Functionalization Of Metal-organic Frameworks And Their Application In Catalysis

Metal-organic frameworks (MOFs), also known as porous coordination polymers, are novel nanometer porous functional materials, having periodic work structures, that self-assemble with metal ions and organic ligands. While large surface areas, high micropore volumes, good thermal stability and large windows are desirable for many applications. Heterogeneous catalysis is one of the earliest proposed applications for MOFs, as well as one of the earliest demonstrated applications. Despite MOFs have many catalytically features of large internal surface areas and uniform pore and cavity sizes, Current works are undertaken on extending construction methods of MOFs and introducing a variety of catalytic active groups. Optimization of catalytic groups with configuration and electronic synergy effects to make MOFs have a better application prospects. This thesis mainly concerns on the construction of catalytic functional MOFs with different functional ligands and metals by appropriate methods and studies on the catalytic applications of MOFs.The first part of this thesis focused on the construction of chiral MOFs by using5-hydroxyisophthalic acid with external alkynes groups. Coordination of this ligand with different metal ions resulted three MOFs:Eu-DPYI, Zn-DPYIl and Zn-DPYI2. Enantiomeric MOFs, having L-or D-proline chiral functionality, were achieved through incorporating two opposite chiral adducts into the preassembled MOFs by in situ click reactions. The catalytic activity of these MOFs were examined in asymmetric Aldol reactions, resulting in an exponentially greater yield compared to the uncatalyzed reaction (from<10%to85%). The high post-synthetic yield (from20%to90%) obtained from these heterogeneous catalysts may derive from the larger channel size and lower functional group density in MOFs.Regarding photocatalysis, we primarily focused on the construction of MOFs by using triphenylamine with good photochemical activity deriving carboxylic acid groups. Coordination of this ligand with different metal ions resulted in two porous MOFs: Zn-TCA-HOTP and Co-TCA. The strong reductive excited state of the triphenylamine moiety within these MOFs initiated a photo-induced electron transfer, rendering an active intermediate for a-alkylation. The photo-catalytic activity of these MOFs were studied on using different metal ions. The results of the catalytic reactions showed that the photo-catalytic activity of MOFs with antimagnetic metal ion has better yield than MOFs with paramagnetic metal ion (Yield>95%). Then we synthetized a3D interpenetrating structure MOFs Co-BTPY-NH2, which was assembled by incorporating a non-noble transition metal Co2+and the strong electron-donating ligand3-amino-4,4’-bipyridine. In the mixture of water and acetonitrile solution, Co-BTPY-NH2with Ru(bpy)3(PF6)2as the photosensitizer can lead to hydrogen production and TON attain110. And all the heterogeneous catalysts can also be recycled, renewable.