@article {1253,
	title = {Activation and cleavage of alkynes by the dinuclear tantalum complexes ([NPN]Ta)(2)(mu-H)(4) and ([NPN]Ta)(2)(mu-eta(1):eta(2)-N-2)(mu-H)(2) (where NPN = PhP(CH2SiMe2NPh)(2))},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {83},
	number = {6-7},
	year = {2005},
	note = {ISI Document Delivery No.: 963UVTimes Cited: 4Cited Reference Count: 29},
	month = {Jun},
	pages = {652-660},
	type = {Article},
	abstract = {Reaction of phenylacetylene with the dinuclear tetrahydride complex ([NPN]Ta)(2)(mu-H)(4) gives the product ([NPN]Ta)(2)(mu-PhCCH)(mu-H)(2) (where NPN is PhP(CH2SiMe2NPh)(2)). Activation of other terminal alkynes by ([NPN]Ta)(2)(mu-H)(4) accesses ([NPN]Ta)(2)(mu-RCCH)(mu-H)(2) (R = n-Pr, t-Bu). Crystallographic analysis of the R = Ph derivative showed it to be a bis(mu-alkylidene) bound asymmetrically to the two tantalum centres. Storage of solutions of ([NPN]Ta)(2)(mu-PhCCH)(mu-H)(2) under vacuum promotes the loss of H-2 and cleavage of the C-C bond to give a bis(mu-alkylidyne) complex, ([NPN]Ta)(2)(mu-CPh)(mu-CH). Addition of diphenylacetylene did not give the desired ([NPN]Ta)(2)(mu-CPh)(2), but rather promotes a complex decomposition of the supporting [NPN] ligands. Reaction of phenylacetylene with the dinitrogen complex ([NPN]Ta)(2)(mu-eta(1):eta(2)-N-2)(mu-H)(2) results in the dissociation of the bound dinitrogen and the formation of ([NPN]Ta)(2)(mu-PhCCH)(mu-H)(2), which is identical to that derived from the reaction with the dinuclear tetrahydride.},
	keywords = {activation of small molecules, alkylidene, alkylidyne, ALKYLIDYNE COMPLEXES, ALKYNE, amidodiphosphine, BONDS, DIAMIDOPHOSPHINE COMPLEXES, DINITROGEN CLEAVAGE, DINUCLEAR, END-ON, FUNCTIONALIZATION, hydride dinitrogen, LIGAND, N-2, NIOBIUM(III), SIDE-ON, tantalum},
	isbn = {0008-4042},
	url = {<Go to ISI>://000231832500020},
	author = {Shaver, M. P. and Johnson, S. A. and Fryzuk,Michael D.}
}
@article {4326,
	title = {Density functional study of spin state in CpM(NO)X-2 (M=Mo, Cr; X=Cl, NH2, CH3): Spectrochemical and nephelauxetic effects in organometallic compounds},
	journal = {Organometallics},
	volume = {17},
	number = {4},
	year = {1998},
	note = {ISI Document Delivery No.: YY508Times Cited: 19Cited Reference Count: 83},
	month = {Feb},
	pages = {615-622},
	type = {Article},
	abstract = {The relationship between spin state and metal-ligand bonding interactions in CpM(NO)Xa species was investigated using density functional computational techniques. The geometries of CpM(NO)Cl-2 (M = Cr, Mo), CpCr(NO)(NH2)X, and CpCr(NO)(CH3)X (X = Cl, CH3) were optimized at the DFT-B3LYP level for both the diamagnetic (S = 0) and paramagnetic (S = 1) electronic configurations. While the geometric parameters of the singlet compounds matched well with structures determined experimentally, the Cr-NO bond lengths in the triplet Species exceeded the experimentally observed range by a significant margin, thereby indicating a propensity for nitrosyl-ligand dissociation from the high-spin complexes. The order of relative singlet vs triplet spin-state stability (expressed as Delta Es-t (kcal/mol)) was determined to be CpCr(NO)Cl-2 (8.20) > CpCr(NO)(CH3)Cl (1.52) approximate to CpCr(NO)(NH2)Cl (0.95), > CpCr(NO)(CH3)(2) (-2.37) > CpCr(NO)(NH2)CH3 (-9.55) > CpMQ(NO)Cl-2 (-17.62). The amide pi-donation increases the HOMO-LUMO energy splitting, thus favoring the diamagnetic configuration. The alkyl ligand reduces the electron-electron repulsion through orbital expansion, thereby lowering the relative energy of the singlet state. Extended Huckel molecular-orbital calculations were performed on the DFT-optimized structures to help rationalize the metal-ligand bonding interactions, and interelectron repulsions were quantified by evaluation of the Coulomb (S) and exchange (K) integrals based on the B3LYP-optimized triplet spin-state geometries.},
	keywords = {DINITROGEN CLEAVAGE, EFFECTIVE CORE POTENTIALS, GROUP-6 COMPLEXES, LIGANDS, MOLECULAR CALCULATIONS, NITROSYL CHEMISTRY, OLEFIN POLYMERIZATION, PI-ACCEPTOR, POLYMERIZATION CATALYSTS, TRANSITION-METAL COMPLEXES, X-RAY},
	isbn = {0276-7333},
	url = {<Go to ISI>://000072154500023},
	author = {Legzdins,Peter and McNeil, W. S. and Smith, K. M. and Poli, R.}
}
