Macromolecules
Article
Kade, M. J.; Hawker, C. J. Chem. Rev. 2009, 109, 5620. (c) Xi, W.;
Scott, T. F.; Kloxin, C. J.; Bowman, C. N. Adv. Funct. Mater. 2014, 24,
2572.
(3) (a) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B.
Angew. Chem., Int. Ed. 2002, 41, 2596. (b) Tornoe, C. W.; Christensen,
C.; Meldal, M. J. Org. Chem. 2002, 67, 3057.
(4) (a) Lowe, A. B. Polym. Chem. 2010, 1, 17. (b) Hoyle, C. E.;
Bowman, C. N. Angew. Chem., Int. Ed. 2010, 49, 1540.
(5) Nair, D. P.; Podgorski, M.; Chatani, S.; Gong, T.; Xi, W. X.;
Fenoli, C. R.; Bowman, C. N. Chem. Mater. 2014, 26, 724.
(6) Li, H. B.; Yu, B.; Matsushima, H.; Hoyle, C. E.; Lowe, A. B.
Macromolecules 2009, 42, 6537.
(7) Tasdelen, M. A.; Yagci, Y. Angew. Chem., Int. Ed. 2013, 52, 5930.
(8) (a) Tasdelen, M. A.; Yagci, Y. Tetrahedron lett. 2010, 51, 6945.
(b) Adzima, B. J.; Tao, Y.; Kloxin, C. J.; DeForest, C. A.; Anseth, K. S.;
Bowman, C. N. Nat. Chem. 2011, 3, 256.
(9) Poloukhtine, A. A.; Mbua, N. E.; Wolfert, M. A.; Boons, G. J.;
Popik, V. V. J. Am. Chem. Soc. 2009, 131, 15769.
Figure 5. Plots of tan δ and elastic modulus vs temperature for two
stage networks formed through thiol−acrylate−methacrylate monomer
cross-linking (PETMA−TMPTA−TMPTMA, molar ratio = 3:2:2)
system. Stage 1 (predominately the thiol−acrylate cross-linking
reaction) data are in red and stage 2 (the subsequent thiol-methacrylate
cross-linking reaction) data are in black.
(10) (a) Wang, Y. Z.; Song, W. J.; Hu, W. J.; Lin, Q. Angew. Chem.,
Int. Ed. 2009, 48, 5330. (b) Song, W.; Wang, Y.; Qu, J.; Lin, Q. J. Am.
Chem. Soc. 2008, 130, 9654. (c) Song, W.; Wang, Y.; Qu, J.; Madden,
M. M.; Lin, Q. Angew. Chem., Int. Ed. 2008, 47, 2832.
(11) (a) Arumugam, S.; Popik, V. V. J. Am. Chem. Soc. 2012, 134,
8408. (b) Arumugam, S.; Orski, S. V.; Locklin, J.; Popik, V. V. J. Am.
Chem. Soc. 2012, 134, 179. (c) Arumugam, S.; Popik, V. V. J. Am.
Chem. Soc. 2011, 133, 15730.
CONCLUSIONS
■
(12) Pauloehrl, T.; Delaittre, G.; Bruns, M.; Meissler, M.; Borner, H.
G.; Bastmeyer, M.; Barner-Kowollik, C. Angew. Chem., Int. Ed. 2012,
51, 9181.
In summary, we designed and synthesized five different
photoinduced amine catalysts for the thiol−Michael addition
to enhance both the quantum yield of the photolabile group
and the basicity of the amine catalyst. All these catalyst were
evaluated in a model thiol−Michael addition reaction between
thiol and acrylate. Among these photocaged amines, photo-
labile superbases (NVOC-TMG and NPPOC-TMG) exhibit
excellent catalytic activities and achieve over 90% conversion
within several minutes. The successful implementation of these
photocaged catalysts in both photopatterning and kinetically
controlled two-stage polymer network formation demonstrates
the capability of photo thiol−Michael addition for spatiotem-
poral control. This work provides a new route for thiol−
Michael catalysis on-demand (via light activation) and will
enable new applications of this reaction in polymer chemistry
and materials science.
(13) (a) Blasco, E.; Pinol, M.; Oriol, L.; Schmidt, B. V. K. J.; Welle,
A.; Trouillet, V.; Bruns, M.; Barner-Kowollik, C. Adv. Funct. Mater.
2013, 23, 4011. (b) Rodriguez-Emmenegger, C.; Preuss, C. M.;
Yameen, B.; Pop-Georgievski, O.; Bachmann, M.; Mueller, J. O.;
Bruns, M.; Goldmann, A. S.; Bastmeyer, M.; Barner-Kowollik, C. Adv.
