Facilitated ion transfers (FIT) of potassium (K+) and terbium(III) (Tb3+) were studied electrochemically at a micro-interface between two immiscible electrolytic solutions (ITIES) to to characterize binding of the ions by ionophore ligands. FIT of K+ by dibenzo-18-crown-6 (DB18C6) and FIT of Tb3+ by a tripodal carbamoylmethylphosphine oxide (TREN-CMPO-OEt) ligand were characterized using cyclic voltammetry at a water/1,2-dichloroethane (DCE) ITIES. The Tomeš criteria identified in steady state voltammograms were 75.4 mV for the K+-DB18C6 complex and 45.2 mV for the NO3−-Tb3+-TREN-CMPO-OEt complex which is consistent with reversible or quasi-reversible binding of cations with an effective charge of +1 and +2 respectively to their respective ligands. The binding constant (β) observed for the K+-DB18C6 complex was 1.6 × 1010, in good agreement with earlier literature. Proton FIT by TREN-CMPO-OEt was also observed. Ongoing work will address β for the NO3−-Tb3+-TREN-CMPO-OEt complex as well as comparisons of Tb3+ binding by other tripodal ligands.

Electrochemical investigation of facilitated terbium(III) transfer at micro-liquid/liquid interfaces

255th National Meeting (2018)

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