Porphyrin-Stabilized Transition Metal Nanoparticles and Their Applications in the Reduction of 4-Nitrophenol and the Generation of Hydroxyl Radicals

Article abstract of DOI:10.1002/ejic.201900172

The synthesis of robust transition metal nanoparticles (TMNPs) are still intensively investigated because of multiple up-to date applications in catalysis, solar cells, nonlinear optics, biological labeling, nanoelectronics, medicine and energy storage de

Full text of DOI:10.1002/ejic.201900172

DOI: 10.1002/ejic.201900172
Full Paper
Transition-Metal Nanoparticles
Porphyrin-Stabilized Transition Metal Nanoparticles and Their
Applications in the Reduction of 4-Nitrophenol and the
Generation of Hydroxyl Radicals
Jiaying Yan,[a,b] Genjiang Liu,[a] Ning Li,[a] Nuonuo Zhang,[a] and Xiang Liu*[a]
Abstract: The synthesis of robust transition metal nanoparti- at 0 °C. The as-synthesized nanocomposites show high catalytic
cles (TMNPs) are still intensively investigated because of multi- activity in the reduction of 4-nitrophenol, a pertinacious pollu-
ple up-to date applications in catalysis, solar cells, nonlinear tant occurring in industrial waste water. In addition, it is evident
optics, biological labeling, nanoelectronics, medicine and en- that a drastic absorption change has been observed in UV/Vis
ergy storage devices. Here we report synthesis of tetrahydroxy- spectra, confirming that generation of hydroxyl radicals in-
phenylporphyrin (TPP-OH)-stabilized TMNPs (including AuNPs, duced by AgNPs and further oxidized methylene blue (MB) to
AgNPs and PdNPs) by mixing TPP-OH and simple commercial hydroxymethylene blue (MB-OH).
metal salt and followed by the addition of sodium borohydride
1. Introduction
to understand and study effective interaction between por-
phyrin and TMNPs. Our laboratory has long term interest in the
synthesis of porphyrins, their precursors, and their applica-
tions.[11] Hence, in the present study, we first report tetra-
hydroxyphenylporphyrin (TPP-OH)-stabilized Au-, Ag- and
PdNPs and their applications in the reduction of 4-nitrophenol
and production of hydroxyl radicals. The four hydroxy groups
present in the periphery of the porphyrin has a decisive effect
on stabilizing the nanoparticles in a controlled fashion to pre-
vent the aggregation. Construction of the TMNPs has been con-
ducted by here direct coordination of transition metal ions onto
stoichiometric porphyrin followed by NaBH4 reduction in the
mixture of ethanol and water. Then Au-, Ag- and PdNPs's com-
pared catalytic performance in 4-nitrophenol reduction by
NaBH4 has been scrutinized by kinetic studies including induc-
tion times and determinations of rate constants in water. In
addition, AgNPs has also been measured for the induced the
accumulation of hydroxyl radicals in the presence of hydrogen
peroxide.
Transition metal nanoparticles (TMNPs) have gained extensive
attention due to their tremendous specific surface area, shape-
and size-dependent optical, chemical and physical properties
that are totally distinguished from those of the metal blocks.[1]
Therefore, they have been widely used in catalysis, solar cells,
nonlinear optics, biological labeling, nanoelectronics, medicines
and energy storage devices.[2] Over the past decades, in order
to avoid the agglomeration of TMNPs, many nanoreactors have
been designed and developed for stabilizing TMNPs, such as
surfactants, dendrimers, cucurbit uril, polymers, biresorcinar-
enes, cyclodextrins, M6L4 capsules, ionic liquids, soft ball, graph-
ene quantum dots and porphyrins.[3]
Porphyrin and its derivatives are a group of versatile and
multifunctional 18 π-electrons conjugated heterocyclic macro-
cycle organic compounds with fascinating photocatalytic, opti-
cal, and chemical properties that have exhibited great potential
applications in catalysis,[4] photodynamic and photothermal
therapy,[5] electrochemical sensor,[6] antimicrobial material,[7]
cell imaging,[8] electronic and optical devices through covalent
linking to TMNPs.[9] Porphyrins as stabilizer on transition metal
nanoparticles (TMNPs) also have the advantage of exploiting
multiple binding sites to obtain a better control of the orienta-
tion of porphyrins on the core of TMNPs.[10] It is still essential
2. Results and Discussion
2.1. Synthesis of the Porphyrin-Stabilized TMNPs
First, tetrahydroxyphenylporphyrin (TPP-OH) is known and has
been easily assembled by classical cycloidization of p-hydroxy-
benzaldehyde and pyrrole in the presence of propionic acid in
dimethyl sulfoxide at 140 °C for 2 h.[12] The synthesis of TPP-
OH-stabilized AuNPs 1–3 was conducted by using as synthe-
sized TPP-OH and simple commercial chloroauric acid dissolved
in the mixture of EtOH (1 mL) and water (9 mL) in a standard
molar ratio 2:1, 1:1 or 1:2 of metal ion/porphyrin and followed
by the addition of sodium borohydride as the reductant at 0 °C,
[a] College of Materials and Chemical Engineering, Key Laboratory of
Inorganic Nonmetallic Crystalline and Energy Conversion Materials,
China Three Gorges University,
Yichang, Hubei 443002, China
E-mail: xiang.liu@ctgu.edu.cn
[b] State Key Laboratory of Coordination Chemistry, Nanjing University,
Nanjing, Jiangsu, 210093, P.R. China
Supporting information and ORCID(s) from the author(s) for this article are
available on the WWW under https://doi.org/10.1002/ejic.201900172.
