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Highly efficient organic photocatalysts discovered via a computer-aided-design strategy for visible-light-driven atom transfer radical polymerization


Organocatalysed photoredox-mediated atom transfer radical polymerization (O-ATRP) is a very promising polymerization method as it eliminates concerns associated with transition-metal contamination of polymer products. However, reducing the amount of catalyst and expanding the monomer scope remain major challenges in O-ATRP. Herein, we report a systematic computer-aided-design strategy to identify powerful visible-light photoredox catalysts for O-ATRP. One of our discovered organic photoredox catalysts controls the polymerization of methyl methacrylate at sub-ppm catalyst loadings (0.5 ppm—a very meaningful amount enabling the direct use of polymers without a catalyst removal process); that is, 100–1,000 times lower loadings than other organic photoredox catalysts reported so far. Another organic photoredox catalyst with supra-reducing power in an excited state and high redox stability facilitates the challenging polymerization of the non-acrylic monomer styrene, which is not successful using existing photoredox catalysts. This work provides access to diverse challenging organic/polymer syntheses and makes O-ATRP viable for many industrial and biomedical applications.

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  1. 1.

    Matyjaszewski, K. Advanced materials by atom transfer radical polymerization. Adv. Mater. 30, 1706441 (2018).

  2. 2.

    Matyjaszewski, K. & Tsarevsky, N. V. Macromolecular engineering by atom transfer radical polymerization. J. Am. Chem. Soc. 136, 6513–6533 (2014).

  3. 3.

    Corrigan, N., Shamugam, S., Xu, J. & Boyer, C. Photocatalysis in organic polymer synthesis. Chem. Soc. Rev. 45, 6165–6212 (2016).

  4. 4.

    Pan, X. et al. Photomediated controlled radical polymerization. Prog. Polymer Sci. 62, 73–125 (2016).

  5. 5.

    Shanmugam, S. & Boyer, C. Organic photocatalysts for cleaner polymer synthesis. Science 352, 1053–1054 (2016).

  6. 6.

    Theriot, J. C., McCarthy, B. G., Lim, C. H. & Miyake, G. M. Organocatalyzed atom transfer radical polymerization: perspectives on catalyst design and performance. Macromol. Rapid Commun. 38, 1700040 (2017).

  7. 7.

    Treat, N. J. et al. Metal-free atom transfer radical polymerization. J. Am. Chem. Soc. 136, 16096–16101 (2014).

  8. 8.

    Pan, X. et al. Mechanism of photoinduced metal-free atom transfer radical polymerization: experimental and computational studies. J. Am. Chem. Soc. 138, 2411–2425 (2016).

  9. 9.

    Theriot, J. C. et al. Organocatalyzed atom transfer radical polymerization driven by visible light. Science 352, 1082–1086 (2016).

  10. 10.

    Pearson, R. M., Lim, C. H., McCarthy, B. G., Musgrave, C. B. & Miyake, G. M. Organocatalyzed atom transfer radical polymerization using N-aryl phenoxazines as photoredox catalysts. J. Am. Chem. Soc. 138, 11399–11407 (2016).

  11. 11.

    Lim, C. H. et al. Intramolecular charge transfer and ion pairing in N,N-diaryl dihydrophenazine photoredox catalysts for efficient organocatalyzed atom transfer radical polymerization. J. Am. Chem. Soc. 139, 348–355 (2017).

  12. 12.

    McCarthy, B. G. et al. Structure–property relationships for tailoring phenoxazines as reducing photoredox catalysts. J. Am. Chem. Soc. 140, 5088–5101 (2018).

  13. 13.

    Sartor, S. M., McCarthy, B. G., Pearson, R. M., Miyake, G. M. & Damrauer, N. H. Exploiting charge-transfer states for maximizing intersystem crossing yields in organic photoredox catalysts. J. Am. Chem. Soc. 140, 4778–4781 (2018).

  14. 14.

    Ghosh, I., Ghosh, T., Bardagi, J. I. & Konig, B. Reduction of aryl halides by consecutive visible light-induced electron transfer processes. Science 346, 725–728 (2014).

  15. 15.

    Murphy, J. J. et al. Asymmetric catalytic formation of quaternary carbons by iminium ion trapping of radicals. Nature 532, 218–222 (2016).

  16. 16.

    Silvi, M., Verrier, C., Rey, Y. P., Buzzetti, L. & Melchiorre, P. Visible-light excitation of iminium ions enables the enantioselective catalytic β-alylation of enals. Nat. Chem. 9, 868–873 (2017).

  17. 17.

    Pandey, G. & Laha, R. Visible-light-catalyzed direct benzylic C(sp 3)–H amination reaction by cross-dehydrogenative coupling. Angew. Chem. Int. Ed. 54, 14875–14879 (2015).

  18. 18.

    Rybicka-Jasinska, K., Shan, W., Zawada, K., Kadish, K. M. & Gryko, D. Porphyrins as photoredox catalysts: experimental and theoretical studies. J. Am. Chem. Soc. 138, 15451–15458 (2016).

  19. 19.

