A Co_(12)coordination cage with a cuboctahedral architecture,and incorporating a mixture of tritopic(facecapping)and ditopic(edge-bridging)ligands,shows strong vip binding of large aromatic fluorophores(fluorescein ...A Co_(12)coordination cage with a cuboctahedral architecture,and incorporating a mixture of tritopic(facecapping)and ditopic(edge-bridging)ligands,shows strong vip binding of large aromatic fluorophores(fluorescein and its derivatives 6-carboxyfluorescein and Eosin-Y)with 1:1 binding constants in water in the range log K=6.7-7.9;its large central cavity(>1000Å^(3))facilitates binding of much larger vips than was possible with the smaller Co_(8)cage that we have reported previously.vip binding is accompanied by catalysed reactions of bound vips because the high positive charge on the cage surface(24+)also attracts anions,allowing the organic vips and anionic reaction partners to be co-located,resulting for example in cage-catalysed hydrolysis of phosphate esters(the insecticides Me-paraoxon and Et-paraoxon)and conversion of diacetyl fluorescein to fluorescein.In addition,we demonstrate a new type of cage-based catalysis which relies on the redox activity of the Co(Ⅱ)/Co(Ⅲ)couple in the cage to activate the peroxymonosulfate(PMS)anion by converting it to the highly reactive SO_(4)^(·−)radical ion,which bleaches cavity-bound fluorescein by complete oxidation.This is an example of an‘advanced oxidation process’in which the host cage not only brings the fluorescein and the PMS together via orthogonal hydrophobic and electrostatic interactions,but also provides redox activation of the PMS via a Co(Ⅱ)/Co(Ⅲ)couple,with the cage taking an active role in the catalytic process rather than acting simply as a passive reaction vessel.展开更多
The structure and the magnetic moment of transition metal encapsulated in a Au 12 cage cluster have been studied by using the density functional theory.The results show that all of the transition metal atoms（TMA） ca...The structure and the magnetic moment of transition metal encapsulated in a Au 12 cage cluster have been studied by using the density functional theory.The results show that all of the transition metal atoms（TMA） can embed into the Au 12 cage and increase the stability of the clusters except Mn.Half of them have the I h or O h symmetry.The curves of binding energy have oscillation characteristics when the extra-nuclear electrons increase;the reason for this may be the interaction between parity changes of extra-nuclear electrons and Au atoms.The curves of highest occupied molecular orbital-lowest unoccupied molecular orbital（HOMO-LUMO） gap also have oscillation characteristics when the extra-nuclear electrons increase.The binding energies of many M@Au 12 clusters are much larger than that of the pure Au 13 cluster,while the gaps of some of them are less than that of Au 13,so maybe Cr@Au 12,Nb@Au 12,and W@Au 12 clusters are most stable in fact.For magnetic calculations,some clusters are quenched totally,but the Au 13 cluster has the largest magnetic moment of 5 μ B.When the number of extra-nuclear electrons of the encapsulated TMA is even,the magnetic moment of relevant M@Au 12 cluster is even,and so are the odd ones.展开更多
The design and synthesis of highly stable metal-organic framework(MOF)materials are urgently needed but are still challenging.Demonstrated herein is a superstable 3p-block metal-organic framework platform(3p-MOFs,SNNU...The design and synthesis of highly stable metal-organic framework(MOF)materials are urgently needed but are still challenging.Demonstrated herein is a superstable 3p-block metal-organic framework platform(3p-MOFs,SNNU-5-Al,Ga and In)inspired by the periodic law of elements.Apart from extra-high thermal stability(up to 500°C),SNNU-5-Al shows excellent water tolerance(24 days at RT and 1 day at 80°C in pure water)and prominent pH stability(4 to 12).Superlarge cuboctahedral and octahedral cages in SNNU-5s lead to excellent CO_(2)and C1/C2-hydrocarbon uptake and separation performance as well as excellent methane storage capacity under 65 bar pressure(345 cm^(3)g^(-1)at 273 K and 279 cm^(3)g^(-1)at 298 K for SNNU-5-Al).The strong Lewis acid nature of open 3p metal sites further makes SNNU-5 MOFs ideal heterogeneous catalysts for CO_(2)catalytic fixation with epoxides.Overall,this work provided a significant advance in the development of robust functional MOF materials for energy and environmental applications.展开更多
基金University of Warwick(UK)for financial support via a Warwick/Monash Alliance accelerator grant involving X.Z.the Development and Promotion of Science and Technology Talents Project,Thailand,for a PhD studentship to B.S.
