@article {2116,
	title = {Amine-tethered N-heterocyclic carbene complexes of rhodium(I)},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {86},
	number = {8},
	year = {2008},
	note = {ISI Document Delivery No.: 329TMTimes Cited: 9Cited Reference Count: 50Jong, Howard Patrick, Brian O. Fryzuk, Michael D.},
	month = {Aug},
	pages = {803-810},
	type = {Article},
	abstract = {A new family of rhodium-diene based complexes has been developed that incorporates an N-heterocyclic carbene ligand with an N-donor tether. The ligand is denoted (Mes)[CNH] 2 (where (Mes)[CNH] is 2,4,6-Me3C6H2NC3H2NCH2CH2NH-2,4,6-Me3C6H2) and (Mes)[CN] for the amido form. The synthesis of the (Mes)[CNH] ligand involves reaction of N-mesitylimidazole with 2-chloroethyl-N-mesitylamine under melt conditions, followed by deprotonation with KN(SiMe3)(2). The reaction of (Mes)[CNH] with [(diene)RhCl](2) results in the formation of the monodentate complexes, (Mes)[CNH]Rh(diene)Cl (where diene = 1,5-cyclooctadiene (COD): 3a; diene = 2,5-norbornadiene (NBD): 3b). Bidentate variants could be isolated as either a neutral species, (Mes)[CN]Rh(diene) 4a-4b, via deprotonation, or an ionic analogue such as [(Mes)[CNH]Rh(diene)]BF4 5a-5b by reaction with NaBF4. Compounds 4-5 are the first examples of rhodium compounds that contained a bidentate NHC ligand with a pendant amino or amido donor. Complexes 3-5 were characterized fully and the solid-state single crystal X-ray structures of 3a, 4a, and 5b are discussed. The utility of these complexes as catalyst precursors for hydrogenation reactions was examined and it was determined that these systems are not significantly more active than colloidal rhodium when parallel reactions were run. Various methods of transfer hydrogenations were also investigated with 3a, which did not yield an appreciable conversion of either benzophenone or N-benzylideneaniline as substrates.},
	keywords = {CATALYSIS, HYDROGENATION, HYDROSILYLATION CATALYSTS, imines, IRIDIUM, KETONES, LIGANDS, N-heterocyclic carbene, REACTIVITY, rhodium, SEARCH, STABLE CARBENES, TRANSFER HYDROGENATION},
	isbn = {0008-4042},
	url = {<Go to ISI>://000257893500010},
	author = {Jong, H. and Patrick, B. O. and Fryzuk,Michael D.}
}
@article {1572,
	title = {Synthesis, reactivity, and DFT studies of tantalum complexes incorporating diamido-N-heterocyclic carbene ligands. Facile endocyclic C-H bond activation},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {38},
	year = {2006},
	note = {ISI Document Delivery No.: 085OFTimes Cited: 25Cited Reference Count: 73Spencer, Liam P. Beddie, Chad Hall, Michael B. Fryzuk, Michael D.},
	month = {Sep},
	pages = {12531-12543},
	type = {Article},
	abstract = {The syntheses of tantalum derivatives with the potentially tridentate diamido-N-heterocyclic carbene (NHC) ligand are described. Aminolysis and alkane elimination reactions with the diamine-NHC ligands, (Ar)[NCN]H-2 (where (Ar)[NCN]H-2 = (ArNHCH2CH2)(2)(C3N2); Ar = Mes, p-Tol), provided complexes with a bidentate amide-amine donor configuration. Attempts to promote coordination of the remaining pendent amine donor were unsuccessful. Metathesis reactions with the dilithiated diamido-NHC ligand ((Ar)[NCN]-Li-2) and various ClxTa(NR{\textquoteright}(2))(5-x) precursors were successful and generated the desired octahedral (Ar)[NCN]TaClx(NR{\textquoteright}(2))(3-x) complexes. Attempts to prepare trialkyl tantalum complexes by this methodology resulted in the formation of an unusual metallaaziridine derivative. DFT calculations on model complexes show that the strained metallaaziridine ring forms because it allows the remaining substituents to adopt preferable bonding positions. The calculations predict that the lowest energy pathway involves a tantalum alkylidene intermediate, which undergoes C-H bond activation R to the amido to form the metallaaziridine moiety. This mechanism was confirmed by examining the distribution of deuterium atoms in an experiment between (Mes)[NCN]Li-2 and Cl2Ta(CD2Ph)(3). The single-crystal X-ray structures of (p-Tol)[NCNH]Ta(NMe2)(4) (3), (Mes)[NCNH]Ta=CHPh(CH2Ph)(2) (4), (p-Tol)[NCN]Ta(NMe2)(3) (7), (Mes)[NCCN]Ta((CH2Bu)-Bu-t)(2) (11), and (Mes)[NCCN]-TaCl((CH2Bu)-Bu-t) (14) are included.},
