Maurer, Joerg and Linseis, Michael and Sarkar, Biprajit and Schwederski, Brigitte and Niemeyer, Mark and Kaim, Wolfgang and Zalis, Stanislav and Anson, Chris and Zabel, Manfred and Winter, Rainer F. (2008) Ruthenium complexes with vinyl, styryl, and vinylpyrenyl ligands: A case of non-innocence in organometallic chemistry. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 130 (1). pp. 259-268. ISSN 0002-7863,
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We herein,describe a systematic account of mononuclear ruthenium vinyl complexes L-{Ru}-CH CH-R where the phosphine ligands at the (PR'(3))(2)Ru(CO)Cl={Ru} moiety, the coordination number at the metal (L = 4-ethylisonicotinate or a vacant coordination site) and the substituent R (R = (n)butyl, phenyl, 1-pyrenyl) have been varied. Structures of the enynyl complex Ru(CO)Cl(PPh3)(2)(eta(1):eta 2-nBuHC = CHC equivalent to(CBu)-Bu-n), which results from the coupling of the hexenyl ligand of complex la with another molecule of 1-hexyne, of the hexenyl complexes ((BuCH)-Bu-n = CH)Ru(CO)Cl((PPr3)-Pr-i)(2) (1c) and ((BuCH)-Bu-n = CH)Ru(CO)Cl(PPh3)(2)(NC5H4COOEt-4) (1b), and of the pyrenyl complexes (1-Pyr-CH=CH)Ru(CO)Cl((PPr3)-Pr-i)(2) (3c) and (1-Pyr-CH=CH)Ru(CO)Cl(PPh3)(3) (3a-P) have been established by X-ray crystallography. All vinyl complexes undergo a one-electron oxidation at fairly low potentials and a second oxidation at more positive potentials. Anodic half-wave or peak potentials show a progressive shift to lower values as pi-coniugation within the vinyl ligand increases. Carbonyl band shifts of the metal-bonded CO ligand upon monooxidation are significantly smaller than is expected of a metal-centered oxidation process and are further diminished as the vinyl CH = CH entity is incorporated into a more extended pi-system. ESR spectra of the electrogenerated radical cations display negligible g-value anisotropies and small deviations of the average g-value from that of the free electron. The vinyl ligands thus strongly contribute to or even dominate the anodic oxidation processes. This renders them a class of truly "non-innocent" ligands in organometallic ruthenium chemistry. Experimental findings are fully supported by quantum chemical calculations: The contribution of the vinyl ligand to the HOMO increases from 46% (Ru-vinyl delocalized) to 84% (vinyl dominated) as R changes from (n)butyl to 1-pyrenyl.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRANSITION-METAL-COMPLEXES; X-RAY CRYSTAL; BRIDGED DIRUTHENIUM COMPLEXES; ELECTRON-SPIN RESONANCE; VALENCE TAUTOMERISM; SPECTROSCOPIC PROPERTIES; COORDINATION NETWORKS; ACETYLIDE COMPLEXES; INSERTION REACTIONS; PHOSPHINE-LIGANDS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Arbeitskreis Prof. Dr. Rainer Winter |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 10 Nov 2020 11:03 |
| Last Modified: | 10 Nov 2020 11:03 |
| URI: | https://pred.uni-regensburg.de/id/eprint/31512 |
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