title: N-C bond formation promoted by a hafnocene dinitrogen complex: comparison of zirconium and hafnium congeners.
abstract: Nitrogen-carbon bond formation from coordinated dinitrogen has been observed upon addition of 2 equiv of PhNCO to the hafnocene dinitrogen complex, [(eta5-C5Me4H)2Hf]2(mu2,eta2,eta2-N2). The resulting product most likely arises from initial N=C cycloaddition of the first equivalent of heterocumulene, followed by carbonyl insertion of a second equivalent into the newly formed hafnium-nitrogen bond. The resulting product has considerable hafnium imido character, as evidenced by the metrical parameters determined from the solid-state structure as well as reactivity studies, whereby PhNCO, p-tolyl isocyanate, and t-BuCCH each undergo cycloaddition with the hafnium-nitrogen bond. The origin of the nitrogen-carbon-forming chemistry is likely derived from the reluctance of the hafnocene dinitrogen complex to undergo ligand-induced N2 isomerization, as was observed with the zirconium congener.
authors.affiliation: Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Wesley H
authors.initials: WH
authors.lastname: Bernskoetter
authors.forename: Andrea V
authors.initials: AV
authors.lastname: Olmos
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Pool
authors.forename: Emil
authors.initials: E
authors.lastname: Lobkovsky
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chirik