Three half-sandwich titanium complexes with a pendant ethereal group, CH3OCH2CH2CpTiCl3, CH3OCH(CH3)CH2CpTiCl3, and tetrahydrofurfurylcyclopentadienyltitanium trichloride activated by MAO have been found to trimerize ethylene with high selectivity and moderate activity. Compared with the catalytic behavior of CpTiCl3/MAO and n-Pr-CpTiCl3/MAO, we can identify that the pendant ethereal group plays an important role in this selective trimerization process. Their different catalytic behavior toward temperature is discussed. (C) 2004 Elsevier B.V. All rights reserved.