Molybdenum‐Mediated N<sub>2</sub>‐Splitting and Functionalization in the Presence of a Coordinated Alkyne
Hannah K. Wagner, Hubert Wadepohl, Joachim Ballmann
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 N 2 ‐complex, which is converted to a dinuclear μ ‐( η 1 : η 1 )‐N 2 ‐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 N 2 .