Abstract
The 9-phenyl-9-tritylone photoremovable protecting group was examined using both photoproduct analysis and laser flash photolysis in order to determine the details of its mechanism of alcohol release. It is shown that formation of the tritylone anion radical is required for alcohol release. Attempts to trigger release via intramolecular photoinduced electron transfer were unsuccessful due to rapid back electron transfer reactions of the triplet diradical anion.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Notes and references
P. Klán, T. Šolomek, C. G. Bochet, A. Blanc, R. Givens, M. Rubina, V. Popik, A. Kostikov and J. Wirz, Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy, Chem. Rev., 2013, 113, 119–191.
T. W. Greene and P. G. M. Wuts, Protective groups in organic synthesis, Wiley, New York, 1999.
Y. Sun, Y. Yan, M. Wang, C. Chen, H. Xu and J. R. Lu, Controlled Release of Hydrophilic Guest Molecules from Photoresponsive Nucleolipid Vesicles, ACS Appl. Mater. Interfaces, 2013, 5, 6232–6236.
Q. Lin, Q. Huang, C. Li, C. Bao, Z. Liu, F. Li and L. Zhu, Anticancer Drug Release from a Mesoporous Silica Based Nanophotocage Regulated by Either a One- or Two-Photon Process, J. Am. Chem. Soc., 2010, 132, 10645–10647.
G. Miller, Shining New Light on Neural Circuits, Science, 2006, 314, 1674.
B. Parasar and P. V. Chang, Chemical optogenetic modulation of inflammation and immunity, Chem. Sci., 2017, 8, 1450–1453.
D. Wöll, N. Lukzen and U. E. Steiner, Diffusion-controlled sensitization of photocleavage reactions on surfaces, Photochem. Photobiol. Sci., 2012, 11, 533–538.
J. E. Beecher, J. F. Cameron and J. M. J. Fréchet, Photogeneration of polymeric amines: synthesis, photocrosslinking and photoimaging of copolymers containing photoactive carbamate pendant groups, J. Mater. Chem., 1992, 2, 811–816.
M. C. Pirrung, L. Fallon, J. Zhu and Y. R. Lee, Photochemically Removable Silyl Protecting Groups, J. Am. Chem. Soc., 2001, 123, 3638–3643.
X.-Y. Duan, B.-C. Zhai and Q.-H. Song, Water-soluble o-hydroxycinnamate as an efficient photoremovable protecting group of alcohols with fluorescence reporting, Photochem. Photobiol. Sci., 2012, 11, 593–598.
D. P. Walton and D. A. Dougherty, A General Strategy for Visible-Light Decaging Based on the Quinone Trimethyl Lock, J. Am. Chem. Soc., 2017, 139, 4655–4658.
A. Konosonoks, P. J. Wright, M.-L. Tsao, J. Pika, K. Novak, S. M. Mandel, J. A. Krause Bauer, C. Bohne and A. D. Gudmundsdóttir, Photoenolization of 2-(2-Methyl Benzoyl) Benzoic Acid, Methyl Ester: Effect of E Photoenol Lifetime on the Photochemistry, J. Org. Chem., 2005, 70, 2763–2770.
A. Z. Suzuki, T. Watanabe, M. Kawamoto, K. Nishiyama, H. Yamashita, M. Ishii, M. Iwamura and T. Furuta, Coumarin-4-ylmethoxycarbonyls as Phototriggers for Alcohols and Phenols, Org. Lett., 2003, 5, 4867–4870.
D. M. Denning, N. J. Pedowitz, M. D. Thum and D. E. Falvey, Uncaging Alcohols Using UV or Visible Light Photoinduced Electron Transfer to 9-Phenyl-9-tritylone Ethers, Org. Lett., 2015, 17, 5986–5989.
Y. R. Luo, Comprehensive Handbook of Chemical Bond Energies, CRC Press, 2007.
A. V. Buettner and J. Dedinas, Photoreduction of benzophenone in benzene. II. Flash photolysis study of primary photochemical reactions, J. Phys. Chem., 1971, 75, 187–191.
A. Beckett and G. Porter, Primary photochemical processes in aromatic molecules. Part 9.-Photochemistry of benzophenone in solution, Trans. Faraday Soc., 1963, 59, 2038–2050.
H. J. Timpe and K. P. Kronfeld, Light-induced polymer and, polymerization reactions XXXIII: direct photoinitiation of methyl methacrylate polymerization by excited states of ketones, J. Photochem. Photobiol., A, 1989, 46, 253–267.
G. S. Hammond and W. M. Moore, The role of a triplet state in the photoreduction of benzophenone, J. Am. Chem. Soc., 1959, 81, 6334–6334.
E. Land, G. Porter and E. Strachan, Primary photochemical processes in aromatic molecules. Part 6.—The absorption spectra and acidity constants of phenoxyl radicals, Trans. Faraday Soc., 1961, 57, 1885–1893.
Author information
Authors and Affiliations
Corresponding author
Additional information
Electronic supplementary information (ESI) available. See DOI: 10.1039/c9pp00183b
Rights and permissions
About this article
Cite this article
Zeppuhar, A.N., Hill-Byrne, K. & Falvey, D.E. Mechanism of the photorelease of alcohols from the 9-phenyl-9-tritylone protecting group. Photochem Photobiol Sci 18, 1990–1995 (2019). https://doi.org/10.1039/c9pp00183b
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1039/c9pp00183b