@article {1113,
	title = {Intramolecular C-H and N-H transfer by ruthenium(II) amidophosphine complexes},
	journal = {Organometallics},
	volume = {24},
	number = {22},
	year = {2005},
	note = {ISI Document Delivery No.: 976PNTimes Cited: 6Cited Reference Count: 51},
	month = {Oct},
	pages = {5440-5454},
	type = {Article},
	abstract = {The formation of ruthenium amidophosphine complexes was accomplished by the addition Of [P2N2]Li-2(Diox) (where P2N2 is PhP(CH2SiMe2NSiMe2CH2)(2)PPh and Diox is 1,4-dioxane) to [RuCl2(cod)](x) to generate [P2N2]Ru(cod), or to RuCl2(PPh3)(3) to generate [P2NNH]Ru(C6H4PPh2) In the former complex, the Ru(II) center is in an octahedral environment perched above the P2N2 macrocycle having two formally anionic amido donors; in the latter complex, there is only one amido ligand with the other as an amine donor where the proton originates from the cyclometalated triphenylphosphine group. Reaction of the tridentate amidophosphine ligand precursor [NPN]Li-2(THF)(2) (where NPN is PhP(CH2SiMe2NPh)(2)) with [RuCl2(cod)](x) results in the formation of two diastereomeric complexes of the formula [NPNH]Ru(eta(3):eta(2)-C8H11), wherein the cyclooctadiene ligand has been deprotonated by the ancillary ligand to generate a cyclooctadienyl unit. These Ru(II) complexes are five-coordinate with a bidentate PN ligand and a dangling amine unit. The diastereomers are in equilibrium, as shown by variable-temperature NMR studies. The fluxional process that interconverts diastereomers involves proton transfer from the dangling amine arm to the amido unit, a process that equilibrates the two ends of the tridentate NPN ligand on the chemical time scale. Deprotonation of the amine arm by MN(SiMe3)(2) generates a series of ruthenate complexes of the formula [M(THF)]([NPN]Ru(eta(3):eta(2)-C8H11)), where M = Li or Na. Addition of Me3SiCl results in the formation of new diastereomers that contain silylated dangling arms, and these diastereomers do not interconvert.},
	keywords = {ACTIVATION, AMIDO COMPLEXES, asymmetric, D6 ML5 COMPLEXES, ENANTIOSELECTIVE HYDROGENATION, EXCHANGE-REACTIONS, HYDROGENATION, KETONES, OPPORTUNITIES NOBEL LECTURE, RU-X BOND, STEREOSELECTIVE HYDROGENATION},
	isbn = {0276-7333},
	url = {<Go to ISI>://000232745700031},
	author = {Fryzuk,Michael D. and Petrella, M. J. and Patrick, B. O.}
}
@article {7248,
	title = {MUONIUM REACTION-KINETICS WITH THE HYDROGEN HALIDE GASES},
	journal = {Journal of Chemical Physics},
	volume = {97},
	number = {9},
	year = {1992},
	note = {ISI Document Delivery No.: JX295Times Cited: 14Cited Reference Count: 80},
	month = {Nov},
	pages = {6309-6321},
	type = {Article},
	abstract = {The reaction rates of the muonium (Mu) atom with HBr and HI in approximately 1 atm N2 moderator have been measured over the temperature range 160-490 K using the muSR technique. While both abstraction and exchange reactions are possible, only the abstraction reaction should be observable, being moderately exothermic. Comparisons with the corresponding H(D) reactions reveal small kinetic isotope effects in both reactions, which do not vary strongly with temperature (k(Mu)/k(H) almost-equal-to 3.5 near 300 K), consistent with the (classical) ratio of mean velocities. Surprisingly, quantum tunneling, normally facile for similarly exothermic reactions of the ultralight Mu atom (m(Mu)/M(H) almost-equal-to 1/9), appears to be of little importance here. This despite the fact that the (temperature-independent) experimental activation energies are much less than the expected vibrationally adiabatic barrier heights (estimated to be almost-equal-to 1. 5 kcal mol-1) and, particularly in the case of Mu + HI, much less than the corresponding H-atom activation energy: 0. 13 +/- 0.03 vs 0.70 +/- 0. 3 kcal mol-1. In the case of reactions with HBr, the experimental Mu- and H-atom activation energies are much more similar: 0. 51 +/- 0.03 and 0.74 +/- 0. 12 kcal mol-1, respectively, over comparable temperature ranges. These data pose a conundrum in which several compensating effects related to the much lighter Mu-atom mass seem to be involved. Theoretical calculations are urgently required. In our view the topography of the potential-energy surface(s) for H-2X is poorly known, particularly in the region of the barrier. It may be that the abstraction barriers for both Mu + HI and Mu + HBr are considerably later and even smaller than current calculations indicate, resulting in a cancellation of the effects of zero-point-energy shifts and quantum tunneling at the transition state. Differences in skewing angles between Mu and H + HX could favor a shorter tunneling path for the H-atom reaction, possibly compensating for its heavier mass. Steric or rebound effects from "bottlenecks" on the (mass-weighted) potential surfaces for Mu reactivity may also play some role. An upper limit for the 300 K reaction rate of Mu + HCI is given as well. In contrast to both HBr and HI, this reaction is quite endothermic and hence exhibits an inverse kinetic isotope effect (k(Mu) much less than k(H)).},
	keywords = {ABSTRACTION REACTIONS, CALCULATIONS, CHEMICAL-REACTIONS, EV COLLISION ENERGY, EXCHANGE-REACTIONS, H+HX COLLISIONS, ISOTOPIC, POTENTIAL-ENERGY SURFACE, QUANTUM-MECHANICAL, RATE CONSTANTS, TRANSITION-STATE THEORY, VARIANTS},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1992JX29500038},
	author = {Gonzalez, A. C. and Tempelmann, A. and Arseneau, D. J. and Fleming, Donald G. and Senba, M. and Kempton, J. R. and Pan, J. J.}
}
