%0 Journal Article %T Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3. %+ Institut des Sciences Chimiques de Rennes (ISCR) %A Theurkauff, Gabriel %A Bondon, Arnaud %A Dorcet, Vincent %A Carpentier, Jean-François %A Kirillov, Evgueni %< avec comité de lecture %@ 1433-7851 %J Angewandte Chemie International Edition %I Wiley-VCH Verlag %V 54 %N 21 %P 6343-6346 %8 2015-04-07 %D 2015 %R 10.1002/anie.201501967 %M 25851273 %K structure elucidation %K zirconocenes %K ion pairs %K C-H activation %K aluminum %Z Chemical SciencesJournal articles %X The reactivity towards AlMe3 of discrete cationic ansa-zirconocenes 2 a,b that are ubiquitously used in isoselective propylene polymerization and based on [{Ph(H)C(3,6-tBu2-Flu)(3-tBu-5-Et-Cp)}ZrMe2)] {Cp-Flu} and rac-[{Me2Si-(2-Me-4-Ph-Ind)2}ZrMe2] {SBI} was scrutinized. The first example of a structurally characterized Group 4 metallocene AlMe3 adduct (3 b) is reported. In the presence of excess AlMe3, the {SBI}-based AlMe3 adduct 3 b undergoes a slow decomposition via C[BOND]H activation in a bridging methyl unit to yield a new species (4 b) with a trimetallic {Zr(μ-CH2)(μ-Me)AlMe(μ-Me)AlMe2} core. EXSY NMR data for the process 2 b⇄3 b[RIGHTWARDS ARROW]4 b suggest very rapid and reversible binding of an additional AlMe3 molecule onto AlMe3 adduct 3 b. The resulting heterotrimetallic species intermediates exchange of methyl groups between different metal centers and slowly undergoes the C[BOND]H activation reaction towards 4 b. %G English %L hal-01142068 %U https://univ-rennes.hal.science/hal-01142068 %~ UNIV-RENNES1 %~ CNRS %~ INSA-RENNES %~ ENSC-RENNES %~ ISCR %~ SCR_ICMV %~ SCR_OMC2012 %~ ISCR-OMC %~ STATS-UR1 %~ UR1-SPM %~ ISCR-PRATS %~ INC-CNRS %~ UR1-UFR-SPM %~ UR1-HAL %~ ISCR-CORINT %~ UR1-SDLM %~ UR1-SDLMJONCH %~ TEST-UNIV-RENNES %~ TEST-UR-CSS %~ UNIV-RENNES %~ INSA-GROUPE %~ ISCR-CORINT1 %~ UR1-MMS %~ TEST2-HALCNRS