Suzuki-Miyaura Cross-Coupling Using Plasmonic Pd-Decorated Au Nanorods as Catalyst: A Study on the Contribution of Laser Illumination

Article abstract of DOI:10.1002/cctc.201901112

The interaction between plasmonic metal catalysts and visible light can be exploited to increase their catalytic activity. This activity increase results from the generation of hot charge carriers or hot surfaces, or a combination of both. We have studied the light-induced Suzuki-Miyaura cross-coupling reaction of bromobenzene and m-tolylboronic acid using Pd-decorated Au nanorods as plasmonic catalyst in order to assess which physical effect dominates. Comparative experiments under laser illumination and in dark were performed, demonstrating that under the experimental conditions applied in our study the catalytic activity achieved upon illumination is dominantly based on the conversion of light to heat by the plasmonic catalyst. Pd leached from the catalyst also plays a significant role in the reaction mechanism.

Full text of DOI:10.1002/cctc.201901112

Accepted Article
Title: Suzuki-Miyaura Cross-Coupling Using Plasmonic Pd-Decorated
Au Nanorods as Catalyst: A Study on the Contribution of Laser
Illumination
Authors: Mattheus Verkaaik, Roos Grote, Nicole Meulendijks, Francesc
Sastre, Bert Weckhuysen, and Pascal Buskens
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To be cited as: ChemCatChem 10.1002/cctc.201901112
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Suzuki-Miyaura Cross-Coupling Using Plasmonic Pd-Decorated
Au Nanorods as Catalyst: A Study on the Contribution of Laser
Illumination
Mattheus Verkaaik,[a] Roos Grote,[a] Nicole Meulendijks,[a] Francesc Sastre,[a] Bert M. Weckhuysen,*,[b]
and Pascal Buskens*,[a]
Abstract: The interaction between plasmonic metal catalysts and
visible light can be exploited to increase their catalytic activity. This
activity increase results from the generation of hot charge carriers or
hot surfaces, or a combination of both. We have studied the light-
induced Suzuki-Miyaura cross-coupling reaction of bromobenzene
and m-tolylboronic acid using Pd-decorated Au nanorods as
plasmonic catalyst in order to assess which physical effect dominates.
Comparative experiments under laser illumination and in dark were
performed, demonstrating that under the experimental conditions
applied in our study the catalytic activity achieved upon illumination is
dominantly based on the conversion of light to heat by the plasmonic
catalyst. Pd leached from the catalyst also plays a significant role in
the reaction mechanism.
reactions, ranging from steam reforming of ethanol[3] to hydrogen
dissociation,[4] and reduction of CO2 to CH4.[5]
Catalysis by photoplasmonic nanoparticles can be attributed
to hot carriers as well as to nanoparticle heating. Discriminating
between the two is difficult, however. The bulk temperature of the
catalyst or reaction mixture may significantly differ from the local
temperature at the surface of the catalytic metal nanoparticles,
where the chemical processes take place. This absolute local
temperature is very challenging to measure directly and precisely
on an individual nanoparticle.[6] Heat transport phenomena and
reaction energetics can complicate this even further. Recently,
several studies distinguishing between photochemical and
photothermal contributions of plasmon-assisted catalytic systems
were published.[5b,7]
Introduction
Noble metal nanoparticles have an interesting property: they
can be very efficient absorbers of electromagnetic radiation with
wavelengths much longer than their own physical dimensions.
The absorption of photons by nanoparticles leads to the formation
of local surface plasmon resonance (LSPR): the collective
oscillations of metal valence electrons within an individual
nanoparticle.[1] The LSPR will dephase within femtoseconds,
leading to excited electron-hole pairs (Landau damping),
radiation damping, and
damping due to electron-surface
collisions.[2] These damping effects make plasmonic
nanocatalysts efficient sources of heat and hot electrons, which
form the fundament of plasmon catalysis and opens up ways to
improve reaction speed and selectivity of chemical reactions.
