title: A Terminally Bound Niobium Methylidyne.
abstract: Complex (PNP)Nb(CH3)2(OAr) (PNP = N[2-P(i)Pr2-4-methylphenyl]2(-), Ar = 2,6-(i)Pr2C6H3), prepared from treatment of (PNP)NbCl3 with NaOAr followed by 2 equiv of H3CMgCl, can be oxidized with [FeCp2][OTf] to afford (PNP)Nb(CH3)2(OAr)(OTf). While photolysis of the latter resulted in formation of a rare example of a niobium methylidene, (PNP)Nb═CH2(OAr)(OTf), treatment of the dimethyl triflate precursor with the ylide H2CPPh3 produced the mononuclear group 5 methylidyne complex, (PNP)Nb≡CH(OAr). Adding a Brønsted base to (PNP)Nb═CH2(OAr)(OTf) also resulted in formation of the methylidyne. Solid-state structural analysis confirms both methylidene and methylidyne moieties to be terminal, having very short Nb-C distances of 1.963(2) and 1.820(2) Å, respectively. It is also shown that methylidyne for nitride cross-metathesis between (PNP)Nb≡CH(OAr) and NCR (R = tert-butyl or 1-adamantyl) results in formation of a neutral and mononuclear niobium nitride, (PNP)Nb≡N(OAr), along with the terminal alkyne HC≡CR.
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kurogi
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Carroll
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Mindiola