Co-reporter:Akihito Konishi
Topics in Current Chemistry 2017 Volume 375( Issue 6) pp:83
Publication Date(Web):17 October 2017
DOI:10.1007/s41061-017-0171-2
Reactivity and physical properties of π-conjugated hydrocarbon systems depend predominantly on the topology of π-electrons array. Quinoidal conjugations serve as giving diradical character to molecules, leading to unique chemical behaviors. The simplest member of quinodimethanes are o-, m-, and p-quinodimethanes, which are very reactive due to diradical character and cannot be isolated under normal experimental conditions. However, chemical modifications, such as π-extension or introduction of substituent groups, of quinodimethanes imparts stabilities to quinodimethanes that can be handled under ambient conditions. This chapter offers an overview of reactivity and magnetic properties of benzenoid o-, m-, and p-quinodimethanes.
Co-reporter:Kazuyuki Uchida; Soichi Ito; Masayoshi Nakano; Manabu Abe
Journal of the American Chemical Society 2016 Volume 138(Issue 7) pp:2399-2410
Publication Date(Web):January 29, 2016
DOI:10.1021/jacs.5b13033
First isolation and characterization of biphenalenylidenes, which have long been unidentified reactive intermediates on the decomposition pathway of phenalenyl radical, were accomplished. Photoinduced electrocyclic ring-opening reaction of anti-dihydroperopyrene resulted in a successful conversion to E-biphenalenylidene, which enabled a detailed investigation of the electronic structure of E-biphenalenylidene by means of spectroscopic techniques. A stereoisomer, Z-biphenalenylidene, was also observed by suppressing a facile E–Z isomerization to E-biphenalenylidene in a rigid matrix. Furthermore, Z-biphenalenylidene demonstrated a thermal ring-closure in conrotatory process, which is not conforming to the Woodward–Hoffmann rule. These unusual reactivities of biphenalenylidene are ascribed to the ground states destabilized by its singlet biradical character, which was fully supported by theoretical calculations. The presence of E-biphenalenylidene on the decomposition pathway of phenalenyl was confirmed experimentally, leading to the full understanding of the decomposition mechanism of phenalenyl.
Co-reporter:Kazuyuki Uchida; Zhongyu Mou; Miklos Kertesz
Journal of the American Chemical Society 2016 Volume 138(Issue 13) pp:4665-4672
Publication Date(Web):March 10, 2016
DOI:10.1021/jacs.6b01791
Direct evidence for σ-bond fluxionality in a phenalenyl σ-dimer was successfully obtained by a detailed investigation of the solution-state dynamics of 2,5,8-trimethylphenalenyl (TMPLY) using both experimental and theoretical approaches. TMPLY formed three diamagnetic dimers, namely, the σ-dimer (RR/SS), σ-dimer (RS), and π-dimer, which were fully characterized by 1H NMR spectroscopy and electronic absorption measurements. The experimental findings gave the first quantitative insights into the essential preference of these competitive and unusual dimerization modes. The spectroscopic analyses suggested that the σ-dimer (RR/SS) is the most stable in terms of energy, whereas the others are metastable; the energy differences between these three isomers are less than 1 kcal mol–1. Furthermore, the intriguing dynamics of the TMPLY dimers in the solution state were fully revealed by means of 1H–1H exchange spectroscopy (EXSY) measurements and variable-temperature 1H NMR studies. Surprisingly, the σ-dimer (RR/SS) demonstrated a sixfold σ-bond shift between the six sets of α-carbon pairs. This unusual σ-bond fluxionality is ascribed to the presence of a direct interconversion pathway between the σ-dimer (RR/SS) and the π-dimer, which was unambiguously corroborated by the EXSY measurements. The proposed mechanism of the sixfold σ-bond shift based on the experimental findings was well-supported by theoretical calculations.
