Studies On The Construction And Catalytic Properties Of Metal-Organic Frameworks Involving Triphenylamine Motifs

The employment of metal-organic frameworks(MOFs)as heterogeneous catalysts for asymmetric photocatalytic organic synthesis has always been a challenging subject.First,the MOFs have to contain both photocatalytic and asymmetric catalytic functions;second,the MOFs must include chiral confined channels;third,the processes emphasize the effective cooperation of photoredox catalysis and asymmetric catalysis,and require efficient electron and energy transfer between the substrates and MOF catalysts.In this thesis,tri phenyl amine with good performances on light absorption,photosensitization,photoredox and conformational chirality was used as building block,and the chirality characteristics and optical function advantages of triphenylamine were fully explored by studying the preparation and application of triphenylamine-based chiral MOFs and optical functional MOFs,respectively.By integrating the two characteristics of triphenylamine based on the multifunction collaborative design concept of MOFs,the synthesis and asymmetric photocatalysis of triphenylamine-based MOFs catalysts with chirality and optical function were performed.The results were expected to provide experimental reference and theoretical guidance for the reasonable design of new and efficient MOFs-based asymmetric photocatalysts.The specific contents are as follows:(1)Based on the potential conformational chirality characteristics of triphenylamine,a series of homochiral Ag(I)-MOFs were obtained by the assembly of achiral triphenylamine Schiff base ligands and Ag+ via the spontaneous resolution and chirality-inducing crystallization.The chiral catalysts were used for the asymmetric 1,3-dipolar cycloaddition between azomethine ylides and methacrylate,and no less than 82%yields and 86%ee values of the transformation were observed.The experimental criterion of chiral induction principles was obtained by determining the crystal structures of Ag(I)-MOFs encapsulating substrate molecules.The reaction substrate was first employed as chiral inducer to finish the one-pot chemical transformation that merging spontaneous resolution and asymmetric catalysis and also to control the enantioselectivity direction of the cycloaddition adducts.The results reflect the advantages of triphenylamine for constructing strongly confined chiral channels.(2)Based on the optical function characteristics of triphenylamine,a series of isostructural 3D MOFs(Ln-1?Ln-8)with Ln-OH-Ln cluster units were synthesized by reactions of blue-light-emitting 4,4,,4"-nitrilotrisbenzoicacid with lanthanide ions(Eu3+/Tb3+).By modifying the ratio of Eu3+/Tb3+,the solid-state green-light(Ln-1),red-emission(Ln-2)and white-light(Ln-8)emissions of Ln-MOFs were achieved.The Ln-5 presented remarkable fluorescent color response(from fuchsia to blue)and efficiently hydrolyse for the nerve agent simulant dimethyl 4-nitrophenyl phosphate(DMNP)in water.The results verified the good light absorption,photosensitization,and rapid energy transfer ability of triphenylamine.(3)Combined with the optical and chiral functions of triphenylamine,a pair of two-fold interpenetrated MOFs-based asymmetric photocatalysts,InP-1 and InP-2,were prepared by the reactions of 4,4',4"-nitrilotrisbenzoicacid photoredox group and L-/D-pyrrolidin-2-ylimidazole asymmetric organocatalyst with Zn2+,and were used to achieve the first example of the heterogeneous asymmetric photocatalysis for the direct ?-functionalization of saturated aldehydes and ketones through the unique 5?e-carbonyl activation mode.The framework interpentration not only greatly accelerated the electron transfer between the oxidized photosensitizer and enamine intermediate to improve the regioselectivity and conversion efficiency,but also enhanced the chiral confined effect of the helical triphenylamine channels.Meanwhile,the enriched acid/base catalytic sites within the MOF framework avoided the addition of multiple additives to stabilize active radicals,and made the reaction condition simpler,more manageable and environmentally friendly.