10 gms. of nickel acetylacetonate and 40.95 gms. of triphenylphosphine are dissolved in 400 ml. of absolute ether and the solution is reduced with 16 ml. of ethoxydiethyl aluminum at 0° C. This results in a red-brown solution from which red-brown crystals precipitate after standing for 30 minutes. Complete precipitation of the crystals is achieved by cooling. The crystals are filtered with suction, washed with ether and dried. There are obtained 32 gms. (80% of the theoretical yield) of red-brown crystals, the elementary analysis of which agrees with the formula Ni(P(C6H5)3)4. The compound is sensitive to air. When allowing oxygen to act on it, triphenylphosphine oxide is formed. The compound is capable of catalyzing the formation of cyclooctadiene from butadiene.
