Naoki Haruta
Kyoto University
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Publication
Featured researches published by Naoki Haruta.
Journal of Organic Chemistry | 2012
Naoki Haruta; Tohru Sato; Kazuyoshi Tanaka
The chemical reactivity in nucleophilic cycloaddition to C70 is investigated on the basis of vibronic (electron-vibration) coupling density and vibronic coupling constants. Because the e1″ LUMOs of C70 are doubly degenerate and delocalized throughout the molecule, it is difficult to predict the regioselectivity by frontier orbital theory. It is found that vibronic coupling density analysis for the effective mode as a reaction mode illustrates the idea of a functional group embedded in the reactive sites. Furthermore, the vibronic coupling constants for localized stretching vibrational modes enable us to estimate the quantitative reactivity. These calculated results agree well with the experimental findings. The principle of chemical reactivity proposed by Parr and Yang is modified as follows: the preferred direction is the one for which the initial vibronic coupling density for a reaction mode of the isolated reactant is a minimum.
Journal of Physics: Conference Series | 2013
Tohru Sato; Motoyuki Uejima; Naoya Iwahara; Naoki Haruta; Katsuyuki Shizu; Kazuyoshi Tanaka
Vibronic coupling density is derived from a general point of view as a one-electron property density. Related concepts as well as their applications are presented. Linear and nonlinear vibronic coupling density and related concepts, orbital vibronic coupling density, reduced vibronic coupling density, atomic vibronic coupling constant, and effective vibronic coupling density, illustrate the origin of vibronic couplings and enable us to design novel functional molecules or to elucidate chemical reactions. Transition dipole moment density is defined as an example of the one-electron property density. Vibronic coupling density and transition dipole moment density open a way to design light-emitting molecules with high efficiency.
Scientific Reports | 2017
Tohru Sato; Rika Hayashi; Naoki Haruta; Yong-Jin Pu
To elucidate the high external quantum efficiency observed for organic light-emitting diodes using a bisanthracene derivative (BD1), non-radiative transition processes as well as radiative ones are discussed employing time-dependent density functional theory. It has been previously reported that the observed high external quantum efficiency of BD1 cannot be explained by the conventional thermally activated delayed fluorescence involving T1 exciton nor triplet-triplet annihilation. The calculated off-diagonal vibronic coupling constants of BD1, which govern the non-radiative transition rates, suggest a fluorescence via higher triplets (FvHT) mechanism, which entails the conversion of a high triplet exciton generated during electrical excitation into a fluorescent singlet exciton. This mechanism is valid as long as the relaxation of high triplet states to lower states is suppressed. In the case of BD1, its pseudo-degenerate electronic structure helps the suppression. A general condition is also discussed for the suppression of transitions in molecules with pseudo-degenerate electronic structures.
Journal of Organic Chemistry | 2015
Naoki Haruta; Tohru Sato; Kazuyoshi Tanaka
The regioselectivities of La2@C80 in thermal nucleophilic and electrophilic attacks were theoretically investigated using vibronic coupling density (VCD) analysis. Nucleophilic and electrophilic cycloadditions to La2@C80 were experimentally reported to yield [6,6] and [6,5] adducts, respectively, as major products. VCD analysis provided a clear explanation for these experimental results. For nucleophilic reactions, it was found that the reactive [6,6] bonds did not have a large lowest unoccupied molecular orbital (LUMO) density and Fukui function but a large potential derivative with respect to a reaction mode. The VCD illustrates the origin of the interaction between the electronic and vibrational states. On the other hand, conventional reactivity indices such as frontier orbital density take only the electronic state into account. The result suggested that the stabilization due to vibronic couplings plays an important role in the regioselectivity of nucleophilic cycloadditions. The VCD with respect to the effective mode could provide a picture of the functional groups, which are the double bonds of ethylene moieties. VCD analysis with respect to hypothetical localized modes enabled the quantitative prediction of regioselectivities.
Journal of Physics: Conference Series | 2013
Naoki Haruta; Tohru Sato; Naoya Iwahara; Kazuyoshi Tanaka
It is known to be difficult to predict the regioselectivity of cycloadditions to fullerenes based on the frontier orbital theory. To discuss the chemical reactivity of C60, vibronic coupling constants for localized stretching vibrational modes of C60 anion which are the hypothetical reaction modes of cycloadditions are calculated. Furthermore, the product ratio of C60 bisadduct (C60X2) is evaluated in the same way by considering the electronic state of C60 monoadduct anion (C60X anion). It is found that there is a good correlation between vibronic coupling constants for the localized modes and experimental regioselectivity.
Chemical Physics Letters | 2012
Tohru Sato; Naoya Iwahara; Naoki Haruta; Kazuyoshi Tanaka
Tetrahedron Letters | 2013
Naoki Haruta; Tohru Sato; Kazuyoshi Tanaka; Michel Baron
Tetrahedron | 2017
Paulo F.M. Oliveira; Naoki Haruta; Alain Chamayou; Brigitte Guidetti; Michel Baltas; Kazuyoshi Tanaka; Tohru Sato; Michel Baron
ChemistrySelect | 2016
Paulo F.M. Oliveira; Michel Baron; Alain Chamayou; Michel Baltas; Brigitte Guidetti; Naoki Haruta; Kazuyoshi Tanaka; Tohru Sato
Tetrahedron | 2014
Naoki Haruta; Tohru Sato; Kazuyoshi Tanaka