3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption

Kobayashi, Toshimichi; Itabashi, Yuki; Iwai, Kento; Inoue, Tsuyoshi; Ohkubo, Kei; Asahara, Haruyasu

doi:https://doi.org/10.1002/asia.70415

3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption

Kobayashi, Toshimichi; Itabashi, Yuki; Iwai, Kento et al.

Chemistry – An Asian Journal, 2025, e70415

アクセス数:1件（2025-11-18 23:58 集計）

固定URL: https://hdl.handle.net/11094/103024

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タイトル	3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption
著者	著者名 Kobayashi, Toshimichi
	NRID 1000060971538 1000060971538 ORCID 0000-0002-5418-156X 0000-0002-5418-156X researchmap permalink yukiitabashi yukiitabashi 著者名 Itabashi, Yuki
	NRID 1000050909231 1000050909231 著者名 Iwai, Kento
	NRID 1000020263204 1000020263204 ORCID 0000-0001-5337-5066 0000-0001-5337-5066 researchmap permalink read0185256 read0185256 Scopus Author ID 7501390753 7501390753 著者名 Inoue, Tsuyoshi
	NRID 1000000379140 1000000379140 ORCID 0000-0001-8328-9249 0000-0001-8328-9249 researchmap permalink Kei_Ohkubo Kei_Ohkubo Scopus Author ID 7101788990 7101788990 著者名 Ohkubo, Kei
	NRID 1000020632318 1000020632318 ORCID 0000-0002-1808-7373 0000-0002-1808-7373 researchmap permalink pikurin3 pikurin3 Scopus Author ID 8856988200 8856988200 著者名 Asahara, Haruyasu
キーワード等	3-azafluorenone
	emission properties
	excited state properties
	redox potential
内容	This is the accepted version of the following article: Kobayashi Toshimichi, Itabashi Yuki, Iwai Kento, et al. 3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption. Chemistry – An Asian Journal, e70415 (2025),which has been published in final form at https://doi.org/10.1002/asia.70415. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html]
抄録	A versatile synthetic strategy for 3-azafluorenone derivatives was developed. The strategy enabled efficient access to previously inaccessible structural analogs. Crucially, tert-butyl protection of ketocarboxylic acid intermediates significantly improved isolated yields and enabled the incorporation of electron-donating, electron-withdrawing, and π-extended substituents. The photophysical properties of the compounds were characterized by UV–Vis absorption and fluorescence spectroscopic measurements, and the electrochemical behavior was monitored using cyclic voltammetry. The electron-donating and π-extended substituents induced pronounced bathochromic shifts in absorption and emission, consistent with the narrowing of the HOMO–LUMO gap, whereas strong electron-withdrawing groups or 6-methoxy substitution caused a slight hypsochromic shift. Nitrogen incorporation and electron-withdrawing substituents stabilized the LUMO, affording more positive ground- and excited-state reduction potentials. Most derivatives exhibited higher excited-state reduction potentials than fluorenone, with the majority exceeding +1.6 V versus saturated calomel electrode (SCE). Further, time-dependent density functional theory (TD-DFT) calculations reproduced the observed spectral trends and oscillator strengths, confirming the π–π* nature of the lowest-energy transitions. All derivatives exhibited intense, red-shifted visible light absorption, and most showed high excited-state reduction potentials, demonstrating their potential for photoredox applications. These results establish detailed structure–property relationships for 3-azafluorenones, providing design principles for the rational tuning of optical and redox properties.
出版者	Wiley
収録物名	Chemistry – An Asian Journal
ページ	e70415
刊行年月	2025-11-05
言語	英語
ハンドルURL	https://hdl.handle.net/11094/103024
PISSN	18614728
eISSN	1861471X
関連情報 (isVersionOf)	DOI (出版社版) https://doi.org/10.1002/asia.70415
アクセス権	embargoed access
権利情報	© 2025 Wiley-VCH GmbH
権利情報	The full-text file will be made open to the public on 5 November 2026 in accordance with the publisher's policy.
出版タイプ	Accepted Manuscript
カテゴリ	学術雑誌論文 Journal Article

資源タイプ	学術雑誌論文
ローカル資源タイプ	学術雑誌論文
DCMI資源タイプ	text
DCTERMS.bibliographicCitation	Chemistry – An Asian Journal. 2025, p. e70415
DC.title	3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption
DC.creator	Kobayashi, Toshimichi
	Itabashi, Yuki
	Iwai, Kento
	Inoue, Tsuyoshi
	Ohkubo, Kei
	Asahara, Haruyasu
DC.publisher	Wiley
DC.language' scheme='DCTERMS.RFC1766	英語
DC.type' scheme='DCTERMS.DCMIType	text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2025-11-05
DC.identifier	https://doi.org/10.1002/asia.70415
DC.subject	3-azafluorenone
	emission properties
	excited state properties
	redox potential
DC.description	This is the accepted version of the following article: Kobayashi Toshimichi, Itabashi Yuki, Iwai Kento, et al. 3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption. Chemistry – An Asian Journal, e70415 (2025),which has been published in final form at https://doi.org/10.1002/asia.70415. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html]
DCTERMS.abstract	A versatile synthetic strategy for 3-azafluorenone derivatives was developed. The strategy enabled efficient access to previously inaccessible structural analogs. Crucially, tert-butyl protection of ketocarboxylic acid intermediates significantly improved isolated yields and enabled the incorporation of electron-donating, electron-withdrawing, and π-extended substituents. The photophysical properties of the compounds were characterized by UV–Vis absorption and fluorescence spectroscopic measurements, and the electrochemical behavior was monitored using cyclic voltammetry. The electron-donating and π-extended substituents induced pronounced bathochromic shifts in absorption and emission, consistent with the narrowing of the HOMO–LUMO gap, whereas strong electron-withdrawing groups or 6-methoxy substitution caused a slight hypsochromic shift. Nitrogen incorporation and electron-withdrawing substituents stabilized the LUMO, affording more positive ground- and excited-state reduction potentials. Most derivatives exhibited higher excited-state reduction potentials than fluorenone, with the majority exceeding +1.6 V versus saturated calomel electrode (SCE). Further, time-dependent density functional theory (TD-DFT) calculations reproduced the observed spectral trends and oscillator strengths, confirming the π–π* nature of the lowest-energy transitions. All derivatives exhibited intense, red-shifted visible light absorption, and most showed high excited-state reduction potentials, demonstrating their potential for photoredox applications. These results establish detailed structure–property relationships for 3-azafluorenones, providing design principles for the rational tuning of optical and redox properties.
DC.rights	© 2025 Wiley-VCH GmbH
DC.rights	The full-text file will be made open to the public on 5 November 2026 in accordance with the publisher's policy.
DC.format	103024
citation_title	3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption
citation_author	Kobayashi, Toshimichi
	Itabashi, Yuki
	Iwai, Kento
	Inoue, Tsuyoshi
	Ohkubo, Kei
	Asahara, Haruyasu
citation_publisher	Wiley
citation_language	英語
citation_date	2025-11-05
citation_journal_title	Chemistry – An Asian Journal
citation_firstpage	e70415
citation_doi	https://doi.org/10.1002/asia.70415
citation_public_url	https://hdl.handle.net/11094/103024

3‐Azafluorenone Derivatives with Small HOMO–LUMO Gaps, Allowing Visible‐Light Absorption

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