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respectively (Figure 1). EtOH has been added for dissolving por-
phyrin, AuIII ions were bonded to a nitrogen or oxygen atom of
the porphyrin, and the corresponding nanoparticles had a small
size and were good catalysts. These porphyrin ligands are neu-
tral and weak, leaving the surface atoms in a zero oxidation
state by the reduction of sodium borohydride. However, the
characteristic peaks of AuNPs did not appear in the UV/Vis spec-
tra, due to the interference of porphyrins. In addition, the stabil-
ity of AuNPs-2 has also been investigated, AuNPs solution is
stirred for 2 h at 45 °C, 60 °C, 75 °C and 90 °C, respectively. We
found AuNPs-2 is very stable even at 90 °C for 2 h (Figure
S11–S14 in the Supporting Information). Then TEM have been
measured to further confirm the morphology and size of the
AuNPs. As shown in Figure 2a- 2c, we found the sizes of AuNP-
2 (3.2 nm) is much smaller than those of AuNP-1 (3.8 nm) and
AuNP-3 (4.8 nm). The size of these AuNPs also is modulated by
variation of the volume ratio of ethanol in the solution, then
the AuNP-4 (4.1 nm) and AuNP-5 (4.0 nm) are obtained in the
mixture of EtOH (2 mL)/water (8 mL) and EtOH (4 mL)/water
(6 mL) as the same condition as AuNP-2, respectively (Figure 2d
and Figure 2e). Moreover, the size of these AuNPs is also modu-
lated by variation of the reaction temperature. AuNP-6 (5.5 nm),
obtained at 30 °C (Figure 2f), is much larger than AuNP-2 at
0 °C (3.2 nm). It is probably on account of Ostwald ripening
that occurs at 30 °C following Au atom nucleation, however,
resulting in the decrease in the number of Au nuclei and to
AuNPs overgrowth. Thus, the standard molar ratio 1:1 of metal
ion/porphyrin, 0 °C and volume ratio 1:9 of EtOH/water are the
optimal conditions. Therefore, PdNPs and AgNPs have been syn-
thesized as the same condition as AuNP-2. The TEM image
shows the size of PdNPs is only 1.7 nm, while AgNPs (14 nm) is
much larger (Figure 3). To further verify the formation of TMNPs,
the X-ray photoelectron spectroscopy (XPS) spectra of AuNP-2
Figure 2. TEM images of AuNPs. (a)-(f): 1–6.
Figure 3. (a) TEM image of PdNPs. (b) TEM image of AgNPs.
Figure 1. Schematic illustration of the synthesis of TPP-OH-stabilized Au-, Ag-, and PdNPs.
