Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of ph...Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of photosystem II to generate dioxygen,protons,and electrons.In artificial energy schemes,water oxidation is one of the half reactions of water splitting,which is an appealing strategy for energy conversion via photocatalytic,electrocatalytic,or photoelectrocatalytic processes.Because it is thermodynamically unfavorable and kinetically slow,water oxidation is the bottleneck for achieving large-scale water splitting.Thus,developing highly efficient water oxidation catalysts has attracted the interests of researchers in the past decades.The formation of O-O bonds is typically the rate-determining step of the water oxidation catalytic cycle.Therefore,better understanding this key step is critical for the rational design of more efficient catalysts.This review focuses on elucidating the evolution of metal-oxygen species during transition metal-catalyzed water oxidation,and more importantly,on discussing the feasible O-O bond formation mechanisms during the oxygen evolution reaction over synthetic molecular catalysts.展开更多
The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic ...The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic Pnma with a=23. 495(8), b=13. 603(5),c=8. 474(3); V=2706(1); Z=4 ; Dc=1. 71 g/cm3; F(000)=1408, μ=17. 0 cm-1 (MOKα). The final R=0. 052 and Rw= 0. 054(unit weight) for 1367 observed reflections. The La( Ⅲ) ion is 11-coordinated by three nitrale anions, four oxygen atoms from a crown ligand and one O atom of a water molecule. The other crown molecule is hydrogen bonded wilh the coordinated water molecule. The imposed mirror plane in the structure made both crown ligands and one of nitrate groups severely disordered.展开更多
In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reaction...In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reactions of inert C–H bonds catalyzed by transition metal complexes of Ir,Rh,Ru,Pt,Pd,Ni,and Sc,and the strategies utilized to access the site-selective C–H silylation products have been summarized.Furthermore,the mechanisms of C–H silylation reactions have been discussed briefly.展开更多
Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surfa...Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.展开更多
The bridging Re-Xe-Re bond with a remarkable stability is firstly predicted. The average binding energies for Re-Xe bond in RezCpz（PF3）4Xe with bridging Xe are calculated to be higher than that in ReCp（CO）2Xe, ReC...The bridging Re-Xe-Re bond with a remarkable stability is firstly predicted. The average binding energies for Re-Xe bond in RezCpz（PF3）4Xe with bridging Xe are calculated to be higher than that in ReCp（CO）2Xe, ReCp（CO）（PF3）Xe and ReCp（PF3）2Xe with terminal Xe. The interaction between two ReCp（PF3）2 fragments provides an additional contribution for the stability of bridging Re-Xe-Re bond. Besides, the RezCp2（PF3）4Xe isomers with bridging Xe are also stable in energy than the isomers with bridging PF3. As the terminal Re-Xe bond was found to exist in experiments, the more stable bridging Re-Xe-Re bond might be existent under similar or even milder condition.展开更多
The transition metal-mediated C–H bond activation has emerged as a powerful and ideal method for the total syntheses of natural products and pharmaceuticals, and has had a significant impact on synthetic planning and...The transition metal-mediated C–H bond activation has emerged as a powerful and ideal method for the total syntheses of natural products and pharmaceuticals, and has had a significant impact on synthetic planning and strategy in complex natural products.In this review, we describe selected recent examples of the transition metal-mediated C–H bond activation strategies for the rapid syntheses of natural products.展开更多
Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and c...Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and characterization of the imido, oxo, sulfido, and carbene-containing complexes of thorium. Such thorium complexes are of interest because of their unique structural properties, their potential application in novel group transfer reactions and catalysis, as well as their ability to engage the 5f orbitals in metal-ligand bonding. This short review summarizes the synthesis and reactivity of these thorium complexes.展开更多
文摘Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of photosystem II to generate dioxygen,protons,and electrons.In artificial energy schemes,water oxidation is one of the half reactions of water splitting,which is an appealing strategy for energy conversion via photocatalytic,electrocatalytic,or photoelectrocatalytic processes.Because it is thermodynamically unfavorable and kinetically slow,water oxidation is the bottleneck for achieving large-scale water splitting.Thus,developing highly efficient water oxidation catalysts has attracted the interests of researchers in the past decades.The formation of O-O bonds is typically the rate-determining step of the water oxidation catalytic cycle.Therefore,better understanding this key step is critical for the rational design of more efficient catalysts.This review focuses on elucidating the evolution of metal-oxygen species during transition metal-catalyzed water oxidation,and more importantly,on discussing the feasible O-O bond formation mechanisms during the oxygen evolution reaction over synthetic molecular catalysts.
