The rare bridging mode of 1,4-bis(2-phenolato)-1,4-diazabutadiene = glyoxalbis(2-hydroxyanil) (L2−) is adopted in {(µ-L2−)[RuII(bpy)2]2}2+ (12+), obtained as bis-perchlorate. Four well accessible redox forms of 1n (n = 4+, 3+, 2+, +) have been characterised by UV-VIS-NIR spectroelectrochemistry. The (3+) and (+) intermediates have also been investigated by EPR, both showing radical-type signals close to g = 2. This observation stands in stark contrast to EPR results previously obtained for the related {(µ-L)[Ru(acac)2]2}n, n = + and −, both of which exhibit metal-centred spin. In combination with the UV-VIS-NIR spectra these results suggest the preferential involvement of the multistep ligand redox system Ln− in the electron transfer processes. The relative stabilisation of RuII by π-accepting bpy is made responsible for the oxidation of the ligand L2− instead of the metal.
You have access to this article
Please wait while we load your content...
Something went wrong. Try again?