Synthesis And Properties Of Dual-Emission Fluorescent Response Based On MOFs Composites

Synthesis and properties of dual-emission fluorescent response based on MOFs composites,which are high-sensitivity,high-selectivity,high-accuracy,self-calibrating ratio-type fluorescence sensors that avoid the disadvantages of single fluorescent emission.Which are one of the important members of the"new fluorescent intelligent detection materials",have been widely used in chemical sensing,chiral recognition and separation in recent years.This paper aims to synthesize stable and excellent luminescence MOFs materials,and further develop dual-emission fluorescence response composites based on dye@MOF and chiral Eu³⁺@MOF,which are applied to the precise determination of volatile organic small molecules and chiral amino acids.The main results of this paper are as follows:1.Solvothermal reactions of zinc salts and rigid H₄tptc（terphenyl-2,2′,5,5′-tetracarboxylic acid）ligand under different conditions generated five kinds of fluorescent coordination materials with three-dimensional frameworks:Zn₆（?₃-O）₂（tptc）₃（1）;Zn₂（tptc）（bpp）（DMF）（2）;Zn₂（tptc）（bpa）·2（1,4-dioxane）（3）;Na₄[Zn₄（?₂-O）₂（tptc）₃]（4）;Zn₂（tptc）（bpe）₂（5）.Based on the pore structure of 1,we encapsulated Rhodamine B（RB）to form a double-emitting fluorescent RB@1 composite centered on the ligand and dye,and also made them into membrane devices,which efficient identify small organic molecules such as pyridine,nitrobenzene and acetophenone.The compound 2 is a three-dimensional structure based on the paddle-wheel type of dinuclear zinc clusters as secondary building unit.Because of its uncoordinated carboxyl oxygen atom,the piezochromic EPBPA@2 composite material is obtained by doping the yellow fluorescent organic molecule dibenzoylphenothiazine（EPBPA）.2.N-（2-carboxylbenzyl）-L-serine[（L）-H₂cbs]and N-（2-carboxylbenzyl）-L-histidine[（L）-H₂cbh]which is selected as the chiral ligand with zinc/nickel salts to construct two chain based frameworks:Zn[（L）-cbs)]（6）and Ni[（L）-cbh)]（H₂O）₂（7）,both of which have chiral characteristics.Based on the chiral site of 6,the chiral amino acid was recognized by fluorescent method,but the effect was not well,and the sensitivity of single-emission fluorescence was low and the repeatability was poor.Therefore,we introduced Eu³⁺to obtain chiral Eu³⁺@6 double-emitting fluorescence material.The result was that the composite material exhibits better recognition effect on D/L-proline and D/L-tryptophan.