Efficient palladium-catalyzed Suzuki cross-coupling reaction with β-ketoamine ligands

Article abstract of DOI:10.1016/j.inoche.2011.01.044

A series of β-ketoamine ligands with different steric and electronic substituents on the backbone and with aniline moieties have been synthesized and characterized. In the presence of PdCl₂, catalytic studies indicated that they are effective l

Full text of DOI:10.1016/j.inoche.2011.01.044

Inorganic Chemistry Communications 14 (2011) 659–662
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Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Efficient palladium-catalyzed Suzuki cross-coupling reaction
with β-ketoamine ligands
⁎
⁎
Zong-Zhou Zhou, Feng-Shou Liu , Dong-Sheng Shen , Cheng Tan, Ling-Yan Luo
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan, 528458, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of β-ketoamine ligands with different steric and electronic substituents on the backbone and with
aniline moieties have been synthesized and characterized. In the presence of PdCl2, catalytic studies indicated
that they are effective ligands for Suzuki cross-coupling of various aryl bromides with phenylboronic acid,
under aerobic conditions.
Received 25 November 2010
Accepted 28 January 2011
Available online 6 March 2011
© 2011 Elsevier B.V. All rights reserved.
Keywords:
β-ketoamine ligands
Backbone
Aniline moiety
Suzuki cross-coupling reaction
Palladium-catalyzed reactions, such as C―C bond formation, have
attracted significant interest over the past few decades [1,2].
Specifically, the Suzuki cross-coupling reaction of aryl halides with
organoboron reagents is becoming one of the most important and
reliable methods for the construction of biaryls, which are present in a
wide range of natural products, pharmaceuticals, agrochemicals and
functional polymer materials [3–10]. Like other types of palladium-
catalyzed coupling reactions, the Suzuki coupling reaction is also
highly dependent on the nature of the ligand structure. Bulky,
electron-rich phosphine ligands are outstanding in the palladium-
catalyzed Suzuki cross-coupling reaction, resulting from their supe-
rior donor capability and stabilization effects [11–14]. Though these
catalysts exhibited excellent catalytic properties, most phosphines are
highly toxic and are air- and moisture-sensitive, and therefore require
oxygen-free handling to minimize ligand oxidation. These drawbacks
place a significant limitation on their synthetic applications. However,
the development of phosphine-free ligands has seriously challenged
this situation. Recently, the use of N-heterocyclic carbenes (NHCs) in
Suzuki cross-couplings has gained much popularity for both superior
σ-donating properties and easily variable steric substituents, which
allow for the stabilization of the active metal center and the
enhancement of the catalytic activity [15,16]. NHCs/palladium
complexes are quite stable, but the ligand can be sensitive to oxygen.
Therefore, additional research on new ligands that are moisture- and
air-stable is needed.
inexpensive, easily prepared and moisture- and air-stable. Among
them, β-ketoamine ligands, previously used as excellent candidates
for olefin and ε-caprolactone polymerization [42,43], have recently
been applied to Suzuki cross-coupling [38–41]. Hong and coworkers
found that β-ketoamine ligands derived from acetylacetone exhibited
moderate activity toward aryl bromides [38]. Recently, Jin and
coworkers developed a series of β-ketoamine palladium complexes
with triphenylphosphine as an ancillary ligand that showed high
activity toward both aryl and heteroaryl chlorides [39–41]. Never-
theless, the β-ketoamine palladium complexes developed were
exclusively based on acetylacetone. Considering that both the
backbone and the amines have profound effects on the catalytic
properties of the palladium complexes, herein we present a simple
and efficient preparation of a series of novel β-ketoamines complexes
with aryl backbones and substituted aniline moieties generated in
situ. Furthermore, conditions are described that easily provide the
desired products in moderate to high yields under aerobic conditions,
with great tolerance for a broad range of functional groups on the aryl
bromides.
As shown in Scheme 1, the target β-ketoamine ligands with
various steric and electronic substituents were prepared according to
a previously reported protocol [44–48], with some modifications. At
first, the enaminones were synthesized from the starting material,
acetophenone, and then were reacted with 1.2 equiv of aniline in
refluxing ethanol or glacial acetic acid. After recrystallization from
methanol, β-ketoamine ligands (L1–5) were obtained in moderate to
high yields [49].
