Two ligands, 1, 3-bis(4-carboxyphenyl)imidazolium chloride and 4, 4-bipyridine, were employed to prepare nickel and zinc azolium based MOFs, Ni-MOF and Zn-MOF by the mixed ligand solvothermal approach. The positively ...Two ligands, 1, 3-bis(4-carboxyphenyl)imidazolium chloride and 4, 4-bipyridine, were employed to prepare nickel and zinc azolium based MOFs, Ni-MOF and Zn-MOF by the mixed ligand solvothermal approach. The positively charged azolium moieties in the imidazolium linker resulted in a charged environment in the as-synthesized frameworks. As a result, Ni-MOF and Zn-MOF demonstrated preferential adsorption of CO_(2) over methane molecules in the gas phase adsorption due to the higher quadruple moment of CO_(2), which interacts more with the positively charged frameworks. Besides, in aqueous media, Ni-MOF and Zn-MOF exhibited incredible adsorption efficiency for anionic dyes. In the following, Ni-MOF was metallated at the carbene site of the azolium linker to generate the novel heterogeneous catalyst Pd/Ni-MOF, which was successfully applied for Sonogashira and Suzuki-Miyaura coupling reactions without losing its activity after three cycles.展开更多
We have developed an N-heterocyclic carbene(NHC)-catalyzed domino reaction with aryl alde-hyde through a simple acyl azolium intermediate using phenyliodine(III)diacetate(PIDA)as an oxi-dant.Controlled experiments and...We have developed an N-heterocyclic carbene(NHC)-catalyzed domino reaction with aryl alde-hyde through a simple acyl azolium intermediate using phenyliodine(III)diacetate(PIDA)as an oxi-dant.Controlled experiments and density functional theory calculations supported a domino two-stage mechanism from aldehyde/amine to anα-oxygen-ation product,including NHC-catalyzed oxidation of the aldehyde to carboxylic acid via acyl azolium intermediate,and further,an addition of carboxyl-ate to iminium intermediate.Our study reveals a new model for the oxidation of Breslow intermedi-ate via electrophilic attack of the hydroxyl group by PIDA.展开更多
文摘Two ligands, 1, 3-bis(4-carboxyphenyl)imidazolium chloride and 4, 4-bipyridine, were employed to prepare nickel and zinc azolium based MOFs, Ni-MOF and Zn-MOF by the mixed ligand solvothermal approach. The positively charged azolium moieties in the imidazolium linker resulted in a charged environment in the as-synthesized frameworks. As a result, Ni-MOF and Zn-MOF demonstrated preferential adsorption of CO_(2) over methane molecules in the gas phase adsorption due to the higher quadruple moment of CO_(2), which interacts more with the positively charged frameworks. Besides, in aqueous media, Ni-MOF and Zn-MOF exhibited incredible adsorption efficiency for anionic dyes. In the following, Ni-MOF was metallated at the carbene site of the azolium linker to generate the novel heterogeneous catalyst Pd/Ni-MOF, which was successfully applied for Sonogashira and Suzuki-Miyaura coupling reactions without losing its activity after three cycles.
基金Financial support from the National Natural Science Foundation of China(Grant#s:21425207,21521002,21573233,and 21672216)the Chinese Academy of Sciences is greatly acknowledged.
文摘We have developed an N-heterocyclic carbene(NHC)-catalyzed domino reaction with aryl alde-hyde through a simple acyl azolium intermediate using phenyliodine(III)diacetate(PIDA)as an oxi-dant.Controlled experiments and density functional theory calculations supported a domino two-stage mechanism from aldehyde/amine to anα-oxygen-ation product,including NHC-catalyzed oxidation of the aldehyde to carboxylic acid via acyl azolium intermediate,and further,an addition of carboxyl-ate to iminium intermediate.Our study reveals a new model for the oxidation of Breslow intermedi-ate via electrophilic attack of the hydroxyl group by PIDA.
