Universität zu Köln

Qiu, Zijie, Ju, Cheng-Wei ORCID: 0000-0002-2250-8548, Frederic, Lucas ORCID: 0000-0002-4700-2279, Hu, Yunbin ORCID: 0000-0001-5346-7059, Schollmeyer, Dieter, Pieters, Gregory ORCID: 0000-0002-3924-8287, Muellen, Klaus and Narita, Akimitsu (2021). Amplification of Dissymmetry Factors in pi-Extended [7]- and [9]Helicenes. J. Am. Chem. Soc., 143 (12). S. 4661 - 4668. WASHINGTON: AMER CHEMICAL SOC. ISSN 1520-5126

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Abstract

pi-Extended helicenes constitute an important class of polycyclic aromatic hydrocarbons with intrinsic chirality. Herein, we report the syntheses of pi-extended [7]helicene 4 and pi-extended [9]helicene 6 through regioselective cyclodehydrogenation in high yields, where a prefusion strategy plays a key role in preventing undesirable aryl rearrangements. The unique helical structures are unambiguously confirmed by X-ray crystal structure analysis. Compared to the parent pristine [7]helicene and [9]helicene, these novel pi-extended helicenes display significantly improved photophysical properties, with a quantum yield of 0.41 for 6. After optical resolution by chiral high-performance liquid chromatography, the chiroptical properties of enantiomers 4-P/M and 6-P/M are investigated, revealing that the small variation in helical length from [7] to [9] can cause an approximately 10-fold increase in the dissymmetry factors. The circularly polarized luminescence brightness of 6 reaches 12.6 M-1 cm(-1) as one of the highest among carbohelicenes.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Qiu, Zijie UNSPECIFIED UNSPECIFIED UNSPECIFIED Ju, Cheng-Wei UNSPECIFIED orcid.org/0000-0002-2250-8548 UNSPECIFIED Frederic, Lucas UNSPECIFIED orcid.org/0000-0002-4700-2279 UNSPECIFIED Hu, Yunbin UNSPECIFIED orcid.org/0000-0001-5346-7059 UNSPECIFIED Schollmeyer, Dieter UNSPECIFIED UNSPECIFIED UNSPECIFIED Pieters, Gregory UNSPECIFIED orcid.org/0000-0002-3924-8287 UNSPECIFIED Muellen, Klaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Narita, Akimitsu UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-596442
DOI:	10.1021/jacs.0c13197
Journal or Publication Title:	J. Am. Chem. Soc.
Volume:	143
Number:	12
Page Range:	S. 4661 - 4668
Date:	2021
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1520-5126
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CIRCULARLY-POLARIZED LUMINESCENCE; SPIN SELECTIVITY; HELICENE Multiple languages Chemistry, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59644