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

Solvatochromic solvent polarity measurements reveal that the cesium extract ion strength afforded by solutions composed of calix[4]arene-bis-(tert-octy lbenzocrown-6) at 0.005 M in 1,2-dichloroethane containing a variety of nov el 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 c arbon atom contains a substituent of variable electron-withdrawing ability. The betaine dye 4-(2,4,6-triphenyl-pyridinium)-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 b oth higher E-T(N) values and higher cesium distribution values. The trend o bserved in HDB parallels the expected trend in alcohol acidity.