Journal of the American Chemical Society
Article
In contrast, the addition of protons promotes 20% decrease in
nowledges the “Reg
doctoral fellowship.
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ion Bourgogne” and CNRS for a post-
4
+
4−
the SSHG intensity of [P /P ] (see Figure 6e) due to the
4
−
association between P and protons that partially breaks down
4
+
4−
the assembly between P and P . However, the fundamental
beam polarization angle dependence of the SSHG intensity did
not change substantially (see Figure 6e), suggesting that the
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4. CONCLUSION
The interfacial four-electron reduction of oxygen by self-
assembled oppositely charged water-soluble porphyrins rafts
was demonstrated. Their catalytic activity is as good as that
of synthetic cofacial porphyrins, proving that it is possible to
perform such reaction in an efficient way, without the need of
synthesizing cofacial porphyrins, a route that is expensive and
tedious. This work is a clear example that it is possible to design
molecular or supramolecular rafts to carry out selective reac-
tions at liquid|liquid interfaces.
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(
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ASSOCIATED CONTENT
■
2
(
*
S
Supporting Information
Short explanation of SSHG, synthesis and characterization of
the porphyrins, schematic representation of the four-electrode
cell used for ion-transfer voltammetry and ion-transfer volta-
mmograms of the porphyrins, secondary electrons SEM image
of the cationic porphyrin crystallized directly from water, UV−
visible spectra of the organic phase after biphasic reaction uisng
mixtures of the free bases of the porphyrins and cobalt por-
phyrins as catalysts, chemical structures of the synthetic cofacial
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AUTHOR INFORMATION
(
(
́
́
ACKNOWLEDGMENTS
■
(
We thank the NCCR SNF MUST project, the EPFL and
the “Centre National de la Recherche Scientifique” (CNRS,
ICMUB, UMR 5260) for financial support. H.J.X. also ack-
Wallingford CT, 2009.
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Rev. Lett. 2003, 91, 146401.
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dx.doi.org/10.1021/ja2087322 | J. Am. Chem.Soc. 2012, 134, 498−506