The metal-substituted silylenes are of high interest,as the theoretical studies indicated that the silylenes with electropositive substituents have a small ΔE_(S-T)(singlet-triplet energy gap)or even the ground-state...The metal-substituted silylenes are of high interest,as the theoretical studies indicated that the silylenes with electropositive substituents have a small ΔE_(S-T)(singlet-triplet energy gap)or even the ground-state triplets.However,such compounds are highly unstable,and only two transient alkali metal-substituted silylenes M(^(t)Bu_(3)Si)Si:(M=Li,K)were generated by photoextrusion of the alkali metal-substituted silacyclopropenes and merely studied by spectroscopic method(EPR)at low temperature(14 to 50 K).Herein,we report the generation of transient zinc-substituted silylenes from zinc silacyclopropanyl complexes under very mild and convenient conditions.The generated transient zinc-substituted silylenes are highly reactive and undergo intermolecular cycloaddition with alkenes for the synthesis of zinc-substituted Si-heterocyclic compounds.If there is no substrate,the zinc-substituted silylenes attack the C-C bonds of the β-diketiminato ligands and break the C-C bonds.DFT studies further highlight the silylene nature of the zinc-substituted silylene and a very small ΔE_(S-T)(4.4 kcal/mol).展开更多
Ligands play a key role in controlling activity of organometallic complexes so that development of new ligands to overcome the challenge is the main topic of modern chemistry.The first example of 1,1-hydride migratory...Ligands play a key role in controlling activity of organometallic complexes so that development of new ligands to overcome the challenge is the main topic of modern chemistry.The first example of 1,1-hydride migratory insertion and intramolecular redox reaction has been realized in this work by applying a new ligand in rare-earth metal chemistry.The novel rare-earth metal complexes L^(Mes)RECH2TMS(THF)(RE=Y(1a),Dy(1b),Er(1c),Yb(1d),L^(Mes)=1-(3-(2,6-iPr_(2)C_(6)H_(3)N=CH)C8H4N)-CH_(2)CH_(2)-3-(2-CH2–4,6-Me_(2)C_(6)H_(2))-(N(CH)_(2)NC),THF=tetrahydrofuran)bearing a ligand with imino,indolyl,NHC(N-heterocyclic carbene)multiple functionalities were synthesized and characterized.Treatment of complexes 1 with silanes(PhSiH3or PhSiH2Me or PhSiD3)selectively produced the unprecedented 1,1-hydride(or deuterated H)migratory insertion of the indolyl moiety of the novel unsymmetrical dinuclear rare-earth metal complexes 2.The complex 2a reacts with Ph_(2)C=O to give the selective C=O double bond insertion to the RE–Co-methylene-Mesbond product 3a which further reacts with another Ph_(2)C=O(or DMAP,4-N,N-dimethylaminopyridine)affording the novelμ-η^(2):η^(3)-dianionic 3-iminoindolyl dinuclear rare-earth metal complex 4a.The latter is formed through an unusual intramolecular redox reaction(through electron migration from the 2-carbanion of the indolyl ring to the imino motif)resulting in the re-aromatization of the indolyl ring.展开更多
The peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C（SiMe3）PPh2}THF] （L=[MeC（NDIPP）CHC（NDIPP）Me]-）, DIPP= 2,6-（Pr）2C6H3） leads to an interesting versatile reactivity, which is de...The peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C（SiMe3）PPh2}THF] （L=[MeC（NDIPP）CHC（NDIPP）Me]-）, DIPP= 2,6-（Pr）2C6H3） leads to an interesting versatile reactivity, which is demonstrated both experimentally and computationally. The complex undergoes [2＋2] cycloaddition reactions with alkynes, and easily activates various X-O bonds such as C-O of propylene oxide, N-O of 3,5-dimethylisoxazole, B-O of pinacolborane and Si-O of triethoxysilane. These reactions occur on the Sc-C bond of the phosphinoalkylidene complex. Interestingly, the Sc-P bond can also be activated as the presence of a Sc-C-P three center π interaction in the complex allows performing C-F activation of 2,6-difluoro- pyridine and 1,2 addition with imine or ketone. The complex also reacts with metal complexes, [（COD）RhCl]2 and （Ph3P）AuCl, to form structural intriguing heterobimetallic complexes.展开更多
The study of small-molecule activation by f-block elements still lags far behind that of transition metals.Although a few uranium complexes have been reported to activate dinitrogen,reports on the activation of heavie...The study of small-molecule activation by f-block elements still lags far behind that of transition metals.Although a few uranium complexes have been reported to activate dinitrogen,reports on the activation of heavier congeners,such as white phosphorus(P_(4)),by uranium species are extremely rare,and no example of uranium-mediated activation of elemental arsenic has appeared.展开更多
基金supported by the National Natural Science Foundation of China(21890721,21732007)the Shanghai Municipal Committee of Science and Technologythe Chinese Academy of Sciences President’s International Fellowship Initiative。
文摘The metal-substituted silylenes are of high interest,as the theoretical studies indicated that the silylenes with electropositive substituents have a small ΔE_(S-T)(singlet-triplet energy gap)or even the ground-state triplets.However,such compounds are highly unstable,and only two transient alkali metal-substituted silylenes M(^(t)Bu_(3)Si)Si:(M=Li,K)were generated by photoextrusion of the alkali metal-substituted silacyclopropenes and merely studied by spectroscopic method(EPR)at low temperature(14 to 50 K).Herein,we report the generation of transient zinc-substituted silylenes from zinc silacyclopropanyl complexes under very mild and convenient conditions.The generated transient zinc-substituted silylenes are highly reactive and undergo intermolecular cycloaddition with alkenes for the synthesis of zinc-substituted Si-heterocyclic compounds.If there is no substrate,the zinc-substituted silylenes attack the C-C bonds of the β-diketiminato ligands and break the C-C bonds.DFT studies further highlight the silylene nature of the zinc-substituted silylene and a very small ΔE_(S-T)(4.4 kcal/mol).
