Thermodynamic and NMR Study of the Interactions of Cyclodextrins with Cyclohexane Derivatives

Rekharsky, Mikhail V.; Schwarz, Frederick P.; Tewari, Yadu B.; Goldberg, Robert N.; Tanaka, Minoru; Yamashoji, Yuko

doi:10.1021/j100066a032

Cited by 85 publications

(92 citation statements)

References 7 publications

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“…and are in agreement with literature data (differences lower than 10%), at least in the case of already studied complexes (26)(27)(28)(29)(30)(31)(32)(33).…”

Section: Insert Figure3supporting

confidence: 92%

Inclusion ability of a monothiourea-tethered bis(β-cyclodextrin)

Baudel

Landy

Surpateanu

2009

Supramolecular Chemistry

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Abstract-The tail to tail monothioureido β-cyclodextrin dimer has been prepared by reacting 6-amino-6-deoxy-β-cyclodextrin with 6-isothiocyanato-6-deoxy-β-cyclodextrin. The inclusion ability of this dimer has been evaluated by UV-visible spectroscopy for substrates of moderate molecular volumes (a wide variety of hydroxylated substrates) and compared to genuine β-cyclodextrin and randomly methylated β-cyclodextrin. The definition of a complexation index allowed the treatment of these three host molecules on a hierarchical basis : the bis-cyclodextrin appears to be more efficient (average index equal to 1.17) than the methylated (1.07) or genuine (1.00) monomers. Thus, it seems that the cooperative phenomenon may lead to a general increase of the complexation ability, and not only to an enhanced recognition of specific guests. Surprisingly, this phenomenom is even really effective for the smallest substrates of our study. Such results prompted us to illustrate, on a steric point of view, the possibility of the face to face conformation, by means of molecular modelling.

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“…and are in agreement with literature data (differences lower than 10%), at least in the case of already studied complexes (26)(27)(28)(29)(30)(31)(32)(33).…”

Section: Insert Figure3supporting

confidence: 92%

Inclusion ability of a monothiourea-tethered bis(β-cyclodextrin)

Baudel

Landy

Surpateanu

2009

Supramolecular Chemistry

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“…From calorimetric measurements performed as a function of temperature, the result ∆C p,m = (57 ± 14) J·K -1 ·mol -1 (298 to 316 K) was also obtained [33]. Additional confirmation of these results has come from use of an isothermal titration calorimeter that was used [34] in a study of the enzyme-catalyzed reaction. Here, the result was ∆H m (298.15 K) = -(14.80 ± 0.20) kJ·mol -1 .…”

Section: Sucrose Hydrolysismentioning

confidence: 95%

Standards in isothermal microcalorimetry (IUPAC Technical Report)

Wadsö

Goldberg

2001

Pure and Applied Chemistry

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322

119

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The main calorimetric principles used in isothermal microcalorimetry are briefly discussed. Different chemical calibration and test reactions are discussed, with a focus on reactions suitable for ambient conditions: reactions initiated by mixing of liquids (including titration microcalorimetry), dissolution of solid compounds and of slightly soluble gases, a photochemical process, and thermal power signals released over an extended period of time. Guidelines on the use of standardized chemical test and calibration reactions in isothermal microcalorimetry are presented. A standardized terminology in reporting characteristics of isothermal microcalorimeters is proposed.

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“…Analysis of data for the interaction of cyclohexanol with aand ,B-cyclodextrins (4) indicates that the discrepancies shown above are not limited to processes involving proteins. The results obtained in these cases are summarized in Table 4 in the same format as employed in Table 1.…”

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confidence: 99%

“…If we denote the equilibrium constant for the main reaction as [SL] Kapp = [S][L] [2] and lump all the other unspecified processes into a single constant K', then we may write the true equilibrium constant as KT = KappK'. [3] The van't Hoff equation is (a lnKT) AHcal [4] a8 (1/T)/p T' where AHIcai is the actually observed enthalpy change, including all contributions from any processes involving buffer or solution components. Although the analysis given here makes it clear that the true enthalpy change in the actually observed process is indeed AHcal, it must be realized that this quantity applies to a complex process including steps that are not indicated by the simple equilibrium S + L a SL and that are not readily identified.…”

mentioning

confidence: 99%

Significant discrepancies between van't Hoff and calorimetric enthalpies.

Naghibi

Tamura

Sturtevant

1995

Proc. Natl. Acad. Sci. U.S.A.

281

199

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In this paper we show that the usual assumption in studies of the temperature variation of equilibrium constants for equilibria of the form A + B T± AB that a plot of In K vs. 1/T (K = equilibrium constant, T = temperature in degrees kelvin) is a straight line with slope equal to -AHVH/R (AHVH = van't Hoff or apparent enthalpy, R = gas constant) is not valid in many cases. In all the cases considered here, AHVH is temperature dependent and is significantly different from the true or calorimetrically measured enthalpy, and the respective values for ACp are also significantly different.The ready availability of sensitive isothermal titration calorimeters makes possible the accurate determination of both enthalpies and equilibrium constants on the same sample for a wide variety of processes. In view of this situation, detailed comparisons of calorimetrically determined enthalpies of reaction (AHcal) and enthalpies derived from equilibrium constants by means of the van't Hoff equation (AHVH) highlighted by the fact that ACp as evaluated from the equilibrium constants is -0.287 kcal-K-1 mol-1, which is 45% larger in magnitude than that derived from the observed enthalpies-namely, -0.198 kcal K-1 mol-'.To check on the possibility that a significant contribution to AHcal might arise from an exchange of protons between the protein and the buffer, the two reactants were mixed in the absence of buffer at pH 5.5 at -25°C. The results indicated that the reaction leads to the liberation of 0.025 ± 0.05 mol of HI per mol of protein, corresponding in acetate buffer to -0.05 kcal mol-1 due to buffer protonation and probably a similar, perhaps compensating, contribution due to deprotonation of the protein.

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Thermodynamic and NMR Study of the Interactions of Cyclodextrins with Cyclohexane Derivatives

Cited by 85 publications

References 7 publications

Inclusion ability of a monothiourea-tethered bis(β-cyclodextrin)

Inclusion ability of a monothiourea-tethered bis(β-cyclodextrin)

Standards in isothermal microcalorimetry (IUPAC Technical Report)

Significant discrepancies between van't Hoff and calorimetric enthalpies.

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