title: Ancillary ligand determination of the spin location in both oxidised and reduced forms of diruthenium complexes bridged by bis-bidentate 1,4-bis(2-phenolato)-1,4-diazabutadiene.
abstract: The rare bridging mode of 1,4-bis(2-phenolato)-1,4-diazabutadiene = glyoxalbis(2-hydroxyanil) (L(2-)) is adopted in {(mu-L(2-))[Ru11(bpy)22}2+ (1(2+)), obtained as bis-perchlorate. Four well accessible redox forms of 1(n) (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 {(mu-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 L(n-) in the electron transfer processes. The relative stabilisation of Ru11 by pi-accepting bpy is made responsible for the oxidation of the ligand L(2-) instead of the metal.
authors: Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India.
authors: Sanjib
authors: S
authors: Kar
authors: Biprajit
authors: B
authors: Sarkar
authors: Sandeep
authors: S
authors: Ghumaan
authors: Markus
authors: M
authors: Leboschka
authors: Jan
authors: J
authors: Fiedler
authors: Wolfgang
authors: W
authors: Kaim
authors: Goutam Kumar
authors: GK
authors: Lahiri