@article{engelman_feng_ison_2011, title={C-H Bond Functionalization of Benzoic Acid: Catalytic Synthesis of 2-Hydroxy-6H-benzo[c]chromen-6-ones Using (Cp*IrCl2)(2)}, volume={30}, ISSN={["1520-6041"]}, DOI={10.1021/om200343b}, abstractNote={Catalytic H/D exchange reactions of benzene and benzoic acid with deuterated solvents have been studied using (Cp*IrCl2)2. A 1:1 mixture of D2O/CD3OD produced the highest turnover numbers for benzene. High levels of deuterium incorporation into benzoic acid were observed only when sodium acetate was added to the reaction mixture. Attempts at producing hydroxybenzoic acid by catalytic C–H functionalization of benzoic acid with benzoquinone were unsuccessful. Instead, 2-hydroxy-6H-benzo[c]chromen-6-one was isolated as the major product. An array of substituted benzoic acids was analyzed for this functionalization reaction. Preliminary mechanistic studies indicate that the benzochromenones are formed by C–H bond activation of benzoic acid followed by insertion of benzoquinone into the iridium–carbon bond.}, number={17}, journal={ORGANOMETALLICS}, author={Engelman, Kristi L. and Feng, Yuee and Ison, Elon A.}, year={2011}, month={Sep}, pages={4572–4577} }
 @article{feng_jiang_boyle_ison_2010, title={Effect of Ancillary Ligands and Solvents on H/D Exchange Reactions Catalyzed by Cp*Ir Complexes}, volume={29}, ISSN={["1520-6041"]}, DOI={10.1021/om100018x}, abstractNote={A series of complexes of the form Cp*Ir(NHC)(X)n and [Cp*Ir(NHC)(L)2][OTf]2, where NHC = 1,3,4,5-tetramethylimidazol-2-ylidene (n = 2, X = Cl− (1-Cl), NO3− (1-NO3), −OC(O)CF3 (=TFA, 1-TFA); n = 1, X = SO42− (1-SO4); L = H2O (1-H2O), CH3CN (1-CH3CN), OTf = trifluoromethanesulfonato), were prepared. X-ray crystal structures of 1-OH2, 1-SO4, and 1-NO3 and the dimeric complex [(Cp*Ir(NHC)Cl)2][OTf]2 (2) were obtained. In solution, the complex 1-TFA was found to exist in equilibrium with [Cp*Ir(NHC)(OH2)2][OCOCF3]2 (1-aqua-TFA), where the aqua ligands are strongly hydrogen bound to the −OCOCF3 counterion. A van’t Hoff plot from −10 to 30 °C yielded values for the reaction enthalpy and entropy of ΔH° = −7.6 ± 0.7 kcal/mol and ΔS° = −30.6 ± 2.4 eu, respectively. These data are consistent with the observation that at higher temperatures the complex 1-TFA is favored. An X-ray crystal structure of 1-aqua-TFA was obtained. Catalytic H/D exchange reactions between benzene and various deuterium sources (CD3OD, CF3COOD...}, number={13}, journal={ORGANOMETALLICS}, author={Feng, Yuee and Jiang, Bi and Boyle, Paul A. and Ison, Elon A.}, year={2010}, month={Jul}, pages={2857–2867} }
 @article{feng_aponte_houseworth_boyle_ison_2009, title={Synthesis of Oxorhenium(V) Complexes with Diamido Amine Ancillary Ligands and Their Role in Oxygen Atom Transfer Catalysis}, volume={48}, ISSN={["1520-510X"]}, DOI={10.1021/ic901434u}, abstractNote={The detailed syntheses of complexes of the form [Re(O)(X)(RNCH(2)CH(2))(2)N(Me)] (X = Me, Cl, I, R = mesityl, C(6)F(5)), 1-3, incorporating diamidoamine ancillary ligands are described. X-ray crystal structures for the complexes [Re(O)(Me)((C(6)F(5))NCH(2)CH(2))(2)N(Me)], 1a, [Re(O)(I)((C(6)F(5))N CH(2)CH(2))(2)N(Me)], 3a, and [Re(O)(I)((Mes)NCH(2))(2)N(Me)], 3b, are reported. The geometry about the metal center in 1a is best described as a severely distorted square pyramid with the oxo ligand in the apical position. In contrast, the geometry about the metal center in 3a is best described as a severely distorted trigonal bipyramid, with the iodo ligand occupying the apical position and the diamido nitrogens and the oxo ligand occupying the equatorial plane. The catalytic activities of these complexes for oxygen atom transfer, OAT, from pyridine-N-oxides, PyO, to PPh(3) were also examined. The reactions exhibited a clear dependence on the diamido ligand substituent and the X ligand (Me, I, Cl) attached to the metal, with the combined effect that electron-withdrawing substituents on the diamido ligand and poor sigma donors directly attached to the metal center increases the rate of catalytic activity. The kinetics of OAT from pyridine-N-oxides to Re were also investigated. The reactions displayed clean first order kinetics in Re and saturation kinetics for the dependence on PyO. Changing the PyO substrate had no effect on the saturation value, k(sat), suggesting that the OAT reaction in these five-coordinate complexes appears to be governed by isomerization of the starting complex. Attempts to isolate a postulated Re(VII) intermediate were not successful because of hydrolytic degradation. The product of hydrolytic degradation [((C(6)F(5))N(H)CH(2)CH(2)))(2)NH(Me)][X], (X = ReO(4)(-), or I(-)), 4 can be isolated, and its X-ray crystal structure is reported. Although the Re(VII) intermediate could not be isolated, its activity in OAT reactions was probed by competition experiments with PPh(3) and four para-substituted triarylphosphines (p-X-Ph)(3)P (X = OMe, Me, Cl, CF(3)). These experiments led to a Hammett that yielded a reaction constant of rho = -0.30 +/- 0.01. This data suggests a positive charge buildup on phosphorus for the OAT reaction and is consistent with the nucleophilic attack of phosphorus on an electrophilic metal oxo.}, number={23}, journal={INORGANIC CHEMISTRY}, author={Feng, Yuee and Aponte, Joel and Houseworth, Paul J. and Boyle, Paul D. and Ison, Elon A.}, year={2009}, month={Dec}, pages={11058–11066} }