文摘The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic Pnma with a=23. 495(8), b=13. 603(5),c=8. 474(3); V=2706(1); Z=4 ; Dc=1. 71 g/cm3; F(000)=1408, μ=17. 0 cm-1 (MOKα). The final R=0. 052 and Rw= 0. 054(unit weight) for 1367 observed reflections. The La( Ⅲ) ion is 11-coordinated by three nitrale anions, four oxygen atoms from a crown ligand and one O atom of a water molecule. The other crown molecule is hydrogen bonded wilh the coordinated water molecule. The imposed mirror plane in the structure made both crown ligands and one of nitrate groups severely disordered.
基金financially supported by the National Natural Science Foundation of China(21322203,21272238,21472194)the National Basic Research Program of China(2012CB821600)
文摘In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reactions of inert C–H bonds catalyzed by transition metal complexes of Ir,Rh,Ru,Pt,Pd,Ni,and Sc,and the strategies utilized to access the site-selective C–H silylation products have been summarized.Furthermore,the mechanisms of C–H silylation reactions have been discussed briefly.
基金supported by the National Science Fund for Distinguished Young Scholars(52125309)the National Natural Science Foundation of China(51991343,51920105002,51991340,52188101,and 11974156)+3 种基金Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341 and 2019ZT08C044)the Bureau of Industry and Information Technology of Shenzhen for the “2017 Graphene Manufacturing Innovation Center Project”(201901171523)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20190809180605522)Shenzhen Science and Technology Program(KQTD20190929173815000 and 20200925161102001)。
文摘Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.
基金supported by the National Natural Science Foundation of China (21273093, 21301041, 51476049)the Natural Science Foundation of Heilongjiang Province of China (B201409)the Doctoral Scientific Research Foundation of Harbin University of Commerce (13DL019)
文摘The bridging Re-Xe-Re bond with a remarkable stability is firstly predicted. The average binding energies for Re-Xe bond in RezCpz（PF3）4Xe with bridging Xe are calculated to be higher than that in ReCp（CO）2Xe, ReCp（CO）（PF3）Xe and ReCp（PF3）2Xe with terminal Xe. The interaction between two ReCp（PF3）2 fragments provides an additional contribution for the stability of bridging Re-Xe-Re bond. Besides, the RezCp2（PF3）4Xe isomers with bridging Xe are also stable in energy than the isomers with bridging PF3. As the terminal Re-Xe bond was found to exist in experiments, the more stable bridging Re-Xe-Re bond might be existent under similar or even milder condition.
基金supported by the National Natural Science Foundation of China (21290183, 21572008, 21372017)the State Key Laboratory of Bioorganic and Natural Products Chemistry
文摘The transition metal-mediated C–H bond activation has emerged as a powerful and ideal method for the total syntheses of natural products and pharmaceuticals, and has had a significant impact on synthetic planning and strategy in complex natural products.In this review, we describe selected recent examples of the transition metal-mediated C–H bond activation strategies for the rapid syntheses of natural products.
基金supported by the National Natural Science Foundation of China(21172022)the Program for New Century Excellent Talents in University(NCET-10-0253)Beijing Municipal Commission of Education
文摘Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and characterization of the imido, oxo, sulfido, and carbene-containing complexes of thorium. Such thorium complexes are of interest because of their unique structural properties, their potential application in novel group transfer reactions and catalysis, as well as their ability to engage the 5f orbitals in metal-ligand bonding. This short review summarizes the synthesis and reactivity of these thorium complexes.
