Biomimetic Water Oxidation Catalyzed by a Binuclear Ruthenium (IV) Nitrido-Chloride Complex with Lithium Counter-Cations

Zinaida M Dzhabieva; Gennady V Shilov; Lidia V Avdeeva; Vladislav V Dobrygin; Virineya Yu Tkachenko; Taimuraz S Dzhabiev

doi:10.3390/biomimetics5010003

Biomimetic Water Oxidation Catalyzed by a Binuclear Ruthenium (IV) Nitrido-Chloride Complex with Lithium Counter-Cations

Biomimetics (Basel). 2020 Jan 16;5(1):3. doi: 10.3390/biomimetics5010003.

Authors

Zinaida M Dzhabieva¹, Gennady V Shilov¹, Lidia V Avdeeva¹, Vladislav V Dobrygin², Virineya Yu Tkachenko^{1

2}, Taimuraz S Dzhabiev¹

Affiliations

¹ Institute of Problems of Chemical Physics of RAS, Moscow Region, Academician Semenov Ave., 1, 142432 Chernogolovka, Russia.
² Faculty of fundamental physical and chemical engineering, Lomonosov Moscow State University, GSP-1, 1 Leninskiye Gory, 119991 Moscow, Russia.

Abstract

The lithium salt of the binuclear nitrido complex of ruthenium (IV) Li₃(Ru₂NCl₈·2H₂O) was synthesized. Using UV spectroscopy and voltammetry, we studied complex behavior in aqueous solutions. It was found that in dilute solutions of this compound, Cl^- ions are replaced by H₂O molecules, and the intra-sphere redox reaction between Ru (IV) and H₂O, as well as the oxidation of water with the formation of oxygen and the acidic dissociation of coordinated water molecules also have been taking place. It was established by IR spectroscopy and ESI mass spectrometric analysis that not only the binuclear structure of the complex is preserved in acidic solutions, but also its dimerization product into the tetra-ruthenium dinitrido cluster Ru₄N₂O₅⁺, which is a catalyst for the water oxidation reaction. The activity of the catalyst was TOF = 0.33 s^-1, TON = 304.

Keywords: binuclear nitrido complex Ru(IV) with lithium counter-cations; biomimetic catalysis; oxygen; water oxidation.