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Photochemical Processed Materials

  • Masuki KawamotoEmail author
  • Takehisa Matsuda
  • Yoshihiro Ito
Chapter

Abstract

This chapter describes photochemical processes of polymers including photopolymerization and photocrosslinkable polymerization. Photoinitiators are key components in photopolymerization that generate reactive species of free radicals or ions via Norrish type I or Norrish type II reactions. Visible-light photoinitiators are fascinating compounds, because visible-light curing is a challenging issue due to high demands in diverse applications such as dental restoration, reprography, and three-dimensional printing. Photo-iniferters are also attractive photoinitiators that yield high-reactive free radicals, leading to a living radical polymerization with narrow polydispersity. Photoreactive polymers including the photoinitiators have functional properties for biological applications, for example, the photo-induced micropatterned surfaces in synthetic polymers for immobilization of cells, and photo-cross-linking in biopolymers for tissue engineering. We also describe photolabile compounds, photodegradation of chemical structures, for development of a mild chemical approach for dealing with sensitive biomolecules against acids and bases.

Keywords

Photopolymerization Photocrosslinkable polymerization Photoinitiator Photo-iniferter Photoreactive polymer 

References

  1. 1.
    Ifkovits, J.L., Burdick, J.A.: Photopolymerizable and degradable biomaterials for tissue engineering applications. Tissue Eng. 13, 2369–2385 (2007)CrossRefPubMedGoogle Scholar
  2. 2.
    Mishra, M., Yagci, Y.: Handbook of Vinyl Polymers: Radical Polymerization, Process, and Technology, 2nd edn. CRC Press (2008)Google Scholar
  3. 3.
    Gruber, H.F.: Photoinitiators for free radical polymerization. Prog. Polym. Sci. 17, 953–1044 (1992)CrossRefGoogle Scholar
  4. 4.
    Turro, N.J., Ramamurthy, V., Scaiano, J.C.: Principles of Molecular Photochemistry: An Introduction. University Science Books (2009)Google Scholar
  5. 5.
    Lechtken, P.D.C.D., Buethe, I.D.C.D., Hesse, A.D.C.D.: Acylphosphinoxidverbindungen und ihre verwendung Acylphosphine oxide compounds and their use DE19782830927 (1980)Google Scholar
  6. 6.
    Terauchi, K., Sakurai, H.: Ultraviolet spectral studies in the esters of aroylphosphonic acids. Bull. Chem. Soc. Jpn 42, 821–823 (1969)CrossRefGoogle Scholar
  7. 7.
    Sumiyoshi, T., Schnabel, W.: On the reactivity of phosphonyl radicals towards olefinic compounds. Makromol. Chem. 186, 1811–1823 (1985)CrossRefGoogle Scholar
  8. 8.
    Monroe, B.M.: The photochemistry of α-dicarbonyl compounds. In: Advances in Photochemistry, pp. 77–108. Wiley, Inc. (1971)CrossRefGoogle Scholar
  9. 9.
    Pfannenstiel, H., Huebner, H.D.: Verfahren zur herstellung individueller gussteile DE19823240907 (1984)Google Scholar
  10. 10.
    Allen, N.S.: Photoinitiators for UV and visible curing of coatings: mechanisms and properties. J. Photochem. Photobiol. A: Chem. 100, 101–107 (1996)CrossRefGoogle Scholar
  11. 11.
    Jakubiak, J., Rabek, J.F.: Photoinitiators for visible light polymerization. Polimery 44, 447–461 (1999)Google Scholar
  12. 12.
    Gómez, M.L., Previtali, C.M., Montejano, H.A.: Two- and three-component visible light photoinitiating systems for radical polymerization based on onium salts: an overview of mechanistic and laser flash photolysis studies. Int. J. Photoenergy 9 (2012)Google Scholar
  13. 13.
    Bibaut-Renauld, C., Burget, D., Fouassier, J.P., Varelas, C.G., Thomatos, J., Tsagaropoulos, G., Ryrfors, L.O., Karlsson, O.J.: Use of α-diketones as visible photoinitiators for the photocrosslinking of waterborne latex paints. J. Polym. Sci., Part A: Polym. Chem. 40, 3171–3181 (2002)CrossRefGoogle Scholar
  14. 14.
    Jakubiak, J., Sionkowska, A., Lindén, L.Å., Rabek, J.F.: Isothermal photo differential scanning calorimetry. crosslinking polymerization of multifunctional monomers in presence of visible light photoinitiators. J. Therm. Anal. Calorim. 65, 435–443 (2001)CrossRefGoogle Scholar
  15. 15.
