Communication: A concerted mechanism between proton transfer of Zundel anion and displacement of counter cation

Koizumi, Akihito; Suzuki, Kenkichi; Shiga, Motoyuki; Tachikawa, Masanori

doi:10.1063/1.3544212

Cited by 15 publications

(11 citation statements)

References 25 publications

(23 reference statements)

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“…Here, proton transfer barrier heights, corresponding to the energy difference between the TS and EQ structures, are 139.8, 20.5, and 80.2 kJ/mol for CuOH(H 2 O), AgOH(H 2 O), and AuOH(H 2 O), respectively. Thus, contrary to CuOH(H 2 O) and AuOH(H 2 O) clusters, both EQ and TS geometries of AgOH(H 2 O) are similar to those of NaOH(H 2 O) with respect to the R O1H* and bond length between metal and oxygen atoms, although this bond length is much longer than NaOH(H 2 O) cluster11. To analyze the thermal and quantum effects on the structure and dynamics of MOH(H 2 O) clusters, ab initio PIMD simulation has been performed.…”

Section: Resultsmentioning

confidence: 85%

“…The ab initio PIMD simulation is essentially the same manner as in the previous work11; MP2(full)/aug‐cc‐pVDZ‐pp using Trotter number P = 16 with the time step size dt = 0.1 (fs) at 300 K, and chain length parameter L = 4. Using the PIMD code16 linked to TURBOMOLE package15, the simulation was done for 50,000 steps.…”

Section: Resultsmentioning

confidence: 99%

“…We have recently investigated the influence of a series of alkali metal cations M + (M = Li, Na, and K) on the structure and dynamics of the gas‐phase low‐barrier hydrogen bonded species MOH(H 2 O) cluster using ab initio path integral molecular dynamics (PIMD)11. Our simulations showed that the quantum proton transfer in Zundel anion can be strongly coupled to the motion of counter cation located nearby, and a smaller cation can induce larger structural distortion of the Zundel anion fragment making the proton transfer barrier higher.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ab initio path integral simulation of AgOH(H₂O)

Koizumi

Suzuki

Shiga

et al. 2011

Int J of Quantum Chemistry

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Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ab initio path integral simulation of AgOH(H₂O)

Koizumi

Suzuki

Shiga

et al. 2011

Int J of Quantum Chemistry

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“…In PIHMC simulation (later denoted as “quantum simulation”) that takes account of both thermal and nuclear quantum effects, we used the number of beads P = 32 at 150 K and P = 16 at 300 and 450 K, as is the case in previous works . The quantum simulations were performed for 400,000 steps with the step size

Δ t = 1.5

fs at 150 K in A‐T pair and at 150, 300 K in G‐C pair, and

Δ t = 1.8

fs at 300 K in A‐T pair and at 450 K in G‐C pair.…”

Section: Methodsmentioning

confidence: 99%

Nuclear quantum effect and temperature dependency on the hydrogen‐bonded structure of base pairs

2013

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The structure of Watson-Crick-type adenine-thymine and guanine-cytosine pairs has been studied by hybrid Monte Carlo (HMC) and path integral hybrid Monte Carlo (PIHMC) simulations with the use of semiempirical PM6-DH+ method in the gas phase. We elucidated the nuclear quantum effect and temperature dependency on the hydrogen-bonded moiety of base pairs. It was shown that the contribution of nuclear quantum effect on the hydrogen-bonded structure is significant not only at low temperature 150 K but also at temperature as high as 450 K. The relative position of hydrogen-bonded proton between two heavy atoms and the nuclear quantum nature of the proton are also shown. Furthermore, we have applied principal component analysis to HMC and PIHMC simulations to analyze the nuclear quantum effect on intermolecular motions. We found that the ratio of Buckle mode (lowest vibrational mode from normal mode analysis) decreases due to the nuclear quantum effect, whereas that of Propeller mode (second lowest vibrational mode) increases. In addition, nonplanar structures of base pairs were found to become stable due to the nuclear quantum effect from two-dimensional free energy landscape along Buckle and Propeller modes.

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“…Reaction paths including proton transfers [16–36] were carefully examined. It is shown that acetophenone undergoes a remarkable elementary process, an [1,5]hydrogen shift.…”

Section: Introductionmentioning

confidence: 99%

Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

Yamabe¹,

Zeng²,

Guan³

et al. 2014

Beilstein J. Org. Chem.

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SummaryWolff–Kishner reduction reactions were investigated by DFT calculations for the first time. B3LYP/6-311+G(d,p) SCRF=(PCM, solvent = 1,2-ethanediol) optimizations were carried out. To investigate the role of the base catalyst, the base-free reaction was examined by the use of acetone, hydrazine (H2N–NH2) and (H2O)8. A ready reaction channel of acetone → acetone hydrazine (Me2C=N–NH2) was obtained. The channel involves two likely proton-transfer routes. However, it was found that the base-free reaction was unlikely at the N2 extrusion step from the isopropyl diimine intermediate (Me2C(H)–N=N–H). Two base-catalyzed reactions were investigated by models of the ketone, H2N–NH2 and OH−(H2O)7. Here, ketones are acetone and acetophenone. While routes of the ketone → hydrazone → diimine are similar, those from the diimines are different. From the isopropyl diimine, the N2 extrusion and the C–H bond formation takes place concomitantly. The concomitance leads to the propane product concertedly. From the (1-phenyl)ethyl substituted diimine, a carbanion intermediate is formed. The para carbon of the phenyl ring of the anion is subject to the protonation, which leads to a 3-ethylidene-1,4-cyclohexadiene intermediate. Its [1,5]-hydrogen migration gives the ethylbenzene product. For both ketone substrates, the diimines undergoing E2 reactions were found to be key intermediates.

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Communication: A concerted mechanism between proton transfer of Zundel anion and displacement of counter cation

Cited by 15 publications

References 25 publications

Ab initio path integral simulation of AgOH(H₂O)

Ab initio path integral simulation of AgOH(H₂O)

Nuclear quantum effect and temperature dependency on the hydrogen‐bonded structure of base pairs

Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

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Communication: A concerted mechanism between proton transfer of Zundel anion and displacement of counter cation

Cited by 15 publications

References 25 publications

Ab initio path integral simulation of AgOH(H2O)

Ab initio path integral simulation of AgOH(H2O)

Nuclear quantum effect and temperature dependency on the hydrogen‐bonded structure of base pairs

Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

Contact Info

Product

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Ab initio path integral simulation of AgOH(H₂O)

Ab initio path integral simulation of AgOH(H₂O)