Sulfine control agents for synthesizing polymers

A polymer comprising:

• repeat units derived from the controlled free radical polymerization of at least one vinyl-containing monomer, at least one conjugated diene monomer, or combinations thereof, and a sulfine control agent having the formula:
• wherein R1 is alkyl, cycloalkyl, substituted alkyl, heteroalkyl, heterocycloalkyl or substituted heterocycloalkyl, and wherein Y is a thio group defined by SZ′, where Z′ is a substituted alkyl.

A method comprising:

• controlled free radical polymerization of at least one vinyl-containing monomer, at least one conjugated diene monomer, or combinations thereof, in the presence of a sulfine control agent having the formula:
• wherein R1 is alkyl, cycloalkyl, substituted alkyl, heteroalkyl, heterocycloalkyl or substituted heterocycloalkyl;
• wherein Y is alkyl, cycloalkyl, substituted alkyl, heteroalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, amino or thio.