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Author Kuchynka, D. J. ♦ Kochi, J. K.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ALKYNES ♦ REDUCTION ♦ AROMATICS ♦ CARBONYLS ♦ MANGANESE COMPLEXES ♦ ORGANIC PHOSPHORUS COMPOUNDS ♦ ELECTRON SPIN RESONANCE ♦ ELECTRON TRANSFER ♦ EXPERIMENTAL DATA ♦ NMR SPECTRA ♦ PHOSPHORUS 31 ♦ CHEMICAL REACTIONS ♦ COMPLEXES ♦ DATA ♦ HYDROCARBONS ♦ INFORMATION ♦ ISOTOPES ♦ LIGHT NUCLEI ♦ MAGNETIC RESONANCE ♦ NUCLEI ♦ NUMERICAL DATA ♦ ODD-EVEN NUCLEI ♦ ORGANIC COMPOUNDS ♦ PHOSPHORUS ISOTOPES ♦ RESONANCE ♦ SPECTRA ♦ STABLE ISOTOPES ♦ TRANSITION ELEMENT COMPLEXES ♦ Chemical & Physicochemical Properties ♦ Isotope Effects, Isotope Exchange, & Isotope Separation
Abstract The cathodic reduction of the bischelated manganese carbonly cation trans-Mn(CO)/sub 2/(/eta//sup 2/-DPPE)/sub 2//sup +/ (I/sup +/, where DPPE = PPh/sub 2/(CH/sub 2/)/sub 2/PPh/sub 2/) produces the metastable anion Mn(CO)/sub 2/(/eta2/-DPPE)(/eta//sup 1/-DPPE)/sup /minus// (II/sup /minus//) via an overall 2e process at a Pt electrode in either tetrahydrofuran or acetonitrile solution. The unusual observation of a cathodic curve crossing and two isopotential points in the cyclic voltammogram of I/sup +/ can be traced to an electron transfer with II/sup /minus// to afford a pair of neutral radicals, i.e., the 19e I* and the 17e II*. The former (which is also generated during the initial step in the reduction of I/sup +/) is a metastable species and spontaneously extrudes an end of one DPPE ligand to afford the second radical II* with the rate constant k/sub r/ /approximately/ 4 /times/ 10/sup 6/ s/sup /minus/1/. The structures of the anionic and radical intermediates II/sup /minus//, II*, and I* are discussed in the context of their transient electrochemical behavior as well as their /sup 31/P NMR and ESR spectra. The rather slow rate of electron transfer between I/sup +/ and II/sup /minus// is ascribed to steric effects in carbonylmanganese ions encumbered with a pair of DPPE ligands. 59 refs., 7 figs., 1 tab.
Educational Use Research
Learning Resource Type Article
Publisher Date 1988-07-27
Publisher Place United States
Journal Inorg. Chem.
Volume Number 27
Issue Number 15
Organization Univ. of Houston, University Park, TX (USA)


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