Res. Chem. Intermed.
, Vol. 31, No. 9, pp. 833–844 (2005)
Also available online - www.vsppub.com
Photoinduced electron transfer between
TAO LIU, YONG-GANG WEI, QI-HUA WU and QING-XIANG GUO
Department of Chemistry, University of Science and Technology of China, Hefei 230026, P. R. China
Received 5 December 2004; accepted 28 January 2005
Abstract—A series of adamantanamine-(OCH
-phenothiazine (n = 0, 1, 2, 3) electron donors
was synthesized. Photoinduced electron transfer was observed in the supramolecular complex of
the phenothiazine derivatives with p-nitrobenzoyl-β-cyclodextrin (NBCD) through binding of the
adamantyl group by the NBCD cavity, which is stabilized clearly via hydrophobic interactions in
aqueous solution. Detailed Stern–Volmer constants were measured and they were partitioned into
dynamic Stern–Volmer quenching constants and static binding constants. The results revealed an
efﬁcient electron transfer process inside the supramolecular systems compared to that controlled by
diffusion. This observation also indicates that the chain length will inﬂuence the electron transfer
efﬁciency of a supramolecular donor–acceptor system.
Keywords: Photoinduced electron transfer; host–guest complex; β-cyclodextrin; phenothiazine deriv-
atives; ﬂuorescence quenching.
Photoinduced electron transfer plays a central role in photosynthesis and, hence,
has intrigued scientists for many years to look into its detailed mechanism and to
investigate the prospects of molecular materials in photovoltaic energy conversion
[1, 2]. Studies on covalently linked electron donor–acceptor dyads [3–5] have
revealed interesting dependency of the electron transfer rate on the donor–acceptor
distance, the donor–acceptor orientation, the nature of the spacer and the nature
of the solvent. However, these systems cannot fully mimic biological electron
transfer , because in biological systems the donor and acceptor are held together
by proteins without any covalent linkage.
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