Polarizability and isotope effects on dispersion interactions in water

• Published in: Communications chemistry Vol. 2; no. 1
• Main Authors: Zhan, Yi-Yang, Jiang, Qi-Chun, Ishii, Kentaro, Koide, Takuya, Kobayashi, Osamu, Kojima, Tatsuo, Takahashi, Satoshi, Tachikawa, Masanori, Uchiyama, Susumu, Hiraoka, Shuichi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.12.2019; Nature Publishing Group
• Subjects: 639/638/541/965; 639/638/563/606; 639/925/357/341; Aggregates; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Dispersion; Enthalpy; Heat measurement; Isotope effect; Parameters; Titration calorimetry
• ISSN: 2399-3669; 2399-3669
• DOI: 10.1038/s42004-019-0242-0

True understanding of dispersion interaction in solution remains elusive because of difficulty in the precise evaluation of its interaction energy. Here, the effect of substituents with different polarizability on dispersion interactions in water is discussed based on the thermodynamic parameters determined by isothermal titration calorimetry for the formation of discrete aggregates from gear-shaped amphiphiles (GSAs). The substituents with higher polarizability enthalpically more stabilize the nanocube, which is due to stronger dispersion interactions and to the hydrophobic effect. The differences in the thermodynamic parameters for the nanocubes from the GSAs with CH 3 and CD 3 groups are also discussed to lead to the conclusion that the H/D isotope effect on dispersion interactions is negligibly small, which is due to almost perfect entropy-enthalpy compensation between the two isotopomers. The thermodynamic parameters of molecules dispersed in water are influenced by the polarizability of their substituents. Here the formation of discrete aggregates from gear-shaped amphiphiles is determined by isothermal titration calorimetry, showing that substituents with higher polarizability stabilize the nanocubes enthalpically.