1146593-19-2Relevant academic research and scientific papers
Versatile coordination of cyclopentadienyl-arene ligands and its role intitanium-catalyzed ethylene trimerization
Otten, Edwin,Batinas, Aurora A.,Meetsma, Auke,Hessen, Bart
, p. 5298 - 5312 (2009/09/30)
Cationic titanium(IV) complexes with ansa-(n5-cyclopentadienyl, n6-arene) ligands were synthesized and characterized by X-ray crystallography. The strength of the metal-arene interaction in these systems was studied by variable-temperature NMR Spectroscopy. Complexes with a C- bridge between the cyclopentadienyl and arene moieties feature hemilabile coordination behavior of the ligand and consequently are active ethylene trimerization catalysts. Reaction of the titanium(IV) dimethyl cations with CO results in conversion to the analogous cationic titanium(ll) dicarbonyl species. Metal-to-ligand backdonation in these formally low-valent complexes gives rise to a strongly bonded, partially reduced arene moiety. In contrast to the n 6-arene coordinationmode observed for titanium, the more electron-rich vanadium(V) cations [cyclopentadienyl-arene]V(N'Pr 2)(NC6H4 -4-Me)+ feature n 1-arene binding, as determined by a crystallographic study. The three different metal-arene coordinationmodes that we experimentally observed model intermediates in the cycle for titanium-catalyzed ethylene trimerization. The nature of the metal-a rene interaction in these systems was studied by DFT calculations.
