1-Hexene polymerization was conducted by [t-BuNSiMe2(3,6-t-Bu(2)Flu)]TiMe2 (1) using trialkylaluminum-free modified methylaluminoxane (dMMAO) as a cocatalyst in toluene. The system produced living syndiotactic poly(l-hexene) with high turnover frequency of propagation (TOF, 98 s(-1)) at 0 degrees C. The propagation rate was increased linearly against the 1-hexene concentration, which indicates that the first-order dependence of the propagation rate on monomer concentration. Polymerizations of 1-octene, 1-decene and 1-dodecene were also conducted for investigating the effect of chain length of 1-alkene on propagation rate by means of the livingness of this system. The propagation rate decreased according to the chain length until 1-decene but almost unchanged in longer 1-alkene: TOF, 1-octene (62 s(-1)) > 1-decene (32 s(-1)) approximate to 1-dodecene (31 s(-1))