An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were pres...An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N2 sorp-tion confirmed the successful immobilization of chiral Mn(Ⅲ) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobi-lized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectiv-ity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.展开更多
As a highly promising candidate for hydrogen storage,crucial to vehicles powered by fuel cells,metal–organic frameworks(MOFs)have attracted the attention of chemists in recent decades.H_(2) uptake in an MOF is influe...As a highly promising candidate for hydrogen storage,crucial to vehicles powered by fuel cells,metal–organic frameworks(MOFs)have attracted the attention of chemists in recent decades.H_(2) uptake in an MOF is influenced by many factors such as pore size,ligand functionalization,and open metal sites.The synergistic effect of these factors can significantly enhance the H_(2) uptake in an MOF.Herein,we report a twofold interpenetrated MOF(UPC-501)based on a Zn_(4)O(COO)_(6)secondary building unit with the H_(2) uptake of 14.8 mmol g^(−1)(2.96 wt%)at 77 K and 0.1 MPa.This uptake is the highest among all the reported porous Zn-based MOF materials.Both experimental and theoretical results confirm that the reduced pore size derived from twofold interpenetration and the imidazole-functionalized ligand are responsible for the extremely high H_(2) uptake of UPC-501.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 20773069)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 200800551017)
文摘An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N2 sorp-tion confirmed the successful immobilization of chiral Mn(Ⅲ) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobi-lized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectiv-ity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.
基金supported by the NSFC(grant no.21875285)Taishan Scholar Foundation(grant no.ts201511019)+3 种基金Key Research and Development Projects of Shandong Province(grant no.2019JZZY010331)the Strategic Priority Research Program of CAS(grant no.XDB20000000)the Key Research Program of Frontier Sciences,CAS(grant no.QYZDB-SSW-SLH019)the Fundamental Research Funds for the Central Universities(grant no.18CX02047A).
文摘As a highly promising candidate for hydrogen storage,crucial to vehicles powered by fuel cells,metal–organic frameworks(MOFs)have attracted the attention of chemists in recent decades.H_(2) uptake in an MOF is influenced by many factors such as pore size,ligand functionalization,and open metal sites.The synergistic effect of these factors can significantly enhance the H_(2) uptake in an MOF.Herein,we report a twofold interpenetrated MOF(UPC-501)based on a Zn_(4)O(COO)_(6)secondary building unit with the H_(2) uptake of 14.8 mmol g^(−1)(2.96 wt%)at 77 K and 0.1 MPa.This uptake is the highest among all the reported porous Zn-based MOF materials.Both experimental and theoretical results confirm that the reduced pore size derived from twofold interpenetration and the imidazole-functionalized ligand are responsible for the extremely high H_(2) uptake of UPC-501.
