Boron-based electron donors for Ziegler-Natta catalyst systems

A solid pre-catalyst component comprising:

• titanium, magnesium, a halogen, an internal electron donor comprising boron, and a secondary internal electron donor;
• wherein:
• the internal electron donor comprising boron is a compound represented by Formula (I):
• B(OR1)R2R3 (I)
• each R1 is individually H, linear or branched alkyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl, optionally interrupted or substituted by one or more functional groups selected from the group consisting of ether, ester, amide, carbonate, halogens, phosphate, sulfate, sulfide, sulfoxide, sulfone, carbamate, and a combination of any two or more thereof;
• R2 and R3 are individually linear or branched alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, optionally interrupted or substituted by one or more functional groups selected from the group consisting of ether, ester, amide, carbonate, halogens, phosphate, sulfate, sulfide, sulfoxide, sulfone, carbamate, and a combination of any two or more thereof, or OR1, or R2 and R3 may join together and with the boron atom to form a borinane ring;
• and
• the secondary internal electron donor is (6-benzoyloxydibenzofuran-4-yl) benzoate.