Biomedical Engineering Reference
In-Depth Information
Fig. 7
Structural formula of the rotaxane
9
6+
(
top
) and schematic representation of its operation as
an autonomous “four-stroke” linear nanomotor powered by light (
bottom
)
transfer process from A
1
−
(still encircled by R) to the oxidized photoactive unit,
P
+
(process 5).
(c)
Electronic reset
: A back electron transfer process from the “free” A
1
−
station to
P
+
(process 6) restores the electron acceptor power to the A
1
station.
(d)
Nuclear reset
: As a consequence of the electronic reset, back movement of the
ring by Brownian motion from A
2
to A
1
takes place (process 7).
The crucial point for such a mechanism is indeed the favorable competition
between ring displacement (process 4) and back electron transfer (process 5).
The rate constants of the relevant electron transfer processes were measured by
