Proton transfer across liquid│liquid interfaces facilitated by the disproportionation reaction of a lutetium bisphthalocyanine: a voltammetric study at a microinterface water │ nitrobenzene or dichlorohexane.

International audienceProton transfer across the water│solvent (nitrobenzene, 1,6-dichlorohexane) interface is facilitated by the presence in the organic phase of a lutetium bisphthalocyanine. The driving force of the facilitatedfacilitated transfer of H+ is the redox disproportionation reaction of this compound (M0) occurring at the liquid│liquid interface: a reaction induced by the very high affinity of M-, the reduced bisphthalocyanine, for the proton (KA = 10-13.5 mol-1l). The lutetium bisphthalocyanine, which exits as the molecular form over ~0.4 V (Kd = 10-6.4) in the neutral solvent, disproportionates completely in acidic solutions (eg, in nitrobenzene: KdH = 107.1 mol-1l). At the water│nitrobenzene interface, this disproportionation reaction facilitates the proton transfer by almost 0.30 V. Voltammetry at a rotating disk electrode in nitrobenzene confirms the redox disproportionation reaction and the basicity of the reduced lutetium bisphthalocyanine