    Wang, L. et al. Structural design principle of small-molecule organic semiconductors for metal-free, visible-light-promoted photocatalysis. Angew. Chem. Int. Ed. 55, 9783–9787 (2016).

  20. 20.

    Luo, J. & Zhang, J. Donor–acceptor fluorophores for visible-light-promoted organic synthesis: photoredox/Ni dual catalytic C(sp 3)–C(sp 2) cross-coupling. ACS Catal. 6, 873–877 (2016).

  21. 21.

    Poelma, S. O. et al. Chemoselective radical dehalogenation and C–C bond formation on aryl halide substrates using organic photoredox catalysts. J. Org. Chem. 81, 7155–7160 (2016).

  22. 22.

    Kottisch, V., Michaudel, Q. & Fors, B. P. Cationic polymerization of vinyl ethers controlled by visible light. J. Am. Chem. Soc. 138, 15535–15538 (2016).

  23. 23.

    Kottisch, V., Supej, M. J. & Fors, B. P. Enhancing temporal control and enabling chain‐end modification in photoregulated cationic polymerizations by using Ir‐based catalysts. Angew. Chem. Int. Ed. 57, 8260–8264 (2018).

  24. 24.

    Arias-Rotondo, D. M. & McCusker, J. K. The photophysics of photoredox catalysis: a roadmap for catalyst design. Chem. Soc. Rev. 45, 5803–5820 (2016).

  25. 25.

    Dumur, F., Gigmes, D., Fouassier, J. & Lalevee, J. Organic electronics: an El Dorado in the quest of new photocatalysts for polymerization reactions. Acc. Chem. Res. 49, 1980–1989 (2016).

  26. 26.

    Majek, M. & Wangelin, A. J. Mechanistic perspectives on organic photoredox catalysis for aromatic substitutions. Acc. Chem. Res. 49, 2316–2327 (2016).

  27. 27.

    Romero, N. A. & Nicewicz, D. A. Organic photoredox catalysis. Chem. Rev. 116, 10075–10166 (2016).

  28. 28.

    Hirata, S. Recent advances in materials with room-temperature phosphorescence: photophysics for triplet exciton stabilization. Adv. Opt. Mater. 5, 1700116 (2017).

  29. 29.

    El-Sayed, M. A. The triplet state: its radiative and non-radiative properties. Acc. Chem. Res. 1, 8–16 (1968).

  30. 30.

    Turro, N. J. The triplet state. J. Chem. Educ. 46, 2–6 (1969).

  31. 31.

    Bolton, O., Lee, K., Kim, H. J., Lin, K. Y. & Kim, J. Activating efficient phosphorescence from purely organic materials by crystal design. Nat. Chem. 3, 205–210 (2011).

  32. 32.

    Kwon, M. S. et al. Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials. Nat. Commun. 6, 8947 (2015).

  33. 33.

    Zhang, G., Palmer, G. M., Dewhirst, M. W. & Fraser, C. L. A dual-emissive-materials design concept enables tumour hypoxia imaging. Nat. Mater. 8, 747–751 (2009).

  34. 34.

    El-Sayed, M. A. Spin–orbit coupling and the radiationless processes in nitrogen heterocyclics. J. Chem. Phys. 38, 2834–2838 (1963).

  35. 35.

    Flamigni, L. et al. Photochemistry and photophysics of coordination compounds: iridium. Top. Curr. Chem. 21, 143–203 (2007).

  36. 36.

    Kalyanasundaram, K. Photophysics, photochemistry and solar energy conversion with tris(bipyridyl)ruthenium(ii) and its analogues. Coord. Chem. Rev. 46, 159–244 (1982).

  37. 37.

    Fukuzumi, S. et al. Electron-transfer state of 9-mesityl-10-methylacridinium ion with a much longer lifetime and higher energy than that of the natural photosynthetic reaction center. J. Am. Chem. Soc. 126, 1600–1601 (2004).

  38. 38.

    Uoyama, H., Goushi, K., Shizu, K., Nomura, H. & Adachi, C. Highly efficient organic light emitting diodes from delayed fluorescence. Nature 492, 234–238 (2012).

  39. 39.

    Milián-Medina, B. & Gierschner, J. Computational design of low singlet–triplet gap all organic molecules for OLED application. Org. Elec. 13, 985–991 (2012).

  40. 40.

    Bombarelli, R. G. et al. Design of efficient molecular organic light-emitting diodes by a high-throughput virtual screening and experimental approach. Nat. Mater. 15, 1120–1127 (2016).

  41. 41.

    Kucur, E., Riegler, J., Urban, G. A. & Nann, T. Determination of quantum confinement in CdSe nanocrystals by cyclic voltammetry. J. Chem. Phys. 119, 2333–2337 (2003).

  42. 42.

    Zhang, G. & Musgrave, C. B. Comparison of DFT methods for molecular orbital eigenvalue calculations. J. Phys. Chem. C 111, 1554–1561 (2007).

  43. 43.

    Coote, M. L., Lin, C. Y., Beckwith, A. L. J. & Zavitsas, A. A. A comparison of methods for measuring relative radical stabilities of carbon-centered radicals. Phys. Chem. Chem. Phys. 12, 9597–9610 (2010).