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and AgNPs have been measured. AuNP-2 only exhibits Au0 on 2.2. Comparing Catalytic Activities of TMNPs in 4-
the surface atoms of AuNP in the XPS, Au 4f peaks positions at Nitrophenol Reduction
83.0 and 87.0 eV. The binding energy of 83.0 eV and 87.0 eV
4-Nitrophenol, a common by-product in industry, is regarded
for Au 4f7/2 and 4f5/2, respectively (Figure 4a). Similarly, XPS of
as one class of the most highly hazardous and toxic pollu-
AgNPs exhibits Ag 3d peaks positions at 368.1 eV and 374.0 eV.
tants.[13] It has a delayed interaction with blood and forms
The binding energy of 368.1 eV and 374.0 eV for Ag 3d5/2 and
methaemoglobin which is responsible for methemoglobinemia,
3d3/2, respectively, are exclusively assigned to the zero-valent
potentially causing confusion, cyanosis, and unconsciousness.
surface atoms of AgNPs (Figure 4b), more discussion has been
The catalytic reduction of 4-nitrophenol by sodium borohydride
provided in the Supporting Information.
in water was chosen as a model reaction to evaluate the cata-
lytic efficiency of TMNPs (Table 1 and Fig. S17–S30 in the Sup-
porting Information). The reduction of 4-nitrophenol has been
carried out in the presence of 5.0 mol-% TMNPs with 100 equiv.
of NaBH4 in water at room temperature, this large excess NaBH4
being usually utilized to induce an obvious first-order kinetics
and a relative lack of competitive NaBH4 hydrolysis by water as
solvent. Based on the experimental result, all reactions need an
induction time of 180s to 420s in the presence of these AuNPs
1–6, related to the reorganization at the catalyst surface
(Table 1, entries 1–6). This induction time is taken into account
by the stabilization of the AuNPs with porphyrin that the steric
bulk inhibiting substrate approach to the AuNPs surface as a
consequence of intradendritic porphyrin of AuNPs. Among
them, the reaction rate kapp of AuNP-2 (8 × 10–3) is much higher
than these of AuNP-1 (3.7 × 10–3) and AuNP-3 (3.3 × 10–3). The
reaction rate kapp of AuNP-4 and 5 decreases with as the in-
crease of amount of EtOH in the process of the synthesis
(Table 1, entries 4 and 5). It is clear that AuNP-2 shows the
highest reaction rate among these AuNPs (Table 1, entry 6), this
is consistent with the smallest size of 3.2 nm. Catalysis by PtNPs
was found not to need an induction time (Table 1, entry 7),
while AgNPs is inactive (Table 1, entry 8). Thus, the reaction rate
kapp increases in the order Ag < Pd < Au. In addition, TPP-OH
alone do not catalyze the degradation of 4-nitrophenol under
these conditions (the yellow color of 4-nitrophenol does not
change to colorless in two weeks).
2.3. Effect of AgNPs on ·OH Generation
It is well-known that the Fenton-like reaction between AgNPs
Figure 4. (a) XPS of AuNP-2, (b) XPS of AgNPs.
and H2O2, which could generate powerful oxidizing species
Table 1. 4-Nitrophenol reduction catalyzed by TMNPs in water.[a]
T0 [s][c]
Kapp [× 10–3 s–1
]
D [nm][e]
[d]
Entry
TM ions [mmol]
EtOH [mL]
TMNPs
1
2
3
4
1.25×10–4
2.5×10–4
5.0×10–4
2.5×10–4
2.5×10–4
2.5×10–4
2.5×10–4
2.5×10–4
1
1
1
2
4
1
1
1
AuNP-1
AuNP-2
AuNP-3
AuNP-4
AuNP-5
AuNP-6
PdNPs
300
180
180
180
300
420
0
3.7
8
3.8
3.2
4.8
4.1
4.0
5.5
1.7
14.0
3.3
1.4
0.4
2.9
4
5
6[b]
7
8
AgNPs
–
–
[a] 5.0 mol-% AuNPs@GQDs were used in the catalyzed 4-nitrophenol reduction NaBH4 is in excess (100:1). All the AuNPs 1–5 were synthesized at 0 °C except
6. [b] AuNPs@GQDs 6 were synthesized at 30 °C. [c] Induction time. [d] Rate constant. [e] Core size (TEM) of the TMNPs.
