Dimerization of trimethylsilylpropyne on a triosmium cluster. Formation, crystal structure and rearrangement of Os3H[μ3-C(SiMe3)C(Me)CC(SiMe3)CH2](CO)8 complex
| Autor: | F. M. Dolgushin, A. A. Koridze, Pavel V. Petrovskii, A. I. Yanovsky, Yu. T. Struchkov, N. M. Astakhova |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
chemistry.chemical_classification
Heptane Trimethylsilyl Stereochemistry Organic Chemistry chemistry.chemical_element Alkyne Crystal structure Biochemistry Medicinal chemistry Ruthenium Inorganic Chemistry chemistry.chemical_compound chemistry Cyclooctene Materials Chemistry Osmium Physical and Theoretical Chemistry Methyl group |
| Zdroj: | Journal of Organometallic Chemistry. 481:247-252 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/0022-328x(94)85033-x |
| Popis: | Trimethylsilylpropyne reacts with Os 3 (CO) 10 (C 8 H 14 ) 2 (C 8 H 14 = cyclooctene) to give Os 3 (μ 3 -Me 3 SiC 2 Me)(μCO)(CO) 9 ( 3 ). On heating this complex in hydrocarbon solvents, the allenyl compound Os 3 H[μ 3 -C(SiMe 3 )CCH 2 ](CO) 9 ( 4 ) is formed. Reaction of the excess Me 3 SiCCMe with the alkyne compound 3 in refluxing hexane first gives the red compound Os 3 [C 4 (SiMe) 3 )(Me)(SiMe 3 )-Me] (CO) 9 ( 5 ), which is then smoothly converted to the yellow compound Os 3 H[μ 3 -C(SiMe 3 )C(Me)CC(SiMe 3 )CH 2 KCO) 8 ( 6 ). The reaction of excess Me 3 SiCCMe with the vinyl compound Os 3 H(μ-CHCH 2 ) (CO) 10 ( 7 ), proceeds analogously giving 5 and then 6 . Compounds 5 and 6 were characterized by IR and 1 H NMR spectroscopy, and 6 also by X-ray diffraction. Cluster 6 crystallizes in the space group P 2 1 / n , with a = 9.196(2), b = 29.495(2), c = 10.233(2) A, β = 99.48(2)°, Z = 4. The molecular structure involves a triangular array of osmium atoms and σ, π-coordinated organic ligand, formed by linear coupling of two alkyne molecules. This coupling is accompanied by the dehydrogenation of a methyl group and 1,2 shift of a trimethylsilyl group of one of the alkyne molecules. When the reaction of Me 3 SicCMe with 3 was conducted in refluxing heptane, as well as compound 6 , the formation of compound Os 3 H[μ 3 -CHC(SiMe 3 )CC(Me)CH(SiMe 3 )](CO) 8 ( 8 ) was indicated. In a separate experiment, it was established that, in refluxing heptane, 6 → 8 rearrangement takes place. Allenyl compound 4 , in contrast to alkyne compound 3 , does not react with Me 3 SiCCMe in refluxing hexane, and only under more severe conditions in refluxing heptane, does the formation of 6 and 8 take place in very low yields. These results show that compounds 3 and 5 but not 4 are the true intermediates in the reaction of trimethylsilylpropyne dimerization on the triosmium cluster. |
| Databáze: | OpenAIRE |
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