Method of making a functionalized elastomer

1. A method of making a functionalized elastomer, comprising the step of:

polymerizing a conjugated diene monomer in the presence of a lathanide-based coordination polymerization catalyst activated with a magnesium compound of formula 1

where R 1 is phenylene, or a linear or branched alkane diyl group containing 2 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;

Q is of formula 2 or 3

where R 2 is phenyl, or a linear or branched alkyl group containing 2 to 10 carbon atoms; and

where R 3 and R 4 are independently phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R 3 and R 4 taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms.

2. The method of claim 1 , wherein the magnesium compound of formula 1 is selected from the group consisting of

3. The method of claim 1 , wherein the lanthanide-based catalyst is selected from neodymium borohydride complexes and neodymium carboxylates.

4. The method of claim 1 , wherein the lanthanide-based catalyst comprises Nd(BH 4 ) 3 .(THF) 3 .

5. The method of claim 1 , wherein the conjugated diene monomer is selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, and 2-phenyl-1,3-butadiene.

6. The method of claim 5 , wherein the monomer further comprises a functionalized monomer of formula 4

wherein R 6 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; R 7 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms; X 1 is selected from formulas 5 and 6

wherein R 8 and R 9 are independently trialkylsilyl, phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or one of R 8 and R 9 is hydrogen and the other is phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R 8 and R 9 taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms; and X 2 is a sulfur atom or a structure of formula 7 or 8

wherein when X 2 is of formula 8, the S atom of formula 8 is adjacent to the phenyl ring of formula 6 and the N atom of formula 8 is adjacent to R 6 .

7. The method of claim 1 , further comprising the step of terminating the polymerization with a functional terminator substituted with a functional group comprising at least one heteroatom selected from phosphorus, boron, oxygen, halogens and silicon.

8. The method of claim 7 wherein the functional terminator comprises at least one functional group selected from the group consisting of phosphane, phosphonic acid, phosphate, phosphodiester, phosphotriester, silyl, alklysilyl, alkoxysilyl, and siloxy.

9. The method of claim 7 , wherein the functional terminator comprises a terminator selected from the group consisting of tetraethoxysilane, n-octyltriethoxysilane, 3-chloropropyltriethoxysilane, and chlorodiphenylphosphine.

10. The method of claim 1 , wherein the nitrogen containing heterocyclic group is selected from the group consisting of the structures.