Especially, the harvesting of visible (VIS) and near-infrared (NIR)
radiation of sunlight as a sustainable way to drive chemical
reactions is intensively studied. Recently, plasmon catalysis has
been demonstrated for a broad variety of important chemical
[a]
M.F.C. Verkaaik., R.L. Grote, N.M.M. Meulendijks, Dr. F. Sastre,
Prof. Dr. P. Buskens
TNO Materials Solutions
High Tech Campus 25, 5656 AE Eindhoven (The Netherlands)
E-mail: pascal.buskens@tno.nl
[b]
Prof. Dr. B.M. Weckhuysen
Figure 1. A) Suzuki-Miyaura cross-coupling reaction, using Pd nanoparticles
as catalyst. B) Schematic of a plasmonically excited Au nanorod with Pd
nanoparticle catalyst at the tips. The particle is excited by the longitudinal and
transversal waves, depicted red and green, respectively. C) UV-Vis spectral
positions of the longitudinal (asterisk) and transversal (dagger) of the Au@Pd
nanorods with CTAB stabilizer in water.
Inorganic Chemistry and Catalysis Group
Debye Institute for Nanomaterials Science, Utrecht University
Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands)
Fax: (+ 31) 30-251-1027
E-mail: b.m.weckhuysen@uu.nl
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Figure 2. A) Schematic of the experimental set-up. The left cuvette is subjected to laser illumination, the right (reference) cuvette is not illuminated but continuously
equated to temperature of the illuminated cuvette. T: thermocouple, GC: gas chromatograph. B) TEM-EDX images of the Au@Pd nanoparticles, showing elevated
concentrations of Pd at the tips of the nanorods C) Temperature profiles of illuminated reactions with 0.7 to 1.7 W laser illumination, corresponding with 0.08 to
0.20 W/mm2. The dips in the graphs result from reaction mixture sampling. D) Conversion plots of illuminated reactions (squares) and their thermal reference
reactions (circles). Clear correlations between the illuminated and thermal reference reactions are observed, indicating a large thermal influence on the reaction
kinetics, with minor contribution of photocatalytic effects.
A reaction that raised scientific interest in photocatalysis is the
Suzuki-Miyaura cross-coupling reaction. This reaction couples an
aryl halide and an aryl boronic acid to form biphenyl species over
a heterogeneous Pd catalyst under relatively mild reaction
conditions.[8] The reaction is widely used for the industrial
synthesis of e.g. styrenes,[9] poly-olefins,[10] and biphenyls.[11]
biphenyls.[11] The integration of the SCR into a plasmon-enhanced
catalytic particle can be achieved by physically combining
catalytic Pd nanoparticles with a plasmonic Au nanorod (Figure
1B).[15] The Au nanorod is key in this plasmonically catalyzed
system, because Pd nanoparticles are weakly plasmonic and only
show extinction maxima in the Ultraviolet (UV) spectral region.[16]
The use of Au nanorods with tunable absorption makes it possible
to use the abundant NIR region of the solar emission spectrum
(Figure 1C).[17]
We have studied the specific roles of plasmon-assisted
chemistry and photothermal heating properties of Au@Pd
nanoparticles on the bulk reaction mixture. We have
comparatively studied the plasmon-assisted Suzuki-Miyaura
cross-coupling reaction under laser illumination and a non-
illuminated, simultaneous reference reaction to study the
influences of physical parameters and reactant variations on the
reaction kinetics and temperature profiles. The parallel reference
reaction is continuously heated to the bulk temperature of the
illuminated reaction, thereby allowing us to decouple the
influences of plasmon-assisted chemistry and its associated bulk
heating effects. Partial reaction orders were determined by
varying catalyst and reaction concentrations, giving a clue about
thermal and catalytic contributions as well.
Several successful attempts were taken to incorporate
a
photocatalytic component into the Suzuki-Miyaura reaction, for
example by the application of a semiconductive Mott-Schottky-
type SiC support for the Pd nanoparticle catalyst,[12] the in-situ
reduction of
a Pd(II) complex to Pd(0) using a Ru(II)
photosensitizing unit,[13] and the use of Pd nanosheets absorbing
in the visible near-infrared domain.[14] The enhancement of the
reaction kinetics in these plasmonic systems is widely
acknowledged, but the discrimination between the catalytic
contribution of Pd(0) and the photonic heating of the catalyst
remains underexposed.
