Preorientation of olefins toward a single photodimer: Cucurbituril-mediated photodimerization of protonated azastilbenes in water

Murthy V.S.N. Maddipatla, Lakshmi S. Kaanumalle, Arunkumar Natarajan, Mahesh Pattabiraman, V. Ramamurthy

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88 Scopus citations

Abstract

With the view to establishing the generality of cucurbit[8]uril as a template, the photodimerization of hydrochloride salts of eight azastilbenes has been investigated in an aqueous medium. Whereas in solution upon excitation all of these olefins yield products of geometric isomerization, cyclization, and hydration, in the presence of cucurbit[8]uril the predominant product is that of dimerization. Such a change in product distribution is attributed to the localization of the olefins by the host cucurbit[8]uril. Most importantly, instead of a mixture of dimers, predominantly a single dimer was obtained in each case. The nature of the dimer that was formed could be rationalized on the basis of the principles of "best fit" and "minimization of electrostatic repulsion". The superior ability of cucurbit[8]uril compared to micelles to act as a templating agent is attributed to its ability to provide a reaction cavity that is tight and time-independent.

Original languageEnglish (US)
Pages (from-to)7545-7554
Number of pages10
JournalLangmuir
Volume23
Issue number14
DOIs
StatePublished - Jul 3 2007

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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