In contrast, phosphine-free ligands, such as tridentate [17–20] and
bidentate [21–41] ligands containing N, O and S atoms, are typically
The catalytic activity of L1–5 in Suzuki cross-coupling reactions
was then evaluated. In an effort to understand how the ligands would
promote this coupling reaction most efficiently, a reaction in which
Na2CO3 was used as a base and ethanol/water was a cosolvent in the
⁎
Corresponding authors.
E-mail addresses: fengshou2004@126.com (F.-S. Liu), sds8@163.com (D.-S. Shen).
1387-7003/$ – see front matter © 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2011.01.044

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Z.-Z. Zhou et al. / Inorganic Chemistry Communications 14 (2011) 659–662
Table 2
Conditions optimization in Suzuki cross-coupling reaction.
Entry
Solvent
Base
T(°C)
Pd (mo1%)a
t (h)
Yield (%)b
1
2
3
4
Toluene
DMF
Acetone
EtOH
Na2CO3
Na2CO3
Na2CO3
Na2CO3
NaCO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
K3PO4
K2CO3
KF
KOH
NaOH
NaOMe
NaOAc
60
60
60
60
60
60
60
60
60
25
25
25
25
25
25
25
25
25
25
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.2
0.1
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
6
6
6
6
6
6
6
2
1
0.5
1
2
2
2
2
2
2
2
2
33
67
72
73
92
85
93
95
99
67
88
94
68
99
62
81
98
86
52
Scheme 1. Synthetic route of the Ligand L1–5.
5
H2O
6c
Toluene/H2O
DMF/H2O
Acetone/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
EtOH/H2O
7c
reaction of phenylboronic acid with bromobenzene, at 60 °C, within
3 min, and under aerobic conditions, was examined. As shown in
Table 1, the data revealed that the β-ketoamines were effective
ligands for palladium-catalyzed Suzuki cross-coupling. For a compar-
ison, in the absence of ligands, only 45% yield of biphenyl was
produced in the presence of 0.5 mol% of PdCl2 (entry 1, Table 1).
However, when adding the ligands, the yield of product increased
dramatically, to a range of 77–91% (entries 2–5, Table 1), indicating
that the catalysts were formed in situ.
8c
9c
10c
11c
12c
13c
14c
15c
16c
17c
18c
19c
Among the β-ketoamines investigated, L1, with a phenyl backbone
and an aniline group, showed moderate efficiency and yielding the
coupling product at 77% (entry 2, Table 1). L2, with an anisole
backbone, was found to be a more efficient ligand and afforded the
coupling product in 81% yield (entry 3, Table 1). These results
suggested that the increase in the electron-donating properties of the
backbone positively affected catalytic ability. Significantly, L4 (where
a sterically-demanding and electron-donating phenyloxyl group was
substituted on the ortho aniline moiety) exhibited the highest activity.
In this case, the conversion of the biphenyl product reached 91%.
Comparatively, L5, with an electron-withdrawing nitro group on the
para position of the aniline, was less active under the same conditions
(78% yield). These results could be ascribed to the increase in
electron-donating ability of both the backbone and the aniline
moieties of the ligand, leading to an increase in the rate of oxidative
addition and the stabilization of the palladium species. Moreover, the
steric hindrance on the ligands could further facilitate reductive
elimination and facilitate cross-coupling [12].
Reaction conditions: bromobenzene (1.0 mmol), phenylboronic acid (1.2 mmol), Base
(2.0 mmol), solvent (6 ml).
a
The molar ratio of Ligand and Pd is 1:1.
Yield of biphenyl, determined by GC.
The mixture of cosolvent ratio (3 ml:3 ml).
b
c
(DMF), acetone and ethanol, provided the product in moderate yield
(entries 2–4, Table 2). Notably, the coupling reaction in pure water gave
a satisfactory yield of 92% without tetrabutylammonium bromide
(TBAB). Recently, the use of water as an environmentally friendly
solvent has received considerable attention for green chemistry [50].
