Synthesis, structure, and electronic properties of RuN 6 dinuclear Ru-Hbpp complexes

Stephan Roeser, Mehmed Z. Ertem, Clyde Cady, Rainer Lomoth, Jordi Benet-Buchholz, Leif Hammarström, Biprajit Sarkar, Wolfgang Kaim, Christopher J. Cramer, Antoni Llobet

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Abstract

A series of RuN 6 dinuclear Ru-Hbpp complexes (Hbpp is the dinucleating tetraaza ligand 3,5-bis(pyridyl)pyrazole) of general formula {[Ru II(R 2-trpy)(MeCN)] 2(μ-R 1-bpp)} 3+, 10 3+-14 3+, (R 1 = H, Me, or NO 2. and R 2 = H, Me, MeO; see Scheme 1) has been prepared from their Cl - or AcO - bridged precursors. The complexes have been characterized by UV-vis, NMR, CV, and some by X-ray. Complexes 10 3+-14 3+, Ru 2 II,II, were oxidized by 1 equiv in solution, leading to the mixed valence Ru 2 II,III complexes 10 4+-14 4+ containing one unpaired electron and were characterized by EPR and UV-vis-near-IR, which showed metal-centered spin and the presence of low-energy IVCT bands. The H ab parameter indicates a relatively strong electronic coupling between the two ruthenium centers (class II). Further two electron oxidation in solution of the 10 3+-14 3+ led to the formation of EPR silent Ru 2 III,III complexes 10 5+-14 5+, that were further characterized by UV-vis-NIR. TD-DFT calculations are employed to assign the nature of the UV-vis transitions for the complexes in the various oxidation states, which are of metal to ligand charge transfer (MLCT) type for Ru 2 II,II and ligand to metal charge transfer (LMCT) type for Ru 2 III,II and Ru 2 III,III.

Original languageEnglish
Pages (from-to)320-327
Number of pages8
JournalInorganic Chemistry
Volume51
Issue number1
DOIs
Publication statusPublished - Jan 2 2012

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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    Roeser, S., Ertem, M. Z., Cady, C., Lomoth, R., Benet-Buchholz, J., Hammarström, L., Sarkar, B., Kaim, W., Cramer, C. J., & Llobet, A. (2012). Synthesis, structure, and electronic properties of RuN 6 dinuclear Ru-Hbpp complexes. Inorganic Chemistry, 51(1), 320-327. https://doi.org/10.1021/ic201668r