    Ghaemy, M., Bekhradnia, S.: Thermal and photocuring of an acrylate-based coating resin reinforced with nanosilica particles. J. Coat. Technol. Res. 9, 569–578 (2012)CrossRefGoogle Scholar
  16. 16.
    Angiolini, L., Caretti, D., Salatelli, E.: Synthesis and photoinitiation activity of radical polymeric photoinitiators bearing side-chain camphorquinone moieties. Macromol. Chem. Phys. 201, 2646–2653 (2000)CrossRefGoogle Scholar
  17. 17.
    Park, Y.J., Chae, K.H., Rawls, H.R.: Development of a new photoinitiation system for dental light-cure composite resins. Dent. Mater. 15, 120–127 (1999)CrossRefPubMedGoogle Scholar
  18. 18.
    Arikawa, H., Takahashi, H., Kanie, T., Ban, S.: Effect of various visible light photoinitiators on the polymerization and color of light-activated resins. Dent. Mater. J. 28, 454–460 (2009)CrossRefPubMedGoogle Scholar
  19. 19.
    Sun, G.J., Chae, K.H.: Properties of 2,3-Butanedione and 1-Phenyl-1,2-Propanedione as new photosensitizers for visible light cured dental resin composites. Polymer 41, 6205–6212 (2000)CrossRefGoogle Scholar
  20. 20.
    Ikemura, K., Endo, T.: A review of the development of radical photopolymerization initiators used for designing light-curing dental adhesives and resin composites. Dent. Mater. J. 29, 481–501 (2010)CrossRefPubMedGoogle Scholar
  21. 21.
    Ganster, B., Fischer, U.K., Moszner, N., Liska, R.: New Photocleavable Structures, 4. Macromol. Rapid Commun. 29, 57–62 (2008)CrossRefGoogle Scholar
  22. 22.
    Ganster, B., Fischer, U.K., Moszner, N., Liska, R.: New photocleavable structures. diacylgermane-based photoinitiators for visible light curing. Macromolecules 41, 2394–2400 (2008)CrossRefGoogle Scholar
  23. 23.
    Rivarola, C.R., Biasutti, M.A., Barbero, C.A.: A visible light photoinitiator system to produce acrylamide based smart hydrogels: Ru(bpy)3 + 2 as photopolymerization initiator and molecular probe of hydrogel microenvironments. Polymer 50, 3145–3152 (2009)CrossRefGoogle Scholar
  24. 24.
    Gómez, M.L., Fasce, D.P., Williams, R.J.J., Erra-Balsells, R., Kaniz Fatema, M., Nonami, H.: Silsesquioxane functionalized with methacrylate and amine groups as a crosslinker/co-initiator for the synthesis of hydrogels by visible-light photopolymerization. Polymer 49, 3648–3653 (2008)CrossRefGoogle Scholar
  25. 25.
    Nie, J., Bowman, C.N.: Synthesis and photopolymerization of N, N′-Dimethyl,-N, N′-Di(methacryloxy ethyl)-1,6-Hexanediamine as a polymerizable amine coinitiator for dental restorations. Biomaterials 23, 1221–1226 (2002)CrossRefPubMedGoogle Scholar
  26. 26.
    Tiba, A., Culbertson, B.M.: Development of visible light-cured multi-methacrylates for dental restorative materials. J. Macromol. Sci., Part A 36, 489–506 (1999)CrossRefGoogle Scholar
  27. 27.
    Anseth, K.S., Newman, S.M., Bowman, C.N.: Polymeric dental composites: properties and reaction behavior of multimethacrylate dental restorations. In: Peppas, N.A., Langer, R.S. (eds.) Biopolymers II, pp. 177–217. Springer, Berlin (1995)CrossRefGoogle Scholar
  28. 28.
    Crivello, J.V., Lam, J.H.W.: Diaryliodonium salts. A new class of photoinitiators for cationic polymerization. Macromolecules 10, 1307–1315 (1977)CrossRefGoogle Scholar
  29. 29.
    Horspool, W.M., Lenci, F.: CRC Handbook of Organic Photochemistry and Photobiology, vols. 1 & 2, 2nd edn. CRC Press (2003)Google Scholar
  30. 30.
    Crivello, J.V., Lam, J.H.W.: Complex triarylsulfonium salt photoinitiators. I. The Identification, characterization, and syntheses of a new class of triarylsulfonium salt photoinitiators. J. Polym. Sci. Polym. Chem. Ed. 18, 2677–2695 (1980)Google Scholar
  31. 31.