Moreover, reaction activities were dramatically improved using
organic/water cosolvents (entries 6–9, Table 2). For instance, the
biphenyl product obtained in toluene/water resulted in a good yield
(85%), and a nearly quantitative conversion was obtained from the
reactions in ethanol/water and acetone/water. These observations
suggested that the cosolvent system played an important role in the
solubility of the reagents (such as inorganic bases) and the easier
reduction of Pd2+ to Pd(0), facilitating entry into the catalytic cycle
[51]. Although both ethanol/water and acetone/water solvent systems
provided excellent yields for the model reaction, ethanol/water was
chosen for further study because it was readily available, inexpensive
and had a higher efficiency.
With the preliminary results of the cross-coupling reaction in hand,
we performed optimization studies to determine how solvents, bases,
and temperature influenced the coupling reaction (Table 2). Initially,
the reactions were carried out in different solvents at a reaction
temperature of 60 °C, and the polarity of the solvent had a profound
effect. For instance, the nonpolar solvent toluene gave a poor yield
(33%), whereas the polar solvents, such as N, N-dimethylformamide
Based on the earlier results of the ethanol/water system, different
conditions were tested to optimize the reaction. As seen in Table 2,
excellent yields of the cross-coupling reaction were achieved at room
temperature within 2 h (entries 10–12), which further supported the
high efficiency of the β-ketoamines. Moreover, the base usually plays
an important role in Suzuki cross-coupling reactions because the
addition of bases exerts a remarkable accelerating effect on the
transmetalation between Ar–Pd–X and organoboronic acids [3,5].
Thus, several bases have been screened for their influence on the
catalytic system. The investigation suggested that K2CO3, with a mild
basicity, was the best choice. Notably, Na2CO3, which is usually an
effective base for Suzuki cross-couplings, proved to be less active.
Other bases, including K3PO4, KF, KOH, NaOMe, and NaOAc, gave
inferior results and showed slow reaction rates compared to K2CO3
(entries 13–19, Table 2). Although NaOH also worked, it was not
chosen because of its much stronger basicity. K2CO3 was thus found to
be the most effective base and was used in all subsequent reactions.
The improvement of the catalytic activity encouraged us to
examine the cross-coupling reactions of aryl bromide substrates as
well. As shown in Table 3, using K2CO3 as a base and ethanol/water as
Table 1
Screening of the ligands on Suzuki cross-coupling reaction.
Entry
X
Ligand
Pd (mol%)a
t (min)
Yield (%)b
1
2
3
4
5
6
Br
Br
Br
Br
Br
Br
None
L1
L2
L3
L4
0.5
0.5
0.5
0.5
0.5
0.5
3
3
3
3
3
3
45
77
81
83
91
78
L5
Reaction conditions: bromobenzene (1.0 mmol), phenylboronic acid (1.2 mmol),
Na2CO3 (2.0 mmol), EtOH/H2O (3 ml: 3 ml), at a temperature of 60 °C.
a
The molar ratio of Ligand and Pd is 1:1.
Yield of biphenyl, determined by GC.
b

Z.-Z. Zhou et al. / Inorganic Chemistry Communications 14 (2011) 659–662
661
Table 3
Suzuki cross-coupling reaction of aryl halides with phenylboronic acid under aerobic conditions.
Entry
1
Aryl bromide
Product
T (°C)
25
Pd (mol%)
0.01
t (h)
0.05
Yield (%)c
92
2
3
25
25
0.5
1
6
6
98
31
4
5
6
7
60
60
60
60
1
1
1
1
6
6
6
6
96
96
97
99
8
9
60
60
1
1
16
16
93
97
10
11
12
60
60
60
1
1
1
24
16
24
90
63
95
Reaction conditions: aryl bromides (1.0 mmol), phenylboronic acid (1.2 mmol), K2CO3 (2.0 mmol), EtOH/H2O (6 ml). aThe molar ratio of Ligand and Pd is 1:1. bYield of product
determined by GC. cThe reaction carried out under the nitrogen protection.
