ИСТИНА

Recently the authors investigated the mechanism of olefin hydroalumination by HAlBui2 in presence of Cp2ZrCl2 catalyst by means of DNMR spectroscopy and encounter synthesis [1]. It has been shown that complex 1 is the key intermediate for olefin hydroalumination. <Scheme 1> In order to understand the mechanism of formation of 1 we performed a series of calculation of related structures on the DFT level of theory (PBE/3z, program “Priroda 4.07”, Dr Laikov D., Moscow State University). It was found that the formation of 1 occurs via the steps a-d (T=203,15K). <Scheme 2> According to step b the bridged Al,Zr-complex 2 dissociates through transition state 3 with activation energy of 2.7 kcal/mol. Summarised enthalpy of reactions a-d is dHr0 = -65.0 kcal/mol. Acknowledgements: The authors thank the Russian Science Support Foundation (Grants for Young Ph.D. Scientists, Tyumkina T.V., Parfenova L.V.) and the Foundation of the President of Russian Federation (Program for Support of Leading Scientific Schools, U.M. Dzhemilev, Grant NSh-7470.2006.3). Reference [1] Parfenova, L. V.; Pechatkina, S. V.; Khalilov, L. M.; Dzhemilev, U. M. Russ. Chem. Bull., 2005, 54, 316.