η⁶‑Tetramethylfulvene and μ‑η³:η³‑Benzene Complexes of Iridium

The reaction of Cp*Ir­(NHC)­Me₂ (<b>Ir-Me</b>_<b>2</b>) with [CPh₃]⁺[B­(C₆F₅)₄]^ in dichloromethane resulted in conversion of the Cp* ligand to an η⁶-tetramethylfulvene ligand via apparent hydride abstraction (Cp* = η⁵-C₅Me₅; NHC = 1,3-<i>N</i>,<i>N</i>-dimethylimidazol-2-ylidene). The products of this reaction are triphenylmethane and the η⁶-tetramethylfulvene complex [(η⁶-C₅Me₄CH₂)­Ir­(NHC)­(Me₂)]⁺[B­(C₆F₅)₄]^ (<b>fulv-Ir</b>^<b>+</b>). When dichloromethane solutions of the related complex [Cp*Ir­(NHC)­(Ph)­(solv)]⁺[MeB­(C₆F₅)₃]⁻ were allowed to stand at room temperature, crystals of the unusual sandwich complex [{Cp*Ir­(NHC)}₂(μ-η³:η³-C₆H₆)]²⁺ (<b>Ir-C</b>_<b>6</b><b>H</b>_<b>6</b><b>-Ir</b>^<b>2+</b>) were obtained. Complexes <b>fulv-Ir</b>^<b>+</b> and <b>Ir-C</b>_<b>6</b><b>H</b>_<b>6</b><b>-Ir</b>^<b>2+</b> represent unique architectures in the Cp*Ir­(NHC) family. Both compounds were characterized by spectroscopic methods as well as by single-crystal X-ray diffraction