LINEAR OLIGOMERIZATION OF OLEFINS VIA NICKEL CHELATE COMPLEXES AND MECHANISTIC CONSIDERATIONS BASED ON SEMIEMPIRICAL CALCULATIONS

The new complexes (η-4-cyclooctene-1-yl)(1,1,1,-trifluoro-2,4-pentane-dionato) nickel, Ib, and (η-4-cyclooctene-1-yl)(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) nickel, Ic, oligomerize α olefins such as ethylene, propylene, 1-butene, 1-hexene and 1-octene to predominantly linear products without a cocatalyst. The dimers of 1-butene show a linearity of > 80%. The rate of reactivity follows the order ethylene > propylene > 1-butene > 1-hexene > 1-octene. The experimental findings that complex Ic is more reactive than complex Ib are rationalized by preliminary semi-empirical calculations using the EHT method. © 1979.