Quantitative Loading Of Bifunctional Groups On The Pore Surface Of Metal-Organic Frameworks

Multivariate-metal-organic frameworks(MTV-MOFs)have gained increasing interests due to their unique structure and superior performance recently.However,while bringing heterogeneity into an MOF is appealing,it is always difficult to control the proportion of each functionality via direct solvothermal synthesis.Usually,once the initial solution conditions change,their ratio will also change.As a result,the synergistic behavior in the MOF may be affected.Therefore,it has been a major problem to controllably introduce the dual function groups or the multifunctional groups on the MOFs skeleton.Firstly,we reported a stable azide&alkyne appended Zr-MOF,which can undergo quantitative tandem click reactions on the different functional sites,thus providing a unique platform for quantitative loading of bifunctional moieties.Different from the synthetic traditional MTV-MOFs,we can not only control the proportion of functional groups,but also change the type of modification functional molecules.In other words,it has universality.The work of this thesis reads as follows:1.Give a briefly introduction to MOFs,MTV-MOFs,as well as research advances about dual-ligand MOFs,In addition,the problems existing in the dual-ligand MOFs and design ideas of this text are also presented.2.Firstly,a series of Zr-MOFs with different ratio of azide and alkyne groups can be synthesized by modulating the initial ratio utilized in the solvothermal synthesis.Then,we select the Zr-MOF which takes the 1:1 ligand ratio as the research object.Benzyl azide and phenyl acetylene were used to modify MOFs.After post-modification,the ratio between functional groups is the same as the ratio of two carboxyl ligands in the backbone.As an added advantage,the same bifunctional MOF product can be obtained through two independent PSM routes.Finally,acid and base groups have been tandemly introduced onto the predesigned pore surface,leading to the formation of a heterogeneous acid-base MOF organocatalyst:(UiO-68-Ac/Ba).UiO-68-Ac/Ba can be used to catalyse the aldol reaction.The presented strategy provides a general way toward the construction of bifunctional MOFs with a precise control of ratio of different functionalities for desirable applications in future.