Cu,Ag,Cd,Pb,Zr-Based Organic-Inorganic Hybrid Materials And Applications In Photocatalytic And Fluorescent Sensing

The functionalization and performance improvement of materials have always been the focus of research.As a kind of composite material with excellent properties and adjustable frameworks,organic-inorganic hybrid compounds have great potential applications in optical,electrical,magnetic and catalytic fields.In the past few decades,organic-inorganic hybrid compounds have been widely reported due to their fascinating structures and interesting properties.However,until now,it has been difficult to develop or improve the target properties though structural manipulation.In recent years,our research group has always focused on creating hybrid compounds with novel structures and exploring their photocatalytic,fluorescent sensing,photochromism and thermochromism properties.The compounds were functionalized further based on their structure to improve properties.In this thesis,nine metal halide were constructed by hydro(solvo)thermal self-assembly of organic bases and metal ions(Mn+ = Cu+,Ag+,Pb2+,Cd2+).In addition,inspired by the classic MOFs of Ui O-66 series,we explored the structural factors affecting its amino acid sensing.This thesis consists of six chapters:The introduction is listed in first chapter,which briefly introduces the concept of organic-inorganic hybrid compounds,the research progress of metal-halogen compounds and MOFs,the factors affecting their synthesis,and broad applications in many directions.Finally,the purpose and significance of this paper are introduced,and the main research results are summarized in this thesis.The second chapter briefly introduces experimental methods,testing instruments and reagents.In the third chapter,trough employing the in situ N-alkylation between tripyridine molecules and C2H5 OH,four iodometallates [H2(L1′)]2[Pb3I12](L1′+ = 1-Ethyl-3,5-bis-(pyridin-3-ylcarbamoyl)-pyridinium)1,[L1′′][Cu3I6](L1′′3+ = 1-Ethyl-3,5-(1-ethylpyridin-3-niumcarbamoyl)-pyridinium)2,[L1′′][Ag3I6] 3,[H2(L2′)][Ag3I6] and [H2(L2′)][Ag3I6](L2′+ = 1-Ethyl-3,5-bis-(pyridin-4-ylcarbamoyl)-pyridinium)4 were obtained.Among them,the alkylation degree for tripyridine molecules is different,and the in situ generated tripyridine derivatives show the different configurations.This is not only related to the structure of inorganic anions,but also related to the tripyridine molecule itself.The two moieties are actually templates for each other.The compound 1 is found to effectively catalyze the degradation of Rhodamine B(Rh B),and the degradation efficiency reaches 94% in 70 minutes.The degradation efficiency for compounds 2-4 does not exceed 50%.The free radical trapping test suggests that with compound 1 as photocatalyst,superoxide ion radicals(?O2-)and holes(h+)both play a key role.While with other three compounds as photocatalyst,only ?O2-plays a role.The differences should be related to bandwidth of materials.The compound 1 has a slightly wider bandwidth,leading to the higher exciton separation efficiency.Due to the involvement of more free radicals,the usual intermediates don’t appear in catalytic process of 1,while the colored species appear in the catalytic process of 3 and 4.The cyclic test verified that compound 1 still has high catalytic activity after five recycling.We also investigated the catalytic capacity of 1 for the degradation of 5 times quantity of Rh B.The degradation rate reaches 99% in 5.5 hours,indicating that 1 has the good photocatalytic performance in degrading high concentration of Rh B.Since the amount of catalyst and dye used in each study is different,it is difficult to compare.Here we first introduced the method of calculating TOF value to better evaluate the photodegradation performance of each hybrid material.In the fourth chapter,the Ui O-66 series MOFs(Ui O-66-NH2,Ui O-66-(NH2)2,Ui O-67-NH2,Ui O-68-NH2)were synthesized by adding the ligand length and amino group on the basis of the ligand 2-amino-terephthalic acid.The sensitivityexperiments show the response of four MOFs to arginine(Arg)detection under UV lamp.It is found that Ui O-67-NH2 and Ui O-68-NH2 have no effect on the recognition of Arg.Ui O-66-(NH2)2 has a good response to Arg and its sensitivity is much higher than Ui O-66-NH2.This is mainly related to the following two aspects: one is the density of amino group.For the same amount of substrate,the amino density of Ui O-66-(NH2)2 is larger than others,which increases the probability and stability of hydrogen bond.Second is the pore size of MOFs.Although the pore sizes are increased by more benzene rings,it also leads to the decrease of contact frequency between functional sites and target amino acids.Fluorescence tests show that Ui O-66-(NH2)2 not only has good selectivity for Arg,but also could selectively detect Arg under the interference of nearly twenty amino acids.The high sensitivity of Ui O-66-(NH2)2 is suitable for trace detection of Arg.The limit of Arg detection is 8 mg·L-1(4.6×10-5 mol·L-1)for Ui O-66-(NH2)2 paper,which can be used to detect Arg quickly and intuitively.In the fifth chapter,three kinds of rigid organic bases and metal ions(Cu+,Pb2+,Cd2+)were selected to construct five metal halide [L4′][Pb3I8](L4′2+ = 1-(3-methyltriazol-1-1y)-4-(1-(3-methylimidazolylmethyl)))5,[Cd I2(L4)2]·2H2O(L4 = 1-(triazol-1-yl)-4-(1-imidazolylmethyl)benzene)6,[Cd I2(L1)] 7,[L3′]0.5[Pb0.75I2.5](L3′2+ = Pyndine-2,6-dicarboxylic acid bis(pyridin-3-yl)-1-ethylamide)8,[L5′][Cu2I4](L5′2+ = 4,4′-bis(1-ethylpyridine-4-yl)biphenyl)9.Compound 5 is a rare three-dimensional supramolecular network;6 and 7 are 1-D chain and dinuclear cluster by the connection of Cd-I and organic bases,respectively.8 is a special 1-D Pb-I chain,and the chain pattern is rarely reported.9 is a dispersed tetranuclear cluster.Both 6 and 7 have blue light emission,and 7 has fluorescent photochromic properties at room temperature.The sensing performances of 6 and 7 on metal ions are investigated,and 7 shows excellent selectivity,sensitivity and anti-interference performance for the identification of Fe3+(Ksv are 6.37×103 M-1 and 1.79×104 M-1,respectively).The sixth chapter includes the summary of main work during the master’sdegree and the prospect of future research direction of our group.