| Photosynthesis in nature provides substance and energy for humankind.In the photosynthesis process,ordered assembly of the active molecules provide the solid structure basis for the effective electron and proton transfer between them,which drives the efficient photocatalytic reaction.Learning from photosynthesis is a promising strategy to design and prepare the perfect photocatalysts.Coordination-induced supramolecular self-assembly can precisely control the arrangement,spacing,stacking mode,and size of pores between molecules,thereby effectively regulating electron transfer between molecules.Utilizing this strategy,highly efficient heterogeneous photocatalysts will be obtained.Aromatic amides including perylene diimide(PDI)and naphthalene diimide(NDI)own high molar absorption coefficient,low reducing potential and robust photo-and thermal-stability.Recently,PDI was demonstrated to undergo consecutive photoinduced electron transfer(conPET)processes,which breaks the limitation of visible light photocatalysis,realizing the activation of carbon-chloride(C-Cl)bonds in aryl group.However,this type of dyes are easily aggregated due to the strong π…π stacking interaction,therefore dram atically decreasing the photocatalytic efficiency.In this thesis,coordination-induced supramolecular self-assembly was utilized to effectively adjust the supramolecular assembly between PDI/NDI in metal-organic coordination polymer(CP).It was found that the physical and chemical properties,such as electron transfer process and energy bandgap,of the obtained CPs were determined by the supramolecular interactions between dyes,screening out highly efficient photocatalysts for photocatalytic reduced dehalogenation via conPET process.The detailed information are the following:(1)By the incorporation of PDI into a CP Zn-PDI,a heterogeneous approach was achieved to tackle the poor solubility and strong tendency to aggregate of PDIs that restricted the exploitation of conPET process.The interplay between metal-PDI coordination and π… π stacking in Zn-PDI facilitates the conPET process for the visible light-driven reduction of aryl halides by stabilizing the radical-anion intermediate and catalyst-substrate interacted moiety.(2)A three-fold interpenetreated CP Cd-NDI was obtained using NDI as organic linker.Mg-NDI and Sr-NDI own the same ligand with Cd-NDI while the interactions between NDI units of these NDI CPs were distinct and play a role in bandgap value and electrochemistry.The special twine of NDI in Cd-NDI make it the only active photocatalyst conducting conPET process to realize visible-light mediated reduction of 4-bromoacetophenone,whereas Cd-NDI still can’t finish the photoredution of 4-choroacetophenone.(3)The introduction of-SEt into NDI core give a new 3D CP Cd-SEt-NDI which conduct a new two-photon-invovled process,the charge-transfer promoted consecutive photon excitation(CT-CPE)process,via the formation of charge transfer(CT)complex with electron donor(ED).Compared to the traditional conPET process,CT-CPE process can transfer more energy to chemical reaction because of the reduced energy loss during first PET,which is verified by the smooth reduction of 4-choroacetophenone using Cd-SEt-NDI as photocatalyst. |
