title: Small changes have consequences: lessons from tetrabenzyltitanium and -zirconium surface organometallic chemistry.
abstract: Homoleptic benzyl derivatives of titanium and zirconium have been grafted onto silica that was dehydroxylated at 200 and 700 °C, thereby affording bi-grafted and mono-grafted single-site species, respectively, as shown by a combination of experimental techniques (IR, MAS NMR, EXAFS, and elemental analysis) and theoretical calculations. Marked differences between these compounds and their neopentyl analogues are discussed and rationalized by using DFT. These differences were assigned to the selectivity of the grafting process, which, depending on the structure of the molecular precursors, led to different outcomes in terms of the mono- versus bi-grafted species for the same surface concentration of silanol species. The benzylzirconium derivatives were active towards ethylene polymerization in the absence of an activator and the bi-grafted species displayed higher activity than their mono-grafted analogues. In contrast, the benzyltitanium and neopentylzirconium counterparts were not active under similar reaction conditions.
authors.affiliation: C2P2 (CNRS-UMR 5265), Université Lyon 1, ESCPE Lyon, 43 Boulevard du 11 Novembre 1918, 69626 Villeurbanne Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Popoff
authors.forename: Jeff
authors.initials: J
authors.lastname: Espinas
authors.forename: Jérémie
authors.initials: J
authors.lastname: Pelletier
authors.forename: Benoît
authors.initials: B
authors.lastname: Macqueron
authors.forename: Kai C
authors.initials: KC
authors.lastname: Szeto
authors.forename: Olivier
authors.initials: O
authors.lastname: Boyron
authors.forename: Christophe
authors.initials: C
authors.lastname: Boisson
authors.forename: Iker
authors.initials: I
authors.lastname: Del Rosal
authors.forename: Laurent
authors.initials: L
authors.lastname: Maron
authors.forename: Aimery
authors.initials: A
authors.lastname: De Mallmann
authors.forename: Régis M
authors.initials: RM
authors.lastname: Gauvin
authors.forename: Mostafa
authors.initials: M
authors.lastname: Taoufik