Preparation of addition polymerization catalysts via Lewis acid mitigated metal center oxidation

A process for the preparation of a cationic metal complex corresponding to the formula:

• [Cp.sub.a (ZY).sub.b ML.sub.c.sup.+ ].sub.q [J.sub.p A].sup.-q,
• wherein:
• Cp independently each occurrence is a cyclopentadienyl group n-bound to M, or a hydrocarbyl, silyl, halo, halohydrocarbyl, hydrocarbylmetalloid or halohydrocarbylmetalloid substituted derivative of said cyclopentadienyl group, said Cp containing up to 50 nonhydrogen atoms, and, when a is 2, optionally both Cp groups may be joined together by a bridging group;
• a is 1 or 2;
• b is 0 or 1;
• cis 1 or 2;
• the sum of a, b and c is 3;
• Z is a divalent moiety comprising oxygen, nitrogen, phosphorous, boron, or a member of Group 14 of the Periodic Table of the Elements, said moiety having up to 30 nonhydrogen atoms;
• Y is a linking group comprising nitrogen, phosphorus, oxygen or sulfur covalently bonded to M and Z through said nitrogen, phosphorus, oxygen or sulfur atom;
• L independently each occurrence is hydride, halo, or a monovalent anionic ligand selected from covalently bonded hydrocarbyl, silyl, amido, phosphido, alkoxy, aryloxy, and sulfido groups optionally being further substituted with one or more amine, phosphine, ether, or thioether groups, said ligand having up to 50 nonhydrogen atoms;
• M is titanium or zirconium in the +4 oxidation state;
• p is an integer from 0 to 4;
• q is 1 or 2;
• J is the Lewis acid mitigating agent, and
• A is a reduced remnant of a neutral organic oxidizing agent and may be ligating or nonligating,
• the steps of the process comprising contacting in a noninterfering, noncoordinating solvent at a temperature from-100.degree. C. to 300.degree. C.:
• 1) a reduced metal precursor complex corresponding to the formula:
• Cp.sub.a (ZY).sub.b M*L.sub.c, wherein Cp, Z, Y, L, a, b, and c are as previously defined, and M* is the same metal as M but in a +3 oxidation state;
• 2) a neutral organic oxidizing agent, A*, capable of accepting one or more electrons and oxidizing M* to M and which in reduced form is A;
• and, if A is a ligating group,
• 3) a Lewis acid mitigating agent, J.