Co-reporter:Tomohiko Nishiuchi, Shin-ya Uno, Yasukazu Hirao, and Takashi Kubo
The Journal of Organic Chemistry 2016 Volume 81(Issue 5) pp:2106-2112
Publication Date(Web):February 1, 2016
DOI:10.1021/acs.joc.6b00134
We report variable and unique properties of 1,2-di(9-anthryl)benzene 1 as a fundamental moiety of anthracene-based π-cluster molecules. Due to a through-space π-conjugation between anthracene units, excimer emission at room temperature and charge delocalized state in radical cation state of 1 could be observed. Photoirradiation to 1 afforded an intramolecular [4 + 4] cyclized anthracene dimer 1′ having a high strain energy with long C–C bond that exceeded 1.68 Å, resulting in C–C bond dissociation by simple mechanical grinding.
Co-reporter:Takashi Kubo, Shogo Miyazaki, Takuya Kodama, Mitsuya Aoba, Yasukazu Hirao and Hiroyuki Kurata
Chemical Communications 2015 vol. 51(Issue 18) pp:3801-3803
Publication Date(Web):26 Jan 2015
DOI:10.1039/C4CC09883H
The multi-gram-scale synthesis of trinaphtho[3.3.3]propellane (TNP) and its π-extension were achieved. X-ray crystallographic analysis revealed that charge transfer complexes of the π-extended TNP with F4-TCNQ form a two-dimensional honeycomb lattice.
Co-reporter:Takashi Kubo
The Chemical Record 2015 Volume 15( Issue 1) pp:218-232
Publication Date(Web):
DOI:10.1002/tcr.201402065
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.
Co-reporter:Yi Tian ; Kazuyuki Uchida ; Hiroyuki Kurata ; Yasukazu Hirao ; Tomohiko Nishiuchi
Journal of the American Chemical Society 2014 Volume 136(Issue 36) pp:12784-12793
Publication Date(Web):August 18, 2014
DOI:10.1021/ja507005c
Organic neutral radicals have long fascinated chemists with a fundamental understanding of structure–reactivity relationships in organic reactions and with applications as new functional materials. However, the elusive nature of these radicals makes the synthesis, isolation, and characterization very challenging. In this work, the synthesis of three long-lived, fluorenyl-based radicals are reported. The geometry and electronic structures of these radicals were systematically investigated with a combination of various experimental methods, besides density functional theory (DFT) calculations, which include X-ray crystallographic analysis, electron spin resonance (ESR), electron nuclear double resonance (ENDOR), cyclic voltammetry, and UV–vis–NIR measurements. Their half-life periods (τ1/2) in air-saturated solution under ambient conditions were also determined. Surprisingly, all three radicals showed remarkable stabilities: τ1/2 = 7, 3.5, and 43 days.
Co-reporter:Zhongyu Mou ; Kazuyuki Uchida ; Takashi Kubo ;Miklos Kertesz
Journal of the American Chemical Society 2014 Volume 136(Issue 52) pp:18009-18022
Publication Date(Web):November 13, 2014
DOI:10.1021/ja509243p
Phenalenyl and a wide variety of its derivatives form stable radicals, which often associate in various aggregates with interesting properties that include magnetism and high electrical conductivity. The two main modes of aggregation involve π-stacking pancake multicenter bond formation and σ-bond formation. We explore the energetics of the various σ- and π-dimers for six phenalenyl derivatives with both computational and experimental methods. A modern density functional theory (M05-2X) is used to survey the potential energy surface revealing the mechanism of the aggregation. In order to enrich experimental data, the triphenyl and trimethyl derivatives are newly prepared and their aggregation behaviors are investigated by various analytical methods including ESR, 1H NMR, UV–vis, and single-crystal X-ray diffraction. The agreement between computations and experiments are very good forming the basis of describing trends in this series. We find that π-dimer formation can proceed via an asynchronous concerted path from the monomers or in a stepwise process via σ-dimers. The strength of the π-stacking pancake interaction depends strongly on substituents and covers a wide range both in terms of binding energies and contact distances. The spin densities in the π-stacking dimers reflect these trends and display a wide range of diradicaloid characters. Many σ-dimer configurations compete some of which are separated by small barriers leading to fluxional structures between σ-bonded configurations or σ- and π-bonded configurations.
