- Transition Metal-carbonyl, -hydrido and -η-Cyclopentadienyl Derivatives of the Fullerene C60
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Monoadduct derivatives of the fullerene C60, namely 2-C60)>, 2-C60)> (R = H, Bun), 2-C5H5)2(η2-C60)H> and 2-C60)H>, are described.
- Douthwaite, Richard E.,Green, Malcolm L. H.,Stephens, Adam H. H.,Turner, John F. C.
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p. 1522 - 1523
(2007/10/02)
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- Use of BF4 to prepare thiolate complexes of iron and ruthenium
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The complexes BF4 (L = PPh2Me, PPhMe2 P(OMe)3), 3SMe>BF4, and BF4 were prepared by reactions of BF4 and the appropriate neutral M(CO)5-n(L)n precursor.Several other analogous reactions were unsu
- Treichel, P. M.,Rublein, E. K.
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- Reactivity of Fe(CO)4(H)MPh3 (M = Si, Ge) and mechanism of substitution by two-electron-donor ligands: Implications for the mechanism of hydrosilylation of olefins catalyzed by Fe(CO)5
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cis-Fe(CO)4(H)MPh3 (M = Si, Ge) complexes undergo carbonyl displacement with nucleophilic ligands (phosphines, phosphites) to give Fe(CO)3(H)(L)MPh3. With M = Si the geometry of these complexes depends on the nature of the solvent; in nucleophilic solvents the mer-OC-6-43 isomer is formed, while in nonnucleophilic solvents the mer-OC-6-23 isomer is obtained (the cis positions of H and Si are retained). These two isomers undergo concerted reductive elimination of silane with PPh3. The mer-OC-6-43 isomer reacts 183 ± 19 times faster than the mer-OC-6-23 isomer in toluene at 26.0°C, giving the same 16-electron intermediate; the calculated equilibrium constant for the interconversion of OC-6-43 and OC-6-23 is 823 ± 192 at 26.0°C in toluene. Owing to the strong acidity of Fe(CO)4(H)MPh3 (pKa estimated as 3CN) and of Fe(CO)3(H)(PPh3)MPh3 (pKa estimated as ≤8.94 in CH3CN), reaction with basic two-electron-donor ligands [P(alkyl)3, P(cycloalkyl)3, NR3] leads to the formation of the anionic trigonal-bipyramidal complexes [Fe(CO)4MPh3]- and [Fe(CO)3(L)MPh3]-. cis-Fe(CO)4(H)SiPh3 reacts with isoprene to give [Fe(CO)4SiPh3]2; this reaction is not observed with Fe(CO)3(H)(L)SiPh3. The versatile reactivity of these complexes sheds some light on the mechanism of hydrosilylation of olefins and conjugated dienes. Under thermal conditions previous coordination of the olefin to the metal in this reaction seems to be excluded.
- Bellachioma, Gianfranco,Cardaci, Giuseppe,Colomer, Ernest,Corriu, Robert J. P.,Vioux, André
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p. 519 - 525
(2008/10/08)
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- Rates of substitution reactions of derivatives of iron pentacarbonyl, Fe(CO)4L and Fe(CO)3L2 (L = PPh3, AsPh3, P(OPh)3): Application of crystal field activation energies to organometallic complexes
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Dissociation of ligands from Fe(CO)3L2 and Fe(CO)4L (L = PPh3, P(OPh)3, AsPh3) has been investigated by reaction with carbon monoxide. These complexes are relatively inert, requiring temperatures considerably in excess of 100°C. The relative inertness of 18-electron complexes of iron is considered. The order of ligand lability from Fe(CO)3L2 is AsPh3 > PPh3 > P(OPh)3, which apparently represents the general bond strength to low-valent metal centers.
- Modi, Sandeep P.,Atwood, Jim D.
