Metal-Organic Frameworks Based On Semi-Rigid Aromatic Carboxylate: Syntheses,Structures And Functions

In the dissertation,twenty-two new metal-organic frameworks?MOFs?have been successfully constructed based on two semi-rigid aromatic carboxylic acids,viz.4,4'-dicarboxy-4''-nitrotriphenylamine?H₂L?and 4-?carboxymethoxy?-[1,1'-biphenyl]-3,4'-di-carboxylic acid(H₃L_ws),under hydrothermal or solvothermal conditions.Syntheses,structures and properties of these complexes have been investigated and discussed in detail and the main work of this dissertation includes the following four parts:?1?MOFs based on H₂L ligand and Zn²⁺/Cd²⁺ions:[Zn?L??4,4'-bpy?_0.5].?H₂O?_0.25?1?,[Cd₄?L?₄?4,4'-bpy?].2?H₂O??2?and[Zn₄?L?₄?4,4'-bpy??H₂O?₂].2H₂O.2CH₃CN?3?.Complexes1 and 3 are two 2-D layered structures based on 1-D beaded chains,and complex 2 exhibits a two-fold interpenetrating 3-D network.Complexes 1 and 2 can serve as a highly sensitive and selective fluorescence sensor for aqueous detection of hydrogen sulfide,and the detection limit of 1 and 2 was 7.9?M and 0.2?M,respectively.Complex 3 has the ability to detect Fe³⁺ion in DMAc solvent.?2?Three MOFs based on H₂L ligand and Cu²⁺/Co²⁺ions:[Cu?L??H₂O?].?CH₃CN?_0.25?4?,[Co₄?L?₄?4,4'-bpy??H₂O?₂].2H₂O?5?and[Co?L??Phen??6?.Complex 4exhibits a 3-D porous network assembled by 2-D two-fold interpenetrating sheet comprising helical chains,and shows outstanding chemical robustness which can withstand acidic or basic aqueous solution as well as various organic solvents.Complex 4 displays a typical antiferromagnetic interaction between adjacent copper ions.In particular,complex 4 not only displays a notable visible-light photocatalytic activity for degrading oragnic dyes?e.g.crystal violet?CV?,rhodamine 6G?R6G?,congo red?CR?and basic red 2?BR2??with the assistance of H₂O₂ but also can catalyze the oxidation-coupling reaction of phenylboronic acid and its derivatives.Complex 5 is a 2-D layered structure based on octahedral cage,and complex 6 exhibits a 1-D zigzag chain with good thermal stability.?3?MOFs based on H₂L ligand and lanthanide metal ions:[La?H₂L??H₂O?].?CH₃CN?_0.25]?7?,[La₂?L?₃?H₂O?₄].?CH₃CN?₃.H₂O?8?,[Nd₂?L?₃?H₂O?₄].H₂O?9?,Tb₂?L?₃?H₂O?₃.?CH₃CN?.?H₂O?_1.5?10?,Eu₂?L?₃?H₂O?₃.?CH₃CN?₂.?H₂O?(11,Sm₂?L?₃?H₂O?₃.?CH₃CN??12?,Dy₂?L?₃?H₂O?₃.?CH₃CN?.?H₂O??13?,Yb₂?L?₃.?H₂O?_1.5?14?,[Ce₂?L?₃?H₂O?₄].CH₃CN?15?,[Pr₂?L?₃?H₂O?₄].?CH₃CN?₄?16?and Er₂?L?₃.?CH₃CN??17?.Complex 7?La?is a 3-D porous MOF constructed by stacking of 2-D layered structures and can be used as a fluorescent probe for detecting Fe³⁺and Cu²⁺ions.Complexes 8?La'?,9?Nd?,15?Ce?and 16?Pr?are isomorphic with the raz2 topology.Amongst,8?La'?and 9?Nd?can serve as probes to detect Fe³⁺ion.Complexes 10?Tb?,11?Eu?,12?Sm?and 13?Dy?are also isostructural dispalying 3-D porous structures based on rod-shaped metal chains and bridging ligands.Among them,complex 10?Tb?has the ability to identify Fe³⁺and Cu²⁺;Complexes11?Eu?and 12?Sm?can act as a fluorescent probe for detecting benzaldehyde in benzyl alcohol solvent.Complexes 13?Dy?and 14?Yb?display different luminescence responses toward different NACs with superb sensitivity for 2,4-DNP,TNP and PNP.The structures of17?Er?and 14?Yb?are similar,wherein all metal ions adopt the pentagonal double-cone geometry to connect with the ligand forming a three-dimensional network containing three kinds of channels.?4?MOFs based on H₃L_wss and H₂bsal ligands:Co(HL_ws)].?H₂O?₂?18?,Ni₂(L_ws)?OH??H₂O?₃?19?,Cd₂(L_ws)?OH??20?,Cu?Hbsal?₂?4,4'-bpy?₂?21?and Cu?Hbsal??4,4'-bpy??22?.Complexes 18 and 19 are 1-D chain and 2-D layered structures,respectively,and there are a large number of hydrogen bonds in their structures,which greatly improves their hydrolytic stability.Complex 20 is a 3-D non-interpenetrating network,and shows superb sensitivity for NACs especially for 2,4-DNP,TNP and PNP.Complexes 21 is a1-D linear chain,and 22 is a 3-D porous supermolecular framework with sod topology.What is the most interesting finding is that compound 21 can be irreversibly transformed into 22 in a crystal-to-crystal manner in the case that compound 21 is immersed into DMF solvent.Particularly,the 1D-to-3D crystal-to-crystal structural transformaiton also incurres a drastic change in the magnetic properties of 21 and 22.