Construction,Structures And Properties Of Functional Coordination Polymers Based On Zwitterionic Pyridinium Carboxylic Ligands

The flexible pyridinium zwitterionic carboxylate ligands,which combine the various coordination modes of carboxylate compounds,the nimble connection methods of flexible ligand coordination and the advantages of separation of positive and negative charge of zwitterionic ligands,have attracted an increasing number of attentions.In this paper,34 new coordination polymers were obtained through the reactions of eight flexible zwitterionic pyridinium carboxylate ligands(L1-L8).Single-crystal X-ray analysis,powder diffraction,thermogravimetry analysis,fluorescence and magnetic properties of some complexes show that our work is important for the further synthesis and applications of this kind of complexes.Including:1.Using L1,a series of isomorphous 2D lanthanide complexes(nine single metal complexes and three groups of mixed metals complexes)were successfully synthesized.The nitro compounds detection studies of complex 1 indicate that 1-ethanol suspensions can sensitively and efficiently detect TNP.The temperature-dependent luminescence properties of complexes 1,2 and 10e demonstrate that 10e has the potential to quantitatively detect temperature over the low temperature range of 10-90 K.Multi-method-induced color-tunable luminescence properties studies reveal that adjustment of the doped ions concentration,variation of the excitation wavelengths and alteration of the temperature can modulate the luminescent colour,and white light emission can indeed be achieved.Finally,magnetic researches show that antiferromagnetic interactions existed in 3 and 4,and 3 shows a slow magnetic relaxation.Thus,the as-obtained lanthanide coordination polymers materials have the potential to serve as the first example of a multi-functional material for selective and recyclable sensing of TNP,quantitative detection of the cryogenic temperature,multi-factor-induced color-tunable luminescence emission and act as a single molecule magnet.2.Using L2,four isomorphous binuclear 2D network lanthanide coordination polymers was successfully constructed.The microporous structure were confirmed by the N2 adsorption properties of complex 1,Small molecules detecting studies show that 3-methanol suspension has the potential to sensitively and efficiently detect low concentration acetone.To our knowledge,this is the first case of the dual-core 2D microporous structure lanthanide coordination polymers with high efficiency,sensitivity and repeatability detection ability of acetone.3.Using Li and L3,four interesting novel transition metal complexes were synthesized.Their various structures reveal that the diverse structures can be attributed to the different metal centers,the location of the reaction groups,the coordination mode of carboxylate,the linking modes of ligand and the introduction of the flexible group CH2.Properties studies demonstrate that different metal centers and different skeletal structures can affect the properties.Complexes 17 and 20 have the potential as a fluorescent material,18 and 19 can be used in magnetic materials.4.Using L4,L5 and L6,7 transition metal complexes with different dimensions were obtained.Analysis and comparison of these structures show that different lengths of ligands,different metal salts,different coordination mode and different synthesis conditions will affect the final structures.The longer the length of the zwitterionic ligands,the more difficult to synthesize complicated complexes.This study provided a theoretical basis for the later construction of zwitterionic pyridinium carboxylate complexes.5.Using L2,L4,L7 or L8 to combine with different pyridine ligands(1,2-di(pyridin-4-yl)ethane,1,2-di(pyridin-4-yl)ethane or 4,4'-bipyridine),7 novel d10 polymers were synthesized.Analysis declare that the type,location and the coordination mode of the substituents of one ligand will influence the geometry of the metal center,coordination mode and spatial configuration of the next ligand,as well as the pore size and skeleton structures of the complex.Properties studies show that 30 and 33 have potential as fluorescent materials.