Hydrogenation of the (PONOP)Ir(I)CH 3 complex [PONOP = 2,6-bis(di-tert-butylphosphinito)pyridine] yields the unexpected trans-dihydride species (PONOP)IrCH 3 (H) 2 . Mechanistic investigations have revealed that this reaction proceeds via proton-catalyzed H 2 cleavage, a pathway that circumvents the intermediacy of the typically invoked cis-dihydride isomer. Protonation yields the cationic (PONOP)Ir(CH 3 )(H) + complex, which is then trapped by H 2 to yield an η 2 -H 2 complex. Deprotonation of this species yields the trans-dihydride. Intermediates in the proposed pathway have been confirmed by independent low-temperature syntheses and spectroscopic observations. © 2010 American Chemical Society.
|Journal||Journal of the American Chemical Society|
|State||Published - Apr 7 2010|