[(^tBu₂PCH₂SiMe₂)₂N]Rh^I? Rapidly Reversible H−C(sp³) and H−C(sp²) Bond Cleavage by Rhodium(I)

Abstract

The product of the reaction of (tBu2PCH2SiMe2)2N− (MgCl+ salt) with [RhCl(cyclooctene)2]2 is a RhIII complex where one tBu methyl C−H bond has oxidatively added to Rh: (PNP*)RhH. This is in rapid exchange among all 9 × 4 C−H bonds of the four tBu groups. (PNP*)RhH undergoes oxidative addition equilibrium with the C−H bonds of benzene at ∼103 s−1 at 25 °C and oxidatively adds the ring C−H of other arenes. (PNP*)RhH forms η2-olefin complexes with several olefins and dehydrogenates allylic C−H bonds to form (PNP)Rh(H)2.