Takashi Kubo

A phenalenyl-based Kekulé hydrocarbon with singlet biradical character has been isolated and characterized. Strong intra- and intermolecular interactions between the unpaired electrons lead to short π–π contacts and formation of one-dimensional chains (see picture). Thus, wide valence and conduction bands are established, and the compound shows semiconductive behavior. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z502303_s.pd

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 approaches for elucidating the electronic structure and properties of singlet biradical molecules having quinoid skeletons.

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 o

[reaction: see text] A new Kekulé polycyclic hydrocarbon with a singlet biradical index of 50% was synthesized. The singlet biradical character was assessed with UV and 1H-NMR spectroscopy, cyclic voltammetry, SQUID magnetic susceptibility measurement, and quantum chemical calculations.

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. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460565_s.pdf or from the author. Please note: The publisher is not responsible for the content or functi

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.

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.

The structure of TiO2-derived nanotubes with about 10 nm outer diameter and 5 nm inner diameter and a few hundred nanometers in length prepared by the hydrothermal process in an aqueous NaOH solution was investigated. Especially, the local structure of TiO2-derived nanotubes was analyzed in detail on short-range order by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) measurements. It was found that TiO2-derived nanotubes were mainly composed of

Large aza-analogues of curved polycyclic aromatic hydrocarbons with a double-helicene structure present unique features for molecular photonics. We present the preparation and characterization of three such structures. The synthesis of these heterocyclic nanographenes involves only a few high-yield steps that use readily available starting materials. X-ray analysis revealed that each of these new dyes has three conformational isomers: one diastereoisomer in a meso form and two enantiomers in twi

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.

The synthesis of persistent, neutral organic radicals is challenging because of their inherent reactivities. Herein, we report the synthesis and characterization of a highly congested mesityl-substituted tri(9-anthryl)methyl (TAntM) radical (1). The scaffold was successfully synthesized by circumventing the steric hindrance imposed by the bulky groups surrounding the central methyl carbon atom. The radical has a threefold propeller structure, and the unpaired electron is mainly localized on the