@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.}
}
@article {7029,
	title = {AN UNUSUAL 17-ELECTRON ORGANOMETALLIC RADICAL, CPCR(NO)(PPH3)(CH2SIME3)},
	journal = {Journal of the American Chemical Society},
	volume = {113},
	number = {18},
	year = {1991},
	note = {ISI Document Delivery No.: GD306Times Cited: 10Cited Reference Count: 18},
	month = {Aug},
	pages = {7049-7050},
	type = {Note},
	keywords = {BOND, COMPLEXES, NITROSYL CHEMISTRY, REACTIVITY},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1991GD30600060},
	author = {Herring, F. G. and Legzdins,Peter and McNeil, W. S. and Shaw, M. J. and Batchelor, R. J. and Einstein, F. W. B.}
}