In this work, we have quantitatively studied the thermal and
non-thermal contributions of laser illumination to the Suzuki-
Miyaura cross-coupling of bromobenzene and m-tolylboronic acid
using Pd nanoparticles decorated on plasmonic Au nanorods as
catalyst (hereafter referred to as Au@Pd). This is an important
reaction in the synthesis of styrenes,[9] poly-olefins,[10] and
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Figure 3. A) temperature plots of reactions with different amounts of Au@Pd catalyst, performed at 1.7 W (0.20 W/mm2) laser power. B) correlations between
amount of catalyst and temperature plateaus are eminent, as well as the increase in conversion speed.
Results and Discussion
effect itself and the accompanied bulk heating of the reaction
mixture.
The initial composition of all reaction mixtures consisted of
bromobenzene and m-tolylboronic acid as reactants, NaOH as
base, hexadecyltrimethylammonium bromide (CTAB) as stabilizer,
and Au@Pd as plasmonically active catalyst.
Anticipating on the heating power of the cuvette heater on the
one hand and on the laser heating power on the other is
necessary to accurately match the two reaction temperatures
manually: the heating power of the cuvette holder for the
reference reaction is much higher than the laser heating power.
We have found that it’s possible to match the two temperatures
manually with only a few degrees of deviation during the reaction
phase with increasing temperatures.
The concentrations of the reaction mixture during the reaction
were analyzed using gas chromatography (GC). With these
concentrations the reaction rates were calculated in the linear
sections of the graphs, using the formation of biphenyl to calculate
the conversions in time. It was assumed that the breaking of the
C-Br bond was the rate-determining step in this reaction.[18]
For the kinetic studies, sets of two parallel reactions were
performed with various parameter variations in order to quantify
the roles of hot electrons and of the bulk reaction temperature.
Note: all reaction temperatures reported in this manuscript are
temperatures measured for bulk reaction mixtures using a
thermocouple. A schematic of the used setup is shown in Figure
2A. Briefly, two parallel reactions were performed per experiment:
one illuminated with an 809 nm Continuous Wave (CW) laser; the
other is not illuminated but heated. This heated reaction served
as a thermal reference reaction. The bulk reaction temperatures
of both reactions were continuously monitored using
a
thermocouple submerged in the middle of the reaction mixtures.
Subsequently, the temperature of the reference reaction was
continuously adjusted to the temperature of the illuminated
reaction using a temperature-controlled cuvette holder. This
method makes it possible to distinguish between the illumination
Structural and Optical Characterization of the Catalyst
Transmission Electron Microscopy (TEM) was used to
validate the morphology of the particles. The particles applied in
Figure 4. Effects of concentration variations in the reaction mixture. A) Reaction rates of the illuminated reaction at 1.2 W (0.14 W/mm2) of laser power as function
of bromobenzene variation. The rate in the linear area (5-30 min) was calculated. Black dots represent the measured data, red circles represent calculated values
of partial first-orders of reaction in bromobenzene. The reaction was found to be first-order in bromobenzene. B) Arrhenius plots of two sets of reactions: one with
a normal amount of catalyst, and a second with double amount of catalyst. Both reactions were performed with different laser intensities to obtain the values of k.
These values were determined for the amount of bromobenzene per amount of nanoparticles within 25 min. The slope of the illuminated reactions and their
respective thermal reference reactions are comparable, indicating a large thermal dependence of the reaction kinetics.
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Figure 5.
Hot filtration tests: (a) After 14 minutes reaction time at 1.5 W laser illumination (I), the reaction is stopped through cooling to 0°C, and subsequently the nanorods
are removed from the reaction mixture through centrifugation. After one hour (at minute 74), the rod-free supernatant was subjected to 1.5 W laser illumination,
resulting in a temperature increase from 0°C to 40°C, which did not result in an increase in conversion (III); (b) After 14 minutes reaction time at the temperature as
achieved upon illumination (60°C, I), the reaction is stopped through cooling to 0°C, and subsequently the nanorods are removed from the reaction mixture through
centrifugation. After one hour (at minute 74) the rod-free supernatant was subjected to 1.5 W laser illumination, resulting in a temperature increase from 0°C to 37°C,
which did not result in an increase in conversion (III). At minute 92, the reaction mixture was heated to the same temperature as obtained upon illumination of
Au@Pd nanorods, i.e. 60°C, resulting in an increase in conversion of about 20% to 90% (IV).
