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Title:
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Working mechanism for a redox switchable molecular machine based on cyclodextrin : a free energy profile approach.
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Author:
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Zhang, Qiong.; Tu, Yaoquan.; Tian, He.; Zhao, Yanli.; Stoddart, J. Fraser.; Agren, Hans.
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Copyright year:
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2010 |
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Abstract:
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This paper reports the working mechanism for a redox-responsive bistable [2]rotaxane incorporating an
R-cyclodextrin (R-CD) ring (J. Am. Chem. Soc. 2008, 130, 11294-11296), based on free energy profiles
obtained from all-atom molecular dynamics simulations. Employing an umbrella sampling technique, the
free energy profiles (potential of mean force, PMF) were calculated for the shuttling motion of the R-CD ring
between a tetrathiafulvalene (TTF) recognition site and a triazole (TZ) unit on the dumbbell of the rotaxane
for three oxidation states (0, +1, +2) of the TTF unit. These calculated free energy profiles verified the
experimentally observed binding preference for each state. Analysis of the free energy components reveals
that, for these R-CD-based rotaxanes with charged TTF units, the real driving force for the shuttling in the
oxidized states is actually the interactions between water and the rotaxane components, which overwhelms
the attractive interactions between the R-CD ring and the charged dumbbell. In this work, we put forward a
feasible approach to correctly describe the complexation behavior of CD with charged species, that is, free
energy profiles obtained from all-atom molecular dynamics simulation. |
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Subject:
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DRNTU::Engineering::Materials::Microelectronics and semiconductor materials::Nanoelectronics and interconnects . |
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Type:
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Journal Article |
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Series/ Journal Title:
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The Journal of physical chemistry B |
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School:
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School of Physical and Mathematical Sciences |
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Rights:
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© 2010 American Chemical Society |
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Version:
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None of the above |
