Alkali metal mediated C–C bond coupling reaction

Tachikawa, Hiroto

doi:10.1063/1.4906944

Cited by 11 publications

(9 citation statements)

References 30 publications

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“…[36] The transition state for CÀ C coupling (B2*, Scheme 3b) is comparable to that recently calculated for benzene coupling in a Li(benzene) 2 À sandwich. [37] The bridging dianion in complex B3 could lose a hydride (B4*) requiring an activation enthalpy of ΔH = + 15.3 kcal mol À 1 . After relatively facile elimination of H 2 (B5-B6*: + 8.2 kcal mol À 1 ) the final biphenyl product B7 is formed.…”

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confidence: 99%

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

et al. 2022

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Complex [( DIPeP BDI)Ca] 2 (C 6 H 6 ), with a C 6 H 6 2À dianion bridging two Ca 2 + ions, reacts with benzene to yield [( DIPeP BDI)Ca] 2 (biphenyl) with a bridging biphenyl 2À dianion ( DIPeP BDI = HC[C(Me)N-DIPeP] 2 ; DIPeP = 2,6-CH(Et) 2 -phenyl). The biphenyl complex was also prepared by reacting [( DIPeP BDI)Ca] 2 (C 6 H 6 ) with biphenyl or by reduction of [( DIPeP BDI)CaI] 2 with KC 8 in presence of biphenyl. Benzene-benzene coupling was also observed when the deep purple product of ballmilling [( DIPP BDI)CaI(THF)] 2 with K/KI was extracted with benzene (DIPP = 2,6-CH(Me) 2 -phenyl) giving crystalline [( DIPP BDI)Ca(THF)] 2 (biphenyl) (52 % yield). Reduction of [( DIPeP BDI)SrI] 2 with KC 8 gave highly labile [( DIPeP BDI)Sr] 2 (C 6 H 6 ) as a black powder (61 % yield) which reacts rapidly and selectively with benzene to [( DIPeP BDI)Sr] 2 (biphenyl). DFT calculations show that the most likely route for biphenyl formation is a pathway in which the C 6 H 6 2À dianion attacks neutral benzene. This is facilitated by metal-benzene coordination.

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confidence: 99%

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

et al. 2022

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“…In the direct AIMD calculation [31][32][33][34][35][36], the geometry of the neutral cluster (H 2 O) 4 was fully optimized at the MP2/6-311++G (d,p) level. The trajectory on the ionic state potential energy surface was started from the equilibrium point of the parent neutral (H 2 O) 4 cluster.…”

Section: Direct Aimd Calculations From the Optimized Structuresmentioning

confidence: 99%

Ionization dynamics of the branched water cluster: A long-lived non-proton-transferred intermediate

Tachikawa

Takada

2016

Computational and Theoretical Chemistry

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a b s t r a c tThe proton transfer (PT) reaction after water cluster ionization is known to be a very fast process occurring on the 10-30 fs time scale. In the present study, the ionization dynamics of the branched water tetramer (H 2 O) 4 were investigated by means of a direct ab initio molecular dynamics (AIMD) method to elucidate the time scale of PT in the water cluster cation. A long-lived non-proton-transferred intermediate was found to exist after the ionization of the branched-type water cluster. The lifetimes of the intermediate were calculated to be ca. 100-150 fs. PT occurred after the formation of the intermediate. The structure of the intermediate was composed of a symmetric cation core: H 2 O-H 2 O + -H 2 O. The broken symmetry of the structure led to PT from the intermediate. The reaction mechanism is discussed based on the theoretical results.

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“…In addition to the trajectory from the optimized geometry of Ser‐His‐Glu, five trajectories were selected and run from the Franck−Condon (FC) region of Ser‐His‐Glu. The sampling method was described in our previous papers . The equations of motion were numerically solved by the velocity Verlet algorithm method.…”

Section: Computational Sectionmentioning

confidence: 99%

Direct ab‐initio molecular dynamics study on the radiation effects on catalytic triad composed of Ser‐His‐Glu residues

Tachikawa

Kawabata

2015

Int J of Quantum Chemistry

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Abstract:High energy irradiation to the hydrogen bonded system is important in relevance with the initial process of DNA and enzyme damages. In the present study, the effects of radiation to catalytic triad have been investigated by means of direct ab-initio molecular dynamics (AIMD) calculation. As a model of the catalytic triad, Ser-His-Glu residue, which is one of the important enzymes in the acylation reaction, was examined. The ionization and electron attachment processes in Ser-His-Glu were investigated as the radiation effects,. The direct AIMD calculation showed that a proton of His is spontaneously transferred to carbonyl oxygen of Glu after the ionization. However, the whole structure of catalytic triad was essentially kept after the ionization. On the other hand, in the case of the electron capture in the model catalytic triad Ser-His-Glu, the dissociation of Glu residue from [Ser-His] -was found as a product channel. The mechanism of ionization and electron capture process in the catalytic triad was discussed on the basis of theoretical results.

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Alkali metal mediated C–C bond coupling reaction

Cited by 11 publications

References 30 publications

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

Ionization dynamics of the branched water cluster: A long-lived non-proton-transferred intermediate

Direct ab‐initio molecular dynamics study on the radiation effects on catalytic triad composed of Ser‐His‐Glu residues

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