Co-reporter:Kazuhiko Adachi, Yasukazu Hirao, Kouzou Matsumoto, Takashi Kubo, and Hiroyuki Kurata
Organic Letters 2014 Volume 16(Issue 22) pp:5870-5873
Publication Date(Web):October 31, 2014
DOI:10.1021/ol5027816
A bicyclo-type cage-shaped compound consisting of three sexithiophenes was successfully synthesized and characterized by NMR, HRMS, and X-ray crystallographic analysis. The strained cage architecture was reflected in the blue-shifted absorption spectrum relative to its linear analogue. Intramolecular interaction between three-dimensionally fixed sexithiophenes was suggested by electrochemical analysis.
Co-reporter:Kazuyuki Uchida;Dr. Yasukazu Hirao;Dr. Hiroyuki Kurata;Dr. Takashi Kubo;Dr. Sayaka Hatano;Dr. Katsuya Inoue
Chemistry – An Asian Journal 2014 Volume 9( Issue 7) pp:1823-1829
Publication Date(Web):
DOI:10.1002/asia.201402187
Abstract
The 2,5,8-tris(pentafluorophenyl)phenalenyl radical was obtained by a straightforward synthesis in 11 steps from 2,7-dibromonaphthalene. This radical crystallized as a σ dimer from a solution in MeCN and as a π-stack from a melted liquid. The π stack was not confined to dimerization, but extended into a uniform 1D stack with an interplanar distance of 3.503 Å. This unique duality in association mode arose from the thermodynamic stability of the phenalenyl moiety.
Co-reporter:Akihito Konishi ; Yasukazu Hirao ; Kouzou Matsumoto ; Hiroyuki Kurata ; Ryohei Kishi ; Yasuteru Shigeta ; Masayoshi Nakano ; Kazuya Tokunaga ; Kenji Kamada
Journal of the American Chemical Society 2013 Volume 135(Issue 4) pp:1430-1437
Publication Date(Web):January 7, 2013
DOI:10.1021/ja309599m
The characteristics of the edge state, which is a peculiar magnetic state in zigzag-edged graphene nanoribbons (ZGNRs) that originates from electron–electron correlation in an edge-localized π-state, are investigated by preparing and characterizing quarteranthene molecules. The molecular geometry that was determined from the X-ray analysis is consistent with a zigzag-edge-localized structure of unpaired electrons. The localized electrons are responsible for the peculiar magnetic (room-temperature ferromagnetic correlation), optical (the lowest-lying doubly excited state), and chemical (peroxide bond formation) behaviors. On the basis of these distinguishing properties and a careful consideration of the valence bonding, insight into the edge state of ZGNRs can be gained.
Co-reporter:Akihito Konishi, Yasukazu Hirao, Hiroyuki Kurata, Takashi Kubo
Solid State Communications 2013 Volumes 175–176() pp:62-70
Publication Date(Web):December 2013
DOI:10.1016/j.ssc.2013.07.005
•Periacenes are investigated to elucidate the origin of the edge state of ZGNR.•The edge state becomes obvious from the molecular size of teranthene.•The edge state is strongly associated with the formation of aromatic sextets.The edge state, which is a peculiar magnetic state in zigzag-edged graphene nanoribbons (GNRs) originating from an electron–electron correlation in an edge-localized π-state, has promising applications for magnetic and spintronics devices and has attracted much attention of physicists, chemists, and engineers. For deeper understanding the edge state, precise fabrication of edge structures in GNRs has been highly demanded. We focus on [a.b]periacene, which are polycyclic aromatic hydrocarbons (PAHs) that have zigzag and armchair edges on molecular periphery, as a model compound for the understanding and actually prepare and characterize them. This review summarizes our recent studies on the origin of the edge state by investigating [a.b]periacene in terms of the relationship between the molecular structure and spin-localizing character.
