Photochemistry of the charge-transfer complex between ruthenocene and carbon tetrachloride

Abstract

The photolysis and naphthalene-photosensitised reaction of the charge-transfer complex between ruthenocene and carbon tetrachloride has been studied in solutions of methanol and carbon tetrachloride. The reaction forms the ruthenocenium cation in the primary process. The overall quantum yield of formation at 313 nm is 0·72, and at 366 nm is 0·52. By studying the partial inhibition of the reaction with SmCl₃, oxygen, and acrylamide, it was possible to show that, at 313 nm, ϕ for the decomposition by the singlet state is 0·24 and by the triplet state is 0·40.

The naphthalene-photosensitised reaction proceeds through a triplet state. The reaction is inhibited at higher concentrations by the competitive quenching of the naphthalene singlet state by ruthenocene itself.

The association constant for the complex is 1·80 mol fraction^–1(0·012 l mol^–1) at 23 °C. A spectrum is recorded for the ruthenocenium cation.