New Method for the Characterization of Solutes and Solvent Phases Using Solvatochromic Parameters.

摘要

The solvatochromic principle was first introduced by Kamlet and Tait in 1977 when a paper was published on the determination of the Beta1 scale for hydrogen bond basicity using the solvatochromic comparison method. Solvatochromic literally means solvent color, and is derived from the effect the solvent has on the color of an indicator used in the parameter determination. The principle is based on the fact that the wavelength of maximum absorption of specific indicators in the UV and visible region is measurably shifted when the indicators are dissolved in different solvents. The extent of the wavelength shift is determined by the degree and the type of solvent-solute indicator interactions taking place, especially polar/polarizable and hydrogen bonding interactions. The solvatochromic comparison principle measures the polarity or dipolarity of a solvent by its bathochromic shift relative to cyclohexane of the transition of the greatest wavelength of non hydrogen bond donor indicators. Examples of suitable indicators are 4-nitroanisole or 4-(dimethylamino)benzophenone.