Polymerization of propadiene. I. Comparison of catalytic systems in relation to polymer structure and polymerization by a new Ni-based catalyst

A literature survey is given of the methods of preparation of 1,2-and 1,2,2,1-polyallene. The spectroscopic data and other physico-chemical properties are compiled. Spectral analysis of the products in relation to the catalyst used leads to conclusions with regard to the effect of electron-donating and electron-withdrawing ligands to the transition metal of the catalyst on the ratio of 1,2 to 1,2,2,1-polyallene structural units in the polymer obtained. This hypothesis enabled us to prepare a structurally homogeneous 1,2 polyallene in almost quantitative yield. The catalyst was prepared by adding propadiene to a benzene solution of Ni(II) acetylacetonate followed by addition of triisobutylaluminum. This sequence of addition appeared to be the essential factor for obtaining an active catalyst. A kinetic scheme for the polymerization is put forward.