Mater. 2013, 25, 6123. (c) Dietrich, M.; Delaittre, G.; Blinco, J. P.;
Inglis, A. J.; Bruns, M.; Barner-Kowollik, C. Adv. Funct. Mater. 2012,
22, 304. (d) Gupta, N.; Lin, B. F.; Campos, L.; Dimitriou, M. D.;
Hikita, S. T.; Treat, N. D.; Tirrell, M. V.; Clegg, D. O.; Kramer, E. J.;
Hawker, C. J. Nat. Chem. 2010, 2, 138. (e) Kloxin, C. J.; Scott, T. F.;
Park, H. Y.; Bowman, C. N. Adv. Mater. 2011, 23, 1977.
(14) (a) Gruendling, T.; Oehlenschlaeger, K. K.; Frick, E.; Glassner,
M.; Schmid, C.; Barner-Kowollik, C. Macromol. Rapid Commun. 2011,
32, 807. (b) Oehlenschlaeger, K. K.; Mueller, J. O.; Heine, N. B.;
Glassner, M.; Guimard, N. K.; Delaittre, G.; Schmidt, F. G.; Barner-
Kowollik, C. Angew. Chem., Int. Ed. 2013, 52, 762.
ASSOCIATED CONTENT
* Supporting Information
Experimental details, catalyst preparation, photolysis data, and
NMR spectra. This material is available free of charge via the
(15) (a) Valkevich, E. M.; Guenette, R. G.; Sanchez, N. A.; Chen, Y.
C.; Ge, Y.; Strieter, E. R. J. Am. Chem. Soc. 2012, 134, 6916. (b) Bauer,
D. M.; Rogge, A.; Stolzer, L.; Barner-Kowollik, C.; Fruk, L. Chem.
Commun. 2013, 49, 8626.
■
S
(16) (a) Pauloehrl, T.; Welle, A.; Bruns, M.; Linkert, K.; Borner, H.
G.; Bastmeyer, M.; Delaittre, G.; Barner-Kowollik, C. Angew. Chem.,
Int. Ed. 2013, 52, 9714. (b) Pauloehrl, T.; Welle, A.; Oehlenschlaeger,
K. K.; Barner-Kowollik, C. Chem. Sci. 2013, 4, 3503. (c) Tischer, T.;
Claus, T. K.; Bruns, M.; Trouillet, V.; Linkert, K.; Rodriguez-
Emmenegger, C.; Goldmann, A. S.; Perrier, S.; Borner, H. G.; Barner-
Kowollik, C. Biomacromolecules 2013, 14, 4340. (d) Pauloehrl, T.;
Delaittre, G.; Winkler, V.; Welle, A.; Bruns, M.; Borner, H. G.;
Greiner, A. M.; Bastmeyer, M.; Barner-Kowollik, C. Angew. Chem., Int.
Ed. 2012, 51, 1071.
(17) (a) Tucker-Schwartz, A. K.; Farrell, R. A.; Garrell, R. L. J. Am.
Chem. Soc. 2011, 133, 11026. (b) Altintas, O.; Willenbacher, J.; Wuest,
K. N. R.; Oehlenschlaeger, K. K.; Krolla-Sidenstein, P.; Gliemann, H.;
Barner-Kowollik, C. Macromolecules 2013, 46, 8092. (c) Stolzer, L.;
Ahmed, I.; Rodriguez-Emmenegger, C.; Trouillet, V.; Bockstaller, P.;
Barner-Kowollik, C.; Fruk, L. Chem. Commun. 2014, 50, 4430.
(18) (a) Ning, X. H.; Guo, J.; Wolfert, M. A.; Boons, G. J. Angew.
Chem., Int. Ed. 2008, 47, 2253. (b) Shafiq, Z.; Cui, J. X.; Pastor-Perez,
L.; San Miguel, V.; Gropeanu, R. A.; Serrano, C.; del Campo, A. Angew.
Chem., Int. Ed. 2012, 51, 4332.
AUTHOR INFORMATION
Corresponding Author
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We acknowledge financial support from the National Science
Foundation (CHE 1214109) and the National Institutes of
Health (U01 DE023777).
REFERENCES
■
(1) Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem., Int. Ed.
2001, 40, 2004.
(2) (a) Golas, P. L.; Matyjaszewski, K. Chem. Soc. Rev. 2010, 39,
1338. (b) Iha, R. K.; Wooley, K. L.; Nystrom, A. M.; Burke, D. J.;
6164
dx.doi.org/10.1021/ma501366f | Macromolecules 2014, 47, 6159−6165