Olefin polymerization with direct use of ansa-metallocene amide complexes as catalysts

A method of forming polymers of α-olefins using a high activity ansa-metallocene amide catalyst, an aluminum alkyl, said aluminum alkyl having the formula Al(R″′)3 wherein R″′ is C1 to C20 hydrocarbyl radical, and a cocatalyst selected from the group consisting of alumoxanes, triarylcarbenium salts, ammonium salts, silver salts, and ferrocenium salts, tris(pentafluorophenyl)borane and magnesium dichloride, said method comprising:

• preparing a catalyst composition which comprises a metal amide complex of the formula:
• wherein Cp independently and in each occurrence is cyclopentadienyl, indenyl, or fluorenyl, or a hydrocarbyl, alkyl, aryl, silyl, halo, halohydrocarbyl, hydrocarbylmetalloid, or halohydrocarbylmetalloid substituted derivative of said cyclopentadienyl, indenyl, or fluorenyl, X is a bridging group which links the Cp groups, M is a metal selected from the group consisting of Group 3, 4, and 5 metals, R and R′ are the same or different and are each hydrogen or hydrocarbyl radicals of from C1 to C20, or silyl radicals, and n is from 3 to 5;
• and
• an aluminum alkyl of the formula Al(R″′)3 wherein R″′ equals an alkyl group of C1 to C20 carbon atoms, and thereafter adding a cocatalyst selected from the group consisting of alumoxanes, triarylcarbenium salts, ammonium salts, silver salts, and ferrocenium salts, and tris(pentafluorophenyl)borane and magnesium chloride;
• and thereafter
• contacting the catalyst and cocatalyst composition with an α-olefin under conditions to effect polymerization wherein the catalyst is an ansa-metallocene alkyl compound and wherein the combination of catalyst and cocatalyst forms a cationic ansa-metallocene alkyl complex active species wherein the active species has a high olefin polymerization activity.