Solvophobic effects and relationships between the Gibbs energy and enthalpy for the solvation process

Sedov, Igor A.; Stolov, Mikhail

doi:10.1002/poc.1859

Cited by 44 publications

(27 citation statements)

References 26 publications

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“…In aqueous solution, such an association is facilitated by hydrophobic driving forces. It is conceivable that analogous solvent forces [16] (solvophobic) operate in methanol, especially when the association process involves structures with a large surface area, whereas cooperative van der Waals interactions would favour the stacking of sheets. The accompanying expulsion of solvent molecules should contribute favourably to the entropy of association.…”

Section: Unusual Behaviour Of Gly6 and Gly13 Nh Resonancesmentioning

confidence: 99%

A Designed Three‐Stranded β‐Sheet in an α/β Hybrid Peptide

Sonti

Gopi

Umashankara

et al. 2013

Chemistry A European J

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The incorporation of β-amino acid residues into the antiparallel β-strand segments of a multi-stranded β-sheet peptide is demonstrated for a 19-residue peptide, Boc-LV(β)FV(D)PGL(β)FVVL(D)PGLVL(β)FVV-OMe (BBH19). Two centrally positioned (D)Pro-Gly segments facilitate formation of a stable three-stranded β-sheet, in which β-phenylalanine ((β)Phe) residues occur at facing positions 3, 8 and 17. Structure determination in methanol solution is accomplished by using NMR-derived restraints obtained from NOEs, temperature dependence of amide NH chemical shifts, rates of H/D exchange of amide protons and vicinal coupling constants. The data are consistent with a conformationally well-defined three-stranded β-sheet structure in solution. Cross-strand interactions between (β)Phe3/(β)Phe17 and (β)Phe3/Val15 residues define orientations of these side-chains. The observation of close contact distances between the side-chains on the N- and C-terminal strands of the three-stranded β-sheet provides strong support for the designed structure. Evidence is presented for multiple side-chain conformations from an analysis of NOE data. An unusual observation of the disappearance of the Gly NH resonances upon prolonged storage in methanol is rationalised on the basis of a slow aggregation step, resulting in stacking of three-stranded β-sheet structures, which in turn influences the conformational interconversion between type I' and type II' β-turns at the two (D)Pro-Gly segments. Experimental evidence for these processes is presented. The decapeptide fragment Boc-LV(β)FV(D)PGL(β)FVV-OMe (BBH10), which has been previously characterized as a type I' β-turn nucleated hairpin, is shown to favour a type II' β-turn conformation in solution, supporting the occurrence of conformational interconversion at the turn segments in these hairpin and sheet structures.

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Section: Unusual Behaviour Of Gly6 and Gly13 Nh Resonancesmentioning

confidence: 99%

A Designed Three‐Stranded β‐Sheet in an α/β Hybrid Peptide

Sonti

Gopi

Umashankara

et al. 2013

Chemistry A European J

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“…To the best of our knowledge, there are no published studies regarding the inclusion of lipophilic organic molecules within cyclodextrins in structured organic solvents. Taking into account that strongly hydrogen‐bonded solvents (e.g., formamide (FMD) and ethylene glycol) have been studied in the context of the solvophobic effect, the efficient hosting of nonpolar species in such media can be anticipated. The corresponding studies could therefore offer valuable information regarding the origin of the stability of cyclodextrin inclusion complexes.…”

Section: Introductionmentioning

confidence: 99%

Solvophobically Driven Complexation of Adamantyl Mannoside with β‐Cyclodextrin in Water and Structured Organic Solvents

Leko

Hanževački

Brkljača

et al. 2020

Chemistry A European J

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The effects of solventa nd temperature on the complexation of adamantyl mannoside with b-cyclodextrin and 6-O-monotosyl-6-deoxy-b-cyclodextrinw ere explored experimentally and by means of molecular dynamics simulations. Efficientb inding was observedo nly in hydrogenbondeds olvents, which indicated solvophobically driven complexation. Thes tability of the inclusion complex was considerably higheri na queous media. Ap ronouncedt emperature dependence of D r H * and D r S * ,r esulting in perfect enthalpy-entropy compensation, was observedi nw ater.The complexation thermodynamicsw as in line with classical rationale for the hydrophobic effect at lower temperatures and the nonclassical explanation at higher temperatures. This finding linked cyclodextrinc omplexation thermodynam-ics with insights regarding the effecto ft emperature on the hydration water structure. The complexation enthalpies and entropies were weakly dependent on temperature in organic media. The signs of D r H * and D r S * were in accordance with the nonclassicalh ydrophobic (solvophobic) effect.T he structures of the optimized product corresponded to those deduceds pectroscopically,a nd the calculated and experimentally obtained values of D r G * were in very good agreement. This investigation clearly demonstrated that solvophobically drivenf ormation of cyclodextrin complexes could be anticipated in structured solvents in general. However,u nlike in water, adamantane and the host cavity behaved solely as structure breakers in the organic media explored so far.[a] SE = standard error of the mean (N = 3o r4). Figure 6. Relative a) conformation and b) solvation contribution to the hydration enthalpies of reactantsand the complex over the studied temperature range.

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“…Although these forces are quite weak (~4 kJ/mol), they can effectively generate the adsorption of AMNPs to the surface of n ‐decane oil drops. In terms of the solvophobic effect, a more favorable hydrophobic association can be achieved in water, which has a high cohesive energy density (approximately 550 cal/cm 3 ) . Consequently, AMNPs grafted with associative polymer brushes having an appropriate amount of C18 alkyl chains have a strong tendency toward stabilization of pickering emulsion drops.…”

Section: Resultsmentioning

confidence: 99%

Associative Polymer‐grafted Magnetic Nanoparticles for Stabilization and Recovery of Pickering Emulsions

Choi

Son

Park

et al. 2018

Bulletin Korean Chem Soc

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Herein we introduce a smart Pickering emulsion fluid system, in which associative magnetic nanoparticles (AMNPs) are assembled at the oil-water interface to give magnetic-responsiveness to the emulsion drops. AMNPs are synthesized by grafting hydrophobically modified water-soluble poly(2-methacryloyloxyethylphosphorylcholine-co-stearyl methacrylate) onto silica-coated Fe 2 O 3 nanoparticles (NPs) using surface-mediated living radical polymerization. Use of this synthetic protocol allows us to obtain AMNPs with a hydrophobically associative polymer layer with thickness of a few nanometers. We reveal that the AMNPs not only adsorb effectively on the oil-water interface due to the hydrophobic interaction, but also structurally stabilize the pickering emulsion due to the induction of electrostatic repulsion between droplets. Interestingly, we observe that the flow behavior of AMNPs-stabilized pickering emulsions is kinetically controllable in response to the applied magnetic field, thus demonstrating their practical applicability for magnetic-responsive enhanced oil recovery.

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Solvophobic effects and relationships between the Gibbs energy and enthalpy for the solvation process

Cited by 44 publications

References 26 publications

A Designed Three‐Stranded β‐Sheet in an α/β Hybrid Peptide

A Designed Three‐Stranded β‐Sheet in an α/β Hybrid Peptide

Solvophobically Driven Complexation of Adamantyl Mannoside with β‐Cyclodextrin in Water and Structured Organic Solvents

Associative Polymer‐grafted Magnetic Nanoparticles for Stabilization and Recovery of Pickering Emulsions

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