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理論化学研究に立脚した量子干渉現象の分子エレクトロニクスへの展開

光合成細菌の反応中心複合体を用いた高効率な太陽電池の開発

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/bcsj.20190040

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.chemrev.7b00733

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.6b09067

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1518206113

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsnano.5b04615

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/anie.201311134

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/ja111021e

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

Flat layers are usually considered as structurally rigid motifs in two-dimensional (2D) materials. In this work, we demonstrate that a flat honeycomb-layer composed of distorted tri-coordinate copper ions bridged with cyanidos in (tetraethylammonium)Cu2(CN)3 exhibits high in-plane flexibility. This resulted in an extremely large anisotropic 2D-thermal expansion.

DOI： 10.1039/d4cc01232a

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

Epoxy resins are widely used adhesives in industrial fields. To use epoxy resin as an adhesive, it is necessary to mix the epoxy resin with a hardener. Hardeners have various functional groups and skeletons, and the properties of epoxy resins vary depending on the hardener. Although the adhesion of epoxy resins has been extensively studied using density functional theory (DFT) calculations, few studies have evaluated the effect of hardener molecules. Therefore, in this study, DFT calculations of adhesion energies and bonding structures on Cu (111) and Cu2O (111) surfaces are performed for model molecules of adducts of epoxy resin with hardeners having various functional groups and skeletons to evaluate the influence of the hardeners on the adhesion of epoxy resin to the metal surface. The adhesion energy to the Cu (111) surface is governed by the energy due to dispersion forces. Hardeners of the thiol type, which contain relatively heavy sulfur atoms, and hardeners with aromatic rings, displaying high planarity, enable the entire molecule to approach the metal surface, resulting in a relatively high adhesion strength. The calculations for the Cu2O (111) surface show the adhesion strength is more strongly influenced by interactions such as hydrogen bonds between the surface and adhesive molecules than by dispersion forces. Therefore, in adhesion to Cu2O (111), the benzylamine-epoxy adduct with hydrogen bonding and OH−π interactions with the surface, in addition to having a relatively flexible framework, shows a high adhesion strength.

DOI： 10.1021/acs.langmuir.4c01093

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

The adhesion of epoxy adhesives to aluminum materials is an important issue in assembling parts for lightweight mobility. Aluminum surfaces typically possess an oxide layer, which readily adsorbs water. In this study, the aggregation states of water and its effect on the curing reaction were examined by placing a water layer between an amorphous alumina surface and a mixture of epoxy and amine components. This study used molecular dynamics simulations and density functional theory calculations. Before the reaction, water molecules strongly adsorbed onto the alumina surface, aggregating excess water. Some water diffused into the epoxy/amine mixture, accelerating the diffusion of unreacted substances. This led to faster reaction kinetics, particularly in proximity to the alumina surface. The adsorption of water molecules onto the alumina surface and the aggregation of excess water were similarly observed even after the curing process. Subsequently, the interaction between the alumina surface and various functional groups of the epoxy/amine mixture was evaluated before and after the reaction. Epoxy monomers had little interaction with the alumina surface before the reaction, whereas hydroxy groups formed by the ring-opening reaction of epoxy groups exhibited notable interaction. Conversely, sulfonyl and amino groups in amine compounds formed hydrogen bonds with OH groups on the alumina surface before the reaction. However, after the reaction, amino groups weakened their interaction with the alumina OH groups as they transformed from primary to tertiary during the curing reaction. Both epoxy and amine monomers/fragments similarly interacted with water molecules, both before and after the reaction. The insights gained from this study are expected to contribute to a better understanding of the impact of moisture absorption on the application of epoxy resins.

DOI： 10.1021/acs.langmuir.4c01081

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担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Applied Energy Materials  

In this study, a comprehensive theoretical analysis was undertaken to elucidate the remarkably efficient conversion of CO2 into HCOO- employing a coordination polymer featuring Pb-S bonds, namely [Pb(tadt)]n (where tadt stands for 1,3,4-thiadiazole-2,5-dithiolate), referred to as KGF-9. The catalytic activity of this visible-light responsive solid photocatalyst has been carefully compared with that of PbS, a typical compound that also contains the Pb-S bond. The former shows a very high catalytic activity, while the latter shows almost no activity. The photoreduction process of CO2 on the KGF-9 surface was analyzed in detail using periodic density functional theory calculations. The reduced catalyst surface was modeled as a hydrogenated surface. The reaction at the active center of a formate dehydrogenase provides an interesting contrast, suggesting that the S-H group plays an important role in the conversion of CO2 to HCOO-. However, the S-H group on the reduced PbS surface does not facilitate the conversion to the same extent as KGF-9. This is because the electrons supplied to CO2 on the PbS surface come from deep within the solid, whereas on KGF-9, they come from the top surface. This difference is due to differences in the electronic structure of the S-H bond, band gap, and valence band maximum position between the two surfaces, accounting for the marked difference in their catalytic activity. These insights are consistent with experimental and computational results on the thermodynamic and kinetic characteristics of the CO2 reduction reaction of KGF-9 and PbS, and provide guidance for the design of CO2 photoreduction catalysts.

DOI： 10.1021/acsaem.4c00408

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

A better understanding of the aggregation states of adhesive molecules in the interfacial region with an adherend is crucial for controlling the adhesion strength and is of great inherent academic interest. The adhesion mechanism has been described through four theories: adsorption, mechanical, diffusion, and electronic. While interfacial characterization techniques have been developed to validate the aforementioned theories, that related to the electronic theory has not yet been thoroughly studied. We here directly detected the electronic interaction between a commonly used thermosetting adhesive, cured epoxy of diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM), and copper (Cu). This study used a combination of density functional theory (DFT) calculations and femtosecond transient absorption spectroscopic (TAS) measurements as this epoxy adhesive-Cu pairing is extensively used in electronic device packaging. The DFT calculations predicted that π electrons in a DDM molecule adsorbed onto the Cu surface flowed out onto the Cu surface, resulting in a positive charge on the DDM. TAS measurements for the Cu/epoxy multilayer film, a model sample containing many metal/adhesive interfaces, revealed that the electronic states of excited DDM moieties at the Cu interface were different from those in the bulk region. These results were in good accordance with the prediction by DFT calculations. Thus, it can be concluded that TAS is applicable to characterize the electronic interaction of adhesives with metal adherends in a nondestructive manner.

DOI： 10.1021/acs.langmuir.4c00711

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

In the development of adhesives, an understanding of the fracture behavior of the bonded joints is inevitable. Two typical failure modes are known: adhesive failure and cohesive failure. However, a molecular understanding of the cohesive failure process is not as advanced as that of the adhesive failure process. In this study, research was developed to establish a molecular understanding of cohesive failure using the example of a system in which epoxy resin is bonded to a hydroxyl-terminated self-assembled monolayer (SAM) surface. Adhesive failure was modeled as a process in which an epoxy molecule is pulled away from the SAM surface. Cohesive failure, on the other hand, was modeled as the process of an epoxy molecule separating from another epoxy molecule on the SAM surface or breaking of a covalent bond within the epoxy resin. The results of the simulations based on the models described above showed that the results of the calculations using the model of cohesive failure based on the breakdown of intermolecular interactions agreed well with the experimental results in the literature. Therefore, it was suggested that the cohesive failure of epoxy resin adhesives is most likely due to the breakdown of intermolecular interactions between adhesive molecules. We further analyzed the interactions at the adhesive failure and cohesive failure interfaces and found that the interactions at the cohesive failure interface are mainly accounted for by dispersion forces, whereas the interactions at the adhesive failure interface involve not only dispersion forces but also various chemical interactions, including hydrogen bonds. The selectivity between adhesive failure and cohesive failure was explained by the fact that varying the functional group density affected the chemical interactions but not the dispersion forces.

