Header

UZH-Logo

Maintenance Infos

Structural, optical, and electrochemical properties of three-dimensional push–pull corannulenes


Wu, Yi-Lin; Stuparu, Mihaiela C; Boudon, Corinne; Gisselbrecht, Jean-Paul; Schweizer, W Bernd; Baldridge, Kim K; Siegel, Jay S; Diederich, François (2012). Structural, optical, and electrochemical properties of three-dimensional push–pull corannulenes. Journal of Organic Chemistry, 77(24):11014-11026.

Abstract

Electrochemically active corannulene derivatives with various numbers of electron-donating 4-(N,N-dimethylamino)phenylethynyl (1-4) or electron-withdrawing cyanobutadienyl peripheral substitutents (5-8) were prepared. The latter derivatives resulted from formal [2 + 2] cycloaddition of cyanoolefins to 1-4 followed by retro-electrocyclization. Conformational properties were examined by variable-temperature NMR and X-ray diffraction and opto-electronic properties by electronic absorption/emission spectra and electrochemical measurements; these analyses were corroborated by dispersion-corrected density functional calculations at the level of B97-D/def2-TZVPP. In CH(2)Cl(2), 1-4 exhibit intramolecular charge-transfer (ICT) absorptions at 350-550 nm and green (λ(em) ∼ 540 nm) or orange (600 nm) fluorescence with high quantum yields (56-98%) and are more readily reduced than corannulene by up to 490 mV. The variation of optical gap and redox potentials of 1-4 does not correlate with the number of substituents. Cyanobutadienyl corannulenes 5-8 show red-shifted ICT absorptions with end-absorptions approaching 800 nm. Intersubstituent interactions lead to distortions of the corannulene core and lower the molecular symmetry. NMR, X-ray, and computational studies on 5 and 8 with one cyanobutadienyl substituent suggested the formation of intermolecular corannulene dimers. Bowl-inversion barriers around ΔG(⧧) = 10-11 kcal/mol were determined for these two molecules.

Abstract

Electrochemically active corannulene derivatives with various numbers of electron-donating 4-(N,N-dimethylamino)phenylethynyl (1-4) or electron-withdrawing cyanobutadienyl peripheral substitutents (5-8) were prepared. The latter derivatives resulted from formal [2 + 2] cycloaddition of cyanoolefins to 1-4 followed by retro-electrocyclization. Conformational properties were examined by variable-temperature NMR and X-ray diffraction and opto-electronic properties by electronic absorption/emission spectra and electrochemical measurements; these analyses were corroborated by dispersion-corrected density functional calculations at the level of B97-D/def2-TZVPP. In CH(2)Cl(2), 1-4 exhibit intramolecular charge-transfer (ICT) absorptions at 350-550 nm and green (λ(em) ∼ 540 nm) or orange (600 nm) fluorescence with high quantum yields (56-98%) and are more readily reduced than corannulene by up to 490 mV. The variation of optical gap and redox potentials of 1-4 does not correlate with the number of substituents. Cyanobutadienyl corannulenes 5-8 show red-shifted ICT absorptions with end-absorptions approaching 800 nm. Intersubstituent interactions lead to distortions of the corannulene core and lower the molecular symmetry. NMR, X-ray, and computational studies on 5 and 8 with one cyanobutadienyl substituent suggested the formation of intermolecular corannulene dimers. Bowl-inversion barriers around ΔG(⧧) = 10-11 kcal/mol were determined for these two molecules.

Statistics

Citations

32 citations in Web of Science®
28 citations in Scopus®
Google Scholar™

Altmetrics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:5 December 2012
Deposited On:24 Jan 2013 15:26
Last Modified:07 Dec 2017 18:29
Publisher:American Chemical Society
ISSN:0022-3263
Publisher DOI:https://doi.org/10.1021/jo302217n
PubMed ID:23171240

Download

Full text not available from this repository.
View at publisher