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such as ·OH.[14] The oxidized and reduced forms of methylene change could be observed, confirming that generation of
blue (MB) have different absorption bands in the UV/Vis spec- hydroxyl radicals induced by AgNPs and further oxidized MB to
trum. Hence, the progress of ·OH oxidized reaction from MB to MB-OH. Then the influence of hydrogen peroxide concentration
MB-OH can be monitored by measuring the decrease in absorp- on the generation of hydroxyl radicals has been studied as
tion of MB on UV/Vis spectrum at a peak of 666 nm (Fig- shown in Figure 6b (Figure S31–S36 in the Supporting Informa-
ure 5).[15] The time dependent UV/Vis spectrum of MB during tion). The production of hydroxyl radicals was quasi-linearly
0.025 mmol/L AgNPs and 0.125 mmol/L (5 equiv.) H2O2 is pre- proportional to the concentration of H2O2 from 0.1 eq to 1.0
sented in Figure 6a. After 20 min, MB peak intensity decreases eq, compared to the amount of AgNPs. At the amount of H2O2
0.085. As expected, it is evident that a drastic absorption above 1 eq, generation of hydroxyl radicals no longer increased
indicating a saturation of the reactivity of AgNPs. When added
without AgNPs or H2O2, MB peak intensity remains unchanged.
This is totally consistent with the proposed Fenton-like reaction
between AgNPs and hydrogen peroxide to generate hydroxyl
radicals.
3. Conclusion
A green and facile method of synthesis of tetrahydroxyphenyl-
porphyrin (TPP-OH)-stabilized TMNPs has been developed in
this work. Construction of AuNPs 1–6, AgNPs and PdNPs nano-
composites is accomplished by mixing TPP-OH and simple com-
mercial metal salt followed by the addition of sodium boro-
Figure 5. Schematic illustration of ·OH generation by AgNPs.
hydride at 0 °C. TEM images show that the sizes of AuNP-2 and
AgNP are 3.2 nm and 14.0 nm, respectively. Then Au-, Ag- and
PdNPs's compared catalytic performance in 4-nitrophenol re-
duction by NaBH4 has been scrutinized by kinetic studies in-
cluding induction times and determinations of rate constants
in water. In addition, AgNPs has also been measured for the
induced the accumulation of hydroxyl radicals in the presence
of hydrogen peroxide. As expected, it is evident that a drastic
absorption change has been observed in UV/Vis spectra, con-
firming that generation of hydroxyl radicals induced by AgNPs
and further oxidized MB to MB-OH. Therefore, we expect that
these TMNPs nanocomposites may offer wide potential applica-
tions in sensors, clinical diagnosis and catalysis fields.
Experimental Section
1. Preparation of Tetrahydroxyphenylporphyrin (TPP-OH): TPP-
OH has been synthesized following reference 12 of the main text.
First, 60 mL of EtCOOH and 3 mL of DMSO have been put into
250 mL round-bottom flask, it is then heated to reflux. p-hydroxy-
benzaldehyde (3 g, dissolved in 10 mL of EtCOOH) and pyrrole
(0.0025 mol, dissolved in 10 mL of EtCOOH) have been added to
flask. The reaction mixture is stirred for 2 h under reflux. After cool-
ing to room temperature, EtCOOH was removed under vacuum in
which EtOH (≈ 30 mL) was added. Under 0 °C, the desired TPP-OH
as a deep green solid was obtained after filtration. 1H NMR
(300 MHz, CDCl3): δ = 9.92 (s, 4H), 8.81 (s, 8H), 7.94–7.95 (d, 8H),
7.14–7.16 (d, 8H), –2.95 (s, 2H). ESI HRMS: calcd. for C44H30N4O4
[M + H]+: 679.2267, found 679.2332.
2. Preparation of the TPP-OH Stabilized Transition Metal Nano-
particles: First, 2.5 × 10–4 mmol TPP-OH is dissolved in 1 mL of
EtOH in a Schlenk flask with 7 mL of deionized water, and the solu-
tion is stirred for 10 min at 0 °C. And a colorless solution of
Figure 6. (a) UV/Vis absorption spectra for the oxidization of methylene blue
by AgNPs and 5 eq H2O2. (b) Effect of H2O2 on the generation of hydroxyl
HAuCl4·3H2O (2.5 × 10–4 mmol in 1.0 mL of water) is added to the
solution of TPP-OH. And the solution is stirred for 30 min. A 1-mL
radicals from samples containing 3 mL of 0.25 mmol/L AgNPs, 9 uL of
2.5 mmol/L methylene blue and H2O2 at different concentrations.
aqueous solution containing 2.5 × 10–3 mmol of NaBH4 is added
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[3] a) V. Chechik, R. M. Crooks, J. Am. Chem. Soc. 2000, 122, 1243; b) D.
