241492-60-4Relevant academic research and scientific papers
Synthesis, characterization and structures of zirconocene complexes of sterically demanding pentaphenylcyclopentadienyl and tetraphenyl-m-tolyl cyclopentadienyl ligands
Greene, Deborah L.,Chau, Alex,Monreal, Marisa,Mendez, Carmen,Cruz, Iris,Wenj, Tambi,Tikkanen, Wayne,Schick, Brian,Kantardjieff, Katherine
, p. 8 - 13 (2003)
The synthesis, characterization and catalytic activity of zirconium complexes containing bulky pentaarylcyclopentadienyl ligands are reported. The monocyclopentadienyl 12-electron complex, trichloropentaphenylcyclopentadienylzirconium(IV), C5Ph5ZrCl3 (I), has an unusual monomeric structure in the solid state and has short Zr-ligand distances suggesting that the complex has significant Lewis acidity. The phenyl rings adopt a propeller arrangement in the solid state; VT 1H-NMR measurements of the analogous trichloro(tetraphenyl- m -tolylcyclopentadienyl)zirconium(IV) (II) indicate that there is rapid rotational motion of the phenyl rings. The Lewis acidity of this complex is manifested in its ability to catalyze the [4+2] cycloadditions of acrolein and methyl acrylate to cyclopentadiene. The sandwich complex, C5Ph5 CpZrCl2 (III), has more typical Zr-ligand distances, but has a more parallel arrangement of the two cyclopentadienyl rings and does not display the reactivity shown by I and II.
