Molybdenum‐Mediated N2‐Splitting and Functionalization in the Presence of a Coordinated Alkyne. Issue 49 (3rd November 2021)

• Record Type: Journal Article
• Authors: Wagner, Hannah K.; Wadepohl, Hubert; Ballmann, Joachim
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 49(2021)
• Page Start: 25804
• Page End: 25808
• Publication Date: 2021-11-03
• Subjects: molybdenum -- N-functionalization -- nitrides -- nitrogen fixation -- phosphino alkyne ligands; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202111325
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A new [PCCP]‐coordinated molybdenum platform comprising a coordinated alkyne was employed for the cleavage of molecular dinitrogen. The coordinated η 2 ‐alkyne was left unaffected during this reduction. DFT calculations suggest that the reaction proceeds via an initially generated terminal N2 ‐complex, which is converted to a dinuclear μ ‐( η 1 : η 1 )‐N2 ‐bridged intermediate prior to N−N bond cleavage. Protonation, alkylation and acylation of the resulting molybdenum nitrido complex led to the corresponding N ‐functionalized imido complexes. Upon oxidation of the N ‐acylated imido derivative in MeCN, a fumaronitrile fragment was built up via C−C coupling of MeCN to afford a dinuclear molybdenum complex. The key finding that the strong N≡N bond may be cleaved in the presence of a weaker, but spatially constrained C≡C bond contradicts the widespread paradigm that coordinated alkynes are in general more reactive than gaseous N2 . Abstract : A new molybdenum pincer for N2 ‐splitting and functionalization is reported. The N2 ‐cleavage affords a molybdenum nitrido complex and proceeds in the presence of a coordinated alkyne, that is, in the presence of a weaker C≡C bond. The spatially and rationally restricted alkyne moiety is also tolerated during N ‐functionalization of the former nitrido complex.