our study are rod shaped with average dimensions of 107 ± 8 nm
and an average width of 49 ± 5 nm (n = 42), having an aspect
ratio of 2.2. Energy Dispersive X-ray (EDX) images of the Au@Pd
nanoparticles show a solid Au rod core, surrounded with a layer
of Pd nanoparticles of approximately 5 nm in diameter. The tips
of the rods show a higher concentration of Pd particles than the
sides, which is in agreement with earlier publications.[15,19] This
higher Pd nanoparticle concentration at the tips is desirable, since
the longitudinal LSPR has a much larger absorption cross-section
than its transversal counterpart, giving stronger local fields at the
tips of the particle than on the sides. The plasmonic
characteristics of the particles were measured with UV-VIS in
diluted aqueous dispersion, as received. Absorption bands were
determined at 523 nm and 772 nm, corresponding to the
transversal and longitudinal plasmon resonance, respectively.
Elemental analysis of these Au@Pd nanoparticles using atomic
emission spectroscopy (AES) yielded 343 µg/g Au and 214 µg/g
Pd, giving an Au:Pd weight ratio of 1.60. This is qualitatively in
accordance with the TEM-EDX analysis, as shown in Figure 2B.
A stable and fully dispersed catalyst during the course of the
reaction is essential for obtaining useful kinetic information.
Therefore, we’ve tested the stability of the Au@Pd nanoparticles
in the reaction mixture on forehand. Some test reactions with mild
illumination conditions were performed, checking for any
macroscopic changes in the suspension. It was found that the
acquired nanoparticle catalyst was prone to rapid agglomeration,
leading to full sedimentation within 30 min. It was found that using
semiconductor-grade NaOH (99.999%) instead of technical grade
NaOH (98%) as base had a positive effect on the nanoparticle
stability: no sedimentation was observed within 60 min of reaction.
Reproducibility of the illuminated reaction was tested by an in
triplo experiment using standard amounts of reactants and
catalyst and with 1.7 W (0.20 W/mm2) of laser light illumination for
60 min (Figure S1). The result of this experiments demonstrates
good reproducibility with a typical error of approx. 5%.
Five experiments with variable laser powers from 0.7 to 1.7 W
(0.08 to 0.20 W/mm2) were used to study the effects of resonant
laser irradiation on the temperature progression and the
conversion of the reaction (Figures 2C and 2D). Temperatures of
the illuminated reactions immediately increase after switching on
the laser, reaching
a
stable temperature plateau after
approximately 30 min until the reaction was terminated after 60
min. The reached temperature plateaus scale with the applied
laser power in each reaction. An initiation phase, characterized by
an increasing slope of the conversion in time, is visible in all
experiments - both under illumination as when heated. This can
be explained by several phenomena.
Firstly, the viscosity of the reaction mixture is very dependent
on the temperature, ranging from syrup-like at room temperature
to water-like at the observed temperature plateaus. Although the
viscosities of the reaction mixture as a function of temperature
were not quantified, it can be assumed that mass transfer
limitations play a significant role during the bulk heating in the first
minutes after starting the experiments.
Secondly, the CTAB in the reaction mixture cannot be fully
dissolved without elevating the temperature before starting the
reaction. This results in an increase in CTAB concentration in the
first phase of the reaction, with an associated increase in solubility
of the bromobenzene. This might result in non-linear behavior of
the reaction speed in the first phase of the reaction.
Thirdly, the temperature increase of the reaction mixture has
an obvious effect on the reaction kinetics.
The influence of the amount of catalyst on the temperature
progression and reaction speed was studied by changing the
amount of catalyst in the reaction mixture (Figure 3). Amounts
from 0.25 to 4 x the amount relative to standard amount were
used, corresponding to 6.5 µg of Au and 4 µg Pd and 104 µg of
Au and 64 µg Pd, respectively. A clear correlation between
amount of catalyst and the temperature increase and temperature
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plateau was observed. The obtained conversion speeds match
the temperature progressions of the reactions.
observed, and conversion remained at a stable level of around
20%.
The amount of bromobenzene was varied in separate
experiments to find out its partial reaction order and to check the
dependence on the overall reaction speed. Three experiments
with 0.25, 0.5, and 1 times the standard amount of bromobenzene
were carried out at 1.2 W (0.14 W/mm2) laser illumination (Figure
4A).
