Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two com...Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.展开更多
The mechanism is investigated for Cp^(tBu)Rh(OH)_(2)-catalyzed annulation of 2-biphenylboronic acid with three activated alkenes using M06-2X functional.The reaction comprises transmetalation via two steps and followi...The mechanism is investigated for Cp^(tBu)Rh(OH)_(2)-catalyzed annulation of 2-biphenylboronic acid with three activated alkenes using M06-2X functional.The reaction comprises transmetalation via two steps and following C-H activation producing reactive Rh-biphenyl complex with two Rh—Cσbonds.After the coordination/insertion of alkenes,respective fused or bridged cyclic products are yielded depending on different alkenes accompanied by the release of CptBuRh.The promotion of Cp^(tBu)Rh(OH)_(2) lies in the barrier decrease of transmetalation and C-H activation ready for coordination/insertion ensuring the smooth progress of common rate-limiting reductive elimination.The stereoselective transfer and ring rotation are specific for benzoquinone and cyclopropenone.The role of Rh(III)catalyst and release of Rh(I)is supported by Multiwfn analysis on frontier molecular orbital(FMO)of specific transiton states(TSs)and Mayer bond order(MBO)value of vital bonding,breaking.展开更多
The C-C bond activation and recyclization of benzocyclobutenone to poly-fused rings catalyzed by the[Rh(R,S-L)]+complex producing the R,S-,S,R-,R,R-and S,S-product were investigated systematically at the BP86/6-31G(d,...The C-C bond activation and recyclization of benzocyclobutenone to poly-fused rings catalyzed by the[Rh(R,S-L)]+complex producing the R,S-,S,R-,R,R-and S,S-product were investigated systematically at the BP86/6-31G(d,p)level in gas phase and THF,and the R,S-and S,R-reaction pathways were revisited at the M062X/6-31G(d,p)level in THF.The computational results reveal that THF only marginally alters the free-energy barriers,but elevates the relative energies of all species.The BP86 functional testifies that in both gas phase and THF,the activation of strained C-C bonds bears relatively low free-energy barriers,and the rate-determining steps of S,R-and R,R-channels are different from those of R,S-and S,S-channels.The BP86 functional also predicts that the R,S-channel is energetically most favorable in gas phase,but the S,R-product is dominant in THF.The change of NPA charges can mirror the variation of molecular structures to elucidate reaction mechanisms.展开更多
为设计硝基吡唑炸药经物理吸附方式进行废水处理的方案,借助DFT-M06-2X和MP2(full)方法在6-311++G(2d,p)基组水平上研究了Cl–···3,4-二硝基吡唑(3,4-DNP)自由基···H2O体系阴离子氢键诱导协同效应。结果...为设计硝基吡唑炸药经物理吸附方式进行废水处理的方案,借助DFT-M06-2X和MP2(full)方法在6-311++G(2d,p)基组水平上研究了Cl–···3,4-二硝基吡唑(3,4-DNP)自由基···H2O体系阴离子氢键诱导协同效应。结果表明,随着3,4-DNP自由基···H2O体系中Cl–的引入和三聚体的形成,不仅3,4-DNP自由基与H2O之间常规O–H···O和H–O···H氢键的距离、相互作用能、电子密度发生了较大改变,而且Cl–与3,4-DNP自由基或H2O之间形成的H···Cl–阴离子氢键与N···Cl–、C···Cl–、O···Cl–相互作用的相应值也发生了明显改变,从而导致了显著的阴离子氢键诱导协同或反协同效应,形成了稳定的复合物。由此可推断,依据阴离子诱导氢键协同效应,Cl–可用于硝基吡唑类炸药的废水处理。AIM (atom in molecules)、电子密度转移、RDG (reduced density gradient)和NBO (natural bonding orbital)分析揭示了协同效应的本质。展开更多
基金This work was supported by the Natural Science Foundation of Gansu Province(20JR5RA479)the Outstanding Youth Research Program of Lanzhou University of Arts and Sciences(2018JCQN008).
文摘Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.
基金National Natural Science Foundation of China(Nos.21973056,21972079)Natural Science Foundation of Shandong Province,China(No.ZR2019MB050)Project of the Key Laboratory of Agricultural Film Application of Ministry of Agriculture and Rural Affairs,China.
文摘The mechanism is investigated for Cp^(tBu)Rh(OH)_(2)-catalyzed annulation of 2-biphenylboronic acid with three activated alkenes using M06-2X functional.The reaction comprises transmetalation via two steps and following C-H activation producing reactive Rh-biphenyl complex with two Rh—Cσbonds.After the coordination/insertion of alkenes,respective fused or bridged cyclic products are yielded depending on different alkenes accompanied by the release of CptBuRh.The promotion of Cp^(tBu)Rh(OH)_(2) lies in the barrier decrease of transmetalation and C-H activation ready for coordination/insertion ensuring the smooth progress of common rate-limiting reductive elimination.The stereoselective transfer and ring rotation are specific for benzoquinone and cyclopropenone.The role of Rh(III)catalyst and release of Rh(I)is supported by Multiwfn analysis on frontier molecular orbital(FMO)of specific transiton states(TSs)and Mayer bond order(MBO)value of vital bonding,breaking.
基金supported by the National Natural Science Foundation of China(No.21571137)the Natural Science Foundation of Shandong Province(ZR2017LB010)the Science and Technology Planning Project(Guidance Plan)of Tai’an City(Nos.2018GX0041 and 2018GX0073)。
文摘The C-C bond activation and recyclization of benzocyclobutenone to poly-fused rings catalyzed by the[Rh(R,S-L)]+complex producing the R,S-,S,R-,R,R-and S,S-product were investigated systematically at the BP86/6-31G(d,p)level in gas phase and THF,and the R,S-and S,R-reaction pathways were revisited at the M062X/6-31G(d,p)level in THF.The computational results reveal that THF only marginally alters the free-energy barriers,but elevates the relative energies of all species.The BP86 functional testifies that in both gas phase and THF,the activation of strained C-C bonds bears relatively low free-energy barriers,and the rate-determining steps of S,R-and R,R-channels are different from those of R,S-and S,S-channels.The BP86 functional also predicts that the R,S-channel is energetically most favorable in gas phase,but the S,R-product is dominant in THF.The change of NPA charges can mirror the variation of molecular structures to elucidate reaction mechanisms.
文摘为设计硝基吡唑炸药经物理吸附方式进行废水处理的方案,借助DFT-M06-2X和MP2(full)方法在6-311++G(2d,p)基组水平上研究了Cl–···3,4-二硝基吡唑(3,4-DNP)自由基···H2O体系阴离子氢键诱导协同效应。结果表明,随着3,4-DNP自由基···H2O体系中Cl–的引入和三聚体的形成,不仅3,4-DNP自由基与H2O之间常规O–H···O和H–O···H氢键的距离、相互作用能、电子密度发生了较大改变,而且Cl–与3,4-DNP自由基或H2O之间形成的H···Cl–阴离子氢键与N···Cl–、C···Cl–、O···Cl–相互作用的相应值也发生了明显改变,从而导致了显著的阴离子氢键诱导协同或反协同效应,形成了稳定的复合物。由此可推断,依据阴离子诱导氢键协同效应,Cl–可用于硝基吡唑类炸药的废水处理。AIM (atom in molecules)、电子密度转移、RDG (reduced density gradient)和NBO (natural bonding orbital)分析揭示了协同效应的本质。
