Pseudo-random copolymers formed by use of constrained geometry addition polymerization catalysts

A pseudo-random copolymer prepared by polymerizing a monomer mixture comprising an olefin and a hindered vinylidene monomer corresponding to the formula:

• CG.sub.2 =CG'R'", wherein,
• R'"is t-butyl, norbornyl, or an aryl or alicyclic substituent of up to 20 carbons,
• G independently each occurrence is hydrogen or methyl, and
• G' independently each occurrence is hydrogen or methyl or alternatively G' and R'" together form a ring system, in the presence of a catalyst comprising the following components:
• a) a metal coordination complex corresponding to the formula:
• ##STR6## wherein:
• M is a metal of Group 4 or the Lanthanide Series of the Periodic Table of the Elements;
• Cp* is a cyclopentadienyl or a substituted cyclopentadienyl group wherein one or more carbons of the cyclopentadienyl group are substituted with a C.sub.1-2 hydrocarbyl radical, C.sub.1-2 halohydrocarbyl radical, C.sub.1-2 hydrocarbyl substituted Group 14 metalloid radical, or halogen radical, or optionally two or more such substituents together form a fused ring system;
• said Cp* being bound in an .eta..sup.5 bonding mode to M;
• Z is a moiety comprising boron, or a member of Group 14 of the Periodic Table of the Elements, and optionally sulfur or oxygen, said moiety having up to 20 non-hydrogen atoms, and optionally Cp* and Z together form a fused ring system;
• X independently each occurrence is an anionic ligand group having up to 30 non-hydrogen atoms;
• n is 1 or 2 depending on the valence of M;
• and
• Y is an anionic ligand group bonded to Z and M comprising nitrogen, phosphorus, oxygen or sulfur and having up to 20 non-hydrogen atoms, optionally Y and Z together form a fused ring system;
• and
• b) an activating cocatalyst.