Co-reporter:Akihiro Shimizu, Yasukazu Hirao, Kouzou Matsumoto, Hiroyuki Kurata, Takashi Kubo, Mikio Uruichi and Kyuya Yakushi
Chemical Communications 2012 vol. 48(Issue 45) pp:5629-5631
Publication Date(Web):10 Apr 2012
DOI:10.1039/C2CC31955A
An anthracene-linked bisphenalenyl Kekulé molecule with very significant singlet biradical character has shown a prominent covalent bonding interaction between molecules in a molecular aggregate. High aromatic stabilization energy in the anthracene linker is responsible for the significant singlet biradical character.
Co-reporter:Takashi Kubo ; Yoshiki Katada ; Akihiro Shimizu ; Yasukazu Hirao ; Kazunobu Sato ; Takeji Takui ; Mikio Uruichi ; Kyuya Yakushi ;Robert C. Haddon
Journal of the American Chemical Society 2011 Volume 133(Issue 36) pp:14240-14243
Publication Date(Web):August 11, 2011
DOI:10.1021/ja2065768
We have prepared and isolated neutral polycyclic hydrocarbon radicals. A butyl-substituted radical gave single crystals, in which a π-dimeric structure, not a σ-bonded dimer, was observed, even though steric protection was absent. Thermodynamic stabilization due to the highly spin-delocalized structure contributes effectively to the suppression of σ-bond formation.
Co-reporter:Akihiro Shimizu;Masayoshi Nakano;Yasukazu Hirao
Journal of Physical Organic Chemistry 2011 Volume 24( Issue 10) pp:876-882
Publication Date(Web):
DOI:10.1002/poc.1873
Kekulé singlet biradicals stabilized by phenalenyl rings afford one-dimensional stacks in the solid state, in which covalent-bonding interactions exist not only within a molecule but also between molecules. Through the covalent-bonding interactions spreading over the stack, the lowest-energy absorption band shifts to a lower-energy region in the solid state relative to the solution band, and an electro-conductive property in a single component state is also observed. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Kouzou Matsumoto;Kaori Miki;Takuya Inagaki;Tatsuo Nehira;Gennaro Pescitelli;Yasukazu Hirao;Hiroyuki Kurata;Takeshi Kawase
Chirality 2011 Volume 23( Issue 7) pp:543-548
Publication Date(Web):
DOI:10.1002/chir.20965
Abstract
To “mark” the nitrogen atoms in phenyl-(2-pyridyl)-(3-pyridyl)-(4-pyridyl)methane (1), we have synthesized the corresponding tris(pyridine N-oxide) 2 by oxidation of 1 with m-chloroperbenzoic acid. The nitrogen atoms of 2 are unequivocally determined by the X-ray crystal analysis of a single crystal of rac-2 whereas the nitrogen atoms cannot be assigned at all in the case of rac-1. N-Oxide 2 can be resolved by chiral high-performance liquid chromatography under similar conditions to those used for the resolution of 1. The calculated circular dichroism (CD) curve for (R)-1 on the basis of time-dependent density functional theory reproduces the experimental spectra very well to suggest that the second-eluted fraction ([CD(+)283]-2) is the R isomer, namely (R)-[CD(+)283]-2. The independent absolute configuration determinations for 1 and 2 are in keeping with the chemical correlation between the two compounds by oxidation of (R)-2 into (R)-1. Chirality 2011. © 2011 Wiley-Liss, Inc.
