Showing papers by "Takashi Kubo published in 2015"
TL;DR: In this paper, a highlight review focuses on recent advances in experimental analysis of spin state in singlet biradical molecules and arises from the weak coupling of unpaired electrons, which is a feature of singlet binary molecules.
Abstract: Elusive nature in spin state is a feature of singlet biradical molecules and arises from the weak coupling of unpaired electrons. This highlight review focuses on recent advances in experimental ap...
197 citations
TL;DR: This account summarizes the studies so far into PAH radicals containing the phenalenyl scaffold in terms of their amphoteric redox properties and singlet biradical character, which strongly rely on the characteristic electronic structure, that is, non-bonding character and sixfold symmetry of a singly occupied molecular orbital of the phenAlenyl radical.
Abstract: The phenalenyl radical is a polycyclic aromatic hydrocarbon (PAH) radical. Owing to its widely distributed spin structure, phenalenyl is relatively stable compared to other hydrocarbon radicals and has been studied from the viewpoint of its application to electroconductive and magnetic materials. In addition, a strong intermolecular spin-spin coupling nature is another feature of phenalenyl. This account summarizes my studies so far into PAH radicals containing the phenalenyl scaffold in terms of their amphoteric redox properties and singlet biradical character, which strongly rely on the characteristic electronic structure, that is, non-bonding character and sixfold symmetry of a singly occupied molecular orbital of the phenalenyl radical.
151 citations
TL;DR: It is found that the amount of charge transfer between the two monomers in phenalenyl π-dimers correlates with the difference in the SOMO energies of the constituent monomers, where the SomO energy plays the role of a monomer (group) electronegativity index.
Abstract: Homogeneous π-stacking dimers of phenalenyl and its derivatives have gained tremendous interest as components of conducting organic materials. For the first time, we investigate theoretically heterogeneous phenalenyl π-dimers. Key parameters, including charge transfer, interaction energy, singly occupied molecular orbital (SOMO) energy, and spin density, are studied with the help of density functional theory. We find that the amount of charge transfer between the two monomers in phenalenyl π-dimers correlates with the difference in the SOMO energies of the constituent monomers, where the SOMO energy plays the role of a monomer (group) electronegativity index. Charge transfer plays an important role in stabilizing the heterodimers while maintaining a significant diradicaloid character. For five heterodimers the interaction energy is found to be as large as -30 to -50 kcal mol(-1) . The presented correlation between the monomer SOMO energy levels and their stability can provide a simple predictive tool to design new highly stable π-stacking heterodimers.
35 citations
TL;DR: X-ray crystallographic analysis revealed that charge transfer complexes of the π-extended TNP with F4-TCNQ form a two-dimensional honeycomb lattice.
29 citations
TL;DR: A hydrogen-bonded complex was successfully isolated as crystals from the anthranol/anthroxyl pair in the self-exchange proton-coupled electron transfer (PCET) reaction.
Abstract: A hydrogen-bonded complex was successfully isolated as crystals from the anthranol/anthroxyl pair in the self-exchange proton-coupled electron transfer (PCET) reaction. The anthroxyl radical was stabilized by the introduction of a 9-anthryl group at the carbon atom at the 10-position. The hydrogen-bonded complex with anthranol self-assembled by π-π stacking to form a one-dimensional chain in the crystal. The conformation around the hydrogen bond was similar to that of the theoretically predicted PCET activated complex of the phenol/phenoxyl pair. X-ray crystal analyses revealed the self-exchange of a hydrogen atom via the hydrogen bond, indicating the activation of the self-exchange PCET reaction between anthranol and anthroxyl. Magnetic measurements revealed that magnetic ordering inside the one-dimensional chain caused the inactivation of the self-exchange reaction.
24 citations
Chung-Ang University1, Hoseo University2, Osaka University3, University of Strasbourg4, Tohoku University5, University of Brighton6, University of Surrey7, University of York8, Peking University9, University of Tokyo10, Rikkyo University11, University of Oslo12, French Alternative Energies and Atomic Energy Commission13
21 citations
TL;DR: In this article, a highlight review focuses on recent advances in experimental analysis of spin state in singlet biradical molecules and arises from the weak coupling of unpaired electrons, which is a feature of singlet binary molecules.
Abstract: Elusive nature in spin state is a feature of singlet biradical molecules and arises from the weak coupling of unpaired electrons. This highlight review focuses on recent advances in experimental ap...
17 citations
TL;DR: In this paper, the mass spectrum of the unbound nucleus He10 was measured at RIKEN using the Li11(d,He3) reaction at 50A MeV.
Abstract: We present the first missing mass spectrum of the unbound nucleus He10, measured at RIKEN using the Li11(d,He3) reaction at 50A MeV. He10 is believed to be a three-body He8+n+n resonance beyond the limit of nuclear binding. Our observation of a new decay branch, 6He+4n, and of a puzzling reduction of the Li11(d,He3)He10 cross section challenges this view. Moreover, our experiment shows a new trend in the evolution of the proton spectroscopic strength in Li isotopes deduced from the comparison of the (d,He3) cross sections on Li7,8,9,11 with theoretical predictions. We discuss new questions about physics beyond the limits of nuclear existence raised by these findings.
