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. 2023 May 24;145(20):10948-10953.
doi: 10.1021/jacs.3c01796. Epub 2023 Apr 20.

Direct Radical Copolymerizations of Thioamides To Generate Vinyl Polymers with Degradable Thioether Bonds in the Backbones

Hironobu Watanabe  1 , Masami Kamigaito  1
Affiliations

Direct Radical Copolymerizations of Thioamides To Generate Vinyl Polymers with Degradable Thioether Bonds in the Backbones

Hironobu Watanabe et al. J Am Chem Soc. .

Abstract

Direct radical addition reactions of thiocarbonyl (C═S) groups unaccompanied by β-scission have rarely been reported despite their potential for constructing various sulfur-containing compounds. Herein, we report direct radical copolymerizations of the C═S double bonds of simple thioamide derivatives and the C═C double bonds of common vinyl monomers to produce novel degradable vinyl polymers that contain thioether units in the backbones. In particular, N-acylated thioformamides copolymerized smoothly with various vinyl monomers, such as methyl acrylate, vinyl acetate, N,N-dimethylacrylamide, and styrene. RAFT copolymerization was also successfully mediated. The resultant copolymers had high glass transition temperatures and were readily degradable under ambient conditions. This work will expand the potential for use of thiocarbonyl compounds in radical reactions and develop novel poly(thioether)-vinyl polymer hybrid materials with unusual properties.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
(A) Typical radical reaction of thiocarbonyl compound. (B) Radical polymerization of vinyl monomer. (C) Direct radical addition copolymerization of thiocarbonyl compound and vinyl monomer. Copolymn = copolymerizaiton.
Figure 2
Figure 2
1H NMR spectra (CDCl3, 55 °C) of the copolymers obtained in the copolymerization of AcMeThiFA and (A) MA, (B) DMAA, (C) VAc, and (D) St (see entries 4, 5, 7, and 8 in Table 1 for the polymerization conditions).
Figure 3
Figure 3
Free energy profiles of the addition reaction of AcMeThiFA to (A) St radical and (B) VAc radical calculated at G3(MP2)-RAD//B3LYP/6-31G(d) level of theory. Energies are in kcal/mol.
Figure 4
Figure 4
RAFT copolymerization of AcMeThiFA with (A) MA and (B) VAc: [MA]0/[AcMeThiFA]0/[RAFT Agent 1]0/[AIBN]0 = 2000/2000/20/5 mM in DMF at 60 °C for (A) and [VAc]0/[AcMeThiFA]0/[RAFT Agent 2]0/[AIBN]0 = 4900/4900/49/10 mM in bulk at 60 °C for (B).
Figure 5
Figure 5
SEC curves of the copolymers and the products obtained by treatment with AgNO3 solution: [sulfur unit]0/[AgNO3]0 = 5/50 mM in THF/H2O (19/1 v/v) at room temperature for 24 h.
See this image and copyright information in PMC

References

    1. Crich D.; Quintero L. Radical Chemistry Associated with the Thiocarbonyl Group. Chem. Rev. 1989, 89, 1413–1432. 10.1021/cr00097a001. - DOI
    1. Moad G.; Rizzardo E.; Thang S. H. Radical Addition-Fragmentation Chemistry in Polymer Synthesis. Polymer 2008, 49, 1079–1131. 10.1016/j.polymer.2007.11.020. - DOI
    1. Bingham N. M.; Abousalman-Rezvani Z.; Collins K.; Roth P. J. Thiocarbonyl Chemistry in Polymer Science. Polym. Chem. 2022, 13, 2880–2901. 10.1039/D2PY00050D. - DOI
    1. Quiclet-Sire B.; Zard S. Z. Fun with Radicals: Some New Perspectives for Organic Synthesis. Pure Appl. Chem. 2010, 83, 519–551. 10.1351/PAC-CON-10-08-07. - DOI
    1. Tsuchihashi G.; Yamauchi M.; Ohno A. Thiocarbonyl Compounds as Potential Scavengers of Carbon Radicals. Bull. Chem. Soc. Jpn. 1970, 43, 968–968. 10.1246/bcsj.43.968. - DOI