title: Hydrosilane-B(C6F5)3 adducts as activators in zirconocene catalyzed ethylene polymerization.
abstract: Hydrosilane-B(C6F5)3 adducts were found to activate zirconocene dihalides and generate ternary catalytic systems possessing moderate to high activity in ethylene polymerization to high density polyethylene (HDPE). The activation efficacy of the adducts increased with increasing hydride donor ability and decreased with steric crowding of the particular hydrosilane used. NMR investigation of the HSiEt3/B(C6F5)3/Cp*2ZrF2 system (Cp* = η(5)-C5Me5) revealed the formation of a stable intermediate [Cp*2ZrF(FSiEt3-κF)](+)[HB(C6F5)3](-), whereas a crucial role of the [HB(C6F5)3](-) anion as a hydride donor for generation of an active cationic zirconium hydride center was elucidated.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic. jiri.pinkas@jh-inst.cas.cz.
authors.forename: Vojtech
authors.initials: V
authors.lastname: Varga
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic. jiri.pinkas@jh-inst.cas.cz.
authors.forename: Martin
authors.initials: M
authors.lastname: Lamač
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic. jiri.pinkas@jh-inst.cas.cz.
authors.forename: Michal
authors.initials: M
authors.lastname: Horáček
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic. jiri.pinkas@jh-inst.cas.cz.
authors.forename: Róbert
authors.initials: R
authors.lastname: Gyepes
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic. jiri.pinkas@jh-inst.cas.cz.
authors.forename: Jiří
authors.initials: J
authors.lastname: Pinkas