Wang, D. Astruc, Chem. Soc. Rev. 2017, 46, 816–854.
dropwise, provoking the formation of purple (AuNP) color corre-
sponding to the reduction of the cation to the zero-valent metal
and AuNP-2 formation. The AuNP-2 were kept in aqueous solution
for characterization and used as the catalysts. Other TMNPs were
synthesized using the same method.
[4] a) K. S. Lokesh, A. Shambhulinga, N. Manjunatha, M. Imadadulla, M. Ho-
jamberdiev, Dyes Pigm. 2015, 120, 155–160; b) P. Mineo, A. Abbadessa,
A. Mazzaglia, A. Gulino, V. Villari, N. Micali, S. Millesi, C. Satriano, E. Scam-
porrino, Dyes Pigm. 2017, 141, 225–234; c) I. Fratoddi, C. Battocchio, G.
Polzonetti, F. Sciubba, M. Delfini, M. V. Russo, Eur. J. Inorg. Chem. 2011,
4906–4913.
[5] a) M. E. Alea-Reyes, J. Soriano, I. Mora-Espí, M. Rodrigues, D. A. Russell,
L. Barrios, L. Pérez-García, Colloids Surf. B 2017, 158, 602–609; b) J. Zeng,
W. Yang, D. Shi, X. Li, H. Zhang, M. Chen, ACS BioMater. Sci. Eng. 2018, 4,
963–972; c) O. J. Fakayode, S. P. Songca, O. S. Oluwafemi, Mater. Lett.
2017, 199, 37–40.
3. Catalysis of 4-Nitrophenol Reduction: An aqueous solution
(2.5 mL) containing 4-nitrophenol (0.09 mmol) and NaBH4 (9 mmol)
is prepared in a standard quartz cuvette (3 mL, path length: 1 cm).
The TMNPs catalyst (5 mol-%) is injected into this solution, and the
reaction progress is detected by UV/Vis. spectroscopic analysis
every min at 22 °C. (Figure S17–S30).
[6] B. Kaur, K. Malecka, D. A. Cristaldi, C. S. Chay, I. Mames, H. Radecka, J.
Radecki, E. Stulz, Chem. Commun. 2018, 54, 11108–11111.
[7] O. Lyutakov, O. Hejna, A. Solovyev, Y. Kalachyova, V. Svorcik, RSC Adv.
2014, 4, 50624–50630.
[8] N. C. M. Tam, P. Z. McVeigh, T. D. MacDonald, A. Farhadi, B. C. Wilson, G.
Zheng, Bioconjugate Chem. 2012, 23, 1726–1730.
4. Generation of Hydroxyl Radicals: An aqueous solution contain-
ing 3 mL of AgNPs (0.025 mmol/L) and 9 uL methylene blue
(2.5 mmol/L) is prepared in a standard quartz cuvette (3 mL, path
length: 1 cm). The H2O2 (0.1 eq –10 equiv.) is injected into this
solution, and the reaction progress is detected by UV/Vis. spectro-
scopic analysis every min at 22 °C. (Figure S31–S36).
[9] M. Drobizhev, Y. Stepanenko, A. Rebane, C. J. Wilson, T. E. O. Screen, H. L.
Anderson, J. Am. Chem. Soc. 2006, 128, 12432–12433.
[10] T. Hasobe, Phys. Chem. Chem. Phys. 2010, 12, 44–57.
Acknowledgments
[11] a) J. Yan, Y. Yang, M. Ishida, S. Mori, B. Zhang, Y. Feng, H. Furuta, Chem.
Eur. J. 2017, 23, 11375–11384; b) N. Zhang, J. Chen, K. Cheng, Y. Li, L.
Wang, K. Zheng, Q. Yang, D. Li, J. Yan, Res. Chem. Intermed. 2017, 43,
2921; c) Y. Li, J. Yan, K. Cheng, S. Kong, K. Zhang, L. Wang, N. Zhang, Res.