the solvent, high catalytic activity was observed in the coupling of
activated bromides with phenylboronic acid at room temperature
(entries 1–2, Table 3). Conversely, increasing electron density on the
aryl bromides lowered the activity at low reaction temperatures. For
instance, when the electronically deactivated 4-methylbromide was
employed at room temperature, only a 31% yield was obtained after
6 h (entry 3, Table 3). In contrast, an excellent conversion (96%) was
found at the elevated reaction temperature of 60 °C. Similar results
were also observed for 4-tertbutylbromide, 4-bromoanisole and
naphthylbromide (entries 5–7, Table 3). Substrates with ortho-methyl
and ortho-amino substituents, which retard both the oxidative
addition and transmetalation processes, were proven less active in
other catalytic systems [20,23], but could achieve high yield with
prolonged reaction time in this study (entries 8–10, Table 3).
Significantly, the sterically hindered substrate 2,4,6-trimethybro-
mombenzene afforded a satisfactory yield (95%) (entry 12, Table 3).
However, the catalytic system was less effective with substrates such
as aryl chlorides, even under harsh conditions.
In summary, a series of β-ketoamine ligands with different steric
and electronic substituents were synthesized and characterized. The
ligands were complexed to PdCl2 in situ and were successfully
employed in Suzuki cross-coupling reactions, under aerobic condi-
tions. Catalytic studies revealed that L4, with a sterically demanding
and electron-donating structure, was most efficient and enabled the
coupling of a wide variety of aryl bromides with phenylboronic acid in
high yields. Additional studies focused on the coupling of aryl
chlorides using β-ketoamine ligands are currently underway.
Acknowledgments
Financial support from the National Natural Science Foundation of
China (Projects 21004014) is gratefully acknowledged. We thank Prof.
Hua-Jun Fan for technical assistance with GC.
Appendix A. Supplementary material
Supplementary data to this article can be found online at
doi:10.1016/j.inoche.2011.01.044.
References
[1] F. Diederich de Meijer, 2nd ed, Metal-Catalyzed Cross-Coupling Reactions, Vol. 1
and 2, Wiely-VCH, Weinheim, Germany, 2004.
[2] S. Cacchi, G. Fabrizi, Chem. Rev. 105 (2005) 2873–2920.
[3] N. Miyaura, A. Suzuki, Chem. Rev. 95 (1995) 2457–2583.
[4] A. Suzuki, J. Organomet. Chem. 576 (1999) 147–168.
[5] A. Suzuki, Chem. Commun. (2005) 4759–4763.
[6] A.F. Littke, G.C. Fu, Angew. Chem. Int. Ed. 41 (2002) 4176–4211.
[7] N.T.S. Phan, M. Van Der Sluys, C.W. Jones, Adv. Synth. Catal. 348 (2006) 609–679.
[8] F. Alonso, I.P. Beletskaya, M. Yus, Tetrahedron 64 (2008) 3047–3101.
[9] V.F. Slagt, A.H.M. De Vries, J.G. De Vries, R.M. Kellogg, Org. Process Res. Dev. 14
(2010) 30–47.
[10] V. Polshettiwar, A. Decottignies, C. Len, A. Fihri, ChemSusChem 3 (2010) 502–522.
[11] J. Hassan, M. Sévignon, C. Gozzi, E. Schulz, M. Lemaire, Acc. Chem. Res. 40 (2007)
676–684.
[12] R. Martin, S.L. Buchwald, Acc. Chem. Res. 41 (2008) 1461–1473.
[13] G.C. Fu, Acc. Chem. Res. 41 (2008) 1555–1564.
[14] G.A. Molander, B. Canturk, Angew. Chem. Int. Ed. 48 (2009) 9240–9261.
[15] N. Marion, S.P. Nolan, Acc. Chem. Res. 41 (2008) 1440–1449.

662
Z.-Z. Zhou et al. / Inorganic Chemistry Communications 14 (2011) 659–662
[16] S. Würtz, F. Glorius, Acc. Chem. Res. 41 (2008) 1523–1533.
[17] C. Mazet, L.H. Gade, Organometallics 20 (2001) 4144–4146.
[18] D.-H. Lee, Y.H. Lee, D.I. Kim, Y. Kim, W.T. Lim, J.M. Harrowfield, P. Thuéry, M.-J. Jin,
Y.C. Park, I.-M. Lee, Tetrahedron 64 (2008) 7178–7182.