    Yagci, Y., Ledwith, A.: Mechanistic and kinetic studies on the photoinitiated polymerization of tetrahydrofuran. J. Polym. Sci., Part A: Polym. Chem. 26, 1911–1918 (1988)CrossRefGoogle Scholar
  32. 32.
    Yagci, Y., Lukáč, I., Schnabel, W.: Photosensitized cationic polymerization using N-Ethoxy-2-Methylpyridinium Hexafluorophosphate. Polymer 34, 1130–1133 (1993)CrossRefGoogle Scholar
  33. 33.
    Dossow, D., Qin Qin, Z., Hizal, G., Yagci, Y., Schnabel, W.: Photosensitized cationic polymerization of cyclohexene oxide: a mechanistic study concerning the use of pyridinium-type salts. Polymer 37, 2821–2826 (1996)CrossRefGoogle Scholar
  34. 34.
    Hizal, G., Yagci, Y., Schnabel, W.: Charge-transfer complexes of pyridinium ions and methyl- and methoxy-substituted benzenes as photoinitiators for the cationic polymerization of cyclohexene oxide and related compounds. Polymer 35, 2428–2431 (1994)CrossRefGoogle Scholar
  35. 35.
    Yagci, Y., Schnabel, W.: Light-induced cationic polymerization. Makromol. Chem. Makromol. Symp. 13–14, 161–174 (1988)CrossRefGoogle Scholar
  36. 36.
    Ahn, K.-D., Ihn, K.J., Kwon, I.C.: A photosensitive polymer having benzoin ether side chains: Poly(α-Methylolbenzoin Methyl Ether Acrylate). J. Macromol. Sci. Part A Chem. 23, 355–368 (1986)CrossRefGoogle Scholar
  37. 37.
    Hageman, H.J., Jansen, L.G.J.: Photoinitiators and photoinitiation, 9 photoinitiators for radical polymerization which counter oxygen-inhibition. Makromol. Chem. 189, 2781–2795 (1988)CrossRefGoogle Scholar
  38. 38.
    Böttcher, A., Hasebe, K., Hizal, G., Yaḡci, Y., Stellberg, P., Schnabel, W.: Initiation of cationic polymerization via oxidation of free radicals using pyridinium salts. Polymer 32, 2289–2293 (1991)CrossRefGoogle Scholar
  39. 39.
    Yagci, Y., Schnabel, W.: Acylphosphine oxides as free radical promoters in cationic polymerizations. Makromol. Chem. Rapid Commun. 8, 209–213 (1987)CrossRefGoogle Scholar
  40. 40.
    Yaḡci, Y., Borbely, J., Schnabel, W.: On the mechanism of acylphosphine oxide promoted cationic polymerization. Eur. Polym. J. 25, 129–131 (1989)CrossRefGoogle Scholar
  41. 41.
    Catilaz-Simonin, L., Fouassier, J.P.: Investigation of a system capable of photoinitiating radical polymerizations in thick pigmented media. J. Appl. Polym. Sci. 79, 1911–1923 (2001)CrossRefGoogle Scholar
  42. 42.
    Yagci, Y., Denizligil, S.: Photoinitiated cationic polymerization using o-phthaldehyde and pyridinium salt. J. Polym. Sci. A 33, 1461–1464 (1995)CrossRefGoogle Scholar
  43. 43.
    Miller, R.D., Michl, J.: Polysilane high polymers. Chem. Rev. 89, 1359–1410 (1989)CrossRefGoogle Scholar
  44. 44.
    Bi, Y., Neckers, D.C.: A visible light initiating system for free radical promoted cationic polymerization. Macromolecules 27, 3683–3693 (1994)CrossRefGoogle Scholar
  45. 45.
    Crivello, J.V., Dietliker, K.: Photoinitiators for Free Radical Cationic & Anionic Photopolymerization, 2nd edn. SITA Technology Ltd., London, UK (1998)Google Scholar
  46. 46.
    Corrales, T., Catalina, F., Peinado, C., Allen, N.S.: Free radical macrophotoinitiators: an overview on recent advances. J. Photochem. Photobiol. A: Chem. 159, 103–114 (2003)CrossRefGoogle Scholar
  47. 47.
    Otsu, T.: Iniferter concept and living radical polymerization. J. Polym. Sci., Part A: Polym. Chem. 38, 2121–2136 (2000)CrossRefGoogle Scholar
  48. 48.