Chem. Intermed. 2017, 43, 5337; d) J. Yan, M. Takakusaki, Y. Yang, S. Mori,
B. Zhang, Y. Feng, M. Ishida, H. Furuta, Chem. Commun. 2014, 50, 14593–
14596; e) N. Zhang, B. Zhang, J. Yan, X. Xue, X. Peng, Y. Li, Y. Yang, C. Ju,
C. Fang, Y. Feng, Renewable Energy 2015, 77, 579–585; f) Y. J. Li, J. Yan,
S. Xiao, B. Zhang, F. Lu, K. Cheng, D. Li, Y. Feng, N. N. Zhang, Tetrahedron
Lett. 2016, 57, 3226–3230; g) X. Liu, J.-R. Hamon, Coord. Chem. Rev. 2019,
389, 94–118; h) T. T. Zhang, Y. J. Li, J. Yan, Y. Liang, B. B. Xu, K. B. Zheng,
N. N. Zhang, Tetrahedron 2018, 74, 2807–2811; i) Y. Zhou, J. Yan, N.
Zhang, D. Li, S. Xiao, K. Zheng, Sensor Actuat. B-Chem. 2018, 258, 156–
162; j) M. Li, K. Zheng, H. Chen, X. Liu, S. Xiao, J. Yan, X. Tan, N. Zhang,
Spectrochim. Acta Part A 2019, 217, 1–7.
[12] Z. Hou, W. Dehaen, J. Lyskawa, P. Woisel, R. Hoogenboom, Chem. Com-
mun. 2017, 53, 8423–8426.
[13] P. Zhao, X. Feng, D. Huang, G. Yang, D. Astruc, Coord. Chem. Rev. 2015,
287, 114–136.
[14] a) L. Wang, J. Zheng, Y. Li, S. Yang, C. Liu, Y. Xiao, J. Li, Z. Cao, R. Yang,
Anal. Chem. 2014, 86, 12348–12354; b) L.-Y. Duan, Y.-J. Wang, J.-W. Liu,
Y.-M. Wang, N. Li, J.-H. Jiang, Chem. Commun. 2018, 54, 8214–8217; c) H.
Jiang, Z. Chen, H. Cao, Y. Huang, Analyst 2012, 137, 5560–5564.
[15] S. Naraginti, F. B. Stephen, A. Radhakrishnan, A. Sivakumar, Spectrochim.
Acta A 2015, 135, 814–819.
Financial support from the National Natural Science Foundation
of China (Grant Nos. 21805166 and 21606145), the 111 Project
of Hubei Province (Grant No. 2018-19-1), the State Key Labora-
tory of Coordination Chemistry Foundation of Nanjing Uni-
versity (No. SKLCC1811), and China Three Gorges University is
gratefully acknowledged.
Keywords: Porphyrin · Nanoparticles · 4-Nitrophenol ·
Reduction · Radicals
[1] a) M. Sankar, N. Dimitratos, P. J. Miedziak, P. P. Wells, C. J. Kiely, G. J.
Hutchings, Chem. Soc. Rev. 2012, 41, 8099; b) X. Liu, D. Astruc, Adv. Mater.
2017, 29, 1605305; c) Y. Zhu, N. S. Hosmane, Coord. Chem. Rev. 2015,
293, 357; d) M.-C. Daniel, D. Astruc, Chem. Rev. 2004, 104, 293; e) X. Liu,
C. Manzur, N. Novoa, S. Celedon, D. Carrillo, J.-R. Hamon, Coord. Chem.
Rev. 2018, 357, 144–172; f) S. Cao, F. Tao, Y. Tang, Y. Li, J. Yu, Chem. Soc.
Rev. 2016, 45, 4747–4765.
[2] a) L. Liu, A. Corma, Chem. Rev. 2018, 118, 4981–5079; b) X. Liu, D. Astruc,
Adv. Synth. Catal. 2018, 360, 3426–3459; c) H. Kang, J. T. Buchman, R. S.
Rodriguez, H. L. Ring, J. He, K. C. Bantz, C. L. Haynes, Chem. Rev. 2019,
119, 664–699; d) X. Liu, D. Astruc, Coord. Chem. Rev. 2018, 359, 112–126;
e) J. J. Soldevila-Barreda, N. Metzler-Nolte, Chem. Rev. 2019, 119, 829–
869.
Received: February 14, 2019
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Transition-Metal Nanoparticles
J. Yan, G. Liu, N. Li, N. Zhang,
X. Liu* .................................................... 1–6
Porphyrin-Stabilized
Transition
Metal Nanoparticles and Their Ap-
plications in the Reduction of 4-
Nitrophenol and the Generation of
Hydroxyl Radicals
Here we report the synthesis of tetra- as-synthesized nanocomposites show
hydroxyphenylporphyrin-stabilized high catalytic activity in the reduction
TMNPs by mixing TPP-OH and simple of 4-nitrophenol and the generation of
commercial metal salt followed by the hydroxyl radicals.
addition of sodium borohydride. The
DOI: 10.1002/ejic.201900172
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