Spectroelectrochemical and ESR investigation of free radicals derived from indotricarbocyanine dyes for photodynamic therapy

Cyclic voltammetry, UV–Vis absorption spectroscopy, and electron spin resonance are applied to study the properties of indotricarbocyanine dyes their radicals formed during electrooxidation. We use electrochemistry generate relatively stable free under controlled conditions. The undergo electrooxidation chronoamperometric electrolysis at 1.1 V (versus saturated calomel electrode) yielding radical dications. exhibit an band that is blue-shifted relative parent dye (561 nm versus 714 nm). In acetonitrile solutions, characterized by a lifetime ca. 20 min g factor 2.002. oxidation potential slightly greater than bromide ions allowing interact with ions. ability sensitize generation highly reactive bromine might play important role in photodynamic activity.