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

摘要

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(#eta#~5-C_5H_5)_2(#eta#~1-C_5H_5)_2, where M = Ti and Hf, in the solid state using variable-temperature ~(13)C 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.