The First Bowl-Shaped Stable Neutral Radical with a Corannulene System:  Synthesis and Characterization of the Electronic Structure

Morita, Yasushi; Nishida, Shinsuke; Kobayashi, Tadahiro; Fukui, Kozo; Sato, Kazunobu; Shiomi, Daisuke; Takui, Takeji; Nakasuji, Kazuhiro

doi:10.1021/ol0497786

Cited by 40 publications

(17 citation statements)

References 24 publications

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“…Several corannulene derivatives were obtained by metal-catalyzed coupling reaction of decachlorocorannulene (52). Decamethylcorannulene 54 was synthesized in 30% yield by methylations of 52 in the presence of NiCl 2 (dppp) and trimethylaluminum [62].…”

Section: T-bu T-bu T-bu T-bu T-bumentioning

confidence: 99%

“…Similarly, decakis(phenylthio)corannulene (58a) was obtained in 50% yield [75]. For the synthesis of 58b and 58c, the thiol species of the corresponding paraffinic components were ionized in situ by using DBU for the reaction with decachlorocorannulene (52). Corannulene derivatives 58b and 58c were found to form a liquid crystalline assembly [101].…”

Section: T-bu T-bu T-bu T-bu T-bumentioning

confidence: 99%

“…Alternatively, mono-substituted corannulenes 25 (R¼CMe 2 OH or CHO) were also accessed by treatment of 28-Br with n-BuLi forming the corannulyl lithium species and quenching with acetone [51] or DMF [52], respectively. Moreover, Negishi couplings and Sonogashira reactions of 28-Br afford monoaryl and monoalkynyl substituted corannulenes 29 and 30, respectively [53].…”

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Synthesis, Structures, and Physical Properties of Aromatic Molecular-Bowl Hydrocarbons

Siegel

2014

Topics in Current Chemistry

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This chapter summarizes the synthesis, physical properties, structure, and crystal packing of buckybowls. Buckybowls exemplify an intermediate class of polynuclear aromatic compounds between the closed-shell fullerenes and the flat extended arrays of graphene. These warped sheets can be seen as fragments of fullerenes or the end cap of single-walled carbon nanotubes; and, their curvature endows them with physical properties distinct from flat polynuclear hydrocarbons, which opens up unique possibilities for molecular bowls in various organic materials applications.

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Section: T-bu T-bu T-bu T-bu T-bumentioning

confidence: 99%

Section: T-bu T-bu T-bu T-bu T-bumentioning

confidence: 99%

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Synthesis, Structures, and Physical Properties of Aromatic Molecular-Bowl Hydrocarbons

Siegel

2014

Topics in Current Chemistry

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“…A new neutral oxoverdazyl radical conjugated with the corannulene system has been designed and synthesized for the first time as a stable solid in air [767]. The radical 367 was synthesized by the condensation of aldehyde 366 with The synthesis of 1,5-diisopropyl substituted 6-oxo-verdazyls has been accomplished starting from 2,4-diisopropylcarbonohydrazide bis-hydrochloride.…”

Section: Relevant Natural and Useful Compoundsmentioning

confidence: 99%

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

Oliva¹,

Laza²,

Ocáriz³

2011

Modern Heterocyclic Chemistry

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“…Therefore, in order to evaluate an intramolecular exchange interaction in a curved p-conjugated system in a quantitative manner, synthesis and isolation of a stable neutral diradical derivative with extensively spindelocalized nature on its curved p-conjugated system have been the focus of current attention in molecular magnetism and open-shell chemistry. [2,5] Recently, we studied corannulene [6] -based stable neutral monoradical systems, [7] such as a phenoxyl radical derivative 1[7d] with highly spin-delocalized nature on the intrinsically 3D bowl-shaped and nonalternant p-conjugated network. These studies inspired us to propose a 3D intramolecular exchange interaction in this class of curved p radicals: in terms of geometry, they are intermediate between a planar p radical such as a phenalenyl system [8] and a tetrahedral s radical.…”

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Three‐Dimensional Intramolecular Exchange Interaction in a Curved and Nonalternant π‐Conjugated System: Corannulene with Two Phenoxyl Radicals

et al. 2010

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In recent years, curved p-conjugated molecules such as fullerenes and carbon nanotubes have attracted much attention not only in chemistry but also in materials science. [1] Their intra/intermolecular interactions within/between threedimensional (3D) curved p-electron networks play intrinsically vital roles in their unique properties and functionalities. Among them, intramolecular magnetic interaction between electronic spins on a curved p surface was extensively studied for ionic species of C 60 such as C 60 2À and C 60 3À .[2] Their electronic structures are greatly influenced by not only the dynamic spin polarization of electrons but also the negative charges on the spherical p-conjugated system and the countercation.Thus, we have focused on neutral diradical systems, which are known to be the most useful probes for studying intramolecular magnetic interactions in organic molecules. [3] While many neutral diradical derivatives relevant to planar pconjugated systems have so far been investigated, studies on curved p-conjugated neutral diradicals are limited to a single C 60 -based system in which [60]fullerene is linked to two nitroxide radicals.[4] However, their intramolecular exchange interaction J through the C 60 skeleton was very weak (j Jk À1 B j < 0.1 K)[4b] because of the small spin delocalization onto the C 60 p network from the nitroxide radicals with spin-localized nature on the NO moieties. Therefore, in order to evaluate an intramolecular exchange interaction in a curved p-conjugated system in a quantitative manner, synthesis and isolation of a stable neutral diradical derivative with extensively spindelocalized nature on its curved p-conjugated system have been the focus of current attention in molecular magnetism and open-shell chemistry. [2,5] Recently, we studied corannulene [6] -based stable neutral monoradical systems, [7] such as a phenoxyl radical derivative 1[7d] with highly spin-delocalized nature on the intrinsically 3D bowl-shaped and nonalternant p-conjugated network. These studies inspired us to propose a 3D intramolecular exchange interaction in this class of curved p radicals: in terms of geometry, they are intermediate between a planar p radical such as a phenalenyl system [8] and a tetrahedral s radical. We have now, for the first time, synthesized and isolated a corannulene-based neutral diradical, namely, 2, which has two phenoxyl radical moieties, as air-stable crystals. Due to its highly spin-delocalized nature, 2 shows strong intramolecular exchange interaction (Jk À1 B = À405 AE 2 K) through the 3D corannulene p-electron network. Bond-length analyses and DFT calculations showed that 2 has contributions from diradical canonical forms a-g and closed KekulØ structure d (Scheme 1). Furthermore, in the crystalline state the presence of three crystallographically independent diradical molecules with different curvature enabled us to study the relationship between the curvature of the corannulene p skeleton and the

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The First Bowl-Shaped Stable Neutral Radical with a Corannulene System: Synthesis and Characterization of the Electronic Structure

Cited by 40 publications

References 24 publications

Synthesis, Structures, and Physical Properties of Aromatic Molecular-Bowl Hydrocarbons

Synthesis, Structures, and Physical Properties of Aromatic Molecular-Bowl Hydrocarbons

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

Three‐Dimensional Intramolecular Exchange Interaction in a Curved and Nonalternant π‐Conjugated System: Corannulene with Two Phenoxyl Radicals

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