PYRIDINIUM N-PHENOXIDE BETAINES AND THEIR APPLICATION TO THE DETERMINATION OF SOLVENT POLARITIES - XXIV - SYNTHESES AND UV-VIS SPECTROSCOPIC PROPERTIES OF NEW LIPOPHILIC TERT-BUTYL- AND 1-ADAMANTYL SUBSTITUTED, NEGATIVELY SOLVATOCHROMIC PYRIDINIUM N-PHENOLATE BETAINE DYES

Syntheses and negative solvatochromism of two new lipophilic pentaphen yl pyridinium N-phenolate betaine dyes, substituted with seven tert-bu tyl groups (9) or with three tert-butyl and two 1-adamantyl groups (13 ) in the Peripheral phenyl rings, are described in order to get zwitte rionic dyes that are more soluble in nonpolar solvents such as the sta ndard betaine dye, 1, which has been used for the construction of an e mpirical scale of solvent polarity, called the E-T(30) scale.