E
Synlett
T. Osako et al.
Cluster
observed in the hydrogenation of quinoline (14). Although
the hydrogenation of 14 using G1 proceeded in only 39%
conversion, G5 efficiently promoted the hydrogenation to
give 1,2,3,4-tetrahydroquinoline (15) in 78% yield.
tic investigation of the enhancement of catalytic activity
through the iterative preparation of nanoparticles is under-
way in our laboratory.
OH
O
OH
+
Funding Information
ARP–Pt (5 mol% Pt)
+
H2 (balloon)
H2O (3 mL)
80 °C, 8 h
This work was supported by the JST-ACCEL program (JPMJAC401). We
are also grateful for funding from the JSPS KAKENHI [Grants-in-Aid
for Challenging Exploratory Research (No. 26620090) and for Scientif-
tBu
tBu
tBu
tBu
4
5
5
6
7
7
ic Research (C) (No. 16K05876)].
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Catalyst
Conv.
6 (trans/cis)
G1
G5
73%
38%
3%
16% (57:43)
61% (60:40)
3%
100%
26%
Supporting Information
Supporting information for this article is available online at
ARP–Pt (10 mol% Pt)
https://doi.org/10.1055/s-0037-1611813.
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8
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References and Notes
Catalyst
Conv.
9
10
(
1) (a) Aiken, J. D. III; Finke, R. G. J. Mol. Catal. A: Chem. 1999, 145, 1.
G1
G5
95%
63%
7%
32%
93%
(b) Astruc, D.; Lu, F.; Aranzaes, J. R. Angew. Chem. Int. Ed. 2005,
100%
44, 7852. (c) Shiju, N. R.; Guliants, V. V. Appl. Catal., A 2009, 356,
1. (d) Polshettiwar, V.; Varma, R. S. Green Chem. 2010, 12, 743.
ARP–Pt (10 mol% Pt)
(e) Zaera, F. Chem. Soc. Rev. 2013, 42, 2746.
2) (a) Somorjai, G. A.; Park, J. Y. Top. Catal. 2008, 49, 126.
+
(
H2 (balloon)
H2O (3 mL)
80 °C, 24 h
(b) Cuenya, B. R. Thin Solid Films 2010, 518, 3127. (c) An, K.;
11
12
12
13
Somorjai, G. A. ChemCatChem 2012, 4, 1512. (d) Mäki-Arvela, P.;
Murzin, D. Y. Appl. Catal., A 2013, 451, 251.
Catalyst
Conv.
13 (cis/trans)
(
3) For typical examples with platinum nanoparticles, see:
(a) Bratlie, K. M.; Lee, H.; Komvopoulos, K.; Yang, P.; Somorjai, G.
A. Nano Lett. 2007, 7, 3097. (b) Kuhn, J. N.; Huang, W.; Tsung, C.-
K.; Zhang, Y.; Somorjai, G. A. J. Am. Chem. Soc. 2008, 130, 14026.
G1
G5
35%
35%
57%
–
100%
43% (81:19)
(c) Zhu, J.; Yang, M.-L.; Yu, Y.; Zhu, Y.-A.; Sui, Z.-J.; Zhou, X.-G.;
ARP–Pt (10 mol% Pt)
Holmen, A.; Chen, D. ACS Catal. 2015, 5, 6310. (d) Bai, L.; Wang,
X.; Chen, Q.; Ye, Y.; Zheng, H.; Guo, J.; Yin, Y.; Gao, C. Angew.
Chem. Int. Ed. 2016, 55, 15656.
H2 (balloon)
H2O (3 mL)
80 °C, 24 h
N
N
H
14
15
(
4) (a) Roucoux, A.; Schulz, J.; Patin, H. Chem. Rev. 2002, 102, 3757.
(b) Polavarapu, L.; Mourdikoudis, S.; Pastoriza-Santos, I.; Pérez-
Juste, J. CrystEngComm 2015, 17, 3727. (c) Munnik, P.; de Jongh,
P. E.; de Jong, K. P. Chem. Rev. 2015, 115, 6687.
Catalyst
Conv.
15
G1
G5
39%
31%
78%
100%
(
5) (a) Brown, K. R.; Walter, D. G.; Natan, M. J. Chem. Mater. 2000,
12, 306. (b) Niesz, K.; Grass, M.; Somorjai, G. A. Nano Lett. 2005,
5, 2238. (c) Teranish, T.; Miyake, M. Chem. Mater. 1998, 10, 594.
(d) Lyon, J. L.; Fleming, D. A.; Stone, M. B.; Schiffer, P.; Williams,
M. E. Nano Lett. 2004, 4, 719. (e) O’Brien, M. N.; Jones, M. R.;
Brown, K. A.; Mirkin, C. A. J. Am. Chem. Soc. 2014, 136, 7603.
6) (a) Yamada, Y. M. A.; Arakawa, T.; Hocke, H.; Uozumi, Y. Angew.
Chem. Int. Ed. 2007, 46, 704. (b) Osako, T.; Torii, K.; Uozumi, Y.
RSC Adv. 2015, 5, 2647. (c) Osako, T.; Torii, K.; Tazawa, A.;
Uozumi, Y. RSC Adv. 2015, 5, 45760. (d) Osako, T.; Torii, K.;
Hirata, S.; Uozumi, Y. ACS Catal. 2017, 7, 7371.
Scheme 3 Hydrogenation of aromatics with G1 and G5. Reaction condi-
tions: substrate (0.3 mmol), catalyst (10 mol% Pt), H (3 mL), H (balloon),
2
2
80 °C, 24 h. Yields were determined by GC with an internal standard.
In summary, we have demonstrated that iteration of the
(
(
seeded preparation of platinum nanoparticles dispersed in
an amphiphilic polystyrene–poly(ethylene glycol) resin
10,11
(ARP–Pt)
regulates the activity of the catalyst in the hy-
drogenation of aromatic compounds in water and is accom-
panied by a slight modification of its structural properties.
Platinum nanoparticles dispersed in the amphiphilic poly-
mer prepared through four iterations (ARP–Pt G5) showed a
much higher catalytic activity than that of the initial ARP–
Pt (G1) in the hydrogenation of aromatic compounds in wa-
ter. These results suggest that iteration of the seeded prepa-
ration of nanoparticles can be an effective method for the
precise regulation of the catalytic activity and the structur-
al properties of the resulting catalyst. A detailed mechanis-
7) Flow hydrogenations of C=C and C=O double bonds have been
performed with ARP-Pt(G1) for up to 7852 min at 30–100 °C in
aqueous medium, during which no leaching from the catalyst
was observed (ICP-AES analysis). These observations showed
that hydrogenation catalyzed by ARP-Pt takes place heteroge-
neously [see refs 6 (c) and (d)].
(8) 1 g of TentaGel S NH
(particle size: 90 m) contains about
2
6
2.86 × 10 beads. We estimated the densities of platinum based
on the platinum loading and the volume of a polymer bead. For
details, see: http://www.rapp-polymere.com/index.php?id=98.
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2019, 30, A–F