title: Nitride formation by thermolysis of a kinetically stable niobium dinitrogen complex.
abstract: The reduction of [P(2)N(2)]NbCl (where [P(2)N(2)] = PhP(CH(2)SiMe(2)NSiMe(2)CH(2))(2)PPh) with KC(8) under a dinitrogen atmosphere generates the paramagnetic dinuclear dinitrogen complex ([P(2)N(2)]Nb)(2)(mu-N(2)) (2). Complex 2 has been characterized crystallographically and by EPR spectroscopy. Variable-temperature magnetic susceptibility measurements indicate that 2 displays antiferromagnetic coupling between two Nb(IV) (d(1)) centers. A density functional theory calculation on the model complex [(PH(3))(2)(NH(2))(2)Nb](2)(mu-N(2)) was performed. Thermolysis of ([P(2)N(2)]Nb)(2)(mu-N(2)) in toluene generates the paramagnetic bridging nitride species where one N atom of the dinitrogen ligand inserts into the macrocycle backbone to form [P(2)N(2)]Nb(mu-N)Nb[PN(3)] (3) (where [PN(3)] = PhPMe(CHSiMe(2)NSiMe(2)CH(2)P(Ph)CH(2)SiMe(2)NSiMe(2)N)). Complex 3 has been characterized in the solid state as well as by variable-temperature magnetic susceptibility measurements. The reaction of ([P(2)N(2)]Nb)(2)(mu-N(2)) with phenylacetylene displaces the dinitrogen fragment to generate a paramagnetic eta(2)-alkyne complex, [P(2)N(2)]Nb(eta(2)-HCCPh) (4).
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada. fryzuk@chem.ubc.ca
authors.forename: Michael D
authors.initials: MD
authors.lastname: Fryzuk
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kozak
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bowdridge
authors.forename: Brian O
authors.initials: BO
authors.lastname: Patrick
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Rettig