A new spectroelectrochemical cell with a long optical path length for redox studies of phthalocyanines

Abstract

A new spectroelectrochemical cell with a long optical path length has been fabricated for redox studies of phthalocyanines, where the propagation axis of the optical beam is parallel to the electrode/solution interface. It is composed of a homemade Teflon block that fits inside a standard 1 cm quartz optical-cell, equipped with a platinum-foil working electrode, a platinum-wire auxiliary electrode, and a AgCl -coated silver-wire reference electrode. This new cell makes it much easier to acquire spectral data for dilute solutions containing species, like phthalocyanines, that have limited solubility in common organic solvents or that strongly aggregate in solution. As examples, electrolyses of the [tetra(tert-butyl)phthalocyaninato]zinc(II) complex and its cobalt(II) analogue were performed to monitor spectral changes ascribable to phthalocyanine-ligand-centered oxidation and metal-centered reduction, respectively. Spectra of unaggregated electrogenerated species were successfully observed.