Abstract: The present invention relates to metallocenes, wherein the two cyclopentadienyl rings are connected to each other by a single carbon atom characterized by the following general formula III where each A, equal to or different from each other, is selected from the group consisting of: hydrogen, OR3, NRR4, or SR5; and to compounds of formula IV wherein each B, equal to or different from each other, is selected from the group consisting of: OH, NRH or SH, obtained by hydrolizing the corresponding oxygen, nitrogen or sulfur containing groups from compounds of formula III. These compounds are used as active catalyst components in the polymerization of olefins.

Abstract: Catalytic systems particularly suitable for the polymerization of &agr;-olefins containing from two to 20 carbon atoms, as well as for the copolymerization of ethylene with &agr;-olefins containing from three to 20 carbon atoms, dienes, and cycloalkenes in processes wherein the catalyst is suspended in a solvent, in processes in gas phase, as well as in mass polymerization processes at high temperatures and pressures, are disclosed. The catalytic system is a mixture of a catalyst component A and a co-catalyst component B. The catalyst component A is formed by a functionalized inorganic porous oxide, by an organoaluminium compound and by an organometallic compound of a metal of the groups 3, 4, 5, or 6 of the periodic table. Functionalization of the inorganic oxide is by introduction of functional groups to be used to strongly fix the organoaluminium compound and the organometallic compound.