title: Superbulky metallocene complexes of the heavier alkaline-earth metals strontium and barium.
abstract: Superbulky sandwich complexes with the cyclopentadienyl ligand (4-nBu-C(6)H(4))(5)Cp (abbreviated here as Cp(BIG)) have been prepared by reaction of Cp(BIG)H with benzylic strontium or barium reagents. Both metallocenes have been structurally characterized by single crystal X-ray diffraction. Even for the larger metallocene (Cp(BIG))(2)Ba a highly symmetric sandwich complex with parallel Cp rings was isolated (Cp(center)-Ba = 2.667(1) A). Both structures show evidence for a C-HC(pi) network between the Cp ligands. These attractive forces induce an inward out-of-plane bending of the aryl substituents (Sr 3.4(2) degrees; Ba 5.3(2) degrees). A linear correlation between this bending angle and metal size has been found.
authors: Anorganische Chemie, Universitätsstrasse 5, 45117 Essen, Germany.
authors: Lars
authors: L
authors: Orzechowski
authors: Dirk F-J
authors: DF
authors: Piesik
authors: Christian
authors: C
authors: Ruspic
authors: Sjoerd
authors: S
authors: Harder