Mixed Valency vs Radical Bridge Formulation in Symmetrically and Asymmetrically Ligated Diruthenium Complexes

0561665 - ÚFCH JH 2023 RIV DE eng J - Článek v odborném periodiku
Mondal, S. - Schwederski, B. - Záliš, Stanislav - Kaim, W.
Mixed Valency vs Radical Bridge Formulation in Symmetrically and Asymmetrically Ligated Diruthenium Complexes.
European Journal of Inorganic Chemistry. Roč. 2022, č. 26 (2022), č. článku e202200319. ISSN 1434-1948. E-ISSN 1099-0682
Grant CEP: GA ČR(CZ) GA21-05180S
Institucionální podpora: RVO:61388955
Klíčová slova: Mixed valence * Radical complexes * Redox series * Ruthenium compounds * Symmetry
Obor OECD: Physical chemistry
Impakt faktor: 2.3, rok: 2022
Způsob publikování: Open access

The asymmetrical dinuclear [{(trpy*)Ru}(2)(mu-adc-Salph)Cl](PF6) 1(PF6), trpy*=4,4´,4´´-tri-tert-butyl-2,6,2´,6´´-terpyridine, adc-Salph=1-benzoyl-2-salicyloylhydrazido(3-), and the related symmetrical dinuclear [{Cl(trpy*)Ru}(2)(mu,eta(2) : eta(2)-adc-Ph)](PF6) 2(PF6), adc-Ph=1,2-bis(benzoyl)hydrazido(2-), were synthesized and structurally characterized. Both paramagnetic compounds were compared with the previously reported symmetrical [{(trpy*)Ru}(2)(mu,eta(3) : eta(3)-adc-Sal)](PF6) 3(PF6) containing the bis-tridentate bridge 1,2-bis(salicyloyl)hydrazido(4-). Molecular structures and magnetic resonance features (H-1 NMR, EPR) indicate spin density distribution over the metal(s) and the bridging ligand. Reversible one-electron reduction and oxidation were possible in all instances yielding comproportionation constants K-c of about 10(9) for the paramagnetic intermediates 1(+)-3(+). Structural results, spin density distribution and UV-Vis-NIR spectroelectrochemistry were analyzed for 1(+) with the help of TD-DFT calculations for a model compound (tert-Bu> Me). Intense absorptions around lambda(max)=1450-1650 nm for the cations were assigned to mixed metal/ligand transitions with significant inter-valence charge transfer (IVCT) character. For both the symmetrical and asymmetrical arrangements the cationic intermediates can be described as considerably mixed metal/ligand systems.
Trvalý link: https://hdl.handle.net/11104/0334188