The temperature of the thermal reaction, which was
conventionally heated, was similar to the parent illuminated
reaction during the first 14 minutes reaction time (zone I in Fig.
5b). This resulted in approx. 20% conversion. After the
centrifugation step in the absence of nanorods, the resulting
supernatant showed no catalytic activity at a temperature of 0°C
(zone II in Fig. 5b). The temperature of the illuminated rod-free
reaction mixture only reached 37°C (zone III in Fig. 5b). Under
these conditions, no further conversion was observed, and
conversion remained at a stable level of around 20%. A
subsequent temperature increase through conventional heating
to 60°C caused an immediate rise of the conversion, going from
a stagnant 20% to 90% in 20 min (zone IV in Fig. 5b). Based on
these results, we conclude that that the plasmonic Au rods are
essential for conversion of light to heat, and that catalytically
active Pd species leach from the Au@Pd nanorods under the
applied reaction conditions.
The conversion of bromobenzene as a function of the amount
of Au@Pd nanoparticles was used to calculate the conversion
rate. Two sets of experiments were performed: one set with
varying laser powers and the normal amount of catalyst, and a
second with a double amount of catalyst. The values of k were
determined in the linear regime, after 25 min. The influence of
catalyst concentration on the overall reaction rate was also
studied. Two series of reactions with different laser intensities
were performed: one with the normal amount; the other with a
double amount of catalyst. The reaction rates were determined for
the amount of bromobenzene per amount of nanoparticles within
25 min of reaction time. The results are displayed in an Arrhenius
plot (Figure 4B). The Arrhenius plots from the illuminated
reactions and their thermal reference reactions are similar,
showing apparent activation energies of 76 (illuminated) and 61
(heated) kJ/mol for the reactions with single catalyst loading, and
42 (illuminated) and 45 (heated) kJ/mol for the reactions with
double catalyst loading.
Bimetallic nanoparticles are prone to deformation and alloying
upon elevated temperatures.[20] Therefore, we have studied the
morphology and elemental distribution of the Au@Pd
nanoparticles after exposure to laser light in the reaction mixture.
Au@Pd nanoparticles were extracted from a used reaction
mixture using centrifugation. TEM-EDX measurements were used
to study the morphology and composition of the extracted
nanoparticles. No differences between new and used Au@Pd
nanoparticles were found (Figure S2).
Pd is also a common homogeneous catalyst as well as non-
photonically active nanoparticle catalyst. Especially Pd is known
to leach from photocatalytic nanoparticles in basic environments,
forming a highly active homogeneous Pd catalyst.[21] The
influence of potentially leached Pd, which may dissociate from
Au@Pd nanorods under the applied reaction conditions, was
tested with two hot filtration tests (Fig. 5). After 14 min, the
illuminated (Fig. 5a) and the thermal reactions (Fig. 5b) were
stopped by immersing both reaction cuvettes in ice water. The
reaction mixtures were subsequently centrifuged to remove all
Au@Pd nanorods. The catalytic activity of the rod-free
supernatants was tested upon illumination (Fig. 5a), and upon
illumination and conventional heating (Fig. 5b).
Conclusions
The decoupling of the photochemical and the photothermal
effects of plasmonic Au@Pd nanoparticles as catalytic species in
the Suzuki-Miyaura cross-coupling reaction is discussed. It was
shown that matching the bulk temperature of a thermal reference
reaction with its parent illuminated reaction improves the
comparability of both reactions. Furthermore, it was found that
equating the temperature profile of the thermal control reaction
with the temperature of its parent illuminated reaction yielded
highly comparable reaction kinetics. This provides clear evidence
for the predominant role of temperature on the reaction kinetics
over possible heterocatalytic phenomena in this reaction.
Variations in the amount of rate-determining reactant, amount of
catalyst, and illumination intensities all result in the same
observation: there is no distinct difference between the
illuminated reactions and their respective thermal reference
reactions. We therefore conclude that this reaction in particular is
predominantly thermally driven.