    Otsu, T., Yoshida, M.: Role of initiator-transfer agent-terminator (iniferter) in radical polymerizations: polymer design by organic disulfides as iniferters. Makromol. Chem., Rapid Commun. 3, 127–132 (1982)CrossRefGoogle Scholar
  49. 49.
    Allen, N.S.: Photochemistry and Photophysics of Polymeric Materials. Wiley, Hoboken, New Jersey (2010)CrossRefGoogle Scholar
  50. 50.
    Goda, T., Konno, T., Takai, M., Moro, T., Ishihara, K.: Biomimetic phosphorylcholine polymer grafting from polydimethylsiloxane surface using photo-induced polymerization. Biomaterials 27, 5151–5160 (2006)CrossRefPubMedGoogle Scholar
  51. 51.
    de Boer, B., Simon, H.K., Werts, M.P.L., van der Vegte, E.W., Hadziioannou, G.: “Living” free radical photopolymerization initiated from surface-grafted iniferter monolayers. Macromolecules 33, 349–356 (2000)CrossRefGoogle Scholar
  52. 52.
    Luo, N., Hutchison, J.B., Anseth, K.S., Bowman, C.N.: Surface-initiated photopolymerization of Poly(ethylene glycol) Methyl Ether Methacrylate on a Diethyldithiocarbamate-mediated polymer substrate. Macromolecules 35, 2487–2493 (2002)CrossRefGoogle Scholar
  53. 53.
    Rahane, S.B., Kilbey, S.M., Metters, A.T.: Kinetics of surface-initiated photoiniferter-mediated photopolymerization. Macromolecules 38, 8202–8210 (2005)CrossRefGoogle Scholar
  54. 54.
    Benetti, E.M., Zapotoczny, S., Vancso, G.J.: Tunable thermoresponsive polymeric platforms on gold by “Photoiniferter”-based surface grafting. Adv. Mater. 19, 268–271 (2007)CrossRefGoogle Scholar
  55. 55.
    Benetti, E.M., Reimhult, E., de Bruin, J., Zapotoczny, S., Textor, M., Vancso, G.J.: Poly(methacrylic acid) grafts grown from designer surfaces: the effect of initiator coverage on polymerization kinetics, morphology, and properties. Macromolecules 42, 1640–1647 (2009)CrossRefGoogle Scholar
  56. 56.
    Kitano, H., Kawasaki, A., Kawasaki, H., Morokoshi, S.: Resistance of zwitterionic telomers accumulated on metal surfaces against nonspecific adsorption of proteins. J. Colloid Interface Sci. 282, 340–348 (2005)CrossRefPubMedGoogle Scholar
  57. 57.
    Krause, J.E., Brault, N.D., Li, Y., Xue, H., Zhou, Y., Jiang, S.: Photoiniferter-mediated polymerization of zwitterionic carboxybetaine monomers for low-fouling and functionalizable surface coatings. Macromolecules 44, 9213–9220 (2011)CrossRefGoogle Scholar
  58. 58.
    Korshunova, G.A., Sumbatyan, N.V., Topin, A.N., Mtchedlidze, M.T.: Photoactivatable reagents based on Aryl(trifluoromethyl)diazirines: synthesis and application for studying nucleic acid-protein interactions. Mol. Biol. 36, 823–839 (2000)CrossRefGoogle Scholar
  59. 59.
    Hoyle, C.E., Bowman, C.N.: Thiol-Ene click chemistry. Angew. Chem. Int. Ed. 49, 1540–1573 (2010)CrossRefGoogle Scholar
  60. 60.
    Liu, L.-H., Yan, M.: Perfluorophenyl Azides: new applications in surface functionalization and nanomaterial synthesis. Acc. Chem. Res. 43, 1434–1443 (2010)CrossRefPubMedPubMedCentralGoogle Scholar
  61. 61.
    Lavik, E., Langer, R.: Tissue engineering: current state and perspectives. Appl. Microbiol. Biotechnol. 65, 1–8 (2004)CrossRefPubMedGoogle Scholar
  62. 62.
    Fleet, G.W.J., Porter, R.R., Knowles, J.R.: Affinity labelling of antibodies with aryl nitrene as reactive group. Nature 224, 511–512 (1969)CrossRefGoogle Scholar
  63. 63.
    Smith, R.A.G., Knowles, J.R.: Aryldiazirines. potential reagents for photolabeling of biological receptor sites. J. Am. Chem. Soc. 95, 5072–5073 (1973)CrossRefPubMedGoogle Scholar
  64. 64.
