Journal of the American Chemical Society
Article
WP6 solution (0.1−2 mM for each host) in a 40 μL syringe was
injected into the reaction cell (200 μL) charged with G′ or G solution
(0.01−0.2 mM) in the same solution.
A control experiment to determine the heat of dilution was carried
out with each run by performing the same number of injections with
the same concentration of host compound as used in the titration
experiments into a deionized water solution without the guest
compound. The dilution enthalpies determined in control experiments
were subtracted from the enthalpies measured in the titration
experiments to obtain the net reaction heat.
ACKNOWLEDGMENTS
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This work was supported by the National Basic Research
Program of China (2013CB922101, 2011CB808600), National
Natural Science Foundation of China (No. 91227106,
21202083, 21302092), and Jiangsu Provincial Natural Science
Foundation of China (BK2011551). We are grateful to Dr.
Dongmei Zhang and Dr. Jiahuang Li from Nanjing University
for their kind help in the ITC experiments.
ORIGIN software, which was used to simultaneously compute the
equilibrium constant (Ka) and standard molar enthalpy of reaction
(ΔH°) from a single titration curve, gave a standard deviation based
on the scatter of the data points in the titration curve. The net reaction
heat in each run was calculated by the “one set of binding sites” model
unless noted otherwise. Additionally, the first point was removed from
the titration curve, acknowledging that the concentration of guest in
the cell far exceeded the concentration of the host. The knowledge of
the binding constant (Ka) and molar reaction enthalpy (ΔH°) enabled
calculation of entropy changes (ΔS°), according to the equation where
R is the gas constant and T is the absolute temperature. A typical
titration curve and the fitted results for the complexation of WP6 with
G or G′ are shown in Figure S5 and S6 (Supporting Information),
respectively.
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ASSOCIATED CONTENT
* Supporting Information
Experimental procedures and supporting figures. This material
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AUTHOR INFORMATION
Corresponding Author
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Author Contributions
∥Yu Cao and Xiao-Yu Hu contributed equally.
̆
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Org. Chem. 2004, 835. (e) Smisterova, J.; Wagenaar, A.; Stuart, M. C.
A.; Polushkin, E.; ten Brinke, G.; Hulst, R.; Engberts, J. B. F. N.;
Notes
The authors declare no competing financial interest.
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dx.doi.org/10.1021/ja505344t | J. Am. Chem. Soc. 2014, 136, 10762−10769