C–C Activation in the Solid State in an Organometallic σ-Complex

Herein is reported the synthesis, by a solid-state reaction from [Ir(NBD)2(PiPr3)][BArF4], of the first example of a C–C σ-complex with iridium, [Ir(BINOR-S)(PiPr3)][BArF4]. This compound is unique in that in the solid state it undergoes reversible activation of the C–C single bond that interacts with the metal center, establishing a temperature-dependent equilibrium between Ir(III) C–C σ/Ir(V) bis-alkyl complexes. This process has been interrogated by variable-temperature X-ray diffraction, NMR spectroscopy, and DFT calculations.