摘要:
Two novel half-sandwich Ti(IV) complexes, [eta(5) :eta(1)-O-C-5(CH3)(4)CH2CH2OCH3]TiCl3 (3) and (eta(5) :eta(1) -P-C5H4CH2CH2PPh2)TiCl3 (6), were prepared and structurally characterised. At elevated temperatures, complex 3 undergoes a conversion into [eta(5) : sigma-C-5(CH3)(4)CH2CH2O-]TiCl2 (4). The dynamic behaviour of complexes 3 and 6 in solutions has been studied by variable-temperature H-1, C-13 and P-31 NMR spectroscopy. Thermodynamic parameters of the intramolecular dissociation-coordination processes for 3 and 6 were elucidated by the numerical analysis of the 6 (T) dependencies. The intramolecular M(IV)<--E (M = Ti, Zr; E = O, P) coordination in half-sandwich cyclopentadienyl complexes is discussed. (C) 2003 Elsevier Ltd. All rights reserved.