    Yan, M., Cai, S.X., Wybourne, M.N., Keana, J.F.W.: Photochemical functionalization of polymer surfaces and the production of biomolecule-carrying micrometer-scale structures by deep-UV lithography using 4-substituted perfluorophenyl azides. J. Am. Chem. Soc. 115, 814–816 (1993)CrossRefGoogle Scholar
  65. 65.
    Yan, M., Cai, S.X., Wybourne, M.N., Keana, J.F.W.: N-Hydroxysuccinimide ester functionalized perfluorophenyl azides as novel photoactive heterobifunctional crosslinking reagents. the covalent immobilization of biomolecules to polymer surfaces. Bioconjug. Chem. 5, 151–157 (1994)CrossRefPubMedGoogle Scholar
  66. 66.
    Brunner, J., Senn, H., Richards, F.M.: 3-Trifluoromethyl-3-phenyldiazirine. A new carbene generating group for photolabeling reagents. J. Biol. Chem. 255, 3313–3318 (1980)PubMedGoogle Scholar
  67. 67.
    Moss, R.A.: Diazirines: carbene precursors par excellence. Acc. Chem. Res. 39, 267–272 (2006)CrossRefPubMedGoogle Scholar
  68. 68.
    Posner, T.: Beiträge zur Kenntniss der ungesättigten Verbindungen. II. Ueber die Addition von Mercaptanen an ungesättigte Kohlenwasserstoffe. Chem. Ber. 38, 646–657 (1905)CrossRefGoogle Scholar
  69. 69.
    Lowe, A.B.: Thiol-ene, “click” reactions and recent applications in polymer and materials synthesis. Polym. Chem. 1, 17–36 (2010)CrossRefGoogle Scholar
  70. 70.
    Dénès, F., Pichowicz, M., Povie, G., Renaud, P.: Thiyl radicals in organic synthesis. Chem. Rev. 114, 2587–2693 (2014)CrossRefPubMedGoogle Scholar
  71. 71.
    Fairbanks, B.D., Schwartz, M.P., Halevi, A.E., Nuttelman, C.R., Bowman, C.N., Anseth, K.S.: A versatile synthetic extracellular matrix mimic via Thiol-Norbornene photopolymerization. Adv. Mater. 21, 5005–5010 (2009)CrossRefPubMedPubMedCentralGoogle Scholar
  72. 72.
    Ito, Y., Hasuda, H., Sakuragi, M., Tsuzuki, S.: Surface modification of plastic, glass and titanium by photoimmobilization of polyethylene glycol for antibiofouling. Acta Biomater. 3, 1024–1032 (2007)CrossRefPubMedGoogle Scholar
  73. 73.
    Sakuragi, M., Tsuzuki, S., Hasuda, H., Wada, A., Matoba, K., Kubo, I., Ito, Y.: Synthesis of a photoimmobilizable histidine polymer for surface modification. J. Appl. Polym. Sci. 112, 315–319 (2009)CrossRefGoogle Scholar
  74. 74.
    Sakuragi, M., Tsuzuki, S., Obuse, S., Wada, A., Matoba, K., Kubo, I., Ito, Y.: A photoimmobilizable sulfobetaine-based polymer for a nonbiofouling surface. Mater. Sci. Eng., C 30, 316–322 (2010)CrossRefGoogle Scholar
  75. 75.
    Konno, T., Hasuda, H., Ishihara, K., Ito, Y.: Photo-immobilization of a phospholipid polymer for surface modification. Biomaterials 26, 1381–1388 (2005)CrossRefPubMedGoogle Scholar
  76. 76.
    Ito, Y., Nogawa, M.: Preparation of a protein micro-array using a photo-reactive polymer for a cell-adhesion assay. Biomaterials 24, 3021–3026 (2003)CrossRefPubMedGoogle Scholar
  77. 77.
    Ito, Y., Hasuda, H., Yamauchi, T., Komatsu, N., Ikebuchi, K.: Immobilization of erythropoietin to culture erythropoietin-dependent human leukemia cell line. Biomaterials 25, 2293–2298 (2004)CrossRefPubMedGoogle Scholar
  78. 78.
    Kitajima, T., Obuse, S., Adachi, T., Tomita, M., Ito, Y.: Recombinant human gelatin substitute with photoreactive properties for cell culture and tissue engineering. Biotechnol. Bioeng. 108, 2468–2476 (2011)CrossRefPubMedGoogle Scholar
  79. 79.
