Functionalized elastomer containing a sulfur group

A method of making a copolymer, comprising the step of polymerizing a monomer selected from the group consisting of 1,3-butadiene and isoprene and a monomer of formula I in the presence of an (allyl)(arene)Ni(II) polymerization catalyst

• wherein R1 is a covalent bond, phenylene, a linear or branched alkane diyl group containing 1 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms;
• and R2 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms;
• and X is a sulfur atom or a structure of formula II or III, wherein when X is of formula III, the S atom of formula III is adjacent to the phenyl ring of formula I and the N atom of formula III is adjacent to R1