Abstract: An oligomer N-alkyl-iminoalane, made up of a plurality of four and/or six member rings of the formulae: ##STR1## wherein R is an aliphatic, cycloaliphatic or aromatic hydrocarbon combined in a tridimensional cage structure having the chemical composition (HAl-NR).sub.n, in which R has the above meaning and n is a whole number lower than or equal to 10, is prepared by reacting a primary amine containing a secondary or tertiary carbon atom in alpha or beta position with respect to the amine nitrogen atom or amide derivative thereof wherein the amine radical contains a secondary or tertiary carbon atom in alpha or beta position with respect to the nitrogen atom with a complex formed by AlH.sub.3 and a Lewis base, or by reacting said primary amine with an alkali or alkaline-earth metal alanate.

Abstract: Compounds having at least one olefinic unsaturation (e.g. isoprene) are polymerized in the presence of a catalyst system consisting of a transition metal compound such as TiCl.sub.4 and an aluminum hydride derivative which is either (a) an oligomer N-alkylaminoalane of the type: ##STR1## or (b) an oligomer derivative having the general formula:(XAlNR).sub.x (XYAl).sub.y (NHR).sub.y.

Abstract: A poly-N-alkyliminoalane containing repeated imine units of the type ##STR1## wherein R is an aliphatic radical, is prepared by reacting an alane of an alkali or alkali-earth metal with a primary amine in the presence of a hydrocarbon solvent.