Variable-temperature one- and two-dimensional 13C CP/MAS NMR studies of the dynamics of monohaptocyclopentadienyl rings of hafnium and titanium tetracyclopentadienyl in the solid state

Abstract

Organometallic compounds with cyclopentadienyl ligands (C 5H 5) can undergo fluxional motion. We have studied the Group IVB transition metal complexes of the formula M( η 5-C 5H 5) 2( η 1-C 5H 5) 2, where M=Ti and Hf, in the solid state using variable-temperature 13C CP/MAS NMR spectroscopy. We present data which indicate that intramolecular rearrangement proceeds via a sigmatropic shift. Using two-dimensional (2D) exchange NMR, we can follow the rearrangement of the single bonded cyclopentadienyl ligands.