Biphasic Voltammetry and Spectroelectrochemistry in Polymer of Intrinsic Microporosity—4-(3-Phenylpropyl)-Pyridine Organogel/Aqueous Electrolyte Systems: Reactivity of MnPc Versus MnTPP

Abstract

A hydrophobic polymer of intrinsic microporosity (PIM-EA-TB) is employed to stabilize an organogel/aqueous electrolyte phase boundary based on an organic water-insoluble 4-(3-phenylpropyl)-pyridine phase. The organogel with electrocatalytic metal complexes embedded is immobilized on glassy carbon or on transparent mesoporous tin-doped indium oxide (ITO) electrodes. Liquid/liquid ion transfer voltammetry is investigated for a 4-(3-phenylpropyl)-pyridine organogel/aqueous electrolyte interface for two types of redox systems: tetraphenylporphyrinato-Mn(III/II) (MnTPP) and phthalocyanato-Mn(III/II) (MnPc). Electron transfer is shown to be coupled to reversible liquid/liquid anion transfer processes for PF6 −, ClO4 −, SCN−, and NO3 −, with a change in mechanism for the more hydrophilic anions Cl−, F−, and SO4 2−. In situ UV-Vis spectroelectrochemistry reveals reversible Mn(III/II) redox processes coupled to ion transfer for MnTPP. But further complexity and a detrimental side reaction are observed for MnPc causing gradual loss of the electrochemical response in the presence of dioxygen. [Figure not available: see fulltext.]. © 2018, The Author(s).