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1,5-Diamido-9,10-anthraquinone, a Centrosymmetric Redox-Active Bridge with Two Coupled β-Ketiminato Chelate Functions: Symmetric and Asymmetric Diruthenium Complexes
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SYSNO ASEP 0459722 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title 1,5-Diamido-9,10-anthraquinone, a Centrosymmetric Redox-Active Bridge with Two Coupled β-Ketiminato Chelate Functions: Symmetric and Asymmetric Diruthenium Complexes Author(s) Ansari, M. A. (IN)
Mandal, A. (IN)
Paretzki, A. (DE)
Beyer, K. (DE)
Fiedler, Jan (UFCH-W) RID, ORCID
Kaim, W. (DE)Source Title Inorganic Chemistry. - : American Chemical Society - ISSN 0020-1669
Roč. 55, č. 11 (2016), s. 5655-5670Number of pages 16 s. Language eng - English Country US - United States Keywords MIXED-VALENCE COMPLEXES ; RUTHENIUM COMPLEXES ; ELECTRON-TRANSFER Subject RIV CF - Physical ; Theoretical Chemistry R&D Projects LD14129 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UFCH-W - RVO:61388955 UT WOS 000377151000068 EID SCOPUS 84973304450 DOI 10.1021/acs.inorgchem.6b00726 Annotation The dinuclear complexes {(μ-H2L)[Ru(bpy)2]2}(ClO4)2 ([3](ClO4)2), {(μ-H2L)[Ru(pap)2]2}(ClO4)2 ([4](ClO4)2), and the asymmetric [(bpy)2Ru(μ-H2L)Ru(pap)2](ClO4)2 ([5](ClO4)2) were synthesized via the mononuclear species [Ru(H3L)(bpy)2]ClO4 ([1]ClO4) and [Ru(H3L)(pap)2]ClO4 ([2]ClO4), where H4L is the centrosymmetric 1,5-diamino-9,10-anthraquinone, bpy is 2,2′-bipyridine, and pap is 2-phenylazopyridine. Electrochemistry of the structurally characterized [1]ClO4, [2]ClO4, [3](ClO4)2, [4](ClO4)2, and [5](ClO4)2 reveals multistep oxidation and reduction processes, which were analyzed by electron paramagnetic resonance (EPR) of paramagnetic intermediates and by UV–vis–NIR spectro-electrochemistry. With support by time-dependent density functional theory (DFT) calculations the redox processes could be assigned. Significant results include the dimetal/bridging ligand mixed spin distribution in 33+ versus largely bridge-centered spin in 43+—a result of the presence of RuII-stabilizig pap coligands. In addition to the metal/ligand alternative for electron transfer and spin location, the dinuclear systems allow for the observation of ligand/ligand and metal/metal site differentiation within the multistep redox series. DFT-supported EPR and NIR absorption spectroscopy of the latter case revealed class II mixed-valence behavior of the oxidized asymmetric system 53+ with about equal contributions from a radical bridge formulation. In comparison to the analogues with the deprotonated 1,4-diaminoanthraquinone isomer the centrosymmetric H2L2– bridge shows anodically shifted redox potentials and weaker electronic coupling between the chelate sites. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2017
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