A photoactivated 'molecular train' for optoelectronic applications: light-stimulated translocation of a beta-cyclodextrin receptor within a stopperedazobenzone-alkyl chain supramolecular monolayer assembly on a Au-electrode
I. Willner et al., A photoactivated 'molecular train' for optoelectronic applications: light-stimulated translocation of a beta-cyclodextrin receptor within a stopperedazobenzone-alkyl chain supramolecular monolayer assembly on a Au-electrode, J ELEC CHEM, 497(1-2), 2001, pp. 172-177
A light-driven molecular shuttle is organized on a gold electrode surface.
The assembly consists of a ferrocene-functionalized beta -cyclodextrin, Fc-
beta -CD, molecule threaded on a monolayer-immobilized long alkyl component
containing a photoisomerizable azobenzene unit, and terminated with a bulk
y anthracene group. The Fc-beta -CD resides preferentially on the trans-azo
benzene component, and photoisomerization of the trans-azobenzene to the ci
s-azobenzene state causes the translocation of the Fc-beta -CD to the alkyl
-chain component of the assembly. The state of the molecular shuttle is ele
ctronically transduced by chronoamperometry. The interfacial electron trans
fer rate constants for the oxidation of the ferrocene units of Fc-beta -CD
in the respective positions are k(t) = 65 s(-1) and k(c) = 15 s(-1). The li
ght-driven translocation of Fc-beta -CD is reversible, and proceeds by the
cyclic isomerization of the azobenzene component between the trans and cis
states. (C) 2001 Elsevier Science B.V. All rights reserved.