@article {392, title = {Synthesis, characterization, and solution redox properties of (trimpsi)M(CO)(2)(NO) complexes [M = V, Nb, Ta; trimpsi = (BuSi)-Bu-t(CH2PMe2)(3)]}, journal = {Inorganic Chemistry}, volume = {41}, number = {16}, year = {2002}, note = {ISI Document Delivery No.: 582RTTimes Cited: 7Cited Reference Count: 85}, month = {Aug}, pages = {4114-4126}, type = {Article}, abstract = {{Treatment of [Et4N][M(CO)(6)] (M = Nb, Ta) with I-2 in DME at -78 degreesC produces solutions of the bimetallic anions [M-2(mu-l)(3)(CO)(8)](-). Addition of the tripodal phosphine (BuSi)-Bu-t(CH2PMe2)(3) (trimpsi) followed by refluxing affords (trimpsi)M(CO)(3)I [M = Nb (1), Ta (2)], which are isolable in good yields as air-stable, orange-red microcrystalline solids. Reduction of these complexes with 2 equiv of Na/Hg, followed by treatment with Diazald in THF, results in the formation of (trimpsi)M(CO)(2)(NO) [M = Nb (3), Ta (4)] in high isolated yields. The congeneric vanadium complex, (trimpsi)V(CO)(2)(NO) (5), can be prepared by reacting [Et4N][V(CO)(6)] with [NO][BF4] in CH2Cl2 to form V(CO)(5)(NO). These solutions are treated with 1 equiv of trimpsi to obtain (eta(2)-trimpsi)V(CO)(3)(NO). Refluxing orange THF solutions of this material affords 5 in moderate yields. Reaction of (trimpsi)VCl3(THF) (6) with 4 equiv of sodium naphthalenide in THF in the presence of excess CO provides [Et4N][(trimpsi)V(CO)(3)] (7), (trimpsi)V(CO)(3)H, and [(trimpsi)V(mu-Cl)(3)V(trimpsi)][(eta(2)-trimpsi)V(CO)(4)].3THF ([8][9].3THF). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 2.(1)/2THF, 3-5, and [8][9].3THF have been established by X-ray diffraction analyses. The solution redox properties of 3-5 have also been investigated by cyclic voltammetry. Cyclic voltammograms of 3 and 4 both exhibit an irreversible oxidation feature in CH2Cl2 (E-p}, keywords = {CHARACTERIZATION, CHEMISTRY, DERIVATIVES, HIGHLY REDUCED ORGANOMETALLICS, ISOCYANIDE COMPLEXES, NITRIC-OXIDE, PHOSPHINE COMPLEXES, RAY CRYSTAL-STRUCTURES, SPECTROSCOPIC, tantalum, VANADIUM(II)}, isbn = {0020-1669}, url = {://000177365500013}, author = {Hayton, T. W. and Daff, P. J. and Legzdins,Peter and Rettig, S. J. and Patrick, B. O.} } @article {4565, title = {Kinetic isotope effect in the gas-phase reaction of muonium with molecular oxygen}, journal = {Journal of Physical Chemistry A}, volume = {103}, number = {13}, year = {1999}, note = {ISI Document Delivery No.: 184KQTimes Cited: 13Cited Reference Count: 101}, month = {Apr}, pages = {2076-2087}, type = {Review}, abstract = {The rate constant of the gas-phase addition reaction of the light hydrogen isotope muonium to molecular oxygen, Mn + O-2 {\textendash}> MuO(2), was measured over a range of temperatures from 115 to 463 K at a pressure of 2 bar and from 16 to 301 bar at room temperature, using N-2 as the moderator gas. The reaction remains in the termolecular regime over the entire pressure range. At room temperature, the average low-pressure limiting rate constant is k(ch)(0)(Mu) = (8.0 +/- 2.1) x 10(-33) cm(6) s(-1), a factor of almost 7 below the corresponding rate constant for the H + O-2 addition reaction, k(ch)(0)(H). In contrast to k(ch)(0)(H), which exhibits a clear negative temperature dependence, k(ch)(0)(MU) is essentially temperature independent. At room temperature, the kinetic isotope effect (KIE) is strongly pressure (density) dependent and is reversed at pressures near 300 bar. The kinetics are analyzed based on the statistical adiabatic channel model of Tree using a Morse potential, which works well in reproducing the overall KIE. The major factors governing the isotope effect are differences in the moment of inertia and density of vibrational states of the addition complex.