The disclosure provides a procatalyst for the polymerization of ethylene and optionally one or more alpha-olefins having the structure shown in formula (I) below: wherein at least two of Y1-Y3 and at least two of Y4-Y6 are fluorine atoms and when only two of Y1-Y3 and only two of Y4-Y6 are fluorine atoms, the non-fluorine Y1-Y6 are selected from the group consisting of H atom, alkyl groups, aryl groups, heteroaryl groups, and alkoxy groups. Also provided is a polymerization process using the procatalyst.