Spectroelectrochemical Behaviour of 1,4-Dimethoxypillar[5]arene (P5A) and its Monomer in Different Organic Solvents

Abstract

The spectroelectrochemical response of the macrocyclic compound 1,4-dimethoxypillar[5]arene (P5A) and its monomer 1,4-dimethoxybenzene was investigated using cyclic voltammetry combined with UV-Vis spectroscopy. The influence of three different aprotic solvents, acetonitrile, dichloromethane, and dichloroethane, as well as supporting electrolyte, on the anodic behaviour of P5A were studied and discussed. The results indicate that the donor-acceptor Lewis-type interactions between tested compounds and the solvent molecules affect the oxidation processes and thus the formal potentials (Ef). In all solvents we see subsequent oxidation of P5A to P5A5+ followed at higher potential by an irreversible oxidation to the corresponding quinone. The results also show that small amounts of water can significantly influence the redox behaviour of the P5A.