Metal-Organic Frameworks Based On Rigid Aromatic Carboxylate And 1,2,4-triazolate:Syntheses,Structures And Functions

In this dissertation,we have selected four organic ligands for construction of novel metal-organic frameworks(MOFs)which are based on either rigid aromatic carboxylate groups or 1,2,4-triazole units,viz.benzo-(1,2;3,4;5,6)-tris(thiophene-2'-carboxylic acid)(H3BTTC),4,4',4"-tricarboxytriphenylamine(H3TCA),(tris(1,2,4-triazol-4-yl)phenyl)amine(TTPA-4)and N,N,N',N'-tetrakis(1,2,4-triazol-4-yl)phenyl)-1,4-phenylenediamine(TTPPDA-4).Solvothermal reactions of these ligands with different metal ions resulted in 10 structurally different MOFs with interesting functions.The main work of the dissertation is categorized into the following three parts:(1)MOFs based on H3BTTC ligand:Pb-BTTC(Pb13(BTTC)8(OH)2(H20)4·H20·DMA)and Sr-BTTC([(CH3)2NH2]6[Sr13(O)3(BTTC)8(OH)2(H20)16]·xS,(where S represents non-coordinated solvent molecules).Pb-BTTC is a rare 3D MOF that is constructed by octuple intercatenation of discrete icosahedral coordination cages,and Sr-BTTC represents a 3D porous MOF based on truncated octahedral cage with the topology.Sr-BTTC is a zeolitic metal-organic framework(ZMOF)akin to ITQ-21 zeolite framework,which possesses an anionic framework carrying exchangeable[(CH3)2NH2]+ counter-cation.Through cation exchange,Sr-BTTC can selectively absorb cationic organic dyes with the highest absorption capability for Rhodamine B(RB)and Basic Red 2(BR2)compared to reported absorbents to date.Also,photocatalyst[Ru(bpy)3]2+ can be encapsulated into Sr-BTTC in the same way,generating Sr-BTTC supported photocatalyst,Ru(bpy)3@Sr-BTTC that can serve as heterogeneous catalyst for aerobic oxidative hydroxylation of arylboronic acids.Besides,Sr-BTTC can undergo thermo-induced porosity transition from micropore to mesopore,which can help enhance the[Ru(bpy)3]2+ loadings.(2).MOFs based on H3TCA and TTPA-4 ligands:Cd-TCA({[Cd5(TCA)2(H2O)2]·8DMA·16H20}n),La-TCA({La(TCA)(DMA)3}n),Cd-TTPA-1({[Cd(TTPA-4)](NO3)2·3.0H2O·3.5CH3OH}n),Cd-TTPA-2({[Cd(TTPA-4)0.5(TDA)]}n)and Cd-TTPA-3({[Cd3(TTPA-4)(TPA)3(H2O)3]·5.OH2O}n).Cd-TCA is a 3D proton-conductive MOF having curved narrow channels which is composed of 12-connected pentanuclear Cd cluster as secondary building unit(SBU).At 80? and 85%RH,Cd-TCA shows the proton conductivity of 1.45×10-6 S cm-1.La-TCA is a 2D layered structure which displays different luminescence responses toward different NACs especially those with phenolic group.Cd-TTPA-1 possesses a 3D porous cationic framework with(412.63)(49.66)-nia topology.With the aid of 2,5-thiophenedicarboxylic acid(TDA)coligand,a 4-fold interpenetrating 3D network of Cd-TTPA-2 was resulted that is built from(42.6)(44.6.88.104.124)(4)2-net.In the presence of terephthalic acid(TPA)auxiliary ligand,an 8-fold interpenetrating 3D network of Cd-TTPA-3 was produced that comprises eight equivalent(103)-srs net.Particularly,Cd-TTPA-1 displays interesting dual function as the result of its unique structural attributes,which not only shows superb sensitivity for NACs especially 2,4-DNP,TNP and PNP but also impressive removal capabilities of toxic Cr2O72-oxoanion pollutant from aqueous solution.(3)MOFs based on TTPPDA-4 ligand:Cd-TTPPDA-1({[Cd(TTPPDA-4)](C104)2·9H20·DMF}n),Cd-TTPPDA-2({[Cd(TTPPDA-4)2(OH)2]·9H2O·5DMF}n),Zn-TTPPDA({[Zn(TTPPDA-4)0.5(TPA)]·H2O·0.5DMF}n).Cd-TTPPDA-1 exhibits a cationic framework with(42.63.8)-sra topology.Cd-TTPPDA-2 is composed of 1D ribbon chains which stack along crossing directions to form a 3D porous supramolecular framework.With the aid of TPA ligand,a 3D 4-fold interpenetrating network of Zn-TTPPDA was resulted wherein a single 3D net shows(4.64.8)2(42.62.82)-mog topology.All MOFs display different luminescence responses toward different NACs with superb sensitivity for 2,4-DNP,TNP and PNP.Furthermore,Cd-TTPPDA-1 and Zn-TTPPDA can be utilized as chemical sensors for detection of antibiotics with high sensitivity for nitrofurazone and nitrofurantoin.