Ion-Transfer Voltammetry at a Water/1,2-Dichloroethane Interface Using Photoionization by Ultraviolet Irradiation: Detection of Cation Radicals of p-Phenylenediamine Derivatives.

We have attempted to detect electrically neutral substances by ion-transfer voltammetry at an interface between two immiscible electrolyte solutions (ITIES), such as an interface between water and 1,2-dichloroethane (a W/DCE interface), by irradiating the interface with ultraviolet light (200 - 300 nm). In the present work, while considering the facts that p-phenylenediamine derivatives are soluble in DCE, but insoluble in water, and that cation radicals of the derivatives are fairly stable in various media, we photoionized the derivatives in a DCE phase by ultraviolet irradiation, and after that carried out ion-transfer voltammetry at a W/DCE interface. As a result, we could successfully observe ion-transfer waves of cation radicals of the derivatives from the W to DCE phase.

Effect of Ultraviolet Irradiation on Proton Transfer Facilitated by 5,10,15,20-Tetraphenyl-21H,23H-porphine and Its Metal Complexes at a Water/1,2-Dichloroethane Interface.

We examined photochemical effects by ultraviolet irradiation on facilitated proton transfer at a water/1,2-dichloroethane (W/DCE) interface by ion-transfer voltammetry using a Xe flash lamp. 5,10,15,20-Tetraphenyl-21H,23H-porphine (HTPP) or its metal complex, such as cobalt (Co(II)TPP), zinc (Zn(II)TPP), and nickel (Ni(II)TPP) complexes, was added into the DCE phase as an ionophore for the facilitated proton transfer. After we irradiated the W/DCE interface through the W phase, the voltammetric waves for proton transfer facilitated by HTPP and Co(II)TPP were remarkably enhanced and shifted to the lower potential region, compared to those before irradiation.