| Abstract: | Mixtures of π-cyclobutadiene-nickeldihalides and LEWIS acids such as Al(R)nCl3-n,, n = 1–2, represent very active homogeneous catalysts for dimerization of mono-olefins. As active cocatalyst may be used LEWIS bases, in particular compounds containing three-coordinated phosselectivity of the catalytic system has been investigated. The kinetics of the dimerization-reaction is outlined. The mechanisms of the olefin-dimerization is best characterized as a «double-cis-insertionreaction». The main catalytic activity is thought to be connected either to free positively charged nickel cations or to bimetallic nickel-aluminium-complexes, depending on theconditions of reaction, in particular the amount and chemical nature of the cocatalyst. |