DOI： 10.1021/acs.langmuir.3c04015

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nature Electronics  

AbstractGraphene and other two-dimensional (2D) materials can be used to create electronic and optoelectronic devices. However, their development has been limited by the lack of effective large-area transfer processes. Here we report a transfer method that uses functional tapes with adhesive forces controlled by ultraviolet light. The adhesion of the tape is optimized for the transfer of monolayer graphene, providing a yield of over 99%. Once detached from the growth substrate, the graphene/tape stack enables easy transfer of graphene to the desired target substrate. The method can be used to transfer other 2D materials, including bilayer graphene, transition metal dichalcogenides, hexagonal boron nitride and stacked heterostructures. The solvent-free nature of the final release step facilitates transfer to various target substrates including flexible polymers, paper and three-dimensional surfaces. The tape/2D material stacks can also be cut into desired sizes and shapes, allowing site-selective device fabrication with reduced loss of 2D materials.

DOI： 10.1038/s41928-024-01121-3

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その他リンク： https://www.nature.com/articles/s41928-024-01121-3

DOI： 10.1200/JCO.2024.42.3_suppl.93

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記述言語：英語  

DOI： 10.1007/s11523-023-01027-8

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DOI： 10.1080/00219592.2023.2197003

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

The adhesion mechanism of epoxy resin to the γ-alumina (110) surface was investigated using first-principles density functional theory (DFT). Aluminum materials are lightweight and are used in a wide range of industrial fields. Its surface is oxidized to alumina, and the stable surface is known as the γ-alumina (110) surface. The coverage of hydroxy groups by chemisorbed water molecules on this surface varied depending on the pretreatment temperature. In this study, we investigated the adhesive interactions of epoxy resin on four alumina surfaces with different densities of surface hydroxy groups (0, 3, 6, and 9 OH/nm2) and have discussed their effects. At each interface, the energy curves of the vertically displaced epoxy resin were calculated and the adhesive forces were estimated by differentiating these curves. As the coverage of the surface hydroxy groups increased from 0 to 6 OH/nm2, the adhesive strength gradually decreased. However, the adhesive strength at 9 OH/nm2 was relatively large and almost equal to that at 3 OH/nm2. This inverse volcano-type behavior was analyzed via the decomposition of adhesive forces and the crystal orbital Hamilton population (COHP). The decomposition of adhesive forces into DFT and dispersion components revealed that the inverse volcano-type behavior is derived from the DFT component, and the interfacial interactions owing to the DFT component are accompanied by charge transfer. These were investigated using a COHP analysis, which revealed that this behavior was caused by changes in the activity of the aluminum atoms on the surface and surface reconstruction by chemisorbed water molecules. It is noteworthy that the adhesive strength for 9 OH/nm2 was only 6.9% lower than that for 0 OH/nm2 wherein the chemisorbed water molecules were completely removed from the surface. These results are expected to provide a guideline for the adhesion of epoxy resin to aluminum materials.

DOI： 10.1021/acs.langmuir.3c02883

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Organic Chemistry  

Face-to-face stacking of aromatic compounds leads to stacked antiaromaticity, while that of antiaromatic compounds leads to stacked aromaticity. This is a prediction with a long history; in the late 2000s, the prediction was confirmed by high-precision quantum chemical calculations, and finally, in 2016, a π-conjugated system with stacked aromaticity was synthesized. Several variations have since been reported, but essentially, they are all the same molecule. To realize stacked aromaticity in a completely new and different molecular system and to trigger an extension of the concept of stacked aromaticity, it is important to understand the origin of stacked aromaticity. The Hückel method, which has been successful in giving qualitatively correct results for π-conjugated systems despite its bold assumptions, is well suited for the analysis of stacked aromaticity. We use this method to model the face-to-face stacking systems of benzene and cyclobutadiene molecules and discuss their stacked antiaromaticity and stacked aromaticity on the basis of their π-electron energies. By further developing the discussion, we search for clues to realize stacked aromaticity in synthesizable molecular systems.

DOI： 10.1021/acs.joc.3c01167

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リポジトリ公開URL： https://hdl.handle.net/2324/7236797

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Omega  

This paper details the use of computational and informatics methods to design metal nanocluster catalysts for efficient ammonia synthesis. Three main problems are tackled: defining a measure of catalytic activity, choosing the best candidate from a large number of possibilities, and identifying the thermodynamically stable cluster catalyst structure. First-principles calculations, Bayesian optimization, and particle swarm optimization are used to obtain a Ti8 nanocluster as a catalyst candidate. The N2 adsorption structure on Ti8 indicates substantial activation of the N2 molecule, while the NH3 adsorption structure suggests that NH3 is likely to undergo easy desorption. The study also reveals several cluster catalyst candidates that break the general trade-off that surfaces that strongly adsorb reactants also strongly adsorb products.

DOI： 10.1021/acsomega.3c03456

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記述言語：英語  

DOI： 10.1002/cam4.6269

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry A  

Recent studies have theoretically and experimentally demonstrated that antiaromatic molecules with 4n πelectrons exhibit stacked aromaticity according to π-πstacking when arranged in a face-to-face manner. However, the mechanism of its occurrence has not been clearly studied. In this study, we investigated the mechanism of stacked aromaticity using cyclobutadiene. When the antiaromatic molecules are stacked in a face-to-face manner, the orbital interactions between the degenerate singly occupied molecular orbitals (SOMOs) of the monomer unit cause a larger energy gap between the degenerate highest-occupied molecular orbitals (HOMOs) and the lowest-unoccupied molecular orbitals (LUMOs) of the dimer. However, the antiaromatic molecules are more stable in less symmetric conformations, mainly because of pseudo-Jahn-Teller distortions. In the case of cyclobutadiene, the two SOMOs of the monomer unit split into HOMO and LUMO because of the bond alternation. When the molecules are stacked in a face-to-face manner, the HOMO-LUMO gap of the dimer is smaller than that of the monomer due to the interactions between the HOMOs and LUMOs of the two monomer units. When the monomer units are within a specific distance of each other, the HOMO and LUMO of the dimer, which correspond to antibonding and bonding between the units, respectively, are interchanged. This alternation of molecular orbitals may result in an increase in the bond strength between the monomer units, exhibiting stacked aromaticity. We demonstrated that it is possible to control the distance exhibited by stacked aromaticity by engineering the HOMO-LUMO gap of the monomer units.

