Thermodynamics of Host–Guest Interactions between Fullerenes and a Buckycatcher
| Autor: | Matthew McGuire, Vu H. Le, Edwin A. Lewis, Michael Yanney, Andrzej Sygula |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Fullerene
Entropy Proton Magnetic Resonance Spectroscopy Enthalpy Thermodynamics Calorimetry Anisoles 010402 general chemistry Chlorobenzenes 01 natural sciences Article Mass Spectrometry chemistry.chemical_compound Materials Chemistry Hydrocarbons Chlorinated Physical and Theoretical Chemistry Ethane 010405 organic chemistry Chemistry Isothermal titration calorimetry Anisole 0104 chemical sciences Surfaces Coatings and Films Chlorobenzene Proton NMR Physical chemistry Titration Fullerenes Toluene |
| Zdroj: | The Journal of Physical Chemistry. B |
| ISSN: | 1520-5207 1520-6106 |
| Popis: | (1)H NMR and isothermal titration calorimetry (ITC) experiments were employed to obtain reliable thermodynamic data for the formation of the 1:1 inclusion complexes of fullerenes C(60) and C(70) with the buckycatcher (C(60)H(28)). NMR measurements were done in toluene-d8 and chlorobenzene-d5 at 288, 298, and 308 K, while the ITC titrations were performed in toluene, chlorobenzene, o-dichlorobenzene, anisole, and 1,1,2,2-tetrachloroethane at temperatures from 278 to 323 K. The association constants, K(a), obtained with both techniques are in very good agreement. The thermodynamic data obtained by ITC indicate that generally the host-guest association is enthalpy-driven. Interestingly, the entropy contributions are, with rare exceptions, slightly stabilizing or close to zero. Neither ΔH nor ΔS is constant over the temperature range studied, and these thermodynamic functions exhibit classical enthalpy/entropy compensation. The ΔCp values calculated from the temperature dependence of the calorimetric ΔH values are negative for the association of both fullerenes with the buckycatcher in toluene. The negative ΔCp values are consistent with some desolvation of the host-cavity and the guest in the inclusion complexes, C(60)@C(60)H(28) and C(70)@C(60)H(28). |
| Databáze: | OpenAIRE |
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