Selective TPA-Induced Reactions of Anthracene-2-Carboxylic Acid on Tunable Plasmonic Substrate
Pincella et al.
hexanethiol:dodecanethiol = 3:1 (10 mL) in acetone. Stir-
ring was performed for 12 h at RT, and then alkanethiol-
capped AuNPs were extracted with methanol and hexane
and purified by sequential centrifuge and redispersion into
hexane three times.
(with a 5% ND filter), 0.42 NA objective lens (45×Super
Long Working Distance Plan APO from Photon Design),
integration time of 60 s and two acquisitions. For detection
of ACA Raman peaks with the 10-nm AuNP 2D array as
substrate, the power at the sample was set to 190 ꢁW (with
a 10% ND filter), and acquisition time was set to 180 s
(due to the low near-field enhancement of the substrate).
The Raman peaks relative to ACA, ACAD and AQCA
were identified by comparison of the SERS spectra with
DFT-calculated spectra of the same compounds, as shown
in Table I.
4.5. 2D Array Deposition
The 2D array of AuNPs was deposited on the gold sub-
strates by means of a hybrid method developed by our
laboratory.12 Briefly, a dithiol-functionalized gold substrate
was used as a cathode, while a plastic carbon electrode
was used as an anode. The distance between the elec-
trodes was kept at 1.2 mm, while the voltage applied was
1.1 V. Alkanethiol-capped AuNPs were redispersed in a
2-mL hexane:acetone (10:1 v/v) solution. The electrodes
were immersed in the colloidal solution (in a 3-mL plas-
tic vessel) and left in a nitrogen-purged environment until
complete evaporation of the colloidal solution took ꢁplace.
Afterwards, samples were put on a hot plate at 50 C for
24 h to induce chemisorption of the AuNPs on the sub-
strate and finally they were sonicated for 20 s to remove
multilayers. The extinction spectra of the 10-, 23- and
39-nm AuNP 2D arrays are shown in Figure 3.
Acknowledgments: We thank the Japan Society for the
Promotion of Science (JSPS) and the Ministry of Edu-
cation, Culture, Sports, Science and Technology of Japan
(MEXT) for financial support; Grant-in-Aid for Chal-
lenging Exploratory Research (Kazushi Miki, 24656040);
Grant-in-Aid for Scientific Research on Innovative Areas
“Integrated Organic Synthesis” (Kazushi Miki, 22106545
and 24106746); and Grant-in-Aid for Young Scientists
(Katsuhiro Isozaki, 30455274), Japan Science and Tech-
nology Agency (JST) for financial support of e-ASIA JRP.
Also, a part of this research was supported both by the
Research Foundation for Opto-Science and Technology
and by Grant for Environmental Research Projects from
The Sumitomo Foundation. We are grateful to Professor
M. Nakamura and Professor H. Takaya (Kyoto University)
4.6. Deposition of Anthracene Derivative
ACA, AQCA, and ACA photodimer (ACAD) were
deposited onto the AuNP 2D arrays by the immersion
Delivered by Ingenta to: Nanyang Technological University
for their assistance with the analysis and helpful discus-
IP: 5.62.159.86 On: Tue, 14 Jun 2016 04:47:48
method. Deposition by immersion was performed by intro-
ducing a substrate in a sealed vessel containing a nitro-
gen gas-purged (15 min bubbling with N2 gas) 5 mM
anthracene derivative solution prepared by adding 1 mL
of 50 mM solution in DMSO to 9 mL of 6 mM aque-
ous NaOH solution. The samples were kept overnight in
the anthracene derivative solution and then dried under a
nitrogen stream. The anthracene derivative-coated samples
were then characterized by Raman spectroscopy to verify
the effective deposition of the anthracene derivative.
Copyright: American Scientific Publishers
sions. This study was supported by NIMS Molecule and
Material Synthesis Platform in “Nanotechnology Platform
Project” operated by the Ministry of Education, Culture,
Sports, Science and Technology (MEXT), Japan.
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1
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4.8. Raman Measurements
Raman measurements were performed in order to verify all
ACA, AQCA and ACAD coated samples. Raman spectra
of anthracene compounds on 23- and 39-nm AuNPs 2D
arrays were acquired with an incident power of 95 ꢁW
1178
J. Nanosci. Nanotechnol. 15, 1171–1179, 2015