Reversible Gas–Solid Ammonia N–H Bond Activation Mediated by an Organopalladium Complex

N–H bond activation of gaseous ammonia is achieved at room temperature in a reversible solvent-free reaction using a solid dicyclopalladated azobenzene complex. Monitoring of the gas–solid reaction in real-time by <i>in situ</i> solid-state Raman spectroscopy enabled a detailed insight into the stepwise activation pathway proceeding to the final amido complex via a stable diammine intermediate. Gas–solid synthesis allowed for isolation and subsequent structural characterization of the intermediate and the final amido product, which presents the first dipalladated complex with the Pd^II−(μ-NH₂)−Pd^II bridge. Gas–solid reaction is readily followed via color changes associated with conformational switching of the palladated azobenzene backbone. The reaction proceeds analogously in solution and was characterized by UV–vis and NMR spectroscopies showing the same stepwise route to the amido complex. Combining the experimental data with density functional theory calculations we propose a stepwise mechanism of this heterolytic N–H bond activation assisted by exogenous ammonia

Reversible Gas–Solid Ammonia N–H Bond Activation Mediated by an Organopalladium Complex

N–H bond activation of gaseous ammonia is achieved at room temperature in a reversible solvent-free reaction using a solid dicyclopalladated azobenzene complex. Monitoring of the gas–solid reaction in real-time by <i>in situ</i> solid-state Raman spectroscopy enabled a detailed insight into the stepwise activation pathway proceeding to the final amido complex via a stable diammine intermediate. Gas–solid synthesis allowed for isolation and subsequent structural characterization of the intermediate and the final amido product, which presents the first dipalladated complex with the Pd^II−(μ-NH₂)−Pd^II bridge. Gas–solid reaction is readily followed via color changes associated with conformational switching of the palladated azobenzene backbone. The reaction proceeds analogously in solution and was characterized by UV–vis and NMR spectroscopies showing the same stepwise route to the amido complex. Combining the experimental data with density functional theory calculations we propose a stepwise mechanism of this heterolytic N–H bond activation assisted by exogenous ammonia