A Dinitrogen Complex without Donor Ligands: Isolation and Characterization of a [Mn(CO)<sub>5</sub>(η<sup>1</sup>-N<sub>2</sub>)]<sup>+</sup> Salt
Dinitrogen complexes are intermediates in nitrogen fixation. Until now, all isolated molecular dinitrogen complexes have relied on ancillary ligands that are net electron donors, yielding N<sub>2</sub> ligands carrying a clear negative partial charge. Here, we present the synthesis, isolation, and characterization of the complex salt [Mn(CO)<sub>5</sub>(η<sup>1</sup>-N<sub>2</sub>)]<sup>+</sup>[F(Al(OR<sup>F</sup>)<sub>3</sub>)<sub>2</sub>]<sup>-</sup> (R<sup>F</sup> = C(CF<sub>3</sub>)<sub>3</sub>) that resulted from the oxidation of Mn<sub>2</sub>(CO)<sub>10</sub> under a dinitrogen atmosphere in pentafluorobenzene solvent. The IR/Raman spectra reveal a high N<sub>2</sub> frequency of 2301/2303 cm<sup>-1</sup> close to free N<sub>2</sub> gas (2330 cm<sup>-1</sup>) that indicates little π-back-donation. QTAIM and CD-NOCV analyses show that the carbonyl ligands act as net acceptor ligands that induce the formation of an inversely polarized dinitrogen ligand with a +0.2 charge on the terminal atom that holds the potential to be susceptible to nucleophilic attack.
Authors
- James D. Watson (ORCID: https://orcid.org/0000-0003-4457-5722)
- Julia Fischer (ORCID: https://orcid.org/0000-0001-6291-3292)
- Malte Sellin (ORCID: https://orcid.org/0000-0003-0424-2261)
- Graham E. Ball (ORCID: https://orcid.org/0000-0002-0716-2286)
- Ingo Krossing (ORCID: https://orcid.org/0000-0002-7182-4387)
- Manuel Schmitt (ORCID: https://orcid.org/0000-0003-1670-4099)
- Leslie D. Field (ORCID: https://orcid.org/0000-0001-5519-5472)
Institutions
- University of Freiburg (DE)
- Heidelberg University (DE)
- UNSW Sydney (AU)
Publication Details
- Journal
- Journal of the American Chemical Society
- Published
- 2025-09-13
- DOI
- https://doi.org/10.1021/jacs.5c13214
- Primary Topic
- Ammonia Synthesis and Nitrogen Reduction
- Type
- article
- Field-Weighted Citation Impact
- 0.00