Synthesis, Characterization And Properties Of Coordination Polymers Based On Asymmetric Bipyridyl Ligand And Carboxylic Acid

The synthesis of novel coordination polymers with excellent performance has become a hotspot research in modern coordination chemistry and crystal engineering.The aim of this paper based on the formation of coordination polymers that can further undergo solid-phase photochemical reactions was established.Ligands are assisted by transition metal Ag（I）/Cd（II）/Zn（II）ions,asymmetric bipyridyl ligands(trans-1-（2-pyridyl）-2-（3-pyridyl）-vinyl（2,3’-bpe）/trans-1-（3-pyridyl）-2-（4-pyridyl）-vin yl（3,4’-bpe）and different organic carboxylic acid.A series of coordination polymers with different dimensions were successfully prepared under the hydrothermal reaction conditions.X-ray single crystal diffraction,X-ray powder Diffraction,fluorescence spectroscopy,infrared spectroscopy,nuclear magnetic resonance spectroscopy,and high resolution mass spectrometry were used to characterize and investigate their structure and properties.The main results were briefly described as follows:1、Two coordination polymers that include{[Ag₂（1,4-ndc）（1）₂]·2H₂O}_n（2）and{[Zn₂（1,4-ndc）（1）₂]·2H₂O}_n（4）were obtained through the mutual reaction o f metal salts,3,4’-bpe（1）and 1,4-naphthalenedicarboxylic acid（1,4-H₂ndc）.[2+2]photocycloaddition can happen by the bipyridine compound 3,4’-bpe（1）in the mode of head-to-head or head-to-tail collision under the catalysis of ultraviolet light,then the product obtained was two cyclobutane derivatives that was 1,2-Bis（3-pyridyl）-3,4-bis（4-pyridyl）cyclobutane（3）and 1,3-bis（3-pyridyl）-2,4-bis（4-py ridyl）cyclobutane（5）.Solid-phase organic synthesis reaction is happened betwee n the coordination polymers 2 and 4 by using different metal ions as templatin g agents,and a photochemical[2+2]photocycloaddition reaction with region spe cificity occurs.2、A one-dimensional coordination polymer[Cd₂（μ-OH₂）₂（2,5-fdc）₂（2,3’-bpe）₂]_n（6）was synthesized by the reaction of metal salts 2,3’-bpe and 2,5-furandica rboxylic acid（2,5-H₂fdc）.The olefin bonds of a pair of 2,3’-bpe ligands in the adjacent chain of one-dimensional double bond structure was contained in this compound.Compound 6 was converted to two-dimensional compound[Cd2（μ-OH2）2（2,5-fdc）2（bpbpcb）2]n（7）that contain 1,3-bis（2-pyridyl）-2,4-bis（3-pyridyl）c yclobutane（bpbpcb）ligand under ultraviolet light through the[2+2]photocyclo addition reaction.The photoluminescent phenomenon from purple to blue was sh own during the transformation process of the single crystal to single crystal.3、{[Zn₂（μ-OH₂）（5-Me-1,3-bdc）（2,3’-bpe）]·H₂O}_n（8）and{[Ag₂（5-Me-1,3-Hb dc）（2,3’-bpe）₂][Ag（5-Me-1,3-bdc）（2,3’-bpe）]·H₂O}_n（10）were synthesized under h ydrothermal conditions with metal salts,2,3’-bpe and 5-methylisophthalic acid（5-Me-1,3-H₂bdc）.The[2+2]photocycloaddition of single crystal to single cryst al can occur in 8 and 10.Due to the influence of different coordination enviro nments of Zn（II）and Ag（I）ions,{{[Zn₂（μ-OH₂）（5-Me-1,3-bdc）（HT-bpbpcb）_0.5]·H₂O}_n（9,HT-bpbpcb=1,3-bis（2-pyridyl）-2,4-bis（3-pyridyl）cyclobutane）and{[Ag₂（5-Me-1,3-Hbdc）（HH-bpbpcb）₂][Ag（5-Me-1,3-bdc）（2,3’-bpe）]H₂O}_n（11,HH-bpbpcb=1,2-bis（2-pyridyl）-3,4-bis（3-pyridyl）cyclobutane）were synthesized thro ugh 2,3’-bpe molecules arranged in head-to-tail and head-to-head mode under li ght reaction conditions.4、The two coordination polymers[Ag（H₂BTC）（3,4’-bpe）₂]_n（12）and{[Cd（H BTC）（3,4’-bpe）]·H₂O}_n（13）were synthesized through the metal salt,3,4’-bpe an d trimellitic acid（H₃BTC）react with each other.The two different structures o f coordination polymers was obtained by the reaction of H₂BTC,3,4’-bpe with different d¹00 metal ions under hydrothermal conditions.Compound 12 belongs t o a one-dimensional coordination polymer.A two-dimensional supramolecular n etwork was created through the interaction of Ag????O.Each two-dimensional ne twork and other equivalent networks interpenetrate to form the molecular frame work of staggered 2D→3D superposition.Compound 13 has a two-dimensional（4,4）network structure.There are thermal stability and photocatalytic propertie s in these coordination polymers,and it can be applied to the degradation of o rganic contaminants in water.