Pentafulvenkomplexe des Titans — Synthese,Struktur und Fluktuierendes Verhalten von Cp′Ti{η6‐C5H4=C(p‐Tol)2}Cl (Cp′ = Cp*, Cp) |
| |
Authors: | J Stroot A Lützen M Friedemann W Saak R Beckhaus |
| |
Abstract: | Complexes of Titanium — Synthesis, Structure, and Fluxional Behaviour of CpTi{η6‐C5H4=C(p‐Tol)2}Cl (Cp′ = Cp*, Cp) The reaction of Cp′TiCl3 (C′ = Cp* or Cp) with magnesium and 6, 6‐di‐para‐tolylpentafulvene generates good yields of pentafulvene complexes Cp*Ti{η6‐C5H4=C(p‐Tol)2}Cl ( 4 ) and CpTi{η6‐C5H4=C(p‐Tol)2}Cl ( 5 ), respectively. The crystal and molecular structure of 4 have been determined from X‐ray data and exhibits compared to known η6‐pentafulvene complexes an unusual large Ti—C(p‐Tol)2 (Fv)‐distance (2.535(5)Å) evoked by the bulky substituents at the exocyclic carbon. Dynamic 1H‐NMR and spin saturation transfer experiments point out a rotation of the fulvene ligand around the Ti—Ct2 axis (Ct2 = centroid of the fulvene ring carbon atoms) with an activation barrier ΔG≠C = 60.6 ± 0.5 kJ mol−1 (TC = 314 ± 2 K). For 5 this barrier is significantly larger. Analogous dynamic behaviour is well known for diene complexes, but to our knowledge, it is here first‐time described for a pentafulvene complex. |
| |
Keywords: | Titanium Fulvene complexes Fluxionality NMR spectroscopy Isomerization |
|
|