Local temperatures directly at the surface of the nanoparticle
can play a role in plasmon-assisted chemistry. The local
temperatures of plasmonically excited nanoparticles are typically
above the bulk reaction temperature. It is unlikely that such
elevated local temperatures in this system are of any significance,
since the reaction kinetics can already be ascribed to the
observed bulk temperature effects. A hot filtration test was an
effective way to remove the plasmonic nanoparticles from the
reaction mixture, thereby removing the photocatalytic component,
while maintaining all other physical parameters. This showed that
the reaction was at least partially catalyzed by a secondary
species, most likely in the form of leached Pd nanoparticles or Pd
ions. Additionally, it was shown that the reaction requires a
temperature threshold of approximately 40°C, which can explain
the previously reported low conversion rates at low laser powers.
This research corroborates the hypothesis that the bulk
temperature of the reaction and the leaching of catalytically active
Before removal of the Au@Pd nanorods, the temperature of
the illuminated reaction mixture increased as expected upon 1.5
W (0.17 W/mm2) laser illumination to 60°C (zone I in Fig. 5a). This
resulted in a conversion of approx. 20% in 14 minutes reaction
time. After the centrifugation step in the absence of nanorods, the
resulting supernatant showed no catalytic activity at
a
temperature of 0°C (zone II in Fig. 5a). The temperature of the
illuminated rod-free reaction mixture only reached 40°C (zone III
in Fig. 5a). Under these conditions, no further conversion was
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the particles is studied by performing a hot filtration test. The catalytic
reaction at 1.5 W of laser power and the corresponding thermal reaction
mixture are interrupted after 14 min, at which both reaction mixtures were
immediately cooled in an ice-water bath to 0°C. The reaction mixtures were
subjected to centrifugation (4 x 15 min at 15,000 × g) followed by extraction
of the supernatant. The supernatants were subjected again to the same
laser power and consecutive heating for another 40 min.
Pd from the catalyst plays a decisive role in the formation of the
reaction product. We wish to stress that this insight is solely valid
for the Suzuki-Miyaura cross-coupling of bromobenzene and m-
tolylboronic acid, studied using the plasmonic Au@Pd catalyst
and reaction conditions reported in this article. Future research
will have to show how general these observations are for other
chemical reactions. More effort should be invested in the internal
stabilization of the catalyst in order to make the Au@Pd
nanoparticle system suitable for any truly photocatalytic
applications.
Acknowledgements
Analytische Laboratorien GmbH (Lindlar, Germany) is
acknowledged for performing the AAS measurements. Eurofins
Scientific (Eindhoven, the Netherlands) is acknowledged for
performing the TEM-EDX imaging. The Netherlands Organisation
for Scientific Research (NWO) is thanked for funding via a TA
program (project number 731.013.201).
Experimental Section
Chemicals and Materials
Nanoseedz250 Au@Pd NRs were acquired from Nanoseedz Ltd (Hong
Kong SAR, China) and used without purification. Bromobenzene (99%),
m-tolylboronic
acid
(97%),
sodium
hydroxide
(99.99%),
hexadecyltrimethylammonium bromide (CTAB, ≥ 98%), 3-phenyltoluene
(95%), biphenyl (99.5%), 3,3’-dimethylbiphenyl (99%), and hexadecane
(99%) were acquired from Sigma Aldrich and were used as received. All
reaction mixtures were prepared using ultrapure water.
Keywords: Plasmon-assisted chemistry • Suzuki-Myaura cross-
coupling reaction • Nanoplasmonics • Photocatalysis
[1]
297.
[2]
K. A. Willets, R. P. Van Duyne, Annu. Rev. Phys. Chem. 2007, 58, 267-
a) T. V. Shahbazyan, Phys. Rev. B 2016, 94, 235431; b) G. Baffou, J.
Catalyst characterization
Polleux, H. Rigneault, S. Monneret, J. Phys. Chem. C 2014, 118, 4890-4898.
[3] J. R. Adleman, D. A. Boyd, D. G. Goodwin, D. Psaltis, Nano Lett. 2009,
9, 4417-4423.
The catalyst suspension was used as received. Au and Pd contents were
determined with flame atomic absorption spectroscopy (AAS, Perkin Elmer
100 B), morphology and elemental topology were verified with
transmission electron microscopy - energy-dispersive X-ray spectroscopy
(TEM-EDX, JEOL ARM200F operated at 200kV), and plasmon resonance
was checked with UV-Vis spectroscopy (Hitachi U2001).