11 citations
University of Strasbourg1, Osaka University2, Hoseo University3, GSI Helmholtz Centre for Heavy Ion Research4, Tohoku University5, Peking University6, University of Tokyo7, University of Brighton8, French Alternative Energies and Atomic Energy Commission9, University of Surrey10, University of York11, Beihang University12, Rikkyo University13, University of Oslo14, University of Notre Dame15
TL;DR: In this paper, the authors reported new data on the $136,136,Sb]-phantom{\rule{4pt}{0ex}}{6}^{\ensuremath{-}}$ yrast isomer with ${T}_{1/2}=489(40) \mathrm{ns}$ and showed that the decay of the isomer to the ground state is in good agreement with shell-model calculations.
Abstract: We report new data on the $^{136}\mathrm{Sb}\phantom{\rule{4pt}{0ex}}{6}^{\ensuremath{-}}$ yrast isomer with ${T}_{1/2}=489(40) \mathrm{ns}$ and $\ensuremath{\pi}{g}_{7/2}^{1}\ifmmode\times\else\texttimes\fi{}\ensuremath{
u}{f}_{7/2}^{3}$ configuration, populated in the projectile fission of $^{238}\mathrm{U}$ on a $^{9}\mathrm{Be}$ target. The analysis confirms the lifetime, providing a good accuracy measurement. In addition, the decay of the isomer to the ground state is newly suggested. Our result for the isomeric decay scheme is in a good agreement with shell-model calculations.
11 citations
01 Jan 2015
TL;DR: In this article, the origin of the magnetic properties of polycyclic aromatic hydrocarbons in terms of aromatic sextet formation and spin localization, in relation to the edge state of graphene and graphene nanoribbons, is discussed.
Abstract: Graphene, a sheet of carbon atoms arranged in a honeycomb lattice, has attracted much attention from chemists, physicists, and material scientists, because their peculiar electronic properties promise novel functions that radically change our lives in the coming years. Great contribution of physics has been disclosing electronic structures of graphene, whereas some of them can be understood by bottom-up approach, that is, by relating to chemistry of polycyclic aromatic hydrocarbons. This chapter mainly focuses on the origin of the magnetic properties of polycyclic aromatic hydrocarbons in terms of aromatic sextet formation and spin localization, in relation to “edge state” of graphene and graphene nanoribbons.
9 citations
TL;DR: In this article, the half-lives of 21+ states were measured for 102,104Zr and 106,108Mo to test a new implementation of a LaBr3(Ce) array at the RIBF, RIKEN, Japan.
Abstract: The half-lives of 21+ states were measured for 102,104Zr and 106,108Mo to test a new implementation of a LaBr3(Ce) array at the RIBF, RIKEN, Japan. The nuclei of interest were produced through the fission of a 345 MeV/nucleon 238U beam and selected by the BigRIPS separator. Fission fragments were implanted into the WAS3ABi active stopper, surrounding which, 18 LaBr3(Ce) detectors provided fast γ-ray detection. Timing between the LaBr3(Ce) array and plastic scintillators allowed for the measurement of half-lives of low-lying states. The preliminary results, which agree with literature values, are presented along with experimental details.
30 Jun 2015
27 Oct 2015
30 Jun 2015
30 Jun 2015
TL;DR: In this paper, the authors presented the first missing mass spectrum of the unbound system 10He obtained from one nucleon transfer (Li(d,$^{3}$He) reaction at 50'A'MeV.
Abstract: We present the first missing mass spectrum of the unbound system 10He obtained from one nucleon transfer $^{11}$Li(d,$^{3}$He) reaction at 50 A MeV. We found rather large yields for the $^{6}$He + 4n decay channel especially for higher excitation energy, which suggest the importance of the $^{6}$He + 4n structure in $^{10}$He.
TL;DR: The phenalenyl radical is a polycyclic aromatic hydrocarbon (PAH) radical and is relatively stable compared to other hydrocarbon radicals and has been studied from the viewpoint of its application to electroconductive and magnetic materials as discussed by the authors.
Abstract: The phenalenyl radical is a polycyclic aromatic hydrocarbon (PAH) radical. Owing to its widely distributed spin structure, phenalenyl is relatively stable compared to other hydrocarbon radicals and has been studied from the viewpoint of its application to electroconductive and magnetic materials. In addition, a strong intermolecular spin-spin coupling nature is another feature of phenalenyl. This account summarizes my studies so far into PAH radicals containing the phenalenyl scaffold in terms of their amphoteric redox properties and singlet biradical character, which strongly rely on the characteristic electronic structure, that is, non-bonding character and sixfold symmetry of a singly occupied molecular orbital of the phenalenyl radical.
TL;DR: Tetra-4-pyridylmethane (1) was obtained by pyrolysis of tri(4-polygonal) 4-poly(4)-4-pyrized tetrahedral bridging ligand molecules.
Abstract: Tetra-4-pyridylmethane (1), a useful tetrahedral bridging ligand molecule, was effectively obtained by the pyrolysis of tri(4-pyridyl)-4-pyridylazomethane, which was easily prepared from tri-4-pyri...