How big is a Cp? Cycloheptatrienyl zirconium complexes with bulky cyclopentadienyl and indenyl ligands

Dalton Trans. 2012 Jun 14;41(22):6614-24. doi: 10.1039/c2dt12132h. Epub 2012 Feb 9.

Abstract

A combination of phase-transfer and traditional alkylation strategies has been employed to synthesise sterically encumbered 1,3-di(cyclohexyl) and 1,3-di(tert-butyl) substituted indenes in multi-gram quantities. These indenyl ligands and sterically demanding alkyl cyclopentadienyl ligands have been used to prepare a series of [(η(7)-C(7)H(7))Zr(η(5)-L)] (L = Cp and Ind) complexes by straightforward salt metathesis between [(η(7)-C(7)H(7))ZrCl(tmeda)] and the corresponding sodium indenide or cyclopentadienide. All of these Zr complexes have been characterized by elemental analysis, NMR spectroscopy and single crystal X-ray diffraction. The structural information derived from these studies was employed to evaluate the steric demand of these ligands in a realistic manner.