Spectroscopic and Electrochemical Properties of Catenanes Containing the 2,7-Diazapyrenium Unit

Vincenzo Balzani*, Alberto Credi, Steven J. Langford, Anna Prodi, J. Fraser Stoddart, Margherita Venturi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The spectroscopic and electrochemical properties of two cyclophanes containing one and, respectively, two 2,7-diazapyrenium electron-acceptor units, and of their [2]catenanes with macrocycles containing two dioxybenzene or dioxynaphthalene electron-donor units have been investigated. The absorption spectra of the catenanes show weak and broad bands in the visible region, assigned to charge-transfer (CT) interactions. The very strong and structured fluorescence (298K) and the structured fluorescence and phosphorescence (77K) of the diazapyrenium unit are maintained in the two cyclophanes, but they are no longer present in the [2]catenanes, presumably because of a quenching process caused by the lower energy CT excited states. Each diazapyrenium unit undergoes two distinct reduction processes - only the first one of which is fully reversible - that are hardly affected at all when the diazapyrenium units are incorporated in a cyclophane. In the [2]catenanes, the CT interaction displaces the reduction processes of the diazapyrenium units toward more negative potentials. The results obtained for the diazapyrenium and previously investigated 4,4′-bipyridinium salts, selected cyclophane derivatives, and some [2]catenanes obtained by interlocking the cyclophanes with macrocycles containing two dioxyaromatic electron-donor units are compared and discussed.

Original languageEnglish (US)
Pages (from-to)303-311
Number of pages9
JournalSupramolecular Chemistry
Volume13
Issue number2
DOIs
StatePublished - 2001

Keywords

  • Catenanes
  • Charge-transfer
  • Electrochemistry
  • Photochemistry

ASJC Scopus subject areas

  • Chemistry(all)

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