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Kinetische und mechanistische Untersuchungen von fibergangsmetall-Komplex-Reaktionen XXVIII : Kinetische Untersuchungen zur [2 + 2]-Cycloaddition von Vinylethern an Pentacarbonyl(thiobenzaldehyd)wolfram (CO)<sub>5</sub>W[S=C(C<sub>6</sub>H<sub>4</sub>R-p)H] (R = H, Me, OMe, Br, Cl)

Kinetische und mechanistische Untersuchungen von fibergangsmetall-Komplex-Reaktionen XXVIII : Kinetische Untersuchungen zur [2 + 2]-Cycloaddition von Vinylethern an Pentacarbonyl(thiobenzaldehyd)wolfram (CO)5W[S=C(C6H4R-p)H] (R = H, Me, OMe, Br, Cl)

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FISCHER, Helmut, Anne RUCHAY, Rüdiger STUMPF, Claudia KALBAS, 1993. Kinetische und mechanistische Untersuchungen von fibergangsmetall-Komplex-Reaktionen XXVIII : Kinetische Untersuchungen zur [2 + 2]-Cycloaddition von Vinylethern an Pentacarbonyl(thiobenzaldehyd)wolfram (CO)5W[S=C(C6H4R-p)H] (R = H, Me, OMe, Br, Cl). In: Journal of Organometallic Chemistry. 459(1-2), pp. 249-255. ISSN 0022-328X. eISSN 1872-8561

@article{Fischer1993Kinet-23406, title={Kinetische und mechanistische Untersuchungen von fibergangsmetall-Komplex-Reaktionen XXVIII : Kinetische Untersuchungen zur [2 + 2]-Cycloaddition von Vinylethern an Pentacarbonyl(thiobenzaldehyd)wolfram (CO)5W[S=C(C6H4R-p)H] (R = H, Me, OMe, Br, Cl)}, year={1993}, doi={10.1016/0022-328X(93)86077-U}, number={1-2}, volume={459}, issn={0022-328X}, journal={Journal of Organometallic Chemistry}, pages={249--255}, author={Fischer, Helmut and Ruchay, Anne and Stumpf, Rüdiger and Kalbas, Claudia} }

Fischer, Helmut Ruchay, Anne Fischer, Helmut 1993 deposit-license Kalbas, Claudia Stumpf, Rüdiger Journal of Organomerallic Chemistry ; 459 (1993), 1-2. - S. 249-255 Stumpf, Rüdiger 2013-06-27T09:26:19Z 2013-06-27T09:26:19Z The pentacarbonyl(thiobenzaldehyde)tungsten complexes (CO)<sub>5</sub>W[S=C(C<sub>6</sub>H<sub>4</sub>R-p)H][R = H (1A); Me (1B); OMe (1C); Cl (1D); Br (1E)] react with vinylethers such as ethylvinylether (2a), isobutylvinylether (2b), methylisopropenylether (2c), cis-ethyl-1-propenylether (2d), trans-ethyl-1-propenylether (2e), α-methoxystyrene (2f), α-methoxy-p- methylstyrene (2g) and α-methoxy-p-methoxystyrene by [2 + 2]-cycloaddition to form metal-coordinated thietanes (3Aa–h, 3Ba– 3Ea). The reaction follows second-order kinetics: −d[1]/dt=k<sub>2</sub>[1] [2]. For the reaction of 1A with 2a the activation enthalpy is small (ΔH<sup>★</sup>=44(1) kJ mol<sup>−1</sup> and the activation entropy (ΔS<sup>★</sup>= −146(5) J mol<sup>−1</sup> K<sup>−1</sup>) is strongly negative. ΔS<sup>★</sup> is comparable to the reaction entropy of the reversible addition of pyridine to the thiocarbonyl C-atom of 1A and 1B. Electron donation groups R in (CO)<sub>5</sub>W[S=C(C<sub>6</sub>H<sub>4</sub>R-p)H] decrease the reaction rate. A positive correlation (ϱ=1.4) is observed between log k<sub>2</sub> and the Hammett constants σp+. A substitution only in the α-position of the vinylether has remarkable effects, in this case the reaction is accelerated by electron donating substituents. The rate constant for the reaction of 1A with different vinylethers decreases in the series 2h >2g >2c >2f >2b, 2a, 2e >2d. An associative concerted non-synchronous process is proposed. Ruchay, Anne Kinetische und mechanistische Untersuchungen von fibergangsmetall-Komplex-Reaktionen XXVIII : Kinetische Untersuchungen zur [2 + 2]-Cycloaddition von Vinylethern an Pentacarbonyl(thiobenzaldehyd)wolfram (CO)<sub>5</sub>W[S=C(C<sub>6</sub>H<sub>4</sub>R-p)H] (R = H, Me, OMe, Br, Cl) Kalbas, Claudia eng

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