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- METAL DIMERS AS CATALYSTS. III. THE REACTION BETWEEN Fe(CO)5 AND GROUP V DONOR LIGANDS IN THE PRESENCE OF 5-C5H4R)Fe(CO)2>2 (R = H, Me) AND 5-C5Me5)Fe(CO)2>2 AS CATALYST
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The reaction between Fe(CO)5 and Group V donor ligands L, (L = PPh3, AsPh3, SbPh3, PMePh2, PMe2Ph, AsMe2Ph, P(C6H11)3, P(n-Bu)3, P(i-Bu)3, P(OPh)3, P(OEt)3, P(OMe)3) in the presence of 5-C5H4R)Fe(CO)2>2 (R = H, Me) or 5-C5Me5)F
- Albers, Michel O.,Coville, Neil J.,Singleton, Eric
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p. 261 - 266
(2007/10/02)
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- Oxidation of substituted iron carbonyl complexes in acetonitrile, acetone, and dichloromethane at mercury and platinum electrodes
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The oxidative electrochemistry of the substituted iron carbonyl complexes Fe(CO)4L and Fe(CO)3L2, where L is a monodentate tertiary phosphine, arsine, or stibine ligand, has been studied in acetone, dichloromethane, and acetonitrile at both Hg and Pt electrodes. At platinum electrodes, for L = AsPh3 or SbPh3 the initially generated 17-electron cations [Fe(CO)4L]+ and [Fe(CO)3L2]+ are unstable in all solvents while with phosphorus ligands the species [Fe(CO)3(PPh3)2]+ has some stability in dichloromethane. Reactions leading to decomposition are considered. In marked contrast, at mercury electrodes, the cations appear to be substantially more stable than at platinum, and chemically reversible behavior can be observed where the response is completely irreversible at platinum. The data are explained in terms of a chemically modified pathway at mercury electrodes giving rise to mercury stabilized cations.
- Blanch,Bond,Colton
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p. 755 - 761
(2008/10/08)
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- THE TRANSITION METAL CATALYZED REACTION BETWEEN Fe(CO)5 AND GROUP V DONOR LIGANDS. A FACILE, HIGH YIELD SYNTHESIS OF Fe(CO)4PPh3
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The reaction of Fe(CO)5 and L (L=Group V donor ligand), in the presence of CoCl2 * 2 H2O or CoI2 * 4 H2O as catalyst, results in the synthesis of Fe(CO)4L in good yield.Unusual reactivity patterns for the substitution of CO on Fe(CO)5 by L have been found; for CoI2 as catalyst the reaction rate increases in the order PPh3 ca.AsPh3 ca.P(OPh)3 > SbPh3 > PPh2Me > PPhMe2 > P(C6H11)3 > P(OEt)3 > P(n-Bu)3 > P(OMe)3.These results are interpreted in terms of the variation of the catalyst through interaction of CoX2 with L.
- Albers, Michel O.,Coville, Neil J.,Ashworth, Terence V.,Singleton, Eric
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p. 385 - 390
(2007/10/02)
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- Reduction-Oxidation Properties of Organotransition-metal Complexes. Part 8. Formation and Reactivity of the Radical Cations (1+), and the Mechanism of the Oxidative Elimination Reaction of with Halogens
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Cyclic-voltammetric studies in CH2Cl2 show that 2=Ph2PCH2CH2PPh2 (dppe) or Ph2PCH2PPh2 (dppm)> undergoes one-electron oxidation to the radical cation (1+) (2) which may be chemically generated from (1) using silver(I) salts or .The complex (2; L=PPh3) reacts with halogens to give diamagnetic (3) which yields 4-n(PPh3)n> (4; X=I, n=1; X=Br, n=1 and 2; X=Cl, n=2) with X(1-).Halide ions react directly with (2; L=PPh3) to give mixtures of (1; L=PPh3) and (4) via the paramagnetic intermediate (5).A mechanism is proposed for the oxidative elimination reaction of (1) with halogens; the reactions of (2), and i.r. stopped-flow kinetic studies, implicate (2) and (5) as redox-active intermediates.
- Baker, Paul K.,Connelly, Neil G.,Jones, Brian M. R.,Maher, John P.,Somers, Karen R.
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p. 579 - 585
(2007/10/02)
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