DOI： 10.1021/acs.jpca.3c00360

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：ChemCatChem  

The nonoxidative coupling of methane has attracted much attention because it yields two useful products: ethane and hydrogen. However, low conversion at low temperatures and carbon deposition at high temperatures are considered problematic. In this Concept article, a solution to these problems is presented. On the basis of the reaction enthalpy for the initial C−H bond cleavage of methane and the energy difference between C1 species (CH3 and CH) on the catalyst surface, a catalyst search guideline is provided to suppress carbon deposition while keeping the conversion rate as high as possible. Alloys are considered catalyst candidates. Few materials satisfy both of these requirements simultaneously; however, several alloys, including MgPt, are shown to be promising. The results of validation experiments for the catalytic performance of MgPt are also discussed.

DOI： 10.1002/cctc.202201488

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Reaction Chemistry and Engineering  

Catalytic reactions of mixed substrates sometimes behave differently from those of individual substrates. For example, the hydrogenation of propylbenzene over Rh/SiO2 proceeds 120% faster in the presence of toluene. Such an acceleration effect does not agree with the well-accepted Langmuir-Hinshelwood reaction model. In this paper, we examined its mechanism experimentally and computationally. The hydrogenation experiment of vaporised aromatics confirmed that the acceleration was specific to the liquid phase with the isopropanol solvent. Direct adsorption measurements revealed that toluene adsorption synchronises with propylbenzene adsorption. Density functional theory calculations confirmed the associates of toluene and propylbenzene on the catalyst surface in the polar environment. The formation of associates increased the adsorption energy of toluene and decreased that of propylbenzene. Lowered adsorption energy reduces the activation barrier for catalytic reaction and intensifies the reaction rate beyond the Langmuir-Hinshelwood model prediction.

DOI： 10.1039/d3re00032j

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記述言語：日本語   出版者・発行元：公益社団法人 日本表面真空学会  

DOI： 10.1380/vss.66.158

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Small  

To increase chemical reaction rates, general solutions include increasing the concentration/temperature and introducing catalysts. In this study, the rate constant of an electrophilic metal coordination reaction is accelerated 23-fold on the surface of layered aluminosilicate (LAS), where the reaction substrate (ligand molecule) induces dielectric polarization owing to the polar and anionic surface. According to the Arrhenius plot, the frequency factor (A) is increased by almost three orders of magnitude on the surface. This leads to the conclusion that the collision efficiency between the ligands and metal ions is enhanced on the surface due to the dielectric polarization. This is surprising because one side of the ligand is obscured by the surface, so the collision efficiency is expected to be decreased. This unique method to accelerate the chemical reaction is expected to expand the range of utilization of LASs, which are chemically inert, abundant, and environmentally friendly. The concept is also applicable to other metal oxides which have polar surfaces, which will be useful for various chemical reactions in the future.

DOI： 10.1002/smll.202205857

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Hole-collecting monolayers have drawn attention in perovskite solar cell research due to their ease of processing, high performance, and good durability. Since molecules in the hole-collecting monolayer are typically composed of functionalized π-conjugated structures, hole extraction is expected to be more efficient when the π-cores are oriented face-on with respect to the adjacent surfaces. However, strategies for reliably controlling the molecular orientation in monolayers remain elusive. In this work, multiple phosphonic acid anchoring groups were used to control the molecular orientation of a series of triazatruxene derivatives chemisorbed on a transparent conducting oxide electrode surface. Using infrared reflection absorption spectroscopy and metastable atom electron spectroscopy, we found that multipodal derivatives align face-on to the electrode surface, while the monopodal counterpart adopts a more tilted configuration. The face-on orientation was found to facilitate hole extraction, leading to inverted perovskite solar cells with enhanced stability and high-power conversion efficiencies up to 23.0%.

DOI： 10.1021/jacs.3c00805

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記述言語：英語  

DOI： 10.1007/s44211-022-00239-8

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

The low-temperature activation of methane is highly important as a reaction that can dissociate the strongest C-H bond and convert it into useful compounds. This study demonstrated that supported platinum oxide was found to activate methane near room temperature and selectively afford methanol in the presence of oxygen.

DOI： 10.1039/d2cc05351a

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

A coordination-induced trigger for catalytic activity is proposed on an N-heterocyclic carbene (NHC)-decorated ceria catalyst incorporating Cr and Rh (ICy-r-Cr0.19Rh0.06CeOz). ICy-r-Cr0.19Rh0.06CeOz was prepared by grafting 1,3-dicyclohexylimidazol-2-ylidene (ICy) onto H2-reduced Cr0.19Rh0.06CeOz (r-Cr0.19Rh0.06CeOz) surfaces, which went on to exhibit substantial catalytic activity for the 1,4-arylation of cyclohexenone with phenylboronic acid, whereas r-Cr0.19Rh0.06CeOz without ICy was inactive. FT-IR, Rh K-edge XAFS, XPS, and photoluminescence spectroscopy showed that the ICy carbene-coordinated Rh nanoclusters were the key active species. The coordination-induced trigger for catalytic activity on the ICy-bearing Rh nanoclusters could not be attributed to electronic donation from ICy to the Rh nanoclusters. DFT calculations suggested that ICy controlled the adsorption sites of the phenyl group on the Rh nanocluster to promote the C-C bond formation of the phenyl group and cyclohexenone.

DOI： 10.1021/jacs.2c07290

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：JACS Au  

Numerous biomimetic molecular catalysts inspired by methane monooxygenases (MMOs) that utilize iron or copper-oxo species as key intermediates have been developed. However, the catalytic methane oxidation activities of biomimetic molecule-based catalysts are still much lower than those of MMOs. Herein, we report that the close stacking of a μ-nitrido-bridged iron phthalocyanine dimer onto a graphite surface is effective in achieving high catalytic methane oxidation activity. The activity is almost 50 times higher than that of other potent molecule-based methane oxidation catalysts and comparable to those of certain MMOs, in an aqueous solution containing H2O2. It was demonstrated that the graphite-supported μ-nitrido-bridged iron phthalocyanine dimer oxidized methane, even at room temperature. Electrochemical investigation and density functional theory calculations suggested that the stacking of the catalyst onto graphite induced partial charge transfer from the reactive oxo species of the μ-nitrido-bridged iron phthalocyanine dimer and significantly lowered the singly occupied molecular orbital level, thereby facilitating electron transfer from methane to the catalyst in the proton-coupled electron-transfer process. The cofacially stacked structure is advantageous for stable adhesion of the catalyst molecule on the graphite surface in the oxidative reaction condition and for preventing decreases in the oxo-basicity and generation rate of the terminal iron-oxo species. We also demonstrated that the graphite-supported catalyst exhibited appreciably enhanced activity under photoirradiation owing to the photothermal effect.

DOI： 10.1021/jacsau.2c00618

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記述言語：日本語   出版者・発行元：分子科学会  

DOI： 10.3175/molsci.17.a0124

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Omega  

Binary alloy catalysts have the potential to exhibit higher activity than monometallic catalysts in nitrogen activation reactions. However, owing to the multiple possible combinations of metal elements constituting binary alloys, an exhaustive search for the optimal combination is difficult. In this study, we searched for the optimal binary alloy catalyst for nitrogen activation reactions using a combination of Bayesian optimization and density functional theory calculations. The optimal alloy catalyst proposed by Bayesian optimization had a surface energy of ∼0.2 eV/Å2and resulted in a low reaction heat for the dissociation of the NN bond. We demonstrated that the search for such binary alloy catalysts using Bayesian optimization is more efficient than random search.

