ORGANIC
LETTERS
2007
Vol. 9, No. 20
3929-3932
Photoisomerization of Spiropyran for
Driving a Molecular Shuttle
Weidong Zhou, Dugang Chen, Junbo Li, Jialiang Xu, Jing Lv, Huibiao Liu, and
Yuliang Li*
National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids,
Institute of Chemistry, Chinese Academy of Sciences, Beiijng 100080, P. R. China
Received July 5, 2007
ABSTRACT
A novel light-powered molecular shuttle was synthesized which can switch the movement of a macrocycle between two distinct stations
s
dipeptide and zwitterionic ME by exploiting the photoisomerization of spiropyran. The macrocycle resides selectively in the dipeptide station
s
in the SP form and moves to the ME station under the irradiation of UV light. This movement process of the macrocycle is accompanied by
reversible absorptive output signals which can be detected by the naked eye.
With the great development of biotechnology and biochem-
istry in the past decades, scientists have been encouraged to
construct molecular motors for simulating natural motors.1
Considering the extreme complexity of the natural motors,
what can be done, at present, is to construct simple prototypes
of artificial molecular motors, consisting of a few compo-
nents capable of moving in a controllable way, and to
investigate the associated problems. Mechanically interlocked
molecules, such as catenanes and rotaxanes, have become
typical candidates in the design of artificial molecular
machines because they consist of a few noncovalently
interacting components with the ability to move reversibly
between two or more stations on application of external
stimuli.2-5 Various stimuli have been employed to induce
such switching, including metal binding,2 configurational
changes,3 and alteration of the oxidation state4 or protonation
level5 of the molecule. Among them, the chemical fuel-
powered artificial motors described so far are not autonomous
because, after the mechanical movement induced by a
chemical input, they need another, opposite, chemical input
to reset, which also implies generation of waste products.
Light and electricity powered artificial motors are now under
prominent consideration in the construction of molecular
devices due to the convenience of energy input and the
absence of waste products.6
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10.1021/ol7015862 CCC: $37.00
© 2007 American Chemical Society
Published on Web 09/06/2007