| | 1 | Author
| EricaL. Weinberg, J.Thomas Burton, MichaelC. Baird, Max Herberhold | Requires cookie* | | | Title
| A Novel Isomerization of an Electron-Rich Alkene  | | | | Abstract
| Displacement of 2-methvlpropene from [Fp(Me2C = CH2)]BF4 (Fp = (/?5-C5H5)Fe(CO)2) by Z-1,2-dimethoxyethylene (Z-DME) gives [Fp(Z-DME)]BF4. Displacement by E-1,2-dimethoxyethylene (E-DME), in contrast, does not give the expected complex of E-DME, but rather the complex of the Z-alkene. A mechanism involving scission of the C = C bond of the coordinated alkene to give a bis-carbene intermediate is proposed. | | | |
Reference
| Z. Naturforsch. 36b, 485—487 (1981); received February 9 1981 | | | |
Published
| 1981 | | | |
Keywords
| Organoiron Complexes, Olefin Isomerization, 1, 2-Dimethoxyethylene | | | |
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| | | | | TEI-XML for
| default:Reihe_B/36/ZNB-1981-36b-0485.pdf | | | | Identifier
| ZNB-1981-36b-0485 | | | | Volume
| 36 | |
| 2 | Author
| Hans-Ludwig Krauss, Erich Hums | Requires cookie* | | | Title
| Oberflächenverbindungen von Übergangsmetallen, XXII [1] Die Umsetzung von Oberflächen-Chrom(II) auf Silicagel mit Olefinen bei höherer Temperatur. - Zum Mechanismus von Aufbau-, Abbau-, Metathese- und Isomerisierungs-Reaktionen an koordinativ ungesättigten Oberflächen-Metallionen Surface Compounds of Transition Metal, XXII [1] The Reaction of Surface Chromium(II) on Silica with Olefins at Higher Temperature. - A Contribution to the Mechanism of Growth, Degradation, Metathesis and Isomerization on Coordinatively Unsaturated Surface Metal Ions | | | | Abstract
| With chromium(II) supported on silica, at T > 150 °C olefins undergo growth/degra-dation/metathesis reactions by addition/elimination of even and uneven chain fragments including Ci. Simultaneously, catalytic double bond isomerization and C-rearrangements to methyl branched olefins occur. One mechanism is proposed for all these reactions via a pseudo-tetrahedral MC3 intermediate. Polyethylene synthesis at lower temperatures may follow the same way. For growth/degradation/metathesis the formation of a metal carbene unit is postulated as a characteristic step; in case of ethylene, >Cr=CH2 will be formed as a precursor of the final CH4 (resulting from a secondary reaction with support hydrogen). | | | |
Reference
| Z. Naturforsch. 34b, 1628—1636 (1979); eingegangen am 23. Juli 1979 | | | |
Published
| 1979 | | | |
Keywords
| Surface Compounds, Olefin Polymerization/Degradation, Olefin Metathesis, Olefin Isomerization, Carbene Intermediates | | | |
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| default:Reihe_B/34/ZNB-1979-34b-1628.pdf | | | | Identifier
| ZNB-1979-34b-1628 | | | | Volume
| 34 | |
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