Solvatochromic solvent polarity measurements of alcohol solvent modifiers and correlation with cesium extraction strength

Solvatochromic solvent polarity measurements reveal that the cesium extraction strength afforded by solutions composed of calix[4]arene-bis-(tert-octylbenzocrown-6) at 0.005 M in 1,2-dichloroethane containing a variety of novel alcohol phase modifiers at 0.25 M correlates well with the hydrogen-bond donor (HBD) ability of the alcohol. The alcohols comprise a small library of derivatives of 2-(4-tert-octylphenoxy)-1-ethanol, in which the alcohol carbon atom contains a substituent of variable electron-withdrawing ability. The betaine dye 4-(2,4,6-triphenylpyridinium)-2, 6-diphenylphenoxide, also known as Dimroth-Reichardt dye #30, was used to obtain E_T(30) and E_T^N values. Alcohols containing substituents with fluorine atoms gave rise to both higher E_T^N values and higher cesium distribution values. The trend observed in HDB parallels the expected trend in alcohol acidity.