Metal organic frameworks (MOFs) provide unique opportunities for molecular heterogeneous catalysis by mimicking the active sites of enzymes.However,understanding and controlling the interaction between the metal node ...Metal organic frameworks (MOFs) provide unique opportunities for molecular heterogeneous catalysis by mimicking the active sites of enzymes.However,understanding and controlling the interaction between the metal node and the organic linker carrying the catalytic unit and the resulting confinement effects remain challenging.Here,in a combined theoretical and experimental approach,Zr-UiO-67-MOFs with ortho-N-acylproline-functionalized biphenyl-dicarboxylate linkers were prepared and compared with the corresponding MOFs with regioisomeric meta-linkers.As benchmark catalysis,the organocatalytic aldol reaction of p-nitrobenzaldehyde and cyclohexanone was studied.Experimental results revealed that the ortho-linker accelerated the aldol reactions,whereas the regioisomeric meta-linker decreased the reaction rate,which was rationalized by pore blocking of the meta-linker via molecular dynamics simulations.Moreover,the acid modulator used in the MOF preparation also played a critical role in the formation of acetal byproducts through competing acid catalysis.Our study provides novel insights into the cooperative catalysis between the linker-attached organocatalyst and the MOF metal center.展开更多
基金Generous financial support by the Deutsche Forschungsgemeinschaft (DFG,German Research Foundation)-Project-ID 358283783-SFB 1333/2 2022,subprojects A08,B05,B08,C04,C07 and HBFG,shared instrumentation (Grant No.INST 41/897-1 FUGG for 700 MHz-NMR)the Ministerium für Wissenschaft,Forschung und Kunst des Landes Baden-Württemberg,and the Fonds der Chemischen Industrie is gratefully acknowledged+4 种基金K.P.and S.Ko.acknowledge the support by the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy-EXC 2075-390740016 and by the Stuttgart Center for Simulation Science (SC SimTech)S.K.and A.D.Y.acknowledge financial support by the Carl-Zeiss-Stiftung within the NEXUS programThe authors also gratefully acknowledge the scientific support and HPC resources provided by the Erlangen National High Performance Computing Center (NHR@FAU) of the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) under the NHR project MoTrNanoMatNHR funding is provided by federal and Bavarian state authorities.NHR@FAU hardware is partially funded by the German Research Foundation (DFG)-440719683Open Access funding provided by the Max Planck Society.
文摘Metal organic frameworks (MOFs) provide unique opportunities for molecular heterogeneous catalysis by mimicking the active sites of enzymes.However,understanding and controlling the interaction between the metal node and the organic linker carrying the catalytic unit and the resulting confinement effects remain challenging.Here,in a combined theoretical and experimental approach,Zr-UiO-67-MOFs with ortho-N-acylproline-functionalized biphenyl-dicarboxylate linkers were prepared and compared with the corresponding MOFs with regioisomeric meta-linkers.As benchmark catalysis,the organocatalytic aldol reaction of p-nitrobenzaldehyde and cyclohexanone was studied.Experimental results revealed that the ortho-linker accelerated the aldol reactions,whereas the regioisomeric meta-linker decreased the reaction rate,which was rationalized by pore blocking of the meta-linker via molecular dynamics simulations.Moreover,the acid modulator used in the MOF preparation also played a critical role in the formation of acetal byproducts through competing acid catalysis.Our study provides novel insights into the cooperative catalysis between the linker-attached organocatalyst and the MOF metal center.
