Catalytic trimerization of ethylene with highly active half-sandwich titanium complexes bearing pendant p-fluorophenyl groups

Two new complexes [n(5)-C5H4CMe2-(p-fluorophenyl)]TiCl3 (1) and [n(5)-C5H4C(cyclo-C5H10)-(p-fluorophenyl)]TiCl3 (2) were synthesized and characterized. Their activities and selectivities for trimerization of ethylene were investigated. The introduction of fluorine atom greatly weakened the arene coordination, but this disadvantageous factor can be eliminated by introduction of a bulky substituent, such as cyclo-C5H10, to the bridging carbon linked to the Cp ring. The combinative effect of the fluorine substitute and the bridging unit can make complex 2 as a highly active and selective catalyst for ethylene trimerization. Its productivity and selectivity for 1-hexene can reach 1024.0 kg center dot mol(-1)center dot h(-1) and 99.3% respectively.