Presussure and Temperature Induced Valence Tautomeric Interconversion in a o-Dioxolene Adduct of a Cobalt - tetraazamacrocycle Complex

An electronic switch at the molecular level has been realized by using a class of ionic compounds of the formula [Co(L)(diox)]Y (L=tetraazamacrocyclic ligand, Y=mononegative anion). Such compounds undergo temperature- and pressure-induced intramolecular one-electron transfer equilibria. The transition temperature of interconversion varies with the nature of the counterions Y (Y=PF(6), BPh(4), I). Surprisingly the effect of the anion on the transition temperature is not only governed by its volume but also by its coulombic interaction.