    Kim, K.-I., Lee, J.-W., Ito, Y., Kang, J.-H., Song, K.-S., Jang, E.-C., Son, T.-I.: Preparation of photo-reactive azidophenyl chitosan derivative for immobilization of growth factors. J. Appl. Polym. Sci. 117, 3029–3037 (2010)Google Scholar
  80. 80.
    Na, H.-N., Kim, K.-I., Han, J.-H., Lee, J.-G., Son, T.-I., Han, D.-K., Ito, Y., Song, K.-S., Jang, E.-C.: Synthesis of O-carboxylated low molecular chitosan with azido phenyl group: Its application for adhesion prevention. Macromol. Res. 18, 1001–1007 (2010)CrossRefGoogle Scholar
  81. 81.
    Son, T.I., Sakuragi, M., Takahashi, S., Obuse, S., Kang, J., Fujishiro, M., Matsushita, H., Gong, J., Shimizu, S., Tajima, Y., Yoshida, Y., Suzuki, K., Yamamoto, T., Nakamura, M., Ito, Y.: Visible light-induced crosslinkable gelatin. Acta Biomater. 6, 4005–4010 (2010)CrossRefPubMedGoogle Scholar
  82. 82.
    Park, S.-H., Seo, S.-Y., Na, H.-N., Kim, K.-I., Lee, J.-W., Woo, H.-D., Lee, J.-H., Seok, H.-K., Lee, J.-G., Chung, S.-I., Chung, K., Han, D., Ito, Y., Jang, E.-C., Son, T.-I.: Preparation of a visible light-reactive low molecular-O-carboxymethyl chitosan (LM-O-CMCS) derivative and applicability as an anti-adhesion agent. Macromol. Res. 19, 921 (2011)CrossRefGoogle Scholar
  83. 83.
    Seo, S.Y., Park, S.H., Lee, H.J., Na, H.N., Kim, K.I., Han, D.K., Lee, J.K., Ito, Y., Son, T.I.: Visible light-induced photocurable (forming a film) low molecular weight chitosan derivatives for biomedical applications: Synthesis, characterization and in vitro biocompatibility. J. Ind. Eng. Chem. 18, 1258–1262 (2012)CrossRefGoogle Scholar
  84. 84.
    Bochet, C.G.: Photolabile protecting groups and linkers. J. Chem. Soc. Perkin Trans. 1, 125–142 (2002)Google Scholar
  85. 85.
    Ellis-Davies, G.C.R.: Caged compounds: photorelease technology for control of cellular chemistry and physiology. Nat. Meth. 4, 619–628 (2007)CrossRefGoogle Scholar
  86. 86.
    Wang, P.: Photolabile protecting groups: structure and reactivity. Asian J. Org. Chem. 2, 452–464 (2013)CrossRefGoogle Scholar
  87. 87.
    Sheehan, J.C., Wilson, R.M., Oxford, A.W.: Photolysis of methoxy-substituted benzoin esters. Photosensitive protecting group for carboxylic acids. J. Am. Chem. Soc. 93, 7222–7228 (1971)CrossRefGoogle Scholar
  88. 88.
    Sheehan, J.C., Umezawa, K.: Phenacyl photosensitive blocking groups. J. Org. Chem. 38, 3771–3774 (1973)CrossRefGoogle Scholar
  89. 89.
    Barltrop, J.A., Plant, P.J., Schofield, P.: Photosensitive protective groups. Chem. Commun., 822–823 (1966)Google Scholar
  90. 90.
    Patchornik, A., Amit, B., Woodward, R.B.: Photosensitive protecting groups. J. Am. Chem. Soc. 92, 6333–6335 (1970)CrossRefGoogle Scholar
  91. 91.
    Pirrung, M.C., Lee, Y.R., Park, K., Springer, J.B.: Pentadienylnitrobenzyl and Pentadienylnitropiperonyl photochemically removable protecting groups. J. Org. Chem. 64, 5042–5047 (1999)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • Masuki Kawamoto
    • 1
    • 2
    Email author
  • Takehisa Matsuda
    • 3
  • Yoshihiro Ito
    • 1
    • 2
  1. 1.Nano Medical Engineering LaboratoryRIKENWakoJapan
  2. 2.Emergent Bioengineering Materials Research TeamRIKEN Center for Emergent Matter ScienceWakoJapan
  3. 3.Kyoto Institute of TechnologyKyotoJapan

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