title: Sunlight-driven formation and dissociation of a dynamic mixed-valence thallium(III)/thallium(I) porphyrin complex.
abstract: Inspired by a Newton's cradle device and interested in the development of redox-controllable bimetallic molecular switches, a mixed-valence thallium(III)/thallium(I) bis-strap porphyrin complex, with Tl(III) bound out of the plane of the N core and Tl(I) hung to a strap on the opposite side, was formed by the addition of TlOAc to the free base and exposure to indirect sunlight. In this process, oxygen photosensitization by the porphyrin allows the oxidation of Tl(I) to Tl(III). The bimetallic complex is dynamic as the metals exchange their positions symmetrically to the porphyrin plane with Tl(III) funneling through the macrocycle. Further exposure of the complex to direct sunlight leads to thallium dissociation and to total recovery of the free base. Hence, the porphyrin plays a key role at all stages of the cycle of the complex: It hosts two metal ions, and by absorbing light, it allows the formation and dissociation of Tl(III). These results constitute the basis for the further design of innovative light-driven bimetallic molecular devices.
authors: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Université de Rennes 1, 263 avenue du Général Leclerc, 35042 Rennes cedex (France).
authors: Victoria
authors: V
authors: Ndoyom
authors: Luca
authors: L
authors: Fusaro
authors: Vincent
authors: V
authors: Dorcet
authors: Bernard
authors: B
authors: Boitrel
authors: Stéphane
authors: S
authors: Le Gac
keywords: molecular devices; photochemistry; porphyrinoids; redox chemistry; thallium