Distickstoff-Übergangsmetall-Komplexe: Synthese, Eigenschaften und Bedeutung

Trichloro(Dinitrogen)Platinate(II)

Zeise's salt, [PtCl₃ (H₂ C=CH₂ )]^- _, is the oldest known organometallic complex, featuring ethylene strongly bound to a platinum salt. Many derivatives are known, but none involving dinitrogen, and indeed dinitrogen complexes are unknown for both platinum and palladium. Electrospray ionization mass spectrometry of K₂ [PtCl₄ ] solutions generate strong ions corresponding to [PtCl₃ (N₂ )]^- , the identity of which was confirmed through ion-mobility spectrometry and MS/MS experiments that proved it to be distinct from its isobaric counterparts [PtCl₃ (C₂ H₄ )]^- and [PtCl₃ (CO)]^- . Computational analysis established a gas-phase platinum-dinitrogen bond strength of 116 kJ mol^-1 , substantially weaker than the ethylene and carbon monoxide analogues but stronger than for polar solvents such as water, methanol and dimethylformamide, and strong enough that the calculated N-N bond length of 1.119 Å represents weakening to a degree typical of isolated dinitrogen complexes.

Intrinsic Dinitrogen Activation at Bare Metal Atoms

There is ongoing interest in metal complexes which bind dinitrogen and facilitate either its reduction or oxidation under mild conditions. In nature, the enzyme nitrogenase catalyzes this process, and dinitrogen fixation occurs under mild and ambient conditions at a metal-sulfur cluster in the center of the MoFe protein, but the mechanism of this process remains largely unknown. In the last few years, new important discoveries have been made in this field. In this review are discussed recent findings on the interaction of N(2) with metal atoms and metal-atom dimers from all groups of the periodic table as provided by gas-phase as well as matrix-isolation experiments. Intrinsic dinitrogen activation at such bare metal atoms is then related to corresponding processes at complexes, clusters, and surfaces.