Photoinduced dynamics in hydrogen-bonded rotaxanes
Albert M. Brouwer1,** Sandro M. Fazio1, Céline
Frochot1, Francesco G. Gatti2, David A. Leigh2,***,
Jenny K.Y.Wong2, and George W. H.Wurpel1
1University of Amsterdam, Institute of Molecular Chemistry,
Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands; 2School
of Chemistry, University of Edinburgh, The King’s Buildings, West
Mains Road, Edinburgh EH9 3JJ, UK
Abstract: Two classes of rotaxanes are described in
which photoinduced processes modulate a large-amplitude motion. In the
first type, E–Z-isomerization of a fumaric diamide unit to a maleic
diamide leads to a substantial weakening of the hydrogen bonds between
the diamide and the macrocyclic ring that surrounds it. As a result,
the rate of the pirouetting motion is increased approximately by six
orders of magnitude. In the second type, intermolecular photoinduced
electron transfer is used to induce a reversible shuttling motion on
a time scale of microseconds. Medium effects on the rate of shuttling
are presented.
* Lectures presented at the XIXth IUPAC Symposium on Photochemistry,
Budapest, Hungary, 14�19 July 2002. Other presentations are published
in this issue, pp.999�1090.
** Corresponding author
***E-mail: [email protected]
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