DOI： 10.1021/acsomega.2c05988

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Chemistry Chemical Physics  

Adhesive strength varies greatly with direction; various adhesion tests have been conducted. In this study, the shear and tensile adhesive strength of epoxy resin for copper (Cu) and copper oxide (Cu2O) surfaces were estimated based on quantum chemical calculations. Here, density functional theory (DFT) calculations with dispersion correction were used. In the tensile process, the entire epoxy resin is peeled off vertically, whereas in the shear process, a force parallel to the adhesive surface is applied. Then, a bending moment acts on the adhesive layer, and a total force (stress) inclined at an angle θ with respect to the adherend surface is applied to the adhesive interface. We computed adhesive stress-displacement curves for each θ exhaustively and discussed the changes. When θ equals 90°, it corresponds to a tensile process. As θ decreases from 90°, the shear adhesive stress on both surfaces decreases slowly. When θ is less than 30°, the constraint to the surface causes periodic changes in the adhesive stress curves. The constraint to the Cu2O surface is especially strong, and this change is large. This periodicity is similar to the stick-slip phenomenon in tribology. To further understand the shear adhesive forces, force decomposition analysis was performed, revealing that the periodicity of the adhesive stress originates from the DFT contribution rather than the dispersion one. The procedure proposed in this study for estimating shear adhesive strength is expected to be useful in the evaluation and prediction of adhesive and adherend properties.

DOI： 10.1039/D2CP03354B

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society  

The adsorption sites of the top and hollow on the close-packed surfaces of transition metals are well known. In this paper, which site is more preferred for the adsorption of atoms and molecular fragments on the metal surfaces is discussed based on the topology of the adsorption geometry. For this purpose, the method of moments for the electronic density of states is applied to the surface. Adsorption at the hollow site generates a triangular topology, leading to a more negative value of the third moment (μ3) than that at the top site, which generates no triangular topology. When the difference in energy between the two adsorption sites is plotted against the band filling of the metal surface, a characteristic node at around the intermediate band filling can be found. This is a signature that the energy difference curve is controlled by μ3. Roughly speaking, the hollow-site adsorption, which has a more negative μ3 value, takes precedence at low band fillings, while the top site adsorption, which has a less negative μ3 value, takes precedence at high band fillings. One can conclude that an adsorption structure with more three-membered rings on a surface is more stable at low electron counts whereas that with less three-membered rings is more stable at high electron counts. However, if the strength of the metal-adsorbate bond is significantly greater than that of the metal-metal bond, the effect of the second moment (μ2) on the energy difference curve cannot be neglected. The hollow-site adsorption leads to a larger value of μ2 due to the topological feature of a larger coordination number around the adsorbate atom. As a result, the hollow-site adsorption is preferred over the top site at any band filling.

DOI： 10.1021/acs.jpcc.2c04656

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リポジトリ公開URL： https://hdl.handle.net/2324/6795486

掲載種別：研究論文（学術雑誌）   出版者・発行元：Reaction Chemistry and Engineering  

The selectivity of palladium catalysed hydrogenation can be improved by adding a homogeneous modifier (or poison) such as quinoline to the reaction mixture. Although such selectivity improvement by modifiers (selective catalyst poisoning) has been known for decades, we still know little about them. We, ultimately, cannot select a modifier to improve a particular process. In this study, 21 types of modifiers are screened for the semi-hydrogenation of alkynes with varying catalyst type, reaction time, and target substrate using an automated flow reactor system. All of the studied variables changed affected hydrogenation activity and selectivity confirming the effectiveness of a multi-parameter optimization. 1,10-phenanthroline marked the best selectivity beyond quinoline. The density functional theory (DFT) calculations suggest that 1,10-phenanthroline has a remarkable ability to adsorb on the irregular surface of the catalyst that effects undesirable reaction.

DOI： 10.1039/d2re00147k

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DOI： 10.3389/fped.2022.855378

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PubMed

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Omega  

Adhesive strength is known to change significantly depending on the direction of the force applied. In this study, the peel and tensile adhesive forces between the hydroxylated silica (001) surface and epoxy resin are estimated based on quantum chemical calculations. Here, density functional theory (DFT) with dispersion correction is used. In the peel process, the epoxy resin is pulled off from the terminal part, while in the tensile process, the entire epoxy resin is pulled off vertically. As a result of these calculations, the maximum adhesive force in the peel process is decreased to be about 40% of that in the tensile process. The adhesion force−displacement curve for the peeling process shows two characteristic peaks corresponding to the process where the adhesive molecule horizontally oriented to the surface shifts to a vertical orientation to the surface and the process where the vertical adhesive molecule is dissociated from the surface. Force decomposition analysis is performed to further understand the peel adhesion force; the contribution of the dispersion force is found to be slightly larger than that of the DFT force. This feature is common to the tensile process as well. Each force in the peel process is about 40% smaller than the corresponding force in the tensile process.

DOI： 10.1021/acsomega.2c01544

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Chemical Physics  

In this study, we employ the Sachs graph theory to formulate the conduction properties of a single-molecular junction consisting of a molecule in which one carbon atom of an alternant hydrocarbon is replaced with a heteroatom. The derived formula includes odd and even powers of the adjacency matrix, unlike the graph of the parental structure. These powers correspond to odd- and even-length walks. Furthermore, because the heteroatom is represented as a self-loop of unit length in the graph, an odd number of passes of the self-loop will change the parity of the length of the walk. To confirm the aforementioned effects of heteroatoms on conduction in an actual sample, the conduction behavior of meta-connected molecular junctions consisting of a heterocyclic six-membered ring, whose conductive properties have already been experimentally determined, was analyzed based on the enumerated number of walks.

DOI： 10.1063/5.0083486

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Topics in Catalysis  

The catalytic function of metal nanoclusters has attracted much attention because of their specific activity and selectivity. The structures of metal clusters are very diverse, especially when adsorbates are adsorbed on them. This is an obstacle when approaching metal nanocluster catalysts with computational chemistry. In this manuscript, a prescription for this problem is presented. With metal nanoclusters catalyzing reactions involving hydrogen in mind, a comprehensive, systematic, and efficient search for stable structures of metal nanoclusters with an adsorbed hydrogen atom is presented. This can be achieved through a good use of a supercomputer while using the particle swarm optimization algorithm and density functional theory together. In this attempt, three metallic elements, Fe, Ni, and Cu, are selected. When clustered, what kind of structure these elements form and how their affinity for hydrogen changes are detailed. Eventually, a path is presented to explore clusters that are actually useful as catalysts, using surface calculations as a reference.

