Synthesis of group 4 metal diene complexes

A process for preparing a Group 4 metal complex corresponding to the formula:

• ##STR7## wherein:
• M is titanium or zirconium in the +2 formal oxidation state;
• L is a group containing a cyclic, delocalized, anionic, -system through which the group is bound to M;
• Z is a divalent moiety bound to both L and M comprising boron, or a member of Group 14 of the Periodic Table of the Elements, and also comprising nitrogen, phosphorus, sulfur or oxygen, said moiety having up to 60 non-hydrogen atoms;
• and
• X is a neutral, conjugated or nonconjugated diene, optionally substituted with one or more hydrocarbyl groups, said X having up to 40 carbon atoms and forming a -complex with M;
• the steps of the process comprising:
• 1)
• a) contacting a conjugated or nonconjugated C.sub.4-40 diene compound with a metal complex corresponding to the formula:
• ##STR8## wherein, M* is titanium or zirconium in the +3 or +4 formal oxidation state;
• X* independently each occurrence is a C.sub.1-20 hydrocarbyloxide;
• x is one or two;
• G is a neutral Lewis base selected from amines, phosphines and ethers said G having from 3 to 20 non-hydrogen atoms;
• L and Z are as previously defined;
• and
• g is a number from 0 to 3,
• in an inert solvent, and
• b) contacting the resulting mixture with a reducing agent,
• or
• 2)
• a) contacting a conjugated or nonconjugated C.sub.4-40 diene compound with a reducing agent in a suitable noninterfering solvent, and
• b) contacting the resulting mixture with a complex corresponding to the formula:
• ##STR9## wherein, L, Z, M*, X*, x, G and g are as previously defined.