Unusual Metal-Metal Bonding in a Dinuclear Pt-Au Complex: Snapshot of a Transmetalation Process

• Published in: Angewandte Chemie International Edition 2016-06, Vol.55 (24), p.6978-6982
• Main Authors: Baya, Miguel, Belío, Úrsula, Fernández, Israel, Fuertes, Sara, Martín, Antonio
• Format: Article
• Language: English
• Subjects: Crystal structure; DFT calculations; donor-acceptor systems; fluxionality; heterobimetallic complexes; metal-metal bonds
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201602081

The dinuclear Pt–Au complex [(CNC)(PPh3)Pt Au(PPh3)](ClO4) (2) (CNC=2,6‐diphenylpyridinate) was prepared. Its crystal structure shows a rare metal–metal bonding situation, with very short Pt–Au and Au–Cipso(CNC) distances and dissimilar Pt–Cipso(CNC) bonds. Multinuclear NMR spectra of 2 show the persistence of the Pt–Au bond in solution and the occurrence of unusual fluxional behavior involving the [PtII] and [AuI] metal fragments. The [PtII]⋅⋅⋅ [AuI] interaction has been thoroughly studied by means of DFT calculations. The observed bonding situation in 2 can be regarded as a model for an intermediate in a transmetalation process. The swing of a rare metronome: A bimetallic Pt–Au complex was synthesized and its electronic structure studied by DFT methods. In solution, it showed unusual fluxional behavior involving the formation and cleavage of Au−C bonds (see picture). The complex can be viewed as a model for an intermediate in a transmetalation process promoted by cooperative metal catalysts, whereby the Pt−Au bond anchors the two metallic fragments.