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ansa-metallocene derivatives : X. Hydrogenolysis of the zirconium-alkyl bond in bridged and unbridged alkyl zirconocene derivatives. Evidence for direct and ring-mediated hydrogen transfer reactions

ansa-metallocene derivatives : X. Hydrogenolysis of the zirconium-alkyl bond in bridged and unbridged alkyl zirconocene derivatives. Evidence for direct and ring-mediated hydrogen transfer reactions

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WOCHNER, Franz, Hans-Herbert BRINTZINGER, 1986. ansa-metallocene derivatives : X. Hydrogenolysis of the zirconium-alkyl bond in bridged and unbridged alkyl zirconocene derivatives. Evidence for direct and ring-mediated hydrogen transfer reactions. In: Journal of Organometallic Chemistry. 309(1-2), pp. 65-75. ISSN 0022-328X

@article{Wochner1986ansa--23991, title={ansa-metallocene derivatives : X. Hydrogenolysis of the zirconium-alkyl bond in bridged and unbridged alkyl zirconocene derivatives. Evidence for direct and ring-mediated hydrogen transfer reactions}, year={1986}, doi={10.1016/S0022-328X(00)99574-3}, number={1-2}, volume={309}, issn={0022-328X}, journal={Journal of Organometallic Chemistry}, pages={65--75}, author={Wochner, Franz and Brintzinger, Hans-Herbert} }

The rate of hydrogenolytic alkane liberation from permethylzirconocene neopentyl halide compounds, (C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>)<sub>2</sub>Zr(X)CH<sub>2</sub>C(CH<sub>3</sub>)<sub>3</sub>, X = F, Cl, Br), is greatly reduced if the ring ligands are interconnected by an ethylene bridge, as in C<sub>2</sub>H<sub>4</sub>(C<sub>5</sub>(CH<sub>3</sub>)<sub>4</sub>)<sub>2</sub>Zr(X)CH<sub>2</sub>C(CH<sub>3</sub>)<sub>3</sub>. Hydrogenolysis of the corresponding permethylzirconocene neopentyl hydride compounds (X = H), on the other hand, is too fast for kinetic measurements at room temperature, even with the ethylene-bridged derivative. These observations, and the inverse kinetic isotope effect observed for reaction with D<sub>2</sub>, are interpreted with the assumption that H<sub>2</sub>-induced alkane liberation from permethylzirconocene alkyl halides proceeds via an indirect ring-mediated hydrogen transfer reaction which is feasible only with freely rotating ring ligands; hydrogenolysis of permethylzirconocene alkyl hydrides, on the other hand, apparently occurs without such limitation, by direct H<sub>2</sub>-to-alkyl hydrogen transfer. 1986 ansa-metallocene derivatives : X. Hydrogenolysis of the zirconium-alkyl bond in bridged and unbridged alkyl zirconocene derivatives. Evidence for direct and ring-mediated hydrogen transfer reactions Journal of Organometallic Chemistry ; 309 (1986), 1-2. - S. 65-75 Brintzinger, Hans-Herbert Wochner, Franz deposit-license 2013-07-17T11:40:30Z eng Brintzinger, Hans-Herbert Wochner, Franz 2013-07-17T11:40:30Z

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