Synthesis Of Porous Material Supported Catalysts With Multi-nitrogen Ligand And Its Application In Borrowing Hydrogen Reaction

Multi-nitrogen ligand can stabilize the metal center by complexation of N atom with metal.Two methods have been applied to incorporate ligand with porous materials.The first method is grafting ligand to inorganic material.The second method is to prepare polymer materials using ligand as unit.Then,complexation of metal with porous material was carried out to prepared heterogeneous catalysts.Heterogeneous catalysts attracting the attention of many scientific researchers due to their high catalytic activity,recyclability.This porous material supported catalyst has a wide range of applications in organic synthesis.Meanwhile,borrowing hydrogen reaction is a green synthesis reaction with high atomic economy,and the use of hydrogen borrowing strategy to synthesize organic compounds is more consistent with the concept of green chemistry.Therefore,in this work,I will focus on the study heterogeneous catalysts applications in the borrowing hydrogen reaction.(1)A pyridinyl-triazine skeleton ligand was synthesized,and that was grafted onto the inorganic mesoporous silica SBA-15 by silane coupling agent.The mesoporous silica-supported-iridium and ruthenium catalysts(SBA-15@TZP-Ir,SBA-15@TZP-Ru)were synthesized and fully characterized.Fourier transform infrared spectroscopy revealed that iridium or ruthenium species are uniformly distributed on the surface of the supports.The resulting catalysts showed high catalytic activity in selective synthesis of useful substituted perimidines and aminopyrimidines,and the yields of their template substrates can reach 74%and 90% respectively.Additionally,the specific conversion process of the synthesis reaction of perimidines was studied through the mechanism experiments,which was consistent with the dehydrogenation condensation mechanism,and a reasonable conversion pathway was proposed.(2)The pyrazole and pyridine-based porous organic polymer was synthesized by Schiff base reaction.The pyridine and pyrazole-based ruthenium porous organic polymer catalyst Ru@Py-POP was prepared and fully characterized.Fourier-transform infrared spectroscopy showed that the C=O stretch and amine stretches almost disappeared.It was observed that Ru@Py-POP played a key role in the selective synthesis of C3-alkylated indoles.Meanwhile,Ru@Py-POP could be also used to the synthesis of triazine derivatives by dehydrogenation coupling reaction.In addition,Ru@Py-POP demonstrated a broad applicability,high stability and good recyclability in extended the scope of substrates.(3)The thiazole and pyrazole-based porous organic polymer was synthesized by polymerization,in which divinylbenzene was used as cross-linker.The thiazole and pyrazole-based porous organic polymer-supported-ruthenium and iridium catalysts(POP-Tz Pz-Ru,POP-Tz Pz-Ir)were prepared.The substrate expansion experiments found that the two catalysts have good catalytic in the synthesis of phenethylaniline and aminouracil derivatives,respectively.The mechanism exploration experiments also showed that the conversion process belongs to the hydrogen borrowing reaction mechanism.(4)1,3,5-triethynylbenzene was employed as a linker,the pyridine-based conjugated microporous polymer was prepared through the Sonogashira-Hagihara cross-coupling reaction.The X-ray single crystal diffraction results showed that the complex Pyr-Ru formed by coordination of pyridinyl ligand with metal ruthenium compound has a bidentate coordination structure.The pyridine-based conjugated microporous polymer-supported-ruthenium catalyst CMP-Pyr-Ru was prepared.The CMP-Pyr-Ru showed good catalytic activity in N-alkylation reactions between 3-aminodibenzofuran and alcohols,4-morpholinoaniline and alcohols,and the yields of model substrate were 82% and 80%.A reasonable transformation pathway has been proposed through control experiments and mechanism exploration.