Reversible Hydride Migration from C5Me5 to RhI Revealed by a Cooperative Bimetallic Approach

Abstract

The use of cyclopentadienyl ligands in organome-tallic chemistry and catalysis is ubiquitous, mostly due to theirrobust spectator role. Nonetheless, increasing examples of non-innocent behaviour are being documented. Here, we provideevidence for reversible intramolecular C H activation at onemethyl terminus of C5Me5in [(h-C5Me5)Rh(PMe3)2] to forma new Rh H bond, a process so far restricted to early transitionmetals. Experimental evidence was acquired from bimetallicrhodium/gold structures in which the gold center binds either tothe rhodium atom or to the activated Cp* ring. Reversibility ofthe C H activation event regenerates the RhIand AuImonometallic precursors, whose cooperative reactivity towardspolar E H bonds (E=O, N), including the N H bonds inammonia, can be understood in terms of bimetallic frustration.