[43] R.-C. Yu, C.-H. Hung, J.-H. Huang, H.-Y. Lee, J.-T. Chen, Inorg. Chem. 41 (2002)
6450–6455.
[44] B. Al-Saleh, M.A. EI-Apasery, R.S. Abdel-Aziz, M.H. Elnagdi, J. Heterocycl. Chem. 42
(2005) 563–566.
[19] P.R. Kumar, S. Upreti, A.K. Singh, Polyhderon 27 (2008) 1610–1622.
[20] S.A. Patil, C.-M. Weng, P.-C. Huang, F.-E. Hong, Tetrahedron 65 (2009) 2889–2897.
[21] G.A. Grasa, A.C. Hillier, S.P. Nolan, Org. Lett. 3 (2001) 1077–1080.
[22] C. Nájera, J. Gil-Moltό, S. Karlström, L.R. Falvello, Org. Lett. 5 (2003) 1451–1454.
[23] D. Domin, D. Benito-Garagorri, K. Mereiter, J. Fröhlich, K. Kirchner, Organome-
tallics 24 (2005) 3957–3965.
[24] S. Mohanty, B. Punji, M.S. Balakrishna, Polyhedron 25 (2006) 815–820.
[25] S. Li, Y. Lin, J. Cao, S. Zhang, J. Org. Chem. 72 (2007) 4067–4072.
[26] J.M. Chitanda, D.E. Prokopchuk, J.W. Quail, S.R. Foley, Organometallics 27 (2008)
2337–2345.
[27] A. Bermejo, A. Ros, R. Fernández, J.M. Lassaletta, J. Am. Chem. Soc. 130 (2008)
15798–15799.
[28] J. Yorke, C. Dent, A. Decken, A. Xia, Inorg. Chem. Commun. 13 (2010) 54–57.
[29] S. Gülcemal, İ. Kani, F. Yılmaz, B. Çetinkaya, Tetrahedron 66 (2010) 5602–5606.
[30] D. Mingji, B. Liang, C. Wang, Z. You, J. Xiang, G. Dong, J. Chen, Z. Yang, Adv. Synth.
Catal. 346 (2004) 1669–1673.
[45] K. Chanda, M.C. Dutta, E. Karim, J.N. Vishwakarma, J. Heterocycl. Chem. 41 (2004)
627–631.
[46] Y. Li, L. Tang, Y. Duan, X. Chen, Y. Li, J. Liu, G. Zhang, CN Pat. 1850869.
[47] G.D. Scott, US Pat. 2009163545.
[48] J. Deng, D. Shen, Z. Zhou, Acta Cryst. E66 (2010) o2.
[49] The β-ketoamine ligands L1–3 were synthesized by the following procedures. A
solution of enaminone (10 mmol) and the related substituted aniline (12 mmol)
were dissolved in ethanol (20 ml), with the formic acid as catalyst. The mixture
was heated under reflux for 6 hours. As for L4–5, the reaction carried out in the
presence of 20 ml glacial acetic acid instead of ethanol. After recrystallization from
the methanol, the crystals were obtained. L1–2 have been well characterized by
the literatures, however, the analysis data of L3 and L5 was absent. L3: yellow
crystals in 92% yield; 1H NMR (CDCl3, 500 MHz): 12.11 (d, J= 12.6 Hz, 1H, NH),
7.92 (d, J= 8.4 Hz, 2H, Ar-H), 7.40 (m, 1H, CH=), 7.02 (m, 2H, Ar-H), 6.95 (m, 2H,
Ar-H), 6.89 (m, 2H, Ar-H), 5.94 (d, J= 10 Hz, 1H, CH=), 3.81 (s, 3H, OCH3), 3.80 (s,
3H, OCH3).13C NMR (CDCl3, 125 MHz): 189.65, 162.33, 156.20, 145.27, 134.01,
132.11, 129.21, 117.76, 114.99, 113.62, 92.61, 55.89, 55.39. Anal. Calc. for
[31] W. Chen, R. Li, B. Han, B.-J. Li, Y.-C. Chen, Y. Wu, L.-S. Ding, D. Yang, Eur. J. Org.