	keywords = {COORDINATION CHEMISTRY, CRYSTAL-STRUCTURE, EFFECTIVE CORE POTENTIALS, GAUSSIAN-TYPE BASIS, METAL-CARBON BONDS, METHODS, MOLECULAR-ORBITAL, ORGANIC-MOLECULES, SET MODEL CHEMISTRY, STABLE CARBENES, STRUCTURAL-CHARACTERIZATION},
	isbn = {0002-7863},
	url = {<Go to ISI>://000240612700055},
	author = {Spencer, L. P. and Beddie, C. and Hall, M. B. and Fryzuk,Michael D.}
}
@article {1263,
	title = {Synthesis and reactivity of zirconium and hafnium complexes incorporating chelating diamido-N-heterocyclic-carbene ligands},
	journal = {Journal of Organometallic Chemistry},
	volume = {690},
	number = {24-25},
	year = {2005},
	note = {ISI Document Delivery No.: 994VFTimes Cited: 36Cited Reference Count: 51},
	month = {Dec},
	pages = {5788-5803},
	type = {Article},
	abstract = {Early transition metal complexes employing a diamido N-heterocyclic carbene (NHC) ligand set (denoted [NCN]) render the centrally disposed NHC moiety stable to dissociation. Aminolysis reactions with the mesityl-substituted ligand precursor ((Mes)[NCN]H-2) and M(NMe2)(4) (M = Zr, Hf) provide bis(amido)-NHC-metal complexes that can be further converted to chloro and alkyl derivatives. Activation of (Mes)[NCN]M(CH3)(2) with [Ph3C][B(C6F5)(4)] yields {(Mes)[NCN]MCH3} {B(C6F5)(4)}, which is surprisingly inactive for the polymerization of 1-hexene. The zirconium cation did, however, show moderate ability to catalytically polymerize ethylene. The hafnium dialkyls are thermally stable with the exception of the diethyl complex, (Mes)[NCN]Hf(CH2CH3)(2), which undergoes P-hydrogen transfer and subsequent C-H bond activation with an ortho-methyl substituent on the mesityl group. The hafnium dialkyl complexes also insert carbon monoxide and substituted isocyanides to yield eta(2)-acyls and eta(2)-iminoacyls, respectively. In some circumstances, further C-C bond coupling occurs to yield enediolates and eneamidolate metallocycles. The molecular structures of (Mes)[NCN]Hf(CH2CHMe2)(2), (Mes)[NCN]Hf(eta(2)-(2,6-Me2C6H3NCCH3)(CH3), (Mes)[NCN]Hf(eta(2)-(2,6-Me2C6H3NCCH3)(2), (Mes)[NCN]Hf(OC(CH3)=C(CH3)NXy), and [(Mes)[NCN]Hf(OC(Bu-i)=C(Bu-i)O)](2) are included. (c) 2005 Elsevier B.V. All rights reserved.},
	keywords = {AMIDO, CARBON-MONOXIDE, CHEMISTRY, DONORS, ETA-2-IMINOACYL, hafnium, LIVING POLYMERIZATION, MIGRATORY INSERTION, N-heterocyclic carbene, OLEFIN, POLYMERIZATION, PROPERTIES, SPECTROSCOPIC, STABLE CARBENES, STRUCTURAL-CHARACTERIZATION, tridentate ligand, ZIRCONIUM, ZIRCONOCENE COMPLEXES},
	isbn = {0022-328X},
	url = {<Go to ISI>://000234058600046},
	author = {Spencer, L. P. and Fryzuk,Michael D.}
}
@article {990,
	title = {Tridentate amido carbene ligands in early-transition-metal coordination chemistry},
	journal = {Organometallics},
	volume = {23},
	number = {14},
	year = {2004},
	note = {ISI Document Delivery No.: 833IITimes Cited: 52Cited Reference Count: 27},
	month = {Jul},
	pages = {3372-3374},
	type = {Article},
	abstract = {Coordination of the new tridentate N-heterocyclic carbene ligand precursor (p-Me-C6H4NHCH2-CH2)(2)N2C3H2 to Zr(IV) generates an [NCN] donor set where the N represents an amido unit and the C corresponds to the N-heterocyclic carbene. This ancillary ligand allows for the isolation and structural characterization of zirconium amido, chloro, and alkyl derivatives; the carbene donor is rendered stable to dissociation because of its central disposition between two anionic amido units.},
	keywords = {COMPLEXES, CONTAIN, STABLE CARBENES, ZIRCONIUM},
	isbn = {0276-7333},
	url = {<Go to ISI>://000222330500004},
	author = {Spencer, L. P. and Winston, S. and Fryzuk,Michael D.}
}