文摘A Co_(12)coordination cage with a cuboctahedral architecture,and incorporating a mixture of tritopic(facecapping)and ditopic(edge-bridging)ligands,shows strong vip binding of large aromatic fluorophores(fluorescein and its derivatives 6-carboxyfluorescein and Eosin-Y)with 1:1 binding constants in water in the range log K=6.7-7.9;its large central cavity(>1000Å^(3))facilitates binding of much larger vips than was possible with the smaller Co_(8)cage that we have reported previously.vip binding is accompanied by catalysed reactions of bound vips because the high positive charge on the cage surface(24+)also attracts anions,allowing the organic vips and anionic reaction partners to be co-located,resulting for example in cage-catalysed hydrolysis of phosphate esters(the insecticides Me-paraoxon and Et-paraoxon)and conversion of diacetyl fluorescein to fluorescein.In addition,we demonstrate a new type of cage-based catalysis which relies on the redox activity of the Co(Ⅱ)/Co(Ⅲ)couple in the cage to activate the peroxymonosulfate(PMS)anion by converting it to the highly reactive SO_(4)^(·−)radical ion,which bleaches cavity-bound fluorescein by complete oxidation.This is an example of an‘advanced oxidation process’in which the host cage not only brings the fluorescein and the PMS together via orthogonal hydrophobic and electrostatic interactions,but also provides redox activation of the PMS via a Co(Ⅱ)/Co(Ⅲ)couple,with the cage taking an active role in the catalytic process rather than acting simply as a passive reaction vessel.
文摘The structure and the magnetic moment of transition metal encapsulated in a Au 12 cage cluster have been studied by using the density functional theory.The results show that all of the transition metal atoms（TMA） can embed into the Au 12 cage and increase the stability of the clusters except Mn.Half of them have the I h or O h symmetry.The curves of binding energy have oscillation characteristics when the extra-nuclear electrons increase;the reason for this may be the interaction between parity changes of extra-nuclear electrons and Au atoms.The curves of highest occupied molecular orbital-lowest unoccupied molecular orbital（HOMO-LUMO） gap also have oscillation characteristics when the extra-nuclear electrons increase.The binding energies of many M@Au 12 clusters are much larger than that of the pure Au 13 cluster,while the gaps of some of them are less than that of Au 13,so maybe Cr@Au 12,Nb@Au 12,and W@Au 12 clusters are most stable in fact.For magnetic calculations,some clusters are quenched totally,but the Au 13 cluster has the largest magnetic moment of 5 μ B.When the number of extra-nuclear electrons of the encapsulated TMA is even,the magnetic moment of relevant M@Au 12 cluster is even,and so are the odd ones.
基金National Natural Science Foundation of China(21671126&20871167)Natural Science Foundation of Shaanxi Province(2018JC-019)+1 种基金Fundamental Research Funds for the Central Universities(GK201701003)“1331”project of Shanxi Province。
文摘The design and synthesis of highly stable metal-organic framework(MOF)materials are urgently needed but are still challenging.Demonstrated herein is a superstable 3p-block metal-organic framework platform(3p-MOFs,SNNU-5-Al,Ga and In)inspired by the periodic law of elements.Apart from extra-high thermal stability(up to 500°C),SNNU-5-Al shows excellent water tolerance(24 days at RT and 1 day at 80°C in pure water)and prominent pH stability(4 to 12).Superlarge cuboctahedral and octahedral cages in SNNU-5s lead to excellent CO_(2)and C1/C2-hydrocarbon uptake and separation performance as well as excellent methane storage capacity under 65 bar pressure(345 cm^(3)g^(-1)at 273 K and 279 cm^(3)g^(-1)at 298 K for SNNU-5-Al).The strong Lewis acid nature of open 3p metal sites further makes SNNU-5 MOFs ideal heterogeneous catalysts for CO_(2)catalytic fixation with epoxides.Overall,this work provided a significant advance in the development of robust functional MOF materials for energy and environmental applications.