DOI： 10.1007/s11244-021-01512-2

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DOI： 10.1117/12.2630501

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DOI： 10.1117/12.2629635

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記述言語：日本語   出版者・発行元：日本コンピュータ化学会  

<p>π-stacked single-molecule junctions stacked with π-conjugated molecules have the potential to be used as building blocks for single-molecule scale three-dimensional integrated circuits. In this study, we investigate the relationship between π-stacking distance and conductance in face-to-face π-stacked single-molecule junctions with benzene as the monomer unit using the non-equilibrium Green's function (NEGF), which combines the Hückel molecular orbital (HMO) and density functional theory (DFT) methods. As the π-stack distance between two benzene molecules decreases, the pseudo-<i>para</i> junction, which is insulating, turns conductive. Furthermore, it was found that the cause of this change can be explained by orbital interactions.</p>

DOI： 10.2477/jccj.2023-0002

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記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.langmuir.1c02653

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsomega.1c05914

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s43246-021-00159-6

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.langmuir.1c01935

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d1cp00345c

記述言語：その他  

DOI： 10.26434/chemrxiv.14728860.v1

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Although the C-H bond of methane is very strong, it can be easily dissociated on the (110) surface of β-PtO2. This is because a very stable Pt-C bond is formed between the coordinatively unsaturated Pt atom and CH3 on the surface. Owing to the stable nature of the Pt-C bond, CH3 is strongly bound to the surface. When it comes to methanol synthesis from methane, the Pt-C bond has to be cleaved to form a C-O bond during the reaction process. However, this is unlikely to occur on the β-PtO2 surface: The activation energy of the process is calculated to be so large as 47.9 kcal/mol. If the surface can be modified in such a way that the ability for the C-H bond activation is maintained but the Pt-C bond is weakened, a catalyst combining the functions of C-H bond cleavage and C-O bond formation can be created. For this purpose, analyzing the orbital interactions on the surface is found to be very useful, resulting in a prediction that the Pt-C bond can be weakened by replacing the O atom trans to the C atom with a N atom. This would be a sort of process to make β-PtO2 a mixed anion compound. Density functional theory simulations of catalytic reactions on the β-PtO2 surface show that the activation energy of the rate-limiting step of methanol synthesis can be reduced to 27.7 kcal/mol by doping the surface with N.

DOI： 10.1021/acsomega.1c01476

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.langmuir.1c00285

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.0c10907

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsomega.0c04913

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Epoxy resin adhesives are widely used for joining metal alloys in various industrial fields. To elucidate the adhesion mechanism microscopically, we investigated the interfacial interactions of epoxy resin with hydroxylated silica (0 0 1) and γ-alumina (0 0 1) surfaces using periodic density functional theory calculations as well as density of states (DOS) and crystal orbital Hamilton population (COHP) analyses. To better understand the interfacial interactions, we employed and analyzed water and benzene molecules as hydrophilic and hydrophobic adsorbates, respectively. Structural features and calculated adhesion energies reveal that these small adsorbates have a higher affinity for the γ-alumina surface than that for the silica surface, while a fragmentary model for the epoxy resin exhibits a strong interaction with the silica surface. This discrepancy suggests that the structural features of the hydroxylated silica surface dictate its affinity to a specific species. Partial DOS and COHP curves provide evidence for the presence of OH-πinteractions between the OH groups on the surfaces and the benzene rings of the epoxy resin fragments. The orbital interaction energies of the H-bonding and OH-πinteractions evaluated from the integrated COHP indicate that the OH-πinteraction is a nonnegligible origin of the adhesion interaction, even when polymers with hydrophobic benzene rings are adsorbed on hydroxylated surfaces.

DOI： 10.1021/acsomega.0c03798

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This is a longish, theoretical paper dealing with the molecular conductance of H2 and π-stacked ethylene. At different levels of theory ranging from single-determinant to multireference, from open boundary to periodic boundary, from semiempirical to ab initio, from Green's function theory to graph theory, and from localized atomic orbitals to plane waves, the molecular junctions of H2 and ethylene were calculated and analyzed. It was found based on simplistic models as well as sophisticated, higher-level simulations that moderately stretching the H-H bond or compressing the ethylene π-stack increases not only the diradical character of these systems but also their conductance in the range where these two parameters show a positive correlation. Negative correlation is also observed under extreme stretching of the H-H bond or extreme compression of the ethylene πstack. Challenges in experimental realization of the proposed molecular junctions and verification of the theoretical predictions were discussed. Digressions seen here and there in this paper may be informative and taken as a demonstration of theoreticians' way of applying insight gained from a simplistic model to a realistic system.

DOI： 10.1021/acs.jpcc.0c06198

記述言語：その他   掲載種別：研究論文（学術雑誌）  

In this paper, an orbital correlation diagram is proposed for the purpose of understanding and predicting a surface reaction. To deal with the electronic structure of a surface, one may need to rely on a cluster model or a surface slab model. Band (crystal) orbitals calculated at the Σ point in the reciprocal space for the unit cell of the slab model with periodicity are found helpful for the construction of the correlation diagram. By using the diagram thus established, the C-H bond activation reaction of methane on an IrO2 surface is investigated. The energy level of the dz2 orbital of a coordinatively unsaturated Ir atom in the surface is found to be important for determining the activation barrier of the reaction. The activation energy can be reduced by lowering the energy level of the dz2 orbital. Conversely, a rise in the energy of the dz2 orbital leads to an increase in the activation barrier. To make the dz2 orbital energy change, the concept of mixed-anion compounds is adopted. The replacement of an oxide with a different anion allows one to tune the crystal field splitting of metal oxides. IrO2 doped with F as an axial ligand yields a lower-lying dz2 orbital level, while the orbital goes up in energy when IrO2 is doped with N. This trend is consistent with what is expected from the electronegativity of each dopant. A perfect inverse linear correlation is found between the activation energy of the reaction and the electronegativity. By changing the dopant, one may have control over the reactivity of IrO2.

DOI： 10.1021/acs.jpcc.0c04541

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Adhesion  

A die bonding interface consisting of a plated gold surface and conductive silver paste was investigated using two approaches: One was a computational method for the ideal interaction, while the other was an experimental technique to get some ideas about the actual bonding. A density functional theory (DFT) calculation was employed to clarify the adhesive interface between the Au (1 1 1) surface and bisphenol-A type epoxy resin which included dicyandiamide as a curing agent. The computational results showed that the cyano group involved in the hardener strongly binds to a gold atom on the ideal surface. This interaction is likely to be assigned to sigma-donation and pi-back donation. The predicted adhesive strength was 1.15 GPa. To evaluate the real adhesion strength, small-sized single lap-shear joints were fabricated and tensile shear tests were performed. The measured adhesive stress was about 27 MPa. The results of surface analytical methods indicated that the actual die pad surface was not smooth. Furthermore, an altered layer terminated with Au(CN)(x)was found on the top of the die pad. It was inferred that the mechanism of the actual die bonding interaction would be changed to the formation of hydrogen bonds. This could be a reason why reduced adhesive strength was observed.

DOI： 10.1080/00218464.2020.1807958

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記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.0c01106

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.0c01106

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

According to the current superposition law in nanoscale, the conductance gets more than doubled when the number of paths is doubled. The superposition law can be applied to the molecular graph, which is a discrete mathematical expression for a structure consisting of nodes and edges. We previously revealed that the aromatic parallel circuit i.e. benzene molecule breaks the superposition law. In this paper, we show that [4n+2] annulenes also break the current superposition law from the viewpoint of orbital interaction between two fragments in the parallel circuit.

