TY - JOUR
T1 - Mechanical twisting of a guest by a photoresponsive host
AU - Muraoka, Takahiro
AU - Kinbara, Kazushi
AU - Aida, Takuzo
N1 - Funding Information:
Acknowledgements T.M. thanks the JSPS Young Scientist Fellowship. This research was partially supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research on Priority Areas ‘Life-Surveyors’ (to K.K.). We thank Y. Casta and S. Nara for cooperation in synthesis, and N. Tamai and M. Irie for discussion on photophysics.
PY - 2006/3/23
Y1 - 2006/3/23
N2 - Molecular analogues of a variety of mechanical devices such as shuttles, brakes, unidirectional rotors and tweezers have been created1-11. But these 'molecular machines' have not yet been used to mechanically manipulate a second molecule in a controlled and reversible manner. Here we show that light-induced scissor-like conformational changes of one molecule5 can give rise to mechanical twisting of a non-covalently bound guest molecule. To realize this coupling of molecular motions, we use a previously designed system5: a ferrocene moiety with an azobenzene strap, each end of which is attached to one of the two cyclopentadienyl rings of the ferrocene unit, acts as a pivot so that photoisomerization of the strap rotates the ferrocene rings relative to each other and thereby also changes the relative position of two 'pedal' moieties attached to the ferrocene rings. We translate this effect into intermolecular coupling of motion by endowing the pedals with binding sites, which allow the host system to form a stable complex with a bidentate rotor molecule. Using circular dichroism spectroscopy, we show that the photoinduced conformational changes of the host are indeed transmitted and induce mechanical twisting of the rotor molecule. This design concept, which significantly extends the successful coupling of motion beyond the intramolecular level seen in synthetic allosteric receptors12, might allow for the remote control of molecular events in larger interlocked molecular systems.
AB - Molecular analogues of a variety of mechanical devices such as shuttles, brakes, unidirectional rotors and tweezers have been created1-11. But these 'molecular machines' have not yet been used to mechanically manipulate a second molecule in a controlled and reversible manner. Here we show that light-induced scissor-like conformational changes of one molecule5 can give rise to mechanical twisting of a non-covalently bound guest molecule. To realize this coupling of molecular motions, we use a previously designed system5: a ferrocene moiety with an azobenzene strap, each end of which is attached to one of the two cyclopentadienyl rings of the ferrocene unit, acts as a pivot so that photoisomerization of the strap rotates the ferrocene rings relative to each other and thereby also changes the relative position of two 'pedal' moieties attached to the ferrocene rings. We translate this effect into intermolecular coupling of motion by endowing the pedals with binding sites, which allow the host system to form a stable complex with a bidentate rotor molecule. Using circular dichroism spectroscopy, we show that the photoinduced conformational changes of the host are indeed transmitted and induce mechanical twisting of the rotor molecule. This design concept, which significantly extends the successful coupling of motion beyond the intramolecular level seen in synthetic allosteric receptors12, might allow for the remote control of molecular events in larger interlocked molecular systems.
UR - http://www.scopus.com/inward/record.url?scp=33645303805&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33645303805&partnerID=8YFLogxK
U2 - 10.1038/nature04635
DO - 10.1038/nature04635
M3 - Article
C2 - 16554815
AN - SCOPUS:33645303805
VL - 440
SP - 512
EP - 515
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7083
ER -