Synthesis And Preparation Of Several Functional MOFs And Their Application In Catalysis And Sensing

Since the concept of metal-organic framework?MOF?was proposed by Omar.Yaghi in the journal of Nature in 1995,MOFs have been developing with rapid speed.In the past 20 years,tens of thousands metal-organic frameworks were prepared.Nowadays,the chemists are not only interested in the novel metal-organic frameworks,but also to design and synthesize hybrid organic-inorganic materials with well-defined structures and excellent properties.Metal-organic frameworks are made of metal centers and organic ligands contain zero-dimensional to three-dimensional structures.Thanks to the structural features,there are many modification sites,which lay the foundation to change or improve their performance.It is inspiring that MOFs under laboratory conditions have been applied in gas storage,adsorption and separation,optical sensing,drug delivery and release,proton conducting and catalysis,and so.In this thesis,one-dimensional to three-dimensional organic-inorganic coordination polymers were designed and synthesized and their properties,such as solid-state simultaneous exchange of metal nodes and counter-anions,post-synthesis modification,catalytic oxidation,catalytic reduction and up-conversion photocatalysis,were investigated.I.A one-dimensional double-chain coordination polymer?CP-1?with metal nodes of “Cl-Co-Cl” was self-assembled based on a bent tetrazole-bridged ligand?L1?,which is capped by pyridyl group and pyrimidyl group and was synthesized from 5-bromo-pyrimidine through Suzuki coupling reaction,Click reaction and electrophilic substitution.CP-2,CP-3 and CP-4 were formed through solid-state simultaneous exchange of metal nodes and counter-anions observing with eye,when CP-1 was soaked in methanol solution of copper chloride,copper bromide and copper nitrate,respectively.The structural integrity of the cobalt?II? coordination polymer is maintained during the ion-exchange process.For the first time,a simultaneous exchange of metal nodes and counter-anions on the coordination polymers in the solid state was demonstrated.On the other hand,such interesting naked-eye-detectable ion-responsive color changes might be useful in visual sensors for the detection of metal cations and counter-anions.II.Co-MOF-1 was constructed based on a bent imidazole-bridged ligand?L2?,which is capped by pyridyl group and was synthesized from 4,4-dibromobenzil by annulation reaction,necleophilic substitution and Suzuki coupling reaction.Co-MOF-2,with coordination unsaturated metal center,was obtained through the loss of coordination methanol via a single-crystal-to-single-crystal process.Co-MOF-2 is a highly active heterogeneous catalyst which is easily recovered and reused for various organic substrates oxidation under milder conditions,such as,cyclohexane,styrene,benzyl alcohol and 1-phenylethanol,and so.III.Cd-MOF-1 was constructed based on a bent imidazole-bridged ligand?L3?,which is capped by pyridyl group and contains a carboxylic group and was synthesized from 4,4-dibromobenzil by annulation reaction,necleophilic substitution,Suzuki coupling reaction and hydrolysis reaction.Cd-MOF-1 with uncoordinated nitrogen atoms was post-synthetically functionalized with linear alkyl chains to afford imidazolium salt?IM?-type tri-phase transfer catalysts?Cd?II?-MOF-IM?for organic transformations.The imidazolium salt decorated Cd?II?-MOF-IM exhibits firstly typical solid phase transfer catalytic behaviour for the azidation and thiolation of bromo-alkane between aqueous/organic phases.Moreover,they can be easily recovered and reused under the PTC conditions.IV.Two kinds of composite catalysts,Cu?II?@Ui O-66-NH₂ and Cu?0?@Ui O-66-NH₂,were synthesized via the adsorption and reduction of copper?II?salt through Ui O-66-NH₂,which was obtained according to the corresponding literature.They can,respectively,serve as highly efficient heterogeneous catalysts for olefin oxidation and hydrogenation under mild conditions.V Through an inorganic materials induced gel-to-crystal approach,two kinds of multivariate composite catalysts,Na YF₄:Yb,Tm@Cd-MOF and Na YF₄:Yb,Tm@Cd-MOF@Ti O₂ were prepared and fully characterized by powdered X-ray diffraction,infrared spectroscopy,thermogravimetric analysis,scanning electron microscope,transmission electron microscopy,inductive coupled plasma emission spectrometer and elemental analysis.For the first time,a carprofen analogue was synthesized via up-conversion photo-catalyst under NIR irradiation,which was just for use to investigate the photocatalytic activity of Na YF₄:Yb,Tm@Cd-MOF and Na YF₄: Yb,Tm@Cd-MOF@Ti O₂.In conclusion,metal-organic frameworks are great useful in the application of catalysis and worth continuing to investigate.Researches show that new catalysts from MOFs can obtain via ion exchange,post-synthesis modification,metal ion loading and materials composite,and so.