Bis (salicylaldiminato) titanium complex catalysts, highly syndiotactic polypropylene by a chain-end control mechanism, block copolymer containing this

A method of preparing syndiotactic polypropylene having Mw ranging from 10,000 to 500,000 and defects of the type rmr and [rrrr] pentad content greater than 0.50 comprising polymerizing propylene dissolved in an aprotic solvent in the presence of a catalytically effective amount of a complex having the structure:

• where R is selected from group consisting of halogen atoms, C1–C10 branched or straight chain alkyl groups, C1–C6 branched or straight chain alkoxide groups, and C1–C6 branched or straight chain amido groups, R1 is phenyl optionally substituted with one to five C1–C6 branched or straight chain alkyl groups or one to five electron withdrawing atoms or groups, is cyclohexyl substituted with one to five C1–C6 branched or straight chain alkyl groups or one to five electron withdrawing atoms or groups or is C1–C10 branched, cyclic or straight chain alkyl group, and R2 and R3 are the same or different and are selected from the group consisting of H or C1–C6 branched or straight chain alkyl groups;
• where when R2 is t-butyl, R3 is t-butyl;
• and an activating effective amount of compound that converts titanium of the complex to cationic form.