Synthesis of tetra-oligothiophene-substituted calix[4]arenes and their optical and electrochemical properties

Xiao Hua Sun, Chi Shing Chan, Man Shing Wong, Wai Yeung Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)

Abstract

A facile and efficient approach to synthesize tetra-oligothiophene-substituted calix[4]arenes, Calix-OT(n) with n up to 4 using palladium-catalyzed Kumada coupling of thienylmagnesium bromide and bromo-substituted calix[4]arene as a key step has been developed. The close proximity of the tetra-oligothiophenes constructed within a calix[4]arene assembly leads to peak/band broadening, spectral shifting, i.e., blue-shift in absorption and red-shift in emission spectra as well as fluorescence quantum yield quenching as compared to those of monomers indicating the existence of chromophoric interaction. We have shown that the intra-chromophoric interaction lowers the first ionization (raises HOMO level) of an oligothiophene within an assembly. It also stabilizes the formation of a radical cation, which results in an increase in the subsequent voltammetric oxidation and the occurrence of the higher oxidation states as compared to the monomeric counterparts. This assembly can serve as a model for the investigation of molecular interaction of π-conjugated systems.
Original languageEnglish
Pages (from-to)7846-7853
Number of pages8
JournalTetrahedron
Volume62
Issue number33
DOIs
Publication statusPublished - 14 Aug 2006
Externally publishedYes

Keywords

  • Intra-chromophoric interaction
  • Kumada coupling
  • Tetra-oligothiophene-substituted calix[4]arene

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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