 @article{jiang_feng_ison_2008, title={Mechanistic Investigations of the Iridium(III)-Catalyzed Aerobic Oxidation of Primary and Secondary Alcohols}, volume={130}, ISSN={0002-7863 1520-5126}, url={http://dx.doi.org/10.1021/ja8049595}, DOI={10.1021/ja8049595}, abstractNote={The commercially available catalysts [(Cp*IrCl2)2] is employed with O2 as the terminal oxidant in the presence of catalytic amounts of Et3N for the aerobic oxidation of primary and secondary alcohols. A new mechanism for the Ir-catalyzed aerobic oxidation is also presented that suggests that the transition metal maintains its +3 oxidation state throughout the entire catalytic cycle.}, number={44}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Jiang, Bi and Feng, Yuee and Ison, Elon A.}, year={2008}, month={Nov}, pages={14462–14464} }
 @article{munro-leighton_feng_zhang_alsop_gunnoe_boyle_petersen_2008, title={Preparation and reactivity of a monomeric octahedral platinum(IV) amido complex}, volume={47}, DOI={10.1021/icS00843b}, number={14}, journal={Inorganic Chemistry}, author={Munro-Leighton, C. and Feng, Y. and Zhang, J. and Alsop, N. M. and Gunnoe, T. B. and Boyle, P. D. and Petersen, J. L.}, year={2008}, pages={6124–6126} }
 @article{feng_lail_foley_gunnoe_barakat_cundari_petersen_2006, title={Hydrogen-deuterium exchange between TpRu( PMe3)(L)X (L) = PMe3 and X = OH, OPh, Me, Ph, or NHPh; L = NCMe and X = Ph) and deuterated arene solvents: Evidence for metal-mediated processes}, volume={128}, ISSN={["1520-5126"]}, DOI={10.1021/ja0615775}, abstractNote={At elevated temperatures (90-130 degrees C), complexes of the type TpRu(PMe3)2X (X = OH, OPh, Me, Ph, or NHPh; Tp = hydridotris(pyrazolyl)borate) undergo regioselective hydrogen-deuterium (H/D) exchange with deuterated arenes. For X = OH or NHPh, H/D exchange occurs at hydroxide and anilido ligands, respectively. For X = OH, OPh, Me, Ph, or NHPh, isotopic exchange occurs at the Tp 4-positions with only minimal deuterium incorporation at the Tp 3- or 5-positions or PMe3 ligands. For TpRu(PMe3)(NCMe)Ph, the H/D exchange occurs at 60 degrees C at all three Tp positions and the phenyl ring. TpRu(PMe3)2Cl, TpRu(PMe3)2OTf (OTf = trifluoromethanesulfonate), and TpRu(PMe3)2SH do not initiate H/D exchange in C6D6 after extended periods of time at elevated temperatures. Mechanistic studies indicate that the likely pathway for the H/D exchange involves ligand dissociation (PMe3 or NCMe), Ru-mediated activation of an aromatic C-D bond, and deuteration of basic nondative ligand (hydroxide or anilido) or Tp positions via net D+ transfer.}, number={24}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Feng, Yuee and Lail, Marty and Foley, Nicholas A. and Gunnoe, T. Brent and Barakat, Khaldoon A. and Cundari, Thomas R. and Petersen, Jeffrey L.}, year={2006}, month={Jun}, pages={7982–7994} }
 @article{feng_gunnoe_grimes_cundari_2006, title={Octahedral [TpRu(PMe3)(2)OR](n+) complexes (Tp = hydridotris(pyrazolyl) borate; R = H or Ph; n=0 or 1): Reactions at Ru(II) and Ru(III) oxidation states with substrates that possess carbon-hydrogen bonds}, volume={25}, ISSN={["1520-6041"]}, DOI={10.1021/om0606385}, abstractNote={The Ru(II) complexes TpRu(PMe3)2OR (R = H or Ph) react with excess phenylacetylene at elevated temperatures to produce the phenylacetylide complex TpRu(PMe3)2(C⋮CPh). Kinetic studies indicate that the reaction of TpRu(PMe3)2OH and phenylacetylene likely proceeds through a pathway that involves TpRu(PMe3)2OTf as a catalyst. The reaction of TpRu(PMe3)2OH with 1,4-cyclohexadiene at elevated temperature forms benzene and TpRu(PMe3)2H, while TpRu(PMe3)2OPh does not react with 1,4-cyclohexadiene even after 20 days at 85 °C. The paramagnetic Ru(III) complex [TpRu(PMe3)2OH][OTf] is formed upon single-electron oxidation of TpRu(PMe3)2OH with AgOTf. Reactivity studies suggest that [TpRu(PMe3)2OH][OTf] initiates reactions, including hydrogen atom abstraction, with C−H bonds that have bond dissociation energy < 80 kcal/mol. Experimentally, the O−H bond strength of the Ru(II) cation [TpRu(PMe3)2(OH2)][OTf] is estimated to be between 82 and 85 kcal/mol, while computational studies yield a BDE of 84 kcal/mol, which are ...}, number={22}, journal={ORGANOMETALLICS}, author={Feng, Yuee and Gunnoe, T. Brent and Grimes, Thomas V. and Cundari, Thomas R.}, year={2006}, month={Oct}, pages={5456–5465} }