ISSN:
1434-1948
Schlagwort(e):
Tungsten
;
Ditungsten complexes
;
Acetylene complex
;
Tritungsten complex
;
W-W single bond
;
W-W triple bond
;
Photochemistry
;
C-C bond formations
;
Olefins
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
[W2(η5-C5H5)2(CO)4(μ-η2:2-C2H2)] (1) and ethylene (A) react when irradiated with UV light at 253 K predominantly to [W2(η5-C5H5)2(CO)3(μ-η1:4-C4H5)(μ-H)] (3A), [W2(η5-C5H5)2(CO)4(μ-η1:3-C4H6)] (4A), and thermolabile [W2(η5-C5H5)2(CO)3(η4-C4H6)] (5A). Similarly, propene (B), 1-butene (C), and (E)-2-butene (D) yield mixtures of [W2(η5-C5H5)2(CO)3(μ-H)(μ-η1:4-1,3-dien-1-yl)] (3B, 3 C, 3D), [W2(η5-C5H5)2(CO)4(μ-η1:3-C4H5R] (4B, 4C), and [W2(η5-C5H5)2(CO)2(μ-η1:2-CO)(η4-1,3-diene) (5B, 5 C, 5D). With B and C also thermolabile [W2(η5-C5H5)2(CO)3(μ-η2:2-C2H2)(η2-C2H3R)] (2B, 2C) are formed. A by-product of the reaction of 1 with D is [W(η5-C5H5)(CO)(H){η4-(E)-C5H7CH3}], which is generated in two diastereomeric forms (6, 6′). In contrast, 1 yields no complexes with (Z)-2-butene (E) which contain ligands formed from coordinated acetylene and the olefin. From the reaction mixture only trinuclear [W3(η5-C5H5)3(CO)5(μ-η1:2-C2H3)] (7) was isolated, an alicyclic complex with a W-W single and a W-W triple bond. The crystal and molecular structures of 5D and 7 were determined by X-ray structure analysis. The constitutions of the other complexes were ascertained by IR and 1H-NMR spectroscopy.
Materialart:
Digitale Medien
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