Mediating oxidation states in decamethyleuropocene complexes. The role of the diazabutadiene fragment

The Eu diazabutadiene complexes (C5Me5)(2)Eu- DADBu-t) and (C5Me5)(2)Eu(DADC(6)F(5)) (DADBu-t = t-BuNC(H)C(H) NBu-t; DADC(6)F(5) = C6F5NC(Me)C(Me)NC6F5) have been prepared, and on the basis of characterization by X-ray crystallography, magnetic susceptibility, and H-1 NMR and IR spectroscopy, it is concluded that the Eu oxidation states in these complexes are + 2 and + 3, respectively. In the case of (C5Me5)(2)Eu(DADC(6)F(5)), the internal redox process is solvent sensitive.