A Molecular Torsion Balance Study: A Nearby Anionic Group Exerts Little Influence on Hydrophobic Interactions between Nonpolar Surfaces

Abstract

Polar groups have a solvent ordering effect on water and therefore may affect hydrophobic binding energies for nearby lipophilic surfaces. This would mean that determinations of excess surface free energy association energies require consideration of nearby polar functional groups. This paper reports results of a study to measure this possible effect. It was concluded from the models used here that an anionic polar group nearby a hydrophobic surface has little or no effect on the magnitude of hydrophobic association.

Mono-endo-6-N,N-diethylcarbamoyl and bis-endo,endo-6,12-N,N-diethylcarbamoyl derivatives of Tröger’s base. Synthesis and exo-endo isomerization study

“…Additionally, we describe the reactions of a weak base (MeONa) and HCl with both proton and deuterium quench of TB and the mono-carbamoyl derivative 7. Of interest is the fact that isomerization of TB under acidic conditions occurs, as predicted from racemization studies, 13 via methylene bridge opening-reclosure and therefore, as expected, in the case of both 1 and derivative 7, does not lead to proton-deuterium exchange.…”

“…Column chromatography was performed on silica gel (Davisil 35-70 µm). 1 H and 13 C NMR spectra were recorded on a 400 NMR spectrometer. Chemical shifts (δ) are reported relative to a shift-scale calibrated with residual NMR solvent peak CDCl 3 (7.26 ppm for 1 H NMR and 77.23 for 13 C NMR).…”

“…These include, for example, a pH sensitive turn-on fluorescent probe, 2,3 a protein detector, 4 gas separation membranes, [5][6][7] CO 2 absorbents, [8][9][10][11] a dopant for liquid crystals in display screens, 12 and a chemical torsion balance. [13][14][15][16][17] Both TB itself and certain derivatives have elicited interest as ligands in catalysis. 18,19 Recent reviews detail the numerous possible applications of this important molecule and its congeners.…”