Homogeneous olefin polymerization catalyst by abstraction with lewis acids

A process for preparing a catalyst having a limiting charge separated structure corresponding to the formula:

• ##STR4## wherein:
• Cp is a cyclopentadienyl group or a substituted derivative thereof that is .pi.-bound to M wherein each substituent is independently selected from the group consisting of C.sub.1-20 hydrocarbyl radicals, C.sub.1-20 halogenated hydrocarbyl radicals, C.sub.1-20 hydrocarbyl substituted metalloid radicals wherein the metalloid is selected from Group 14 of the Periodic Table of the Elements, and halogen radicals;
• or two or more such radicals may together with Cp form a fused ring system;
• Z is a divalent moiety comprising oxygen, boron, or a member of Group 14 of the Periodic Table of the Elements;
• Y is a ligand group comprising nitrogen, phosphorus, oxygen or sulfur or optionally Z and Y together form a fused ring system;
• M is a metal of Group 4 or the Lanthanide series of the Periodic Table of the Elements;
• X independently each occurrence is hydride or a hydrocarbyl, silyl or germyl group said X having up to 20 carbon, silicon or germanium atoms;
• and
• A.sup.- is an anion of a Lewis acid, A, having relative Lewis acidity greater than or equal to that of phenylbis(perfluorophenyl)borane, said anion being compatible with the metal cation,
• the steps of the process comprising contacting a derivative of a Group 4 or Lanthanide metal corresponding to the formula:
• ##STR5## wherein Cp, Z, Y, M, and X are as previously defined herein,
• with the Lewis acid, A, under conditions to cause abstraction of X and formation of the anion XA.sup.-.