Preparation Of Two Kinds Of Zn（Ⅱ）-MOFs Materials With Separation And Sensing Performance

Metal–organic frameworks（MOFs）are a new class of crystalline porous materials that are self-assembled by organic ligands and metal ions or metal clusters through coordination bonds.Due to structural diversity,high porosity,large surface area,and good affinity for gas molecular,MOFs have a widely applications in gas storage and capture,separation,energy storage,heterogeneous catalysis,optical imaging,chemical sensing and drug delivery.In this paper,two kinds of Zn（II）-MOFs were designed and synthesized by solvothermal method,and the application of two materials in gas separation and fluorescence sensing was studied in depth.The detailed contents and results are listed as follows:1.Preparation and CO₂ selective adsorption of pillar-layered Zn（II）-MOFs.A metal-organic framework[Zn₃（TCA）₂（DPE）]·DMF·6H₂O（referred to as BUT-161）has been solvothermally synthesized by the reaction of a tritopic carboxylic acid 4,4?,4??-nitrilotribenzoic acid（H₃TCA）,an ancillary ditopic pyridine ligand1,2-di（4-pyridyl）ethylene（DPE）and Zn（NO₃）₂·6H₂O.The framework of BUT-161shows a three-dimensional（3D）pillar-layered structure,where two-dimensional（2D）layers constructed from trimeric Zn₃（-CO₂）₆ clusters and TCA^3-ligands are topologically（3,6）-connected net,and the layers are further pillared by the DPE linkers.The resulting 3D framework contains 1D channels along the b axis.Powder X-ray diffraction（PXRD）patterns and gas adsorption studies reveal that the activated phase of BUT-161,as BUT-161a has permanent porosity with a Brunauer-Emmett-Teller（BET）specific surface area of 308 m² g^-1,although the framework structure shrinks after guest removal.In addition,it has been found that BUT-161a can selectively adsorb CO₂ over N₂ or CH₄.2.Preparation and TNP selective detection of fluorescent Zn（II）-MOFs.A metal-organic framework,[Zn（TDHB）_0.5]·3DMF·1.5H₂O（referred to as BUT-162）,has been solvothermally synthesized by the reaction of a tetradentate carboxylic acid 3,3?,5,5?-tetraphene（4-dibenzoicacid）-2,2?,4,4?,6,6?-hexamethyl-1,1?-biphenyl（H₄TDHB）and Zn（NO₃）₂·6H₂O.The single-crystal X-ray diffraction shows that BUT-162 has a 3D network framework contained three kinds of 1D channels.Typical I type N₂ adsorption isotherm shows that BUT-162 has microporous property and permanent porosity with a BET specific surface area of 1249 m² g^-1.In acetonitrile（MeCN）solution,BUT-162 has the largest fluorescence intensity and can be used for rapidly,sensitively,and highly selective detection of 2,4,6-trinitrophenol（TNP）,even in the presence of competitive nitro explosives.This high selectivity may be attributed to the electron transfer of TNP and the remote energy transfer mechanism between TNP and MOFs.The better selectivity indicates that BUT-162has potential application in explosive detection.