3 years ago

Metal Complexes of a Redox-Active [1]Phosphaferrocenophane: Structures, Electrochemistry and Redox-Induced Catalysis

Metal Complexes of a Redox-Active [1]Phosphaferrocenophane: Structures, Electrochemistry and Redox-Induced Catalysis
Karin Fink, Frank Breher, Markus K. Armbruster, Alexander Feyrer
The synthesis and characterisation of several metal complexes of a redox-active, mesityl(Mes)-substituted [1]phosphaferrocenophane, FcPMes (1), are reported. Cyclic voltammetry studies on the bimetallic complexes [M(κ1P-1)(cod)Cl] (M=Rh: 2; M=Ir: 4), [Rh(κ1P-1)2(CO)Cl] (3) and [AuCl(κ1P-1)] (5), in conjunction with DFT calculations, provided indications for a good electronic communication between the metal atoms. To confirm that the ferrocenophane unit might be able to electrochemically influence the reactivity of the coordinated transition metal, the rhodium complex 2 was employed as stimuli-responsive catalyst in the hydrosilylation of terminal alkynes. All reactions were greatly accelerated with in situ generated 2+ as a catalyst as compared to 2. Even more importantly, a markedly different selectivity was observed. Both factors were attributed to different mechanisms operating for 2 and 2+ (alternative Chalk–Harrod and Chalk–Harrod mechanism, respectively). DFT calculations revealed relatively large differences for the activation barriers for 2 and 2+ in the reductive elimination step of the classical Chalk–Harrod mechanism. Thus, the key to the understanding is a cooperative “oxidatively induced reductive elimination” step, which facilitates both a higher activity and a markedly different selectivity. Redox-induced catalysis: Bimetallic complexes of a [1]phosphaferrocenophane are reported featuring a good electronic communication between the metal atoms. A rhodium(I) complex was employed as redox-active catalyst in the hydrosilylation of terminal alkynes. Oxidatively induced reductive elimination facilitates higher activity and markedly different selectivity for the oxidised complex.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700868

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.