X-ray crystal structure of (η 5-pentamethylcyclopentadienyl) (η 3-1,3-dimethylallyl)chlororhodium: localized “Di-π-olefin-σ” bonding of cyclopentadienyl

Abstract

The crystal structure of (η 5-C 5Me 5)(η 3-MeHCCHCHMe)RhCl at −120°C was determined ( R = 0.041 for 1790 reflections). The molecule has approximate mirror symmetry. The cyclopentadienyl ring is bent by 6.8°, acquiring an envelope-like conformation, and its bonding with Rh is of a partially-localized η 4:η 1 type with RhC(“π-diolefin”) of 2.206–2.235 Å and RhC(“σ-bonded”) of 2.151 Å. The syn-arrangement of the Me groups in the π-allyl ligand, assigned by NMR spectra, is confirmed.