Polymers bearing pendant pentafluorophenyl ester groups, and methods of synthesis and functionalization thereof
View Patent ↗A one pot method of preparing cyclic carbonyl compounds comprising an active pendant pentafluorophenyl ester group is disclosed. The cyclic carbonyl compounds can be polymerized by ring opening methods to form ROP polymers comprising repeat units comprising a side chain pentafluorophenyl ester group. Using a suitable nucleophile, the pendant pentafluorophenyl ester group can be selectively transformed into a variety of other functional groups before or after the ring opening polymerization.
1. A method, comprising:
forming a first mixture comprising a catalyst, an initiator comprising a nucleophilic group selected from the group consisting of alcohols, amines, and thiols, an optional accelerator, an optional solvent, and a first cyclic carbonyl compound comprising a pentafluorophenyl ester group; and
agitating the first mixture, thereby forming a first ROP polymer by ring opening polymerization of the first cyclic carbonyl compound, the first ROP polymer comprising a first polymer chain linked to a chain fragment derived from the initiator; wherein i) the chain fragment comprises a first backbone heteroatom derived from the nucleophilic group, the first backbone heteroatom linked to a first end unit of the first polymer chain, the first backbone heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur, ii) the first polymer chain comprises a second end unit comprising a nucleophilic group selected from the group consisting of hydroxy group, primary amine groups, secondary amine groups, and thiol group, and iii) the first polymer chain comprises a first repeat unit, the first repeat unit comprising a) a backbone functional group selected from the group consisting of carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, and dithiocarbonate, and b) a tetrahedral backbone carbon, the tetrahedral backbone carbon being linked to a first side chain comprising a pentafluorophenyl ester group.
2. The method of claim 1 , wherein the first side chain of the first ROP polymer has the structure
wherein the starred bond is linked to the tetrahedral backbone carbon of the first repeat unit.
3. The method of claim 1 , wherein the first cyclic carbonyl monomer has the general formula (4):
wherein
each Y independently represents O, S, NH or NQ″, wherein each Q″ group independently represents an alkyl group comprising 1 to 20 carbons or an aryl group comprising 1 to 20 carbons, or a foregoing Q″ groups substituted with a pentafluorophenyl ester group,
n is an integer from 0 to 6, wherein when n is 0, carbons labeled 4 and 6 are linked together by a single bond,
each Q′ group independently represents a hydrogen, a halide, a pentafluorophenyl ester group, an alkyl group comprising 1 to 20 carbons, an ester group other than a pentafluorophenyl ester group comprising 1 to 20 carbons, an amide group comprising 1 to 20 carbons, an aryl group comprising 1 to 20 carbons, an alkoxy group comprising 1 to 20 carbons, or a foregoing Q′ group substituted with a pentafluorophenyl ester group, and
at least one of the Q′ or Q″ groups comprises a pentafluorophenyl ester group.
4. The method of claim 1 , wherein the first cyclic carbonyl monomer has the general formula (6):
wherein
each Y′ independently represents O, S, NH or NU″, wherein each U″ group independently represents an alkyl group comprising 1 to 20 carbons or an aryl group comprising 1 to 20 carbons, or a foregoing U″ group substituted with a pentafluorophenyl ester group,
each U′ group independently represents a hydrogen, a halide, a pentafluorophenyl ester group, an alkyl group comprising 1 to 20 carbons, an ester group comprising 1 to 20 carbons, an amide group comprising 1 to 20 carbons, an aryl group comprising 1 to 20 carbons, an alkoxy group comprising 1 to 20 carbons, or a foregoing U′ group substituted with a pentafluorophenyl ester group.
5. The method of claim 4 , wherein none of the U′ or U″ groups comprise a pentafluorophenyl ester group.
6. The method of claim 4 , wherein the U′ group at position labeled 5 in formula (6) is ethyl or methyl, and all other U′ groups are hydrogen.
7. The method of claim 1 , wherein the first cyclic carbonyl monomer is selected from the group consisting of
and combinations thereof.
8. The method of claim 1 , wherein the catalyst is an organocatalyst.
9. The method of claim 8 , wherein every individual metal of the group consisting of beryllium, magnesium, calcium, strontium, barium, radium, aluminum, gallium, indium, thallium, germanium, tin, lead, arsenic, antimony, bismuth, tellurium, polonium, and metals of Groups 3 to 12 of the Periodic Table has a concentration in the first ROP polymer of 0 ppm to 100 ppm.
10. The method of claim 8 , wherein the organocatalyst comprises at least one 1,1,1,3,3,3-hexafluoropropan-2-ol-2-yl (HFP) group.
11. The method of claim 1 , wherein the accelerator comprises 2 to 3 nitrogens.
12. The method of claim 1 , wherein the accelerator is (−)-sparteine.
13. The method of claim 1 , wherein the first ROP polymer has a polydispersity index (PDI) of from 1.01 to 1.35.
14. The method of claim 1 , wherein the initiator is a polyether alcohol, and the first ROP polymer is a block copolymer comprising a first block comprising a hydrophilic polyether chain.
15. The method of claim 1 , wherein the initiator is a mono end capped poly(alkylene glycol).
16. The method of claim 1 , wherein the the nucleophilic group of the second end unit is capable of initiating a ring opening polymerization.
17. The method of claim 1 , wherein the first ROP polymer is a copolymer comprising a second repeat unit, the second repeat unit comprising a second backbone functional group selected from the group consisting of esters, carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, and dithiocarbonate.
18. The method of claim 1 , further comprising:
agitating a second mixture comprising i) the first ROP polymer, ii) a nucleophile selected from the group consisting of alcohols, amines and thiols, iii) an optional catalyst, and iv) an optional accelerator, thereby forming a functionalized second polymer and pentafluorophenol byproduct, wherein the functionalized second polymer comprises a second functional group formed by the reaction of the nucleophile with the pentafluorophenyl ester group, the second functional group selected from the group consisting of alcohol based esters other than pentafluorophenyl ester, amides, and thioesters.
19. The method of claim 18 , wherein the optional second catalyst is CsF.
20. The method of claim 18 , wherein the nucleophile is a polyether alcohol, and the functionalized second polymer comprises a hydrophilic polyether side chain group.