@article {2627,
	title = {Noninnocent Behavior of Ancillary Ligands: Apparent Trans Coupling of a Saturated N-Heterocyclic Carbene Unit with an Ethyl Ligand Mediated by Nickel},
	journal = {Journal of the American Chemical Society},
	volume = {131},
	number = {30},
	year = {2009},
	note = {ISI Document Delivery No.: 479FFTimes Cited: 6Cited Reference Count: 26Steinke, Tobias Shaw, Bryan K. Jong, Howard Patrick, Brian O. Fryzuk, Michael D. Green, Jennifer C.},
	month = {Aug},
	pages = {10461-10466},
	type = {Article},
	abstract = {Oxidative addition of the tridentate N-heterocyclic carbene (NHC) diphosphine ligand precursor ([PCP]H)PF6 (1) {[PCP] = o-(Pr2PC6H4)-Pr-i(NC3H4N)o-(C6H4PPr2)-Pr-i} to Ni(COD)(2) results in the formation of the nickel(II) hydride complex ([PCP]NiH)PF6 (2). This hydride undergoes a rapid reaction with ethylene to generate a nickel(O) complex in which an ethyl group has been transferred to the carbene carbon of the original NHC-diphosphine ligand. If the first intermediate is the anticipated square-planar nickel(II) ethyl species, then the formation of the product would require a process that involves a trans C-C coupling of the NHC carbon and a presumed Ni-ethyl intermediate. Deuterium-labeling studies provide evidence for migratory insertion of the added ethylene into the Ni-H bond rather than into the Ni-catene linkage; this is based on the observed deuterium scrambling, which requires reversible P-elimination, alkene rotation, and hydride readdition. However, density functional theory studies suggest that a key intermediate is an agostic ethyl species that has the Ni-C bond cis to the NHC unit. A possible transition state containing two cis-disposed carbon moieties was also identified. Such a process represents a new pathway for catalyst deactivation involving NHC-based metal complexes.},
	keywords = {ACTIVATION, CHEMISTRY, COMPLEXES, MECHANISM, MIGRATORY INSERTION, NHC, ORGANOMETALLIC CATALYSIS, palladium, REDUCTIVE ELIMINATION, ruthenium},
	isbn = {0002-7863},
	url = {<Go to ISI>://000268644400040},
	author = {Steinke, T. and Shaw, B. K. and Jong, H. and Patrick, B. O. and Fryzuk,Michael D. and Green, J. C.}
}
@article {2626,
	title = {Synthesis and Coordination Chemistry of a Tridentate o-Phenylene-Bridged Diphosphine-NHC System},
	journal = {Organometallics},
	volume = {28},
	number = {9},
	year = {2009},
	note = {ISI Document Delivery No.: 441CETimes Cited: 8Cited Reference Count: 48Steinke, Tobias Shaw, Bryan K. Jong, Howard Patrick, Brian O. Fryzuk, Michael D.},
	month = {May},
	pages = {2830-2836},
	type = {Article},
	abstract = {The preparation of a di-o-phenylene-bridged tridentate PCP donor set is described starting with t-BOC-aniline followed by a series of steps that include lithiation, quenching with (Pr2PCl)-P-i, conversion to the phosphine sulfide, and assembling the unsaturated N-heterocyclic carbene unit. After desulfurization, the imidazolinium unit flanked by two phosphine units, represented as [(PCP)H]PF6 is obtained. Subsequent reaction with group 10 M(0) reagents (Ni(COD)(2), Pd(PPh3)(4), and Pt(PPh3)(4)) generates good yields of the Corresponding metal hydride complexes, [(PCP)MH]PF6 salts (where M = Ni(II), Pd(II), and Pt(II)). Each of these species has been characterized by elemental analyses, NMR spectroscopy, and X-ray crystallography. All of the structures show that the PCP unit is twisted with respect to the square plane of the d(8) metal complex.},
	keywords = {BIS(BENZIMIDAZOLIN-2-YLIDENE) PALLADIUM, BONDS, C COUPLING REACTIONS, COMPLEXES, H, HETEROCYCLIC CARBENE COMPLEXES, IMIDAZOLIUM SALTS, LIGANDS, OLEFIN METATHESIS, ONE-POT SYNTHESIS, ORGANOMETALLIC CATALYSIS, OXIDATIVE ADDITION},
	isbn = {0276-7333},
	url = {<Go to ISI>://000265746100022},
	author = {Steinke, T. and Shaw, B. K. and Jong, H. and Patrick, B. O. and Fryzuk,Michael D.}
}