DOI： 10.2477/jccj.2019-0038

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.9b08595

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.9b08595

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.inorgchem.9b03046

記述言語：英語   掲載種別：研究論文（学術雑誌）  

When certain pairs of atoms in a π-conjugated molecule are connected with nanometer-scale source and drain electrodes, the remarkable quantum interference (QI) effect may arise. In this case, the electron transmission probability is significantly suppressed due to the QI effect. Tight-binding approaches, such as the Hückel molecular orbital (HMO) model, have revealed important features of this quantum phenomenon. However, important deviations from experiments and from more sophisticated calculations are known for a variety of cases. Here, we propose an extension of the HMO method to include non-nearest-neighbor interactions. Such long-range interactions (LRIs) are implemented in the HMO model in the form of a damping function that decays as the topological distance - the number of bonds separating two atoms - gets larger. The proposed model is further developed so that a geometric modification, i.e., the rotation around a single bond, can be taken into account. Our results show that LRI affects both the location of the antiresonance peak due to QI and the intensity of QI, even suppressing it in some cases. These results agree well with what was observed in a Density Functional based Tight-Binding (DFTB) study reported in the literature. These properties can be interpreted on the basis of a graph-theoretic path-counting model as well as the molecular orbital theory. In addition, the geometric LRI model is shown to reproduce the change of transmission as a function of rotation around the single bond separating two benzene rings in biphenyl, in agreement with what was observed in both experiment and DFTB calculation.

DOI： 10.1063/1.5097330

記述言語：その他   掲載種別：研究論文（学術雑誌）  

© 2019 Author(s). When certain pairs of atoms in a π-conjugated molecule are connected with nanometer-scale source and drain electrodes, the remarkable quantum interference (QI) effect may arise. In this case, the electron transmission probability is significantly suppressed due to the QI effect. Tight-binding approaches, such as the Hückel molecular orbital (HMO) model, have revealed important features of this quantum phenomenon. However, important deviations from experiments and from more sophisticated calculations are known for a variety of cases. Here, we propose an extension of the HMO method to include non-nearest-neighbor interactions. Such long-range interactions (LRIs) are implemented in the HMO model in the form of a damping function that decays as the topological distance - the number of bonds separating two atoms - gets larger. The proposed model is further developed so that a geometric modification, i.e., the rotation around a single bond, can be taken into account. Our results show that LRI affects both the location of the antiresonance peak due to QI and the intensity of QI, even suppressing it in some cases. These results agree well with what was observed in a Density Functional based Tight-Binding (DFTB) study reported in the literature. These properties can be interpreted on the basis of a graph-theoretic path-counting model as well as the molecular orbital theory. In addition, the geometric LRI model is shown to reproduce the change of transmission as a function of rotation around the single bond separating two benzene rings in biphenyl, in agreement with what was observed in both experiment and DFTB calculation.

DOI： 10.1063/1.5097330

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Methane activation is usually assumed to take place on top of metal surfaces or metal clusters. It can also occur at the metal-support interface in metal-supported catalysts with reducible oxides, such as CeO . In the present work, we exploit density functional theory with an additional Hubbard-like parameter (DFT + U) to calculate the activation of methane at an O site interfacing a Ni metal cluster on a support, CeO (111) surface. Two reaction routes, namely, radical and nonradical routes, are taken into account. We show that the nonradical route is favored with an apparent activation energy of 18.1 kcal/mol, which is lower than that for the radical route by 15.0 kcal/mol. In the nonradical route, the formation of a four-centered transition-state structure is observed while a C-H bond of methane is being cleaved to form an OH moiety and a CH fragment that is being bound to the interfacial Ni atom. It is also found that the interfacial O atoms are out of the CeO surface plane with Ce-O bond distances being much longer than those in the crystalline bulk CeO , which allows them to be easily reduced, and hence, the interfacial O atoms become more reactive toward methane, as compared to the surface O atoms. The interactions between Ni cluster and the CeO (111) surface result in the reduction of two Ce ions to Ce , improving the reducibility of the interfacial O atoms. This should be an important key to the facile methane activation. 2 4 2 3 2 2 4 2 4+ 3+

DOI： 10.1021/acs.jpcc.8b11973

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.9b01420

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.8b11973

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.9b01420

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.9b01420

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsomega.9b00129

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsomega.9b00129

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

DOI： 10.1109/ICSJ.2018.8602784

記述言語：その他  

DOI： 10.1109/ICSJ.2018.8602784

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.nanolett.8b03503

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.nanolett.8b03503

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5048955

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5048955

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.8b03184

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.8b03184

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.chemrev.7b00733

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b10877

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b10877

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1380/vss.61.91

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b03493

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.7b04410

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b03493

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.7b04410

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b02274

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.7b02274

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4972992

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4977080

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4972992

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4977080

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

We investigated the C–H bond cleavage of methane on various binary alloys using periodic density functional theory (DFT) calculations for catalyst screening. Cohesive energy, which strongly correlates with activation energy and heat of reaction for the C–H bond cleavage, was computed for 337 alloys in AFLOW database to enable rapid screening.

DOI： 10.2477/jccj.2017-0058

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jacs.6b09067

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/chem.201600042

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/chem.201600042

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.poly.2015.09.050

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.poly.2015.09.050

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1518206113

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsnano.5b04615

記述言語：その他  

Diradicals, lurking

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4903043

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4903043

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/anie.201311134

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp407835d

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp407835d

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/cphc.201300136

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/bcsj.20130089

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/cphc.201300136

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/bcsj.20130089

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Extended π-stacked molecules have attracted much attention since they play an essential role in both electronic devices and biological systems. In this article electron transport properties of a series of multilayered cyclophanes with the hydroquinone donor and quinone acceptor units in the external positions are theoretically studied with applications to molecular rectifiers in mind. Calculations of electron transport through the π-π stacked structures in the multilayered cyclophanes are performed by using nonequilibrium Green's function method combined with density functional theory. Calculated transmission spectra show that the conductance decreases exponentially with the length of the molecule with a decay factor of 0.75 Å^-1, which lies for the values between π-conjugated molecules and σ-bonded molecules. Applied bias calculations provide current-voltage curves, which exhibit good rectifying behavior. The rectification mechanism in the coherent transport regime is qualitatively explained by the response of the frontier orbital energy levels, especially LUMO levels, to the applied bias, where the rectifying direction is expected to be opposite to the Aviram-Ratner model. The maximum value of rectification ratio increases with an increase in the number of stacking layers due to the effective separation of the donor and acceptor parts, where effects from the opposite electrodes to the donor and acceptor are negligible. Multilayered donor-acceptor cyclophanes are suitable materials for investigating the relationship among electron transport properties, rectification properties, and molecular length (separation between the donor and acceptor parts).