[4]
L. Zhou, C. Zhang, M. J. McClain, A. Manjavacas, C. M. Krauter, S.
Tian, F. Berg, H. O. Everitt, E. A. Carter, P. Nordlander, N. J. Halas, Nano
Lett. 2016, 16, 1478-1484.
[5]
a) X. Zhang, X. Li, D. Zhang, N. Q. Su, W. Yang, H. O. Everitt, J. Liu,
Nat. Commun. 2017, 8, 14542; b) X. Zhang, X. Li, M. E. Reish, D. Zhang, N.
Q. Su, Y. Gutiérrez, F. Moreno, W. Yang, H. O. Everitt, J. Liu, Nano Lett.
2018, 18, 1714-1723; c) F. Sastre, A. V. Puga, L. Liu, A. Corma, H. García, J.
Am. Chem. Soc. 2014, 136, 6798-6801; d) X. Meng, T. Wang, L. Liu, S.
Ouyang, P. Li, H. Hu, T. Kako, H. Iwai, A. Tanaka, J. Ye, Angew. Chem. Int.
Ed. 2014, 53, 11478-11482; e) F. Sastre, C. Versluis, N. Meulendijks, J.
Rodríguez-Fernández, J. Sweelssen, K. Elen, M. K. Van Bael, T. den Hartog,
M. A. Verheijen, P. Buskens, ACS Omega 2019, 4, 7369-7377.
Catalyst testing and stability
A set of two reactions was simultaneously performed in airtight 1x1-cm
quartz cuvettes: one under continuous 808-nm laser irradiation (R808±10-
4WF-04LTR diode laser, Laser Components GmbH, Mönchengladbach,
Germany) focused to a spot size of 3.33 mm and external power control
using a programmable power supply (Keithley 2200-30-5 Tektronics,
Beaverton, USA); the other in a dark, temperature-controlled stage (TC125,
Quantum Northwest Inc, Liberty Lake, USA). The temperatures of both
continuously stirred mixtures were monitored using two immersed
thermocouples (735-2, Testo SA, Lenzkirch, Germany). The temperature
of the parallel isothermal reaction was manually and iteratively adjusted to
the temperature of the irradiated reaction to obtain two temperature plots
with temporal differences of only a few °C. 50 µL aliquots were taken from
the reaction mixture at designated times. The reaction components were
extracted using diethyl ether (Biosolve, analytical grade) and subjected to
GC analysis (Thermo Scientific Trace 1300, equipped with a Restek
RTX200 column). Hexadecane was used as internal standard. Obtained
peaks were automatically integrated using the Chromeleon software
package (Thermo Scientific). A set of reactions was redone when a non-
closed mass balance (90% > MB > 110%) was encountered. Sets of
parallel experiments were performed using the laser in one set-up and the
temperature-controlled reactor in the other. The temperature of the
reaction mixture was continuously recorded, and the thermostat of the
isothermal reaction was continuously set to this value. 50 µL aliquots were
extracted at designated times and subjected to GC analysis. Again, two
sets of two parallel experiments were performed, now with varying
amounts of bromobenzene as rate-determining reactant,[18] and catalyst.
The bromobenzene concentration in the first set of experiments was varied
from 0.01 M to 0.04 M. The catalyst concentration in the second set was
varied from 0.25x to 4x the Au concentration, compared to the fixed
concentration of 26 µg of Au and 16 µg Pd in the other experiments. All
other conditions were kept unchanged. The influence of Pd leaching from
[6]
Nordlander, N. J. Halas, Nano Lett. 2013, 13, 1736-1742.
[7] a) L. Zhou, D. F. Swearer, C. Zhang, H. Robatjazi, H. Zhao, L.
Z. Fang, Y.-R. Zhen, O. Neumann, A. Polman, F. J. García de Abajo, P.
Henderson, L. Dong, P. Christopher, E. A. Carter, P. Nordlander, N. J. Halas,
Science 2018, 362, 69; b) Y. Yu, V. Sundaresan, K. A. Willets, J. Phys. Chem.
C 2018, 122, 5040-5048; c) R. M. Sarhan, W. Koopman, R. Schuetz, T.
Schmid, F. Liebig, J. Koetz, M. Bargheer, Sci. Rep. 2019, 9, 3060.
[8]
N. Miyaura, K. Yamada, A. Suzuki, Tetrahedron Lett. 1979, 20, 3437-
3440.