  44. 44.

    Savéant, J. M. A simple model for the kinetics of dissociative electron transfer in polar solvents. Application to the homogeneous and heterogeneous reduction of alkyl halides. J. Am. Chem. Soc. 109, 6788–6795 (1987).

  45. 45.

    Isse, A. A. et al. Mechanism of carbon–halogen bond reductive cleavage in activated alkyl halide initiators relevant to living radical polymerization: theoretical and experimental study. J. Am. Chem. Soc. 133, 6254–6264 (2011).

  46. 46.

    Kuhlmann, R. & Schnablel, W. Laser flash photolysis investigations on primary processes of the sensitized polymerization of vinyl monomers: 1. Experiments with benzophenone. Polymer 17, 419–422 (1976).

  47. 47.

    Wan, J. & Nakatsuji, H. Theoretical study of the singlet and triplet vertical electronic transitions of styrene by the symmetry adapted cluster–configuration interaction method. Chem. Phys. 302, 125–134 (2004).

  48. 48.

    Saltiel, J., Charlton, J. L. & Mueller, W. B. Nonvertical excitation transfer. Activation parameters for endothermic triplet–triplet energy transfer to the stilbenes. J. Am. Chem. Soc. 101, 1347–1348 (1979).

  49. 49.

    Miyake, G. M. & Theriot, J. C. Perylene as organic photocatalyst for the radical polymerization of functionalized vinyl monomers through oxidative quenching with alkyl bromides and visible light. Macromolecules 47, 8255–8261 (2014).

  50. 50.

    Pier, C. K., Rankic, D. A. & MacMillan, D. W. C. Visible light photoredox catalysis with transition metal complexes: application in organic synthesis. Chem. Rev. 113, 5322–5363 (2013).

  51. 51.

    Narayanam, J. M. R. & Stephenson, C. R. J. Visible light photoredox catalysis: applications in organic synthesis. Chem. Soc. Rev. 40, 102–113 (2011).

  52. 52.

    Yoon, T. P., Ischay, M. A. & Du, J. Visible light photocatalysis as a greener approach to photochemical synthesis. Nat. Chem. 2, 527–532 (2010).

  53. 53.

    Fagnoni, M., Dondi, D., Ravelli, D. & Albini, A. Photocatalysis for the formation of the C–C bond. Chem. Rev. 107, 2725–2756 (2007).

  54. 54.

    Marin, M. L., Santos-Juanes, L., Arques, A., Amat, A. M. & Miranda, M. A. Organic photocatalysts for the oxidation of pollutants and model compounds. Chem. Rev. 112, 1710–1750 (2012).

  55. 55.

    Fukuzumi, S. & Ohkubo, K. Selective photocatalytic reactions with organic photocatalysts. Chem. Sci. 4, 561–574 (2013).

  56. 56.

    Frisch, M. J. et al. Gaussian 09 Revision D.01 (Gaussian, 2009).

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This work was supported by the 2018 Research Fund (1.180067.01) of the Ulsan National Institute of Science and Technology, and Basic Science Research Program through the National Research Foundation of Korea (NRF), which was funded by the Ministry of Education (NRF–2016R1D1A1B03936002) and National Honor Scientist Program (2010–0020414) of the NRF. The work at IMDEA was supported by the ‘Severo Ochoa’ programme for Centers of Excellence in Research and Development (MINECO; grant SEV–2016–0686), European Union structural funds and Comunidad de Madrid MAD2D-CM Program (S2013/MIT–3007), and Campus of International Excellence UAM + CSIC. Financial support at IMDEA and the University of Valencia was further provided by the Spanish Ministry for Science (MINECO–FEDER projects CTQ2014–58801 and CTQ2017–87054).

Author information

M.S.K. conceived and supervised the project. K.S.K. and J.G. supported and assisted in supervising the project. V.K.S. and M.S.K. designed the experiments and analysed the data. V.K.S. and C.Y. performed most of the experiments. S.B., Y.Kim, Y.Kwon, D.K., J.L., T.A. and G.T. helped with the synthesis of OPCs and polymerization studies. P.C.N., R.W. and L.L. performed advanced photophysical measurements. B.M.-M. and J.G. carried out the quantum chemical calculations. L.S.P. and J.L. advised on the experiments. V.K.S., K.S.K., J.G. and M.S.K. prepared the manuscript, with contributions from all authors.

Competing interests

The authors declare no competing interests.

Correspondence to Kwang S. Kim or Johannes Gierschner or Min Sang Kwon.

Supplementary Information

  1. Supplementary Information

    Supplementary Methods, Supplementary Notes 1–7, Supplementary Figures 1–86, Supplementary Tables 1–10 and Supplementary References

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Fig. 1: Strategy for OPC design.
Fig. 2: Molecular structures of OPCs.
Fig. 3: Analyses of the photophysical and electrochemical properties of OPCs.
Fig. 4: Photophysical and electrochemical properties of 2c.
Fig. 5: Photophysical and electrochemical properties of 4g.