@article {4680, title = {Gas phase ion molecule chemistry of tetracarbonyl (eta(5)-cyclopentadienyl) vanadium by Fourier transform ion cyclotron resonance}, journal = {International Journal of Mass Spectrometry}, volume = {182}, year = {1999}, note = {ISI Document Delivery No.: 171QJTimes Cited: 1Cited Reference Count: 36}, month = {Mar}, pages = {139-148}, type = {Article}, abstract = {The kinetics of the reactions between the CpV(CO)(4) molecule and its fragment cations and anions have been examined using Fourier transform ion cyclotron resonance (FTICR) techniques. With 25 eV electron impact ionization the fragment cations V+ and CpV(CO)(n=0-4)(+) react principally by charge exchange or by condensation with the parent neutral molecule. Rate constants for these pathways have been determined along with kinetic evidence for the existence of excited state cations. Some of the product cations show unexpected stability despite their large formal electron deficiency. Exchange of carbonyl ligands was also observed. Under 2.5 eV electron impact, only two anions are produced: CpV(CO)(n=2,3)(-), both of which are unreactive with the parent neutral. (C) 1999 Elsevier Science B.V.}, keywords = {BOND-DISSOCIATION ENERGIES, CARBONYL CLUSTER FRAGMENTS, carbonyl ligands, FE(CO)5, Fourier transform ion cyclotron resonance mass, gas phase ion chemistry, iron, METAL BONDS, MN+, PENTACARBONYL, REACTIVITY, SPECTROMETRY, STATE, SYSTEMS, V+}, isbn = {1387-3806}, url = {://000078874700015}, author = {Taylor, S. M. and Comisarow, M. B.} } @article {4263, title = {One-electron transformations of paramagnetic cobalt complexes. Synthesis and structure of cobalt(II) amidodiphosphine halide and alkyl complexes and their reaction with alkyl halides}, journal = {Journal of the American Chemical Society}, volume = {120}, number = {39}, year = {1998}, note = {ISI Document Delivery No.: 127ZPTimes Cited: 33Cited Reference Count: 106}, month = {Oct}, pages = {10126-10135}, type = {Review}, abstract = {Complexes of the type CoX[N(SiMe2CH2PPh2)(2)], where X = Cl, Br, or I, can be prepared via reaction of CoX2 with LiN(SiMe2CH2PPh2)(2); these derivatives are tetrahedral high-spin d(7) systems. Reaction of these halide complexes with organolithium, sodium, or potassium reagents generates square-planar, low-spin hydrocarbyl complexes of the formula CoR[N(SiMe2CH2PPh2)(2)] (R = Me, CH2Ph, CH2SiMe3, C5H5). One-electron oxidations have been carried out; only the product of halide abstraction is observed. For example, addition of PhCH2X to the halide derivatives CoX[N(SiMe2CH2PPh2)(2)] generates trivalent, paramagnetic complexes, CoX2[N(SiMe2CH2PPh2)(2)]; these derivatives show variable-temperature magnetic susceptibility data that are consistent with zero-field splitting of the S = 1 state. Addition of methyl bromide or methyl iodide to low-spin CoMe[N(SiMe2CH2PPh2)(2)] results in the formation of the Co(II) halide derivatives CoX[N(SiMe2CH2PPh2)(2)] along with methane and bibenzyl. It is proposed that the Co(III) methyl halide complex CoMe(X) [N(SiMe2CH2PPh2)(2)] is unstable and loses methyl radical homolytically to generate the Co(II) halide derivative; the methyl subsequently reacts with the toluene solvent to produce methane and bibenzyl. Addition of excess benzyl halides has also been found to generate the Co(II) halide complexes initially, followed by a one-electron oxidation to the Co(II) dihalide derivatives. In much of the one-electron chemistry of the Co(II) derivatives incorporating the amidodiphosphine ligand, the decomposition of the putative but unstable Cs(III) alkyl halide derivative CoRX[N(SiMe2CH2PPh2)(2)] is proposed as a recurring event.}, keywords = {17-ELECTRON, BOND-DISSOCIATION ENERGIES, COORDINATION CHEMISTRY, D6 ML5 COMPLEXES, DERIVATIVES, HIGHER OXIDATION-STATES, KINETICS, LIGAND, ORGANIC HALIDES, RADICAL REACTIONS}, isbn = {0002-7863}, url = {://000076381000017}, author = {Fryzuk,Michael D. and Leznoff, D. B. and Thompson, R. C. and Rettig, S. J.} }