Molecular recognition of organic anions by a water-soluble calix[4]arene: Evidence for enthalpy–entropy compensation

Bonaccorso, Carmela; Ciadamidaro, Antonio; Zito, Valeria; Sgarlata, Carmelo; Sciotto, Domenico; Arena, Giuseppe

doi:10.1016/j.tca.2011.12.014

Cited by 22 publications

(14 citation statements)

References 59 publications

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“…Such exothermic external association events are also entropically disfavored since only partial desolvation of the guests, which progressively bind an increasingly crowded host exterior, is required. 50,51 Results in Tables 2 and 3 unambiguously show that the solution thermodynamics of multiple and competing host− guest events can be successfully deconvoluted through the multiobservables curve-fitting procedure described.…”

Section: Figurementioning

confidence: 79%

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Sgarlata

Raymond

2016

Anal. Chem.

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The entropic and enthalpic driving forces for encapsulation versus sequential exterior guest binding to the [Ga4L6](12-) supramolecular host in solution are very different, which significantly complicates the determination of these thermodynamic parameters. The simultaneous use of complementary techniques, such as NMR, UV-vis, and isothermal titration calorimetry, enables the disentanglement of such multiple host-guest interactions. Indeed, data collected by each technique measure different components of the host-guest equilibria and together provide a complete picture of the solution thermodynamics. Unfortunately, commercially available programs do not allow for global analysis of different physical observables. We thus resorted to a novel procedure for the simultaneous refinement of multiple parameters (ΔG°, ΔH°, and ΔS°) by treating different observables through a weighted nonlinear least-squares analysis of a constrained model. The refinement procedure is discussed for the multiple binding of the Et4N(+) guest, but it is broadly applicable to the deconvolution of other intricate host-guest equilibria.

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Section: Figurementioning

confidence: 79%

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Sgarlata

Raymond

2016

Anal. Chem.

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“…Data given in Table 2and Figure 3clearly show that the logK valuesf or the exterior ion-association equilibria increasew ith the size of the ammonium guests;h owever,t hese processes are driven by differenta nd often opposing enthalpic and entropic contributions, [44] and thus splitting the Gibbs energy term into the DH8 and DS8 components reveals significant and individualf eatures and differences that are not visible in the DG8 term. [43,[45][46][47] Exterior binding of the smaller Me 4 N + ,E t 4 N + , and 5-Spiro + guests (whicha re less hydrophobic) is mainly attributed to enthalpically favorable electrostatic and cation-p interactions between the highlya nionic and aromatic exterior of the host and the positively charged ammonium guests. Such attractive forces have been previously observed in solidstate [20] and diffusion NMR studies.…”

Section: Guestmentioning

confidence: 99%

Different and Often Opposing Forces Drive the Encapsulation and Multiple Exterior Binding of Charged Guests to a M₄L₆ Supramolecular Vessel in Water

Sgarlata

Mugridge

Pluth

et al. 2017

Chemistry A European J

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The supramolecular assembly [Ga L ] acts as a nanoscale flask to mediate the reactivity of encapsulated reactive guests and also functions as a catalyst to carry out enzyme-like chemical transformations. The guest binding to the interior cavity and exterior of this host is difficult to untangle because multiple equilibria occur in solution, and only when refining simultaneously data obtained from different techniques, such as NMR, UV/Vis, and calorimetry, can the accurate solution thermodynamics of these host-guest systems be determined. This study reports the driving forces for the inclusion and stepwise exterior guest binding of different aliphatic quaternary ammonium guests to the [Ga L ] assembly. Encapsulation into the host cavity was found to be an entropy-driven process, whereas exterior ion association is driven either by enthalpically favorable attractive forces or by the entropy gain due to desolvation, depending on guest size and character. The analysis of the energetics of reaction may help predicting and understanding the intimate role and contribution of the transition state in those rate-accelerated reactions involving this supramolecular assembly as an enzyme-like molecular flask.

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“…The factors controlling the inclusion binding events between anionic or cationic cyclophanes with guest molecules of opposite polarity in water have similarly been extensively examined in the literature 6. In these studies, water was reported to agonistically contribute to the binding mostly through classical hydrophobic effects, i.e.…”

Section: Introductionmentioning

confidence: 99%

Wetting the lock and key enthalpically favours polyelectrolyte binding

et al. 2019

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Molecular recognition of organic anions by a water-soluble calix[4]arene: Evidence for enthalpy–entropy compensation

Cited by 22 publications

References 59 publications

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Different and Often Opposing Forces Drive the Encapsulation and Multiple Exterior Binding of Charged Guests to a M₄L₆ Supramolecular Vessel in Water

Wetting the lock and key enthalpically favours polyelectrolyte binding

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Molecular recognition of organic anions by a water-soluble calix[4]arene: Evidence for enthalpy–entropy compensation

Cited by 22 publications

References 59 publications

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Untangling the Diverse Interior and Multiple Exterior Guest Interactions of a Supramolecular Host by the Simultaneous Analysis of Complementary Observables

Different and Often Opposing Forces Drive the Encapsulation and Multiple Exterior Binding of Charged Guests to a M4L6 Supramolecular Vessel in Water

Wetting the lock and key enthalpically favours polyelectrolyte binding

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Different and Often Opposing Forces Drive the Encapsulation and Multiple Exterior Binding of Charged Guests to a M₄L₆ Supramolecular Vessel in Water