Co-reporter:Akihiro Shimizu ; Takashi Kubo ; Mikio Uruichi ; Kyuya Yakushi ; Masayoshi Nakano ; Daisuke Shiomi ; Kazunobu Sato ; Takeji Takui ; Yasukazu Hirao ; Kouzou Matsumoto ; Hiroyuki Kurata ; Yasushi Morita ;Kazuhiro Nakasuji
Journal of the American Chemical Society 2010 Volume 132(Issue 41) pp:14421-14428
Publication Date(Web):September 27, 2010
DOI:10.1021/ja1037287
A novel naphthoquinoid singlet biradical (2a) stabilized by phenalenyl rings is prepared by a multistep procedure and is investigated in terms of covalent bonding interactions. The molecule 2a gives single crystals, in which a 1D chain is formed with a very short π−π contact at the overlapping phenalenyl rings. The unpaired electrons in 2a are involved in covalent bonding interactions not only within the molecule but also between the molecules in the 1D chain, and a linear conjugation is made of the alternating intra- and intermolecular covalent bonding interactions through conventional π-conjugation and multicenter bonding, respectively. The linear conjugation causes a lower-energy shift of the optical transition band in the crystal, but the transition energy is higher than that of the benzoquinoid singlet biradical (1a). This optical behavior and the magnetic susceptibility measurements reveal that the intermolecular covalent bonding interaction in the 1D chain of 2a is greater in strength than the intramolecular one, despite the fact that a fully conjugated Kekulé structure can be drawn for 2a.
Co-reporter:Akihito Konishi ; Yasukazu Hirao ; Masayoshi Nakano ; Akihiro Shimizu ; Edith Botek ; Benoît Champagne ; Daisuke Shiomi ; Kazunobu Sato ; Takeji Takui ; Kouzou Matsumoto ; Hiroyuki Kurata
Journal of the American Chemical Society 2010 Volume 132(Issue 32) pp:11021-11023
Publication Date(Web):July 26, 2010
DOI:10.1021/ja1049737
A teranthene derivative has been successfully isolated in a crystalline form for the first time. Geometrical considerations and physical property investigations indicate that the molecule possesses prominent biradical character in the ground state.
Co-reporter:Kouzou Matsumoto, Daisuke Inokuchi, Yasukazu Hirao, Hiroyuki Kurata, Kazunobu Sato, Takeji Takui and Takashi Kubo
Organic Letters 2010 Volume 12(Issue 4) pp:836-839
Publication Date(Web):January 14, 2010
DOI:10.1021/ol902937k
A trimethylenemethane (TMM) derivative 12•, in which the parent TMM is π-extended by the symmetric insertion of three pyridine rings into the C−C bonds of TMM, has been synthesized by the alkali metal reduction of the isolated corresponding dication. Although the frozen-glass X-band cw-ESR spectrum of 12• gave unresolved fine structures due to the small ZFS parameters, pulsed ESR two-dimensional electron spin transient nutation (2D-ESTN) spectroscopy unambiguously can afford to identify diradical 12• as a triplet species.
Co-reporter:Kouzou Matsumoto, Daisuke Inokuchi, Yasukazu Hirao, Hiroyuki Kurata and Takashi Kubo
Crystal Growth & Design 2010 Volume 10(Issue 7) pp:2854
Publication Date(Web):June 3, 2010
DOI:10.1021/cg1003353
The crystal structures of the perchlorate, tetrafluoroborate, chloride, and p-toluenesulfonate salts of the diprotonated tetrakis(4-pyridyl)methane (Py4C) dication, [(Py4C)·2H]2+·(ClO4−)2·(CH3CN) (1), [(Py4C)·2H]2+·(BF4−)2·(CH3CN) (2), [(Py4C)·2H]2+·2Cl− (3), and [(Py4C)·2H]2+·2(TsO−) (4), respectively, have been determined by X-ray analysis. Dication [(Py4C)·2H]2+ constructs a three-dimensional polycationic network though the formation of intermolecular N−H···N hydrogen bonds between pyridinium ions and pyridines in 1 and 2, respectively, that is characterized by a 3-fold interpenetrated quartz-type network structure. In contrast, no network structure is observed in 3 and 4, as each pyridinium ion forms a hydrogen bond with a counterion. The network structure of the [(Py4C)·2H]2+ dication described here is not only an aesthetically pleasing form but is expected to possess interesting dielectric and thermal properties.
