@article {619,
	title = {Diamidophosphine complexes of niobium(III) and (IV): imide formation via ancillary ligand decomposition},
	journal = {Inorganica Chimica Acta},
	volume = {350},
	year = {2003},
	note = {ISI Document Delivery No.: 700BTTimes Cited: 10Cited Reference Count: 32},
	month = {Jul},
	pages = {293-298},
	type = {Article},
	abstract = {The diamidophosphine complexes of niobium (CyPh)[NPN]NbCl(DME) (2), (CyPh)[NPN]NbCl2 (6), and (PhPh)[NPN]NbCl2 (9), where (RR{\textquoteright})[NPN]=RP(CH2SiMe2NR{\textquoteright})(2) have been prepared, isolated and characterized. Generation of (RR{\textquoteright})[NPN]NbCl(DME) species competes with the production of ((RR{\textquoteright})[NPN]NbCl)(2)(mu-N-2) and can be controlled with N-2 pressure. (CyPh)[NPN]NbCl2 spontaneously decomposes into (CyPh)[NPN]NbCl(=NPh) (7), CyP(CH2SiMe2)(2)NPh (8), and a paramagnetic impurity. Compound 7 was characterized by an X-ray diffraction study and its structural features are discussed. The Nb-N-imido bond length is 1.789(2) Angstrom with a Nb-N-imido-C bond angle of 167.9(2)degrees in a distorted square pyramidal structure. Reduction of (PhPh)[NPN]NbCl2 (9), with KC8 produced (PhPh)[NPN]NbCl(=NPh), PhP(CH2SiMe2)(2)NPh, and a paramagnetic impurity. (C) 2002 Elsevier Science B.V. All rights reserved.},
	keywords = {ALKYNES, COORDINATION, diamidophosphine ligands, imido, MECHANISM, MEDIATED IMINE METATHESIS, NIOBIUM, ORGANOIMIDO COMPLEXES, REDUCTION, ROUTE, Si-N bond cleavage, tantalum},
	isbn = {0020-1693},
	url = {<Go to ISI>://000184093300036},
	author = {Fryzuk,Michael D. and Shaver, M. P. and Patrick, B. O.}
}
@article {4546,
	title = {Synthesis and structure of the tantalum trimethyl complex [P2N2]TaMe3 and its conversion to the tantalum methylidene species [P2N2]Ta = CH2(Me) ([P2N2] = PhP(CH2SiMe2NSiMe2CH2)(2)PPh)},
	journal = {Organometallics},
	volume = {18},
	number = {20},
	year = {1999},
	note = {ISI Document Delivery No.: 244CDTimes Cited: 25Cited Reference Count: 42},
	month = {Sep},
	pages = {4059-4067},
	type = {Article},
	abstract = {A tantalum(V) trimethyl complex and its photolysis product, a relatively stable tantalum(V) methyl methylidene, were prepared using the macrocyclic bis(amido-phosphine) PhP(CH2SiMe2NSiMe2CH2)(2)PPh, abbreviated [P2N2], as an ancillary ligand. The methylidene precursor [P2N2]TaMe3 is generated by the reaction of [P2N2]Li-2. C4H8O2 (C4H8O2 = 1,4-dioxane) with TaMe3Cl2. The solid-state X-ray molecular structure demonstrates that the geometry of [P2N2]TaMe3 is a seven-coordinate capped trigonal prism, and NMR studies confirm this is also true in solution at low temperature. Photolysis with a UV source generates [P2N2]Ta=CH2(Me), with the elimination of methane. The X-ray solid-state molecular structure of [P2N2]Ta=CH2(Me) is intermediate between octahedral and trigonal-prismatic geometry. Variable-temperature NMR studies demonstrate that the double-bonded methylidene moiety rotates with a barrier of 33.5 +/- 0.6 kJ/mol, in contrast to the larger barrier estimated for the previously characterized 18-electron complex (eta(5)-C5H5)(2)Ta=CH2(Me). Reaction of [P2N2]TaMe3 with Ph3C+BF4- or PhNMe2H+B(C6F5)(4)(-) produced {[P2N2]TaMe2}+BF4- and {[P2N2]TaMe2}B+(C6F5)(4)(-), respectively. Attempts to deprotonate {[P2N2]TaMe2}(+) did not provide a chemical route to [P2N2]Ta=CH2(Me) and instead generated either [P2N2]TaMe2F or the product of deprotonation of the [P2N2] ligand methylene backbone, Ta(Me-2)[(CHSiMe2NSiMe2CH2P(Ph)CH2SiMe2NSiMe2CH2PPh)], depending on the base and counteranion used.},
	keywords = {ABSTRACTION, CATALYSIS, COORDINATION, CRYSTAL-STRUCTURES, DECOMPOSITION, DERIVATIVES, imido, METAL-CARBON BONDS, METHYLENE COMPLEX, REACTIVITY},
	isbn = {0276-7333},
	url = {<Go to ISI>://000083033500019},
	author = {Fryzuk,Michael D. and Johnson, S. A. and Rettig, S. J.}
}