DOI： 10.1021/jp308849t

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp308849t

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Electron transport properties through benzene molecules disubstituted with π-accepting cyanide and isocyanide anchor groups at their para and meta positions are investigated on the basis of a qualitative orbital analysis at the Hückel molecular orbital level of theory. The applicability of a previously derived orbital symmetry rule for electron transport is extended to the systems perturbed by the π-accepting anchor groups, where the HOMO-LUMO symmetry in the molecular orbital energies relative to the Fermi level is removed. The conservation of the HOMO-LUMO symmetry in the spatial distribution of the molecular orbitals between the unperturbed benzene molecule and the perturbed molecules with the anchor groups rationalizes symmetry-allowed electron transport through the para isomers. On the other hand, destructive interferences between the nearly 2-fold degenerate frontier orbitals constructed from the 2-fold degenerate orbitals of the unperturbed benzene molecule and the anchor groups lead to symmetry-forbidden electron transport through the meta isomers. The qualitative orbital thinking is supported by more quantitative density functional theory (DFT) calculations combined with the nonequilibrium Green's function (NEGF) method. The orbital analysis is a powerful tool for the understanding and rational design of molecular devices composed of π-conjugated hydrocarbons and those perturbed by the π-accepting anchor groups.

DOI： 10.1021/jp3068156

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp3068156

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp303843k

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp305448q

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp303843k

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Spintronic properties of cyclobutadiene (CBD) systems are investigated based on a qualitative frontier orbital analysis. CBD undergoes a Jahn-Teller distortion from the square triplet state to the rectangular singlet state. According to the qualitative Hückel molecular orbital analysis, the electron transport through the square triplet state is symmetry allowed, whereas that through the rectangular singlet state is symmetry forbidden. The magnetic triplet state is a possible coexisting system of conductivity and magnetism. Sophisticated first-principles quantum chemical calculations are performed by using a realistic molecular junction model. Obtained results are in good agreement with the prediction based on the qualitative orbital analysis. Interesting spin filtering properties are found in the square-shaped CBD system. The high- and low-spin states of the square-shaped CBD system produce the spin-α and spin-β polarized conductance, respectively. The qualitative orbital analysis is useful as a guiding principle for designing molecular spintronics.

DOI： 10.1021/jp305448q

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/bcsj.20120028

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/bcsj.20120028

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Electron transport through π-π stacked materials has been studied theoretically and experimentally so far with versatile applications in mind. In this paper a novel π-π stacked molecular rectifier is proposed. Electron transport properties through cyclophane-type quinhydrone are investigated by using nonequilibrium Green's function method combined with density functional theory. The investigated molecule has a quinhydrone structure comprised of π-π stacked donor (hydroquinone) and acceptor (benzoquinone) pair due to the in-phase orbital interaction between the HOMO of hydroquinone and the LUMO of benzoquinone. A computed current-voltage curve shows rectifying behavior in the direction perpendicular to the ring plane. The maximum value of rectification ratio of 2.37 is obtained at 0.8 V. In this system the LUMO level plays a key role, and asymmetrical evolution of the LUMO level for positive and negative biases leads to the rectifying behavior. The present study is a basic step for further functionalization of a molecular rectifier based on transannular electron transport. The understanding of insight into the electron transport through a π-π stacked system will provide motivation for design of future molecular devices.

DOI： 10.1021/jp209547a

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp209547a

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/ja2033926

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/ja2033926

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp202785b

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp202785b

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/ja111021e

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp110803a

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp110803a

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/cl.2011.174

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/cl.2011.174

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp905663r

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.tsf.2009.07.037

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.tsf.2009.07.037

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/jp905663r

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

The metal-molecule junctions have recently attracted increasing attention in the field of molecular electronics. The anchor groups that connect molecules with electrodes are of particular importance, since they play crucial roles in the electron transport. We here report that phosphine sulfides act as an anchor unit in single molecule junctions. As a model system, we designed and synthesized oligo(p-phenylene)s having dibenzophosphole sulfide (DBPS) groups as the anchor groups. The conductance measurements of the single molecule junctions using the STM method and theoretical calculations revealed that the DBPS indeed acted as an anchor unit. In addition, the electron-transport mechanism of the DBPS-anchored systems was found to be totally different from that of the thiol-anchored analogues due to the highly electron-accepting character of the DBPS groups.

DOI： 10.11494/kisoyuki.2009.0.221.0

開催年月日： 2018年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：愛知, 名古屋大学   国名：日本国  

14族のリチウム化合物はリチウムテトレライドと呼ばれる。その中でも、もっともリチウムの割合が高いLi17Tt4 (Tt = Si, Ge, Sn, Pb)は余剰電子を有していることが密度汎関数計算から明らかとなった。その余剰電子は核を離れて格子間に存在しているため、電子自身がアニオンとして振る舞う電子化物（エレクトライド）の一種であると考えられる。状態密度や電子密度の解析により、余剰電子の波動関数はそれを取り囲むイオンの波動関数と軌道相互作用をしており、新奇な結合様式が見いだされた。

開催年月日： 2018年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：台湾  

記述言語：日本語  

開催地：福岡、九州大学筑紫キャンパス   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：神奈川大学みなとみらいキャンパス   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東京理科大学野田キャンパス   国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：新化学技術推進協会   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：島根大学   国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

記述言語：日本語  

開催地：オンライン   国名：日本国  

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記述言語：日本語  

開催地：東京理科大学野田キャンパス   国名：日本国  

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記述言語：日本語  

開催地：神奈川大学みなとみらいキャンパス   国名：日本国  

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記述言語：日本語  

開催地：オンライン   国名：日本国  

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記述言語：日本語  

開催地：福岡、九州大学筑紫キャンパス   国名：日本国  

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記述言語：英語  

開催地：九州大学伊都キャンパス   国名：日本国  

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記述言語：英語  

開催地：オンライン   国名：日本国  

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記述言語：日本語  

開催地：新化学技術推進協会   国名：日本国  

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開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

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開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

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開催年月日： 2022年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

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開催年月日： 2022年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2022年3月

記述言語：日本語  

開催地：オンライン   国名：日本国  

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開催年月日： 2021年12月

記述言語：英語  

国名：日本国  

開催年月日： 2021年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2021年5月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2021年3月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2021年3月

記述言語：英語  

国名：日本国  

開催年月日： 2021年3月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2021年3月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2021年3月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2020年11月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2020年9月

記述言語：日本語  

開催地：オンライン   国名：日本国  

開催年月日： 2019年12月

記述言語：英語  

国名：日本国  

開催年月日： 2019年12月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2019年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2019年1月

記述言語：英語  

国名：日本国  

開催年月日： 2018年11月

記述言語：日本語  

開催地：東京大学本郷キャンパス小柴ホール   国名：日本国  

開催年月日： 2018年11月

記述言語：日本語  

開催地：北海道大学 創成科学研究棟   国名：日本国  

開催年月日： 2018年10月

記述言語：日本語  

開催地：筑紫キャンパス　総合研究棟（C-CUBE）   国名：日本国  

開催年月日： 2018年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：広島、JMSアステールプラザ   国名：日本国  

開催年月日： 2018年10月

記述言語：英語  

国名：日本国  

開催年月日： 2018年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2018年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2018年7月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東京大学（本郷キャンパス）   国名：日本国  

開催年月日： 2018年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北海度、国民休暇村　支笏湖   国名：日本国  

開催年月日： 2018年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：愛知、岡崎   国名：日本国  

近年、IrO2 (110)面上においてメタンのCH結合が容易に解離するということが実験的に報告されている。我々はIrO2表面がCH結合を活性化するプロセスについてバンド計算及び分子軌道計算の両面から詳細に調べた。その結果、メタンの構造変形に伴う、HOMOのエネルギー準位および軌道分布の変化が重要であるということが明らかとなった。