Co-reporter:Kenji Kamada, Koji Ohta, Akihiro Shimizu, Takashi Kubo, Ryohei Kishi, Hideaki Takahashi, Edith Botek, Benoît Champagne and Masayoshi Nakano
The Journal of Physical Chemistry Letters 2010 Volume 1(Issue 6) pp:937-940
Publication Date(Web):February 25, 2010
DOI:10.1021/jz100155s
Understanding the electronic structure of the singlet diradical state tackles the fundamentals of the chemical bond itself. The singlet diradical character is a key factor, which determines the chemical reactivity, the reaction products, as well as the chemical/physical (electronic, optical and magnetic) properties, although this quantity is defined in a purely theoretical manner. In this Letter, on the basis of the valence configuration interaction scheme, we present an explicit connection between the singlet diradical character and measured quantities obtained from one- and two-photon absorption spectra as well as from phosphorescence and electron spin resonance peaks. This enables us to estimate the singlet diradical character experimentally.Keywords (keywords): diradical character; optical properties; radicals; two-photon absorption; valence configuration interaction;
Co-reporter:Akihiro Shimizu;Mikio Uruichi Dr.;Kyuya Yakushi Dr.;Hiroyuki Matsuzaki Dr.;Hiroshi Okamoto Dr.;Masayoshi Nakano Dr.;Yasukazu Hirao Dr.;Kouzou Matsumoto Dr.;Hiroyuki Kurata Dr. Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 30) pp:5482-5486
Publication Date(Web):
DOI:10.1002/anie.200901382
Co-reporter:Takeshi Kawase Dr.;Akihito Konishi;Yasukazu Hirao Dr.;Kouzou Matsumoto Dr.;Hiroyuki Kurata Dr. Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 11) pp:2653-2661
Publication Date(Web):
DOI:10.1002/chem.200802471
Co-reporter:Akihiro Shimizu;Mikio Uruichi Dr.;Kyuya Yakushi Dr.;Hiroyuki Matsuzaki Dr.;Hiroshi Okamoto Dr.;Masayoshi Nakano Dr.;Yasukazu Hirao Dr.;Kouzou Matsumoto Dr.;Hiroyuki Kurata Dr. Dr.
Angewandte Chemie 2009 Volume 121( Issue 30) pp:5590-5594
Publication Date(Web):
DOI:10.1002/ange.200901382
Co-reporter:Yuko Goto ;Kyuya Yakushi ;Mikio Uruichi Dr.;Masayoshi Nakano ;Akira Fuyuhiro Dr.;Yasushi Morita ;Kazuhiro Nakasuji
Chemistry – An Asian Journal 2007 Volume 2(Issue 11) pp:1370-1379
Publication Date(Web):7 SEP 2007
DOI:10.1002/asia.200700147
We prepared and isolated a phenalenyl-based neutral hydrocarbon (1 b) with a biradical index of 14 %, as well as its charge-transfer (CT) complex 1 b–F4-TCNQ. The crystal structure and the small HOMO–LUMO gap assessed by electrochemical and optical methods support the singlet-biradical contribution to the ground state of the neutral 1 b. This biradical character suggests that 1 b has the electronic structure of phenalenyl radicals coupled weakly through an acetylene linker, that is, some independence of the two phenalenyl moieties. The monocationic species 1 b.+ was obtained by reaction with the organic electron acceptor F4-TCNQ. The cationic species has a small disproportionation energy ΔE for the reaction 2×1 b.+⇌1 b+1 b2+, which presumably originates from the independence of the phenalenyl moieties. The small ΔE led to a small on-site Coulombic repulsion Ueff=0.61 eV in the CT complex. Moreover, a very effective orbital overlap of the phenalenyl rings between molecules afforded a relatively large transfer integral t=0.09 eV. The small Ueff/4t ratio (=1.7) resulted in a metallic-like conductive behavior at around room temperature. Below 280 K, the CT complex showed a transition into a semiconductive state as a result of bond formation between phenalenyl and F4-TCNQ carbon atoms.
Co-reporter:Takashi Kubo Dr.;Akihiro Shimizu;Maki Sakamoto;Mikio Uruichi Dr.;Kyuya Yakushi Dr.;Masayoshi Nakano Dr.;Daisuke Shiomi Dr.;Kazunobu Sato Dr.;Takeji Takui Dr.;Yasushi Morita Dr.;Kazuhiro Nakasuji Dr.
