Metal/Metal Redox Isomerism Governed by Configuration. Issue 70 (9th November 2020)

• Record Type: Journal Article
• Authors: Ludwig, Stephan; Helmdach, Kai; Hüttenschmidt, Mareike; Oberem, Elisabeth; Rabeah, Jabor; Villinger, Alexander; Ludwig, Ralf; Seidel, Wolfram W.
• Is Part Of: Chemistry. Volume 26:Issue 70(2020)
• Page Start: 16811
• Page End: 16817
• Publication Date: 2020-11-09
• Subjects: alkyne ligands -- bridging ligands -- redox chemistry -- redox isomerism -- regioselectivity; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202003120
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A pair of diastereomeric dinuclear complexes, [Tp′(CO)BrW{μ‐η 2 ‐ C, C′ ‐κ 2 ‐ S, P ‐C2 (PPh2 )S}Ru(η 5 ‐C5 H5 )(PPh3 )], in which W and Ru are bridged by a phosphinyl(thiolato)alkyne in a side‐on carbon P, S ‐chelate coordination mode, were synthesized, separated and fully characterized. Even though the isomers are similar in their spectroscopic properties and redox potentials, the like ‐isomer is oxidized at W while the unlike ‐isomer is oxidized at Ru, which is proven by IR, NIR and EPR‐spectroscopy supported by spectro‐electrochemistry and computational methods. The second oxidation of the complexes was shown to take place at the metal left unaffected in the first redox step. Finally, the tipping point could be realized in the unlike isomer of the electronically tuned thiophenolate congener [Tp′(CO)(PhS)W{μ‐η 2 ‐ C, C′ ‐κ 2 ‐ S, P ‐C2 (PPh2 )S}Ru(η 5 ‐C5 H5 )‐(PPh3 )], in which valence trapped W III /Ru II and W II /Ru III cationic species are at equilibrium. Abstract : Diastereomers differ in physical properties: A case of real metal/metal redox isomerism is observed in a dinuclear complex with a particularly short bridging ligand. The two stereogenic complex moieties at W and Ru, respectively, are linked by an alkyne based phosphine thiolate chelate ligand. Oxidation of the like isomer pertains to tungsten, whereas the unlike isomer is oxidised at ruthenium. The diastereomers show opposite redox behaviour!