Structural Changes in the Carbon Sphere of a Dirhodium Complex Induced by Redox or Deprotonation Reactions

Abstract

Abstract A carbon‐rich molecule is synthesized, which mainly contains conjugated sp2 and sp hybridized carbon centers. Alkenyl and alkynyl binding sites are arranged such that this compound serves as ligand to a binuclear metal unit with a RhI─RhI bond. Furthermore, CH units are placed in proximity to the metal centers. The dicationic complex [Rh2(bipy)2{Ph2Ptrop(C≡CCy)2}]2+(OTf−)2 allows to study possible responses of the carbon‐framework to redox reactions as well as deprotonation reactions. All products are, whenever possible, characterized by X‐ray diffraction (XRD) methods, NMR and EPR spectroscopy as well as electrochemical methods. It is shown that the carbon skeleton of the ligand framework undergoes C─C bond rearrangement reactions of remarkable diversity. In combination with DFT (density functional theory) studies, these results allow to gain insight into the electronic structure changes caused by metal sites in a carbon‐rich environment, which may be of relevance for the properties of metal particles on carbon support materials when they are exposed to hydrogen, electrons, or protons.

Keywords

• alkynyl complexes
• dinuclear complexes
• low‐valent metals
• metal‐metal bonds
• rearrangements
• redox chemistry