}, keywords = {ABSOLUTE RATE, CHARACTERIZATION, COLLISION RATE CONSTANTS, CONSTANTS, ELECTRON-SPIN-EXCHANGE, LOW-PRESSURES, POTENTIAL-ENERGY SURFACE, RATE COEFFICIENTS, THEORETICAL, THERMAL UNIMOLECULAR REACTIONS, TRAJECTORY CALCULATIONS, TRANSITION-STATE THEORY}, isbn = {1089-5639}, url = {://000079611700020}, author = {Himmer, U. and Dilger, H. and Roduner, E. and Pan, J. J. and Arseneau, D. J. and Fleming, Donald G. and Senba, M.} } @article {3287, title = {Iron porphyrin catalyzed oxidation of lignin model compounds: Oxidation of phenylpropane and phenylpropene model compounds}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {73}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: TV232Times Cited: 4Cited Reference Count: 41}, month = {Dec}, pages = {2153-2157}, type = {Article}, abstract = {The oxidation of 1-(4-ethoxy-3-methoxyphenyl)propane (2) and 1-(4-ethoxy-3-methoxyphenyl)propene (3) by meso-tetra(2,6-dichloro-3-sulphonatophe)porphyrin iron chloride (TDCSPPFeCl, 1) and tert-butylhydroperoxide (t-BuOOH) are discussed. In addition to a C-alpha-hydroxylation product, demethoxylation and direct aromatic ring cleavage products were found in the oxidation of 2. When 3 was oxidized by 1 and t-BuOOH in aqueous acetonitrile, an acetonitrile-incorporated product was found. A mechanism for the oxidation of 3 is proposed.}, keywords = {AROMATIC RING CLEAVAGE, BASIDIOMYCETE PHANEROCHAETE-CHRYSOSPORIUM, C BOND-CLEAVAGE, CHARACTERIZATION, DEGRADATION, DEGRADING ENZYME, DIARYLPROPANE, HEME-ENZYME, iron porphyrin, LIGNIN, ligninase, MODEL, OXYGENASE, POTASSIUM MONOPERSULFATE, SPECTRAL, VERATRYL ALCOHOL, WHITE ROT BASIDIOMYCETE}, isbn = {0008-4042}, url = {://A1995TV23200008}, author = {Cui, F. and Dolphin, D.} } @article {3473, title = {MU+NO - KINETIC ISOTOPE EFFECTS IN UNIMOLECULAR DISSOCIATION}, journal = {Journal of Physical Chemistry}, volume = {99}, number = {47}, year = {1995}, note = {ISI Document Delivery No.: TF811Times Cited: 10Cited Reference Count: 80}, month = {Nov}, pages = {17160-17168}, type = {Article}, abstract = {The thermal addition reaction Mu + NO + M reversible arrow MuNO* + M has been studied by a longitudinal magnetic field muon spin relaxation (mu SR) technique, at room temperature, in the presence of up to 60 atm of N-2 as inert moderator. The pressure dependence of the effective rate constant for Mu addition (k(eff)) demonstrates that the system remains well in the low-pressure regime in this pressure range. The termolecular rate constant, k(0)(Mu) = (8.76 +/- 0.46) x 10(-33) cm(6) molecule(-2) s(-1), is about 5 times smaller than that reported for the corresponding H-atom reaction (Tsang, W.; Herron, J. T. J. Phys. Chem. Ref. Data 1991, 20, 609), the largest isotope effect of its kind yet reported for reactions of this nature and most likely due to the increased rate of MuNO* dissociation resulting from the much lighter mass of the Mu atom (m(Mu)/m(H) similar to 1/9). This result should provide an important test of theoretical calculations for dissociating molecules involving few degrees of freedom. Quantum tunneling, normally facile for the much lighter Mu atom, is unlikely to play a major role in establishing the isotope effect seen in k(0). In the present instance, the mu SR technique relies on measuring the relaxation rate for the chemical process of addition (lambda(c)) in competition with that for spin exchange (lambda(se)), with the NO unpaired electron. The pressure-independent average value for the spin exchange rate constant found, k(se) = (3.00 +/- 0.12) x 10(-10) cm(3) molecule(-1) s(-1), is in good agreement with previous values obtained by transverse field mu SR (Fleming, D. G., et al. J. Chem. Phys. 1980, 73, 2751).}, keywords = {CHANNEL MODEL-CALCULATIONS, CHARACTERIZATION, ELECTRON-SPIN EXCHANGE, H+CH3->CH4 RECOMBINATION, INTERPOLATED, MICROCANONICAL VARIATIONAL THEORY, PARTITION-FUNCTION, POTENTIAL-ENERGY, PRESSURE-DEPENDENCE, RADICAL RECOMBINATION, RATE CONSTANTS, SURFACES, THEORETICAL}, isbn = {0022-3654}, url = {://A1995TF81100019}, author = {Pan, J. J. and Senba, M. and Arseneau, D. J. and Gonzalez, A. C. and Kempton, J. R. and Fleming, Donald G.} }