Bis-periazulene (Cyclohepta[<i>def</i>]fluorene) as a Nonalternant Isomer of Pyrene: Synthesis and Characterization of Its Triaryl Derivatives

Horii, Koki; Kishi, Ryohei; Nakano, Masayoshi; Shiomi, Daisuke; Sato, Kazunobu; Takui, Takeji; Konishi, Akihito; Yasuda, Makoto

doi:10.1021/jacs.2c00476

Cited by 59 publications

(42 citation statements)

References 70 publications

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“…Very recently, other attractive systems have also been reported in which both neutral and cationic states were successfully isolated by applying the strategies described here. [128][129][130][131] The redox chemistry of pure hydrocarbons is expanding rapidly, and these examples will be covered in another review. Furthermore, although excluded from this review, the development of pure hydrocarbon-based response systems based on different approaches from electrochemical stimulation is also being actively pursued.…”

Section: Discussionmentioning

confidence: 99%

Redox‐Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems

Harimoto

Ishigaki

2022

ChemPlusChem

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Organic chemistry has developed rapidly as a carbon‐based science. Particularly, hydrocarbons with aromatic rings have attracted much attention as molecular materials for use in organic electronics. In principle, aromatic species can be constructed if carbon and hydrogen atoms are available. Therefore, revealing the nature of pure hydrocarbons with an (anti)aromatic nature should pave the way for the development of as yet unexplored organic materials. In this Review, we focus on pure hydrocarbons composed of only carbon and hydrogen atoms, and present recent studies on their intrinsic electrochemical and spectroscopic properties and structural characterization of their cationic states. We also address more sophisticated hydrocarbon‐based response systems that are capable of modulating their properties in response to external stimuli such as light, heat, and electric potential.

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Section: Discussionmentioning

confidence: 99%

Redox‐Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems

Harimoto

Ishigaki

2022

ChemPlusChem

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“…In(OTf) 3 : indium(III) triflate; LiH: lithium hydride. [108] projected product (128) and its diastereomer (129), which had an indene substructure; these products were expected to have small biradical character according to DFT calculations. Singlecrystal analysis of 126 revealed that azulene and indene were fused on two sides of the molecular skeleton.…”

Section: Alkyne-based Cyclizationmentioning

confidence: 99%

“…Very recently, an elusive isomer of pyrene, bis-periazulene (138), was successfully synthesized by Yasuda et al (Scheme 21a). [108] The first attempt toward bis-periazulene can be dated back to 1955 by Reid, [33] and subsequent efforts were dedicated to this target. However, none of them were successful when conducting deprotonation of 137 + •ClO 4 − or two-electron oxidation of 2Li + •138 2− owing to the intrinsic instability of bis-periazulene.…”

Section: Alkyne-based Cyclizationmentioning

confidence: 99%

Synthesis of Defective Nanographenes Containing Joined Pentagons and Heptagons

Fei

Liu

2022

Advanced Science

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Dedicated to Professor Klaus Müllen on the occasion of his 75 birthdayDefective nanographenes containing joined pentagons and heptagons exhibit striking physicochemical properties from both experimental and theoretical perspectives compared with their pure hexagonal counterparts. Thus, the synthesis and characterization of these unique polyarenes with well-defined defective topologies have attracted increasing attention. Despite extensive research on nonalternant molecules since the last century, most studies focused on the corresponding mutagenic and carcinogenic activities. Recently, researchers have realized that the defective domain induces geometric bending and causes electronic perturbation, thus leading to significant alteration of the photophysical properties. This review discusses the synthesis and characterization of small nonalternant polycyclic hydrocarbons in the early stage and recent developments in embedding pentagon-heptagon (5-7) pairs into large carbon skeletons through in-solution chemistry.

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“…During the submission of our work, Yasuda et al. reported the synthesis of the triaryl derivatives of g , which exhibited singlet ground states, contrary to previous theoretical predictions for g [18b] . Therefore, the experimental access and the intrinsic properties of this kind of non‐alternative PHs remain elusive due to the lack of efficient synthetic strategy.…”

Section: Figurementioning

confidence: 77%

Benzo‐Extended Cyclohepta[def]fluorene Derivatives with Very Low‐Lying Triplet States

Lombardi

et al. 2022

Angewandte Chemie

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Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships.

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Bis-periazulene (Cyclohepta[def]fluorene) as a Nonalternant Isomer of Pyrene: Synthesis and Characterization of Its Triaryl Derivatives

Cited by 59 publications

References 70 publications

Redox‐Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems

Redox‐Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems

Synthesis of Defective Nanographenes Containing Joined Pentagons and Heptagons

Benzo‐Extended Cyclohepta[def]fluorene Derivatives with Very Low‐Lying Triplet States

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