HgII -Mediated TlI -to-TlIII Oxidation in Dynamic PbII /Tl Porphyrin Complexes.

Compared with their purely organic counterparts, molecular switches that are based on metal ion translocations have been underexplored, and more particularly, it remains challenging to control the translocation of several particles in multisite receptors. Recently, bimetallic complexes that undergo double translocation processes have been developed with bis-strapped porphyrin ligands. To implement a redox control for these systems, we have investigated the formation of heterobimetallic lead/thallium complexes, with thallium in the +I and +III oxidation states. Two different complexes were characterized: 1) a PbII /TlI complex, in which both metal ions interact with the N-core on its different sides, and 2) a PbII /TlIII complex with TlIII selectively bound to the N-core and PbII selectively bound to the strap opposite to TlIII . These two complexes undergo interconversion between their two degenerate forms (same coordination of the metal ions but on opposite sides) by different intra or intermolecular translocation pathways. In addition, conversion of the PbII /TlI complex into its PbII /TlIII counterpart was achieved by addition of a stoichiometric amount of HgII salt as a sacrificial electron acceptor. These results further contribute to the elaboration of devices that feature redox-controlled compartmentalized double translocations.