Preparation of high molecular weight polymers by direct arylation and heteroarylation
A method for preparing polymers by direct heteroarylation or arylation polycondensation is described herein. The method includes preparing a reaction mixture including at least a monomer to be polymerized, a catalyst and a ligand; heating the reaction mixture, and, optionally, end-capping the reaction mixture.
1. A method for preparing a high molecular weight polymer comprising:
(a) treating one or more monomers, one or more catalysts and one or more ligands under conditions for the direct arylation or heteroarylation of the at least one monomer to provide the high molecular weight polymer; and
(b) isolating the high molecular weight polymer;
wherein treating comprises treating a monomer of Formula (I) and a monomer of Formula (II):
H*-A 1 -H* (I) and X 1 -A 2 -X 2 (II);
in the presence of one or more catalysts and one or more ligands under conditions for the direct arylation or heteroarylation of the monomer of Formula (I) and monomer of Formula (II) to provide a polymer comprising repeating units of Formula (V):
-[A 1 -A 2 ]-(V);
wherein
H* is a hydrogen that is activated for direct arylation or heteroarylation reactions;
X 1 and X 2 are independently selected from leaving groups for direct arylation or heteroarylation reactions; and
A l and A 2 are independently selected from aryl and heteroaryl; and
wherein the one or more ligands are trialkyl or triaryl phosphines in which the alkyl and aryl groups are substituted or unsubstituted, or complexes thereof with metals; and
wherein the high molecular weight polymer has a molecular weight in excess of about 10 kDa.
2. The method of claim 1 , further comprising, prior to isolating the polymer, adding an end capping reagent to the polymer.
3. The method of claim 1 , wherein X 1 and X 2 are selected from bromine and iodine.
4. The method of claim 1 , wherein A 1 and A 2 are selected from phenyl, biphenyl, naphthyl and indanyl.
5. The method of claim 1 , wherein A 1 and A 2 are independently selected heteroaryl.
6. The method of claim 5 , wherein the heteroaryl comprises at least one thienyl group fused to a 5-membered or 6-membered heterocyclo group.
7. The method of claim 5 , wherein the heteroaryl comprises 2, 3 or 4 thienyl groups.
8. The method of claim 5 , wherein the heteroaryl comprises an oxindole group, indigo group or isoindigo group.
9. The method of claim 5 , wherein the heteroaryl group is selected from:
wherein R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 and R 30 are independently selected from H, CN and C 1-30 alkyl.
10. The method of claim 1 , wherein the one or more ligands are selected from: P(o-Tol) 3 ,
11. The method of claim 1 , wherein the one or more catalysts are palladium (II) catalysts.
12. The method of claim 11 , wherein the palladium catalyst is Pd(OAc)(o-Tol) or Pd(OAc) 2 .
13. The method of claim 1 , wherein the one or more catalysts are used in an amount of about 0.1 mol% to about 5 mol% based on the amount of monomers used.
14. The method of claim 1 , wherein the one or more ligands are used in an amount of about 5 mol% to about 20 mol% based on the amount of monomers used.
15. The method of claim 1 , further comprising addition of one or more mild bases along with the one or more monomers, one or more catalysts and one or more ligands under conditions for the direct arylation or heteroarylation of the at least one monomer to provide the polymer.