Metalla-Assembled Electron-Rich Tweezers: Original Redox-Controlled Guest Release through Supramolecular Dimerization.

Developing methodologies to control on demand the release of a molecular guest requires the rational design of stimuli-responsive hosts bearing functional cavities. While a substantial number of responsive metalla-cages have been described so far, the case of coordination-tweezers has been less explored. Herein, we report the first example of a redox-triggered guest release from a metalla-assembled tweezer. The latter incorporates two redox-active panels facing each other and constructed from the electron-rich 9-(1,3-dithiol-2-ylidene)fluorene unit. The tweezer dimerizes spontaneously in solution and the resulting interpenetrated supramolecular structure is able to dissociate in presence of an electron-poor planar unit, forming a 1:1 host-guest complex. The latter can be dissociated upon tweezer oxidation/dimerization, offering an original redox-triggered molecular delivery pathway.