Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Partic...Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Particularly,the rationally designed chiral supermolecules and their hierarchical assemblies result in superior microenvironments,in which they interact distinctly with molecularly asymmetric guests for enantiospecific recognition.The chemistry of chiral supermolecule-based materials(CSMs)has become a lively research topic,and thus this review seeks to shed light on a range of synthetic CSMs at differing length scales developed in the past 5 years,with emphasis on the representative work from China.This review includes cavity-containing chiral supermolecules,chiral polymers,and chiral crystalline materials,aiming to tackle important issues from their design,synthesis,and structure to cutting-edge applications.This,in turn,allows for fundamental understanding of the transfer,amplification,and functional expression of chirality from the molecular to the supramolecular to the macroscopic scale.Finally,we provide perspectives on the promises,opportunities,and key challenges for the future development of useful chiral functional materials.展开更多
Metal-organic frameworks(MOFs)have achieved great success in the field of heterogeneous catalysis,however,ifs still challenging to design MOF catalysts with enhanced selectivity.Here,we demonstrated a combination stra...Metal-organic frameworks(MOFs)have achieved great success in the field of heterogeneous catalysis,however,ifs still challenging to design MOF catalysts with enhanced selectivity.Here,we demonstrated a combination strategy of metal design and ligand design on the enantioselectivity—that is the enantioselectivities of chiral MOF(CMOF)catalysts could be significantly enhanced by the rational choice of metal ions with higher electronegativities and introducing sterically demanding groups into the ligands.Four isostructural Ca-,Sr-and Zn-based CMOFs were prepared from enantiopure phosphono-carboxylate ligands of 1,V-biphenol that are functionalized with 2,4,6-trimethyl-and 2,4,6-trifluoro-phenyl groups at the Supposition.The uniformly distributed metal phosphonates along the channels could act as Lewis acids and catalyze the asymmetric transfer hydrogenation of heteroaromatic imines(benzoxazines and quinolines).Particularly,the Ca-based MOF 1 with 2,4,6-trimethyl groups at the substituents exhibited enhanced catalytic performance,affording the highest enantioselectivity(up to 97%).It is also the first report of the heterogeneous catalyst with chiral non-noble metal phosphonate active sites for asymmetric transfer hydrogenation reactions with Hantzsch ester as the hydrogen source.The catalyst design strategy demonstrated here is expected to develop new types of chiral materials for asymmetric catalysis and other chiral applications.展开更多
Covalent organic frameworks(COFs) have recently emerged as a new class of photocatalysts.However,integrated design is crucial to maximizing the performance of COF-incorporating photocatalytic systems.Herein,we compare...Covalent organic frameworks(COFs) have recently emerged as a new class of photocatalysts.However,integrated design is crucial to maximizing the performance of COF-incorporating photocatalytic systems.Herein,we compare two strategies of installing earth-abundant metal-based catalytic centers into the matrice of a 2 D COF named NUS-55.Compared to NUS-55(Co)prepared from the post-synthetic metalation of coordination sites within the COF,the molecular co-catalyst impregnated NUS-55/[Co(bpy)3]Cl2 achieves a seven-fold improvement in visible light-driven H2 evolution rate to 2,480 μmol g^-1h^-1,with an apparent quantum efficiency(AQE) of 1.55% at 450 nm.Our results show that the rational design of molecular anchoring sites in COFs for the introduction of catalytic metal sites can be a viable strategy for the development of highly efficient photocatalysts with enhanced stability and photocatalytic activities.展开更多
基金financially supported by the major research plan“Precise Construction of Multilevel Chiral Substances”of the National Natural Science Foundation of China(grant nos.9195600 and 92256303).
文摘Self-assembly of predesigned chiral molecules to form structurally diverse functional materials has been one of the most exciting recent developments in materials science and nanotechnology over the past decade.Particularly,the rationally designed chiral supermolecules and their hierarchical assemblies result in superior microenvironments,in which they interact distinctly with molecularly asymmetric guests for enantiospecific recognition.The chemistry of chiral supermolecule-based materials(CSMs)has become a lively research topic,and thus this review seeks to shed light on a range of synthetic CSMs at differing length scales developed in the past 5 years,with emphasis on the representative work from China.This review includes cavity-containing chiral supermolecules,chiral polymers,and chiral crystalline materials,aiming to tackle important issues from their design,synthesis,and structure to cutting-edge applications.This,in turn,allows for fundamental understanding of the transfer,amplification,and functional expression of chirality from the molecular to the supramolecular to the macroscopic scale.Finally,we provide perspectives on the promises,opportunities,and key challenges for the future development of useful chiral functional materials.
基金the National Natural Science Foundation of China(Nos.91956124,21875136,21620102001,91856204,21978058,21676094)the National Key Basic Research Program of China(No.2016YFA0203400)+1 种基金Key Project of Basic Research of Shanghai(Nos.17JC1403100,18JC1413200,19JC1412600)Shanghai Rising-Star Program(No.19QA1404300).
文摘Metal-organic frameworks(MOFs)have achieved great success in the field of heterogeneous catalysis,however,ifs still challenging to design MOF catalysts with enhanced selectivity.Here,we demonstrated a combination strategy of metal design and ligand design on the enantioselectivity—that is the enantioselectivities of chiral MOF(CMOF)catalysts could be significantly enhanced by the rational choice of metal ions with higher electronegativities and introducing sterically demanding groups into the ligands.Four isostructural Ca-,Sr-and Zn-based CMOFs were prepared from enantiopure phosphono-carboxylate ligands of 1,V-biphenol that are functionalized with 2,4,6-trimethyl-and 2,4,6-trifluoro-phenyl groups at the Supposition.The uniformly distributed metal phosphonates along the channels could act as Lewis acids and catalyze the asymmetric transfer hydrogenation of heteroaromatic imines(benzoxazines and quinolines).Particularly,the Ca-based MOF 1 with 2,4,6-trimethyl groups at the substituents exhibited enhanced catalytic performance,affording the highest enantioselectivity(up to 97%).It is also the first report of the heterogeneous catalyst with chiral non-noble metal phosphonate active sites for asymmetric transfer hydrogenation reactions with Hantzsch ester as the hydrogen source.The catalyst design strategy demonstrated here is expected to develop new types of chiral materials for asymmetric catalysis and other chiral applications.
基金supported by the National Research Foundation of Singapore(NRF2018-NRF-ANR007 POCEMON)the Ministry of Education-Singapore(MOE AcRF Tier 1 R-279-000-540-114,Tier 2 MOE2018-T2-2-148)+1 种基金the Agency for Science,Technology and Research(IRG A1783c0015,IAF-PP A1789a0024)the Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-Aged Teachers and Presidents
文摘Covalent organic frameworks(COFs) have recently emerged as a new class of photocatalysts.However,integrated design is crucial to maximizing the performance of COF-incorporating photocatalytic systems.Herein,we compare two strategies of installing earth-abundant metal-based catalytic centers into the matrice of a 2 D COF named NUS-55.Compared to NUS-55(Co)prepared from the post-synthetic metalation of coordination sites within the COF,the molecular co-catalyst impregnated NUS-55/[Co(bpy)3]Cl2 achieves a seven-fold improvement in visible light-driven H2 evolution rate to 2,480 μmol g^-1h^-1,with an apparent quantum efficiency(AQE) of 1.55% at 450 nm.Our results show that the rational design of molecular anchoring sites in COFs for the introduction of catalytic metal sites can be a viable strategy for the development of highly efficient photocatalysts with enhanced stability and photocatalytic activities.
