Ion-controlled on-off switch of electron transfer from tetrathiafulvalene calix[4]pyrroles to Li +@C 60

Abstract

Binding of chloride anion to a tetrathiafulvalene calix[4]pyrrole (TTF-C4P) donor results in ET to Li +@C 60 to produce the radical pair (TTF-C4P •+/Li +@C 60 •-), the structure of which was characterized by X-ray crystallographic analysis. The addition of tetraethylammonium cation, which binds more effectively than Li +@C 60 •- as a guest within the TTF-C4P cavity, leads to electron back-transfer, restoring the initial oxidation states of the donor and acceptor pair. © 2011 American Chemical Society.