadmium atoms.This situation is extremely rare,which provides the basis for our future research on properties.