engleski

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 in situ 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 PdII−(μ-NH2)−PdII 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.

N-H activation ; gas-solid reaction ; dipalladated complex ; spectroscopy ; DFT calculations

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