Association-mediated chromism of amphiphilic triphenyl-6-oxoverdazyl

Abstract

We synthesized a novel amphiphilic compound, 1,5-diphenyl-3-(4-(8-(pyridin-1-ium-1-yl)octoxy)phenyl)-6-oxoverdazyl bromide (PyC8TOV) thorough modification of 1,3,5-triphenyl-6-oxoverdazyl by introducing a pyridinium head group. This amphiphilic radical dissolved in water at concentrations lower than 0.1 mM but formed aggregates at higher concentrations. Depending on its concentration in water, PyC8TOV afforded crystals, or gels. The solvent- and concentration-dependences of UV and ESR spectra of PyC8TOV are discussed in terms of the environmentally sensitive electronic structure of this amphiphilic radical. The nonlinear dependence of the relaxivity of an aqueous solution of PyC8TOV strongly suggests the formation of aggregates in concentrated solution. PyC8TOV exhibited not only solvatochromism but also association-mediated chromism.