[9]
a) F. Kerins, D. F. O'Shea, J. Org. Chem. 2002, 67, 4968-4971; b) M.
E. Trusova, M. Rodriguez-Zubiri, K. V. Kutonova, N. Jung, S. Bräse, F.-X.
Felpin, P. S. Postnikov, Org. Chem. Front. 2018, 5, 41-45.
[10] a) A. F. Littke, C. Dai, G. C. Fu, J. Am. Chem. Soc. 2000, 122, 4020-
4028; b) W.-Y. Siau, Y. Zhang, Y. Zhao, in Stereoselective Alkene Synthesis
(Ed.: J. Wang), Springer, Berlin, Heidelberg, 2012, pp. 33-58.
[11] H.-J. Lehmler, L. W. Robertson, Chemosphere 2001, 45, 137-143.
[12] a) Z. Jiao, Z. Zhai, X. Guo, X.-Y. Guo, J. Phys. Chem. C 2015, 119,
3238-3243; b) X.-H. Li, M. Baar, S. Blechert, M. Antonietti, Sci. Rep. 2013, 3,
1743.
[13] K. Mori, M. Kawashima, H. Yamashita, Chem. Commun. 2014, 50,
14501-14503.
[14] I. Sarhid, I. Abdellah, C. Martini, V. Huc, D. Dragoe, P. Beaunier, I.
Lampre, H. Remita, New J. Chem. 2019, 43, 4349-4355.
[15] F. Wang, C. Li, H. Chen, R. Jiang, L.-D. Sun, Q. Li, J. Wang, J. C. Yu,
C.-H. Yan, J. Am. Chem. Soc. 2013, 135, 5588-5601.
[16] a) C. Liꢀ, R. Sato, M. Kanehara, H. Zeng, Y. Bando, T. Teranishi,
Angew. Chem. Int. Ed. 2009, 48, 6883-6887; b) J. M. Sanz, D. Ortiz, R.
Alcaraz de la Osa, J. M. Saiz, F. González, A. S. Brown, M. Losurdo, H. O.
Everitt, F. Moreno, J. Phys. Chem. C 2013, 117, 19606-19615.
[17] a) Y. Sang, H. Liu, A. Umar, ChemCatChem 2014, 7, 559-573; b) J. R.
Cole, N. J. Halas, Appl. Phys. Lett. 2006, 89, 153120; c) E. K. Payne, K. L.
Shuford, S. Park, G. C. Schatz, C. A. Mirkin, J. Phys. Chem. B 2006, 110,
2150-2154.
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ChemCatChem
FULL PAPER
[18] G. B. Smith, G. C. Dezeny, D. L. Hughes, A. O. King, T. R. Verhoeven,
J. Org. Chem. 1994, 59, 8151-8156.
[19] a) N. Ortiz, S. J. Hong, F. Fonseca, Y. Liu, G. Wang, J. Phys. Chem. C
2017, 121, 1876-1883; b) H. Jing, H. Wang, CrystEngComm 2014, 16, 9469-
9477.
[20] a) W. Albrecht, J. E. S. van der Hoeven, T.-S. Deng, P. E. de Jongh, A.
van Blaaderen, Nanoscale 2017, 9, 2845-2851; b) A. B. Taylor, A. M.
Siddiquee, J. W. M. Chon, ACS Nano 2014, 8, 12071-12079.
[21] P.-P. Fang, A. Jutand, Z.-Q. Tian, C. Amatore, Angew. Chem. Int. Ed.
2011, 50, 12184-12188.
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Entry for the Table of Contents
FULL PAPER
The individual contributions of
Mattheus Verkaaik, Roos Grote, Nicole
Meulendijks, Francesc Sastre, Bert M.
Weckhuysen*, Pascal Buskens*
photochemistry and photothermal
heating on a Suzuki-Miyaura cross-
coupling reaction of Pd-Au nanorods
under laser illumination has been
evaluated. It was found that thermal
energy dominates the kinetics of this
reaction. Additionally, palladium
leaching from the photocatalyst was
found to play a large role in the overall
reaction process.
Page No. – Page No.
Suzuki-Miyaura Cross-Coupling
Using Plasmonic Pd-Decorated Au
Nanorods as Catalyst: A Study on the
Contribution of Laser Illumination
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