Angewandte Chemie 2005 Volume 117(Issue 40) pp:
Publication Date(Web):13 SEP 2005
DOI:10.1002/ange.200502303
Ein auf Phenalenyl basierender Kekulé-Kohlenwasserstoff mit Singulettdiradikalcharakter wurde isoliert und charakterisiert. Starke intra- und intermolekulare Wechselwirkungen zwischen den ungepaarten Elektronen haben kurze π-π-Kontakte und die Bildung eindimensionaler Ketten (siehe Bild) zur Folge. Dies führt zu breiten Valenz- und Leitungsbändern, und die Verbindung zeigt Halbleitereigenschaften.
Co-reporter:Takashi Kubo, Akihiro Shimizu, Maki Sakamoto, Mikio Uruichi, Kyuya Yakushi, Masayoshi Nakano, Daisuke Shiomi, Kazunobu Sato, Takeji Takui, Yasushi Morita,Kazuhiro Nakasuji
Angewandte Chemie International Edition 2005 44(40) pp:6564-6568
Publication Date(Web):
DOI:10.1002/anie.200502303
Co-reporter:Takashi Kubo Dr.;Maki Sakamoto;Minako Akabane;Yoshinori Fujiwara;Kagetoshi Yamamoto Dr.;Motoko Akita Dr.;Katsuya Inoue Dr.;Takeji Takui Dr.;Kazuhiro Nakasuji Dr.
Angewandte Chemie 2004 Volume 116(Issue 47) pp:
Publication Date(Web):1 DEC 2004
DOI:10.1002/ange.200460565
Ein Phenalenyl-basiertes Singulett-Diradikal mit stark amphoteren Redoxeigenschaften (siehe Schema) wurde schrittweise synthetisiert. Ursache für seinen Singulett-Diradikalcharakter ist nach quantenchemischen Rechnungen und experimentellen Daten eine kleine HOMO-LUMO-Lücke.
Co-reporter:Takashi Kubo Dr.;Maki Sakamoto;Minako Akabane;Yoshinori Fujiwara;Kagetoshi Yamamoto Dr.;Motoko Akita Dr.;Katsuya Inoue Dr.;Takeji Takui Dr.;Kazuhiro Nakasuji Dr.
Angewandte Chemie International Edition 2004 Volume 43(Issue 47) pp:
Publication Date(Web):1 DEC 2004
DOI:10.1002/anie.200460565
A phenalenyl-based singlet biradical that shows highly amphoteric redox properties (see scheme) has been prepared by a stepwise synthesis. Its singlet biradical character originates from a small HOMO–LUMO gap, as suggested by quantum chemical calculations and experimental data.
Co-reporter:Akihiro Shimizu, Yasukazu Hirao, Kouzou Matsumoto, Hiroyuki Kurata, Takashi Kubo, Mikio Uruichi and Kyuya Yakushi
Chemical Communications 2012 - vol. 48(Issue 45) pp:NaN5631-5631
Publication Date(Web):2012/04/10
DOI:10.1039/C2CC31955A
An anthracene-linked bisphenalenyl Kekulé molecule with very significant singlet biradical character has shown a prominent covalent bonding interaction between molecules in a molecular aggregate. High aromatic stabilization energy in the anthracene linker is responsible for the significant singlet biradical character.
Co-reporter:Takashi Kubo, Shogo Miyazaki, Takuya Kodama, Mitsuya Aoba, Yasukazu Hirao and Hiroyuki Kurata
Chemical Communications 2015 - vol. 51(Issue 18) pp:NaN3803-3803
Publication Date(Web):2015/01/26
DOI:10.1039/C4CC09883H
The multi-gram-scale synthesis of trinaphtho[3.3.3]propellane (TNP) and its π-extension were achieved. X-ray crystallographic analysis revealed that charge transfer complexes of the π-extended TNP with F4-TCNQ form a two-dimensional honeycomb lattice.
