Critical Reflections on the Hydrophobic Effect, its Origins, and Manifestation: Water Structure, Chemical Reactivity, Micelles, and Gels

Year 2017, Volume: 4 Issue: 3, 899 - 914, 11.09.2017

Sosale Chandrasekhar

https://doi.org/10.18596/jotcsa.328983

Cited By: 1

Abstract

The origins of the Hydrophobic Effect (HE), its biological significance and its experimental basis are critically addressed in this brief review. It is argued that the mechanistic work reported on the HE in recent decades needs to be reassessed, as its conclusions are apparently debatable. Essentially, it is highly inaccurate to view the HE as a repulsive interaction, which is rather an attractive one. It appears inevitable that the HE is indeed a manifestation of the perturbation of the structure of water upon the introduction of hydrocarbon molecules into its interior. There appears to be no other satisfactory explanation for the formation of micellar aggregates and the existence of the critical micelle concentration. Also, the practical significance of the HE on the reactivity of organic compounds (e.g. cycloadditions) is severely limited by their minuscule solubility levels, itself a manifestation of the HE! Other related phenomena apparently include the formation of gels and the occurrence of certain esterification reactions in water, which are briefly reviewed from a conceptual viewpoint. 

Keywords

Anti-hydrophobic, chaotropic, Diels Alder, denaturation, gels

References

• 1. Biedermann F, Schneider H-J. Experimental Binding Energies in Supramolecular Complexes. Chem. Rev. 2016;116:5216−5300.
• 2. Silverstein TP. The real reason why oil and water don’t mix. J. Chem. Educ. 1998;75:116-8.
• 3. Wenneström H. Interfacial interactions. In: Baszkin A, Norde W, editors. Physical chemistry of biological interfaces. New York/Basel: Marcell Dekker, Inc.; 2000. 85 p.
• 4. Reichardt C, Welton T. Solvents and solvent effects in organic chemistry 4th ed. Weinheim: Wiley-VCH; 2011. 31 p.
• 5. Breslow R. The hydrophobic effect in reaction mechanism studies and in catalysis by artificial enzymes. J. Phys. Org. Chem. 2006;19:813–22.
• 6. Ball P. Water – an enduring mystery. Nature 2008;452:291-2.
• 7. Ball P. Water as an active constituent in cell biology. Chem. Rev. 2008;108:74108.
• 8. Shultz MJ, Vu TH, Meyer B, Bisson P. Water: a responsive small molecule. Acc. Chem. Res. 2012;45:15-22.
• 9. Nordlund K, Ashkenazy Y, Averback RS, Granato AV. Strings and interstitials in liquids, glasses and crystals. Europhys. Lett. 2005;71:625-31. (DOI: 10.1209/epl/i2005-10132-1)
• 10. Breslow, R. Determining the geometries of transition states by use of antihydrophobic additives in water. Acc. Chem. Res. 2004;37:471-8.
• 11. Sangwan, N K, Schneider, H-J. The kinetic effects of water and cyclodextrins on Diels-Alder reactions. Host-guest chemistry. Part 18. J. Chem. Soc. Perkin Trans 2. 1989;1223-7.
• 12. Shrinidhi A. Organic transformations in water: synthetic and mechanistic studies towards green methodologies. PhD Thesis, Indian Institute of Science, Bangalore (India); 2014.
• 13. Otto S, Engberts JBFN. Diels-Alder reactions in water. Pure. Appl. Chem. 2000;72:1365–72.
• 14. Grieco PA, Kaufman MD. Construction of carbocyclic arrays containing nitrogen via intramolecular imino Diels-Alder reactions in polar media. A comparative study: 5.0 M lithium perchlorate-diethyl ether versus water. J. Org. Chem. 1999;64:6041-8.
• 15. Atkins P. Physical chemistry 5th ed. Oxford: Oxford University Press; 1995. C19 p.
• 16. Rusanov AI. The wonderful world of micelles. Colloid J. 2014;76:121–6.
• 17. La Sorella G, Strukul G, Scarso A. Recent advances in catalysis in micellar media. Green Chem. 2015;17:644–83.
• 18. Terech P, Weiss RG. Low molecular mass gelators of organic liquids and the properties of their gels. Chem. Rev. 1997;97:3133-59.
• 19. Zhang M, Weiss RG. Self-assembled networks and molecular gels derived from long-chain, naturally occurring fatty acids. J. Braz. Chem. Soc. 2016;27:239-55.
• 20. Igarashi T, Yagyu D, Naito T, Okumura Y, Nakajo T, Mori Y, Kobayashi S. Appl. Catal. B. 2012;119–120:304–7.