Proton-induced switching and control of intramolecular electron transfer on a benzotriazole-bridged symmetric mixed-valence ruthenium complex

摘要

A simple and efficient pH-induced molecular "on/off" switching has been devised based on a symmetric bridged ruthenium dimer,[(edta)Ru(#mu#-L_b)Ru(edta)]~(n-) (where n=4 or 3; L_b=benzotriazolate or 2H-benzotriazole;edta=ethylenediaminetetraacetate),by exploitingits unusual mixed-valence state behavior as a function of the pH.The intervalence transfer(IT) related phenomena have been rationalized in the light of the Mulliken-Hush formalism.Depending on the proton concentration,the electronic coupling adn delocalization can be modulated to induce class III (deprotonated bridging ligand),class II (protonated), or even an intermediate borderline class II/class III system features.