Synthesis of chalcogen-capped pi-conjugated polymers
Methods for the preparation of mono- and bis-end-functionalized π-conjugated polymers. In the methods, chalcogens are selectively installed at the polymer terminus or termini.
1. A method for mono-end-functionalizing a poly(arylene) with a chalcogen, comprising:
polymerizing an aryl monomer by reaction with a Grignard reagent and an aryl nickel catalyst to provide an aryl nickel complex-terminated poly(arylene); and
treating the aryl nickel complex-terminated poly(arylene) with a chalcogenating agent followed by treatment with an acid to provide a mono-chalcogen-end-functionalized poly(arylene).
2. The method of claim 1 , wherein the aryl monomer is selected from the group consisting of substituted and unsubstituted thiophenes, substituted and unsubstituted fluorenes, substituted and unsubstituted phenylenes, substituted and unsubstituted pyridines, and substituted and unsubstituted pyrroles.
3. A method for mono-end-functionalizing poly(3-hexylthiophene) with a chalcogen, comprising:
polymerizing a 3-hexylthiophene monomer by reaction with a Grignard reagent and an aryl nickel catalyst to provide an aryl nickel complex-terminated poly(3-hexylthiophene); and
treating the aryl nickel complex-terminated poly(3-hexylthiophene) with a chalcogenating agent followed by treatment with an acid to provide a mono-chalcogen-end-functionalized poly(3-hexylthiophene).
4. The method of claim 3 , wherein chalcogenating agent is elemental sulfur.
5. The method of claim 3 , wherein chalcogenating agent is selenium.
6. The method of claim 3 , wherein chalcogenating agent is carbon disulfide.
7. The method of claim 3 , wherein the aryl nickel complex-terminated poly(3-hexylthiophene) is treated with a chalcogenating agent and a base.
8. The method of claim 7 , wherein the base is a nitrogen base.
9. The method of claim 7 , wherein the base is 1,8-diazabicyclo[5.4.0]undec-7-ene.
10. The method of claim 3 , wherein the chalcogenating agent is in molar excess.
11. The method of claim 3 , wherein the aryl nickel complex-terminated poly(3-hexylthiophene) is an α-aryl-terminated ω-aryl nickel complex-terminated poly(3-hexylthiophene) prepared by initiating polymerization of the thiophene monomer with an aryl nickel initiator.
12. The method of claim 11 , wherein the aryl nickel initiator is (aryl)Ni(PPh 3 ) 2 Br.