開催年月日： 2018年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2018年1月

記述言語：英語  

国名：日本国  

記述言語：英語  

国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

記述言語：日本語  

開催地：福岡、北九州国際会議場   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：横浜、慶應大矢上キャンパス   国名：日本国  

記述言語：日本語  

開催地：札幌、北海道大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：横浜、慶応大矢上キャンパス   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：長野、信州大学工学部   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：千葉、東京理科大   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：慶應義塾大学 矢上キャンパス   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：神奈川大学みなとみらいキャンパス   国名：日本国  

記述言語：日本語  

開催地：札幌、北海道大学   国名：日本国  

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記述言語：日本語  

開催地：オンライン   国名：日本国  

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記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

開催地：横浜、慶應大矢上キャンパス   国名：日本国  

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記述言語：日本語  

記述言語：日本語  

開催地：横浜、慶応大矢上キャンパス   国名：日本国  

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記述言語：日本語  

開催地：福岡、北九州国際会議場   国名：日本国  

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記述言語：日本語  

開催地：慶應義塾大学 矢上キャンパス   国名：日本国  

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記述言語：日本語  

開催地：長野、信州大学工学部   国名：日本国  

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記述言語：日本語  

開催地：神奈川大学みなとみらいキャンパス   国名：日本国  

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記述言語：日本語  

記述言語：日本語  

開催地：千葉、東京理科大   国名：日本国  

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記述言語：日本語  

記述言語：日本語  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）  

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）  

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記述言語：その他   出版者・発行元：Comprehensive Inorganic Chemistry III, Third Edition  

The activation and formation of bonds on inorganic surfaces are important elementary processes in heterogeneous catalysis. The purpose of this chapter is to provide one way to clarify these processes in terms of the electronic structure of solid surfaces. In particular, the reader will learn how to rationalize the origin of the activation energy for bond breaking and formation on surfaces, focusing on the orbital interactions between the surface and the bond. There are very useful theoretical chemistry tools such as crystal orbital overlap population and crystal orbital Hamilton population that can be used to effectively retrieve information on bonds that are obscured in a bunch of surface bands. Local information on bonding on the surface is obtained. Information on the occupancy of electrons in the bonding and antibonding orbitals of the bond will prove to be very useful. Using such tools, one prescription is offered for the question of how to understand why the activation energy of bond breaking and formation on inorganic surfaces is high or low. What is covered in this chapter begins with simple metal surfaces and ends with more complex oxide and hydride surfaces. The interaction of various inorganic surfaces with bonds will be overviewed using examples from important topics in catalytic chemistry such as CO activation, Fischer-Tropsch synthesis, methane activation, and ammonia synthesis.

DOI： 10.1016/B978-0-12-823144-9.00132-1

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記述言語：日本語   出版者・発行元：日本塗装技術協会  

CiNii Books

CiNii Research

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記述言語：日本語  

記述言語：日本語   出版者・発行元：技術情報協会  

CiNii Books

CiNii Research

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

DOI： https://doi.org/10.2477/jccj.2021-0013

記述言語：日本語  

記述言語：英語  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

DOI： https://doi.org/10.2477/jccj.2019-0038

記述言語：日本語  

記述言語：日本語  

本稿では，アメリカのニューヨーク州イサカ市にある
コーネル大学にポスドクとして留学した 3 年間の経験を
研究と生活の面から書かせていただこうと思う

DOI： https://doi.org/10.1380/vss.61.91

記述言語：日本語  

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：17

種別：査読等 

外国語雑誌　査読論文数：10

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：12

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

参加者数：30

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：10

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：31

This study examined the nature of the electronic structure of representative cross-conjugated polyenes from a Valence Bond (VB) perspective. Our VBSCF calculations on a prototypical dendralene model reveal a remarkable inhibition of the delocalization compared to linear polyenes. Especially along the C-C backbone, the delocalization is virtually quenched, so that these compounds can essentially be considered as sets of isolated butadiene units.

In recent years, a considerable interest has grown in the design of molecular nanowires with an increasing conductance with length. The development of such nanowires is highly desirable because they could play an important role in future molecular-scale circuitry. Whereas the first experimental observation of this nonclassical behavior still has to be realized, a growing number of candidate wires have been proposed theoretically. In this Letter, we point out that all the wires with an anti-Ohmic increasing conductance with length proposed so far share a common characteristic: their diradical character increases with length.

In this paper, we explore quantum interference (QI) in molecular conductance from the point of view of graph theory and walks on lattices. By virtue of the Cayley–Hamilton theorem for characteristic polynomials and the Coulson–Rushbrooke pairing theorem for alternant hydrocarbons, it is possible to derive a finite series expansion of the Green’s function for electron transmission in terms of the odd powers of the vertex adjacency matrix or Hückel matrix. This means that only odd-length walks on a molecular graph contribute to the conductivity through a molecule. Thus, if there are only even-length walks between two atoms, quantum interference is expected to occur in the electron transport between them.

Site-specific electron transport phenomena through benzene and benzenedithiol derivatives are discussed on the basis of a qualitative Hückel molecular orbital analysis for better understanding of the effect of anchoring sulfur atoms. A recent work for the orbital control of electron transport through aromatic hydrocarbons provided an important concept for the design of high-conductance connections of a molecule with anchoring atoms. In this work the origin of the frontier orbitals of benzenedithiol derivatives, the effect of the sulfur atoms on the orbitals and on the electron transport properties, and the applicability of the theoretical concept on aromatic hydrocarbons with the anchoring units are studied. The results demonstrate that the orbital view predictions are applicable to molecules perturbed by the anchoring units. The electron transport properties of benzene are found to be qualitatively consistent with those of benzenedithiol with respect to the site dependence. To verify the result of the Hückel molecular orbital calculations, fragment molecular orbital analyses with the extended Hückel molecular orbital theory and electron transport calculations with density functional theory are performed. Calculated results are in good agreement with the orbital interaction analysis. The phase, amplitude, and spatial distribution of the frontier orbitals play an essential role in the design of the electron transport properties through aromatic hydrocarbons.

An empirical observation of a relationship between a striking feature of electronic transmission through a π-system, destructive quantum interference (QI), on one hand, and the stability of diradicals on the other, leads to the proof of a general theorem that relates the two. Subject to a number of simplifying assumptions, in a π-electron system, QI occurs when electrodes are attached to those positions of an N-carbon atom N-electron closed-shell hydrocarbon where the matrix elements of the Green’s function vanish. These zeros come in two types, which are called easy and hard. Suppose an N+2 atom, N+2 electron hydrocarbon is formed by substituting 2 CH2 groups at two atoms, where the electrodes were. Then, if a QI feature is associated with electrode attachment to the two atoms of the original N atom system, the resulting augmented N+2 molecule will be a diradical. If there is no QI feature, i.e., transmission of current is normal if electrodes are attached to the two atoms, the resulting hydrocarbon will not be a diradical but will have a classical closed-shell electronic structure. Moreover, where a diradical exists, the easy zero is associated with a nondisjoint diradical, and the hard zero is associated with a disjoint one. A related theorem is proven for deletion of two sites from a hydrocarbon.