Chem. (2006) 1177–1184.
C
17H17NO3: C, 72.07; H, 6.05; N, 4.94. Found: C, 71.95; H, 6.10; N, 4.87. L4:
[32] X. Guo, J. Zhou, X. Li, H. Sun, J. Organomet. Chem. 693 (2008) 3692–3696.
[33] D.F. Brayton, T.M. Larkin, D.A. Vicic, O. Navarro, J. Organomet. Chem. 694 (2009)
3008–3011.
[34] J. Cui, M. Zhang, Y. Wang, Z. Li, Inorg. Chem. Commun. 12 (2009) 839–841.
[35] J. Cui, M. Zhang, Y. Zhan, Inorg. Chem. Commun. 13 (2010) 81–85.
[36] Y.-Y. Peng, J. Liu, X. Lei, Z. Yin, Green Chem. 12 (2010) 1072–1075.
[37] A. Kilic, D. Kilinc, E. Tas, I. Yilmaz, M. Durgun, I. Ozdemir, S. Yasar, J. Organomet.
Chem. 695 (2010) 697–706.
[38] Y.-C. Lai, H.-Y. Chen, W.-C. Hung, C.-C. Lin, F.-E. Hong, Tetrahedron 61 (2005)
9484–9489.
[39] D.-H. Lee, J.-Y. Jung, I.-M. Lee, M.-J. Jin, Eur. J. Org. Chem. (2008) 356–360.
[40] D.-H. Lee, M. Choi, B.-W. Yu, R. Ryoo, A. Taher, S. Hossain, M.-J. Jin, Adv. Synth.
Catal. 351 (2009) 2912–2920.
flavo-green crystals in 73% yield; 1H NMR (CDCl3, 500 MHz): 12.22 (d, J=12 Hz,
1H, NH), 7.94 (d, J=9 Hz, 2H, Ar-H), 7.55 (m, 1H, CH=), 7.39 (m, 2H, Ar-H), 7.29
(m, H, Ar-H), 7.15 (m, 2H, Ar-H), 7.14 (m, 2H, Ar-H), 7.00-6.90 (m, 4H, Ar-H), 6.05
(d, J= 9 Hz, 1H, CH=), 3.89 (s, 3H, OCH3).13C NMR (CDCl3, 125 MHz): 190.12,
162.59, 156.69, 146.46, 143.15, 132.34, 132.30, 130.00, 129.63, 124.09, 124.03,
123.32, 119.51, 118.86, 114.52, 113.76, 94.58, 55.58. Anal. Calc. For C22H19NO3: C,
76.50; H, 5.54; N, 4.06; Found: C, 76.34; H, 5.62; N, 4.01. L5: yellow crystals in 61%
yield; 1H NMR (CDCl3, 500 MHz): 12.24 (d, J=12 Hz, 1H, NH), 8.24 (d, J=7 Hz, 2H,
Ar-H), 7.95 (m, 1H, CH=), 7.48 (m, 2H, Ar-H), 7.13 (m, 2H, Ar-H), 6.97 (m, 2H, Ar-
H), 6.16 (d, J=8 Hz, 1H, CH=), 3.89 (s, 3H, OCH3).13C NMR (CDCl3, 125 MHz):
191.45, 162.67, 145.50, 142.16, 141.13, 130.74, 129.27, 129.27, 125.61, 114.57,
113.40, 96.34, 55.01. Anal. Calc. For C16H14N2O4: C, 64.42; H, 4.73; N, 9.39; Found:
C, 64.35; H, 4.64; N, 9.33.
[41] M.-J. Jin, D.-H. Lee, Angew. Chem. Int. Ed. 49 (2010) 1119–1122.
[42] X.-H. He, Y.-Z. Yao, J.-K. Zhang, Y.-H. Liu, L. Zhang, Q. Wu, Organometallics 22
(2003) 4952–4957.
[50] C.-J. Li, Chem. Rev. 105 (2005) 3095–3166.
[51] S.W. Kim, J.N. Park, Y.J. Jang, Y.H. Chung, S.J.H. Wang, T. Hyeon, Nano Lett. 3 (2003)
1289–1291.