基金supported by the National Natural Science Foundation of China(22031001,21871004,21861162009,22171004)the grants from the Education Department of Anhui Province(GXXT-2021-052)。
文摘Ligands play a key role in controlling activity of organometallic complexes so that development of new ligands to overcome the challenge is the main topic of modern chemistry.The first example of 1,1-hydride migratory insertion and intramolecular redox reaction has been realized in this work by applying a new ligand in rare-earth metal chemistry.The novel rare-earth metal complexes L^(Mes)RECH2TMS(THF)(RE=Y(1a),Dy(1b),Er(1c),Yb(1d),L^(Mes)=1-(3-(2,6-iPr_(2)C_(6)H_(3)N=CH)C8H4N)-CH_(2)CH_(2)-3-(2-CH2–4,6-Me_(2)C_(6)H_(2))-(N(CH)_(2)NC),THF=tetrahydrofuran)bearing a ligand with imino,indolyl,NHC(N-heterocyclic carbene)multiple functionalities were synthesized and characterized.Treatment of complexes 1 with silanes(PhSiH3or PhSiH2Me or PhSiD3)selectively produced the unprecedented 1,1-hydride(or deuterated H)migratory insertion of the indolyl moiety of the novel unsymmetrical dinuclear rare-earth metal complexes 2.The complex 2a reacts with Ph_(2)C=O to give the selective C=O double bond insertion to the RE–Co-methylene-Mesbond product 3a which further reacts with another Ph_(2)C=O(or DMAP,4-N,N-dimethylaminopyridine)affording the novelμ-η^(2):η^(3)-dianionic 3-iminoindolyl dinuclear rare-earth metal complex 4a.The latter is formed through an unusual intramolecular redox reaction(through electron migration from the 2-carbanion of the indolyl ring to the imino motif)resulting in the re-aromatization of the indolyl ring.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21732007 and 21325210）, the Strategic Priority Research Program of the Chinese Academy of Sciences {Grant No. XDB20000000）, and the Program of Shanghai Academ- ic Research Leader. LM is a member of the Institut Universitaire de France. LM acknowledges Humboldt foundation and the Chinese Scholarship Council.
文摘The peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C（SiMe3）PPh2}THF] （L=[MeC（NDIPP）CHC（NDIPP）Me]-）, DIPP= 2,6-（Pr）2C6H3） leads to an interesting versatile reactivity, which is demonstrated both experimentally and computationally. The complex undergoes [2＋2] cycloaddition reactions with alkynes, and easily activates various X-O bonds such as C-O of propylene oxide, N-O of 3,5-dimethylisoxazole, B-O of pinacolborane and Si-O of triethoxysilane. These reactions occur on the Sc-C bond of the phosphinoalkylidene complex. Interestingly, the Sc-P bond can also be activated as the presence of a Sc-C-P three center π interaction in the complex allows performing C-F activation of 2,6-difluoro- pyridine and 1,2 addition with imine or ketone. The complex also reacts with metal complexes, [（COD）RhCl]2 and （Ph3P）AuCl, to form structural intriguing heterobimetallic complexes.
基金supported by the National Natural Science Foundation of China(grant nos.21772088 and 91961116)the Fundamental Research Funds for the Central Universities(nos.14380216 and 14380262)Programs for high-level entrepreneurial and innovative talents introduction of Jiangsu Province(individual and group programs).L.M.is a senior member of the Institut Universitaire de France.The Humboldt Foundation and Chinese Academy of Science are acknowledged for financial support。
文摘The study of small-molecule activation by f-block elements still lags far behind that of transition metals.Although a few uranium complexes have been reported to activate dinitrogen,reports on the activation of heavier congeners,such as white phosphorus(P_(4)),by uranium species are extremely rare,and no example of uranium-mediated activation of elemental arsenic has appeared.
