Charge-transfer in ion pairs: design of photoreactivity in solution and electrical dark- and photoconductivity in the solid

Abstract

Weak supramolecular charge-transfer interactions within 1:1 ion pair complexes composed of anionic metal dithiolenes and cationic bipyridinium compounds have astonishing consequences on solution and solid state properties. In solution the relation between thermal and optical electron transfer can be analyzed in terms of the Hush-model. Irradiation of the dissolved complexes induces an electron transfer to molecular oxygen which can be quantitatively controlled by proper selection of the acceptor redox potential. The electrical conductivity of pressed powder pellets is quantitatively predictable within the range of 10 −11 to 10 −4 Ω −1cm −1 from the solution redox potentials of the components or from the activation energy of thermal electron transfer calculated from the Hush-model. Finally, the action spectrum of the photoconductivity exhibits a maximum in the range of the optical charge-transfer band.