Functionalized thiophene-based [7]helicene

Chirooptical properties versus electron delocalization

Andrzej Rajca, Maren Pink, Shuzhang Xiao, Makoto Miyasaka, Suchada Rajca, Kausik Das, Kristin Plessel

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

(Chemical Equation Presented) The functionalized, enantiomerically pure [7]helicene 1 derived from bis(benzodithiophene) functionalized with four heptyl groups is prepared from 1,8-dibromo-4,5-diheptylbenzo[1,2-b:4,3-b′] dithiophene building block 2. Such [7]helicene structure, functionalized with bromines at the terminal positions of the helicene inner rim and multiple solubilizing alkyl groups, is an attractive building block for long [n]helicenes and oligo[7]helicenes. Chirooptical properties and the degree of electron delocalization are determined and compared to those of analogous carbon-sulfur [7]helicene and [7]helicenes derived from benzodithiophene to provide a correlation between chirooptical properties and the degree of electron delocalization. [7]Helicene 1 possesses amoderately increased electron delocalization, but its chirooptical properties are similar to those for analogous [7]helicenes with relatively lower electron delocalization, indicating that chirooptical properties are not significantly affected by electron delocalization for this series of [7]helicenes. Molecular structures of racemic [7]helicene 1 and its benzodithiophene building block 2 are confirmed by single-crystal X-ray analysis. Crystals of 2 are chiral and adopt the shape of long, flexible, flat needles that can be readily bent.

Original languageEnglish (US)
Pages (from-to)7504-7513
Number of pages10
JournalJournal of Organic Chemistry
Volume74
Issue number19
DOIs
StatePublished - Oct 2 2009

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Thiophenes
Electrons
Bromine
X ray analysis
Sulfur
Needles
Molecular structure
Carbon
helicenes
Single crystals
Crystals

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Functionalized thiophene-based [7]helicene : Chirooptical properties versus electron delocalization. / Rajca, Andrzej; Pink, Maren; Xiao, Shuzhang; Miyasaka, Makoto; Rajca, Suchada; Das, Kausik; Plessel, Kristin.

In: Journal of Organic Chemistry, Vol. 74, No. 19, 02.10.2009, p. 7504-7513.

Research output: Contribution to journalArticle

Rajca, Andrzej ; Pink, Maren ; Xiao, Shuzhang ; Miyasaka, Makoto ; Rajca, Suchada ; Das, Kausik ; Plessel, Kristin. / Functionalized thiophene-based [7]helicene : Chirooptical properties versus electron delocalization. In: Journal of Organic Chemistry. 2009 ; Vol. 74, No. 19. pp. 7504-7513.
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