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Acta Cryst. (2009). E65, m131-m132    [ doi:10.1107/S160053680804381X ]

Tetrakis(2,2'-bipyridyl)dichloridodi-[mu]3-hydroxido-di-[mu]2-hydroxido-tetracopper(II) dinitrate hexahydrate

Y. Fan, Y.-T. Cui, H.-F. Qian, J.-L. Liu and W. Huang

Abstract top

The tetranuclear copper(II) title complex, [Cu4Cl2(OH)4(C10H8N2)4](NO3)2·6H2O, has a crystallographically imposed centre of symmetry. The metal atoms display a distorted tetragonal-pyramidal coordination geometry, and are linked by two [mu]2- and two [mu]3-hydroxo groups, assuming a chair-like conformation for the Cu4O2 core. In the crystal, the complex molecules are linked into a three-dimensional network by intermolecular O-H...O, O-H...Cl, C-H...O and C-H...Cl hydrogen bonds and [pi]-[pi] stacking interactions with centroid-centroid separations of 3.724 (2) and 3.767 (3) Å.

Comment top

Recently, some tetranuclear hydroxo-bridged copper(II) complexes with cubane and the chair-like structure have been reported (Zheng & Lin, 2002; Sletten et al., 1990; Albada et al., 2002; Lu et al., 2007; Chandrasekhar et al., 2000). In this paper, the crystal structure of a new copper(II) complex exhibiting a chair-like tetranuclear motif is presented.

The atom-numbering scheme of the title compound is shown in Fig. 1, while selected bond distances are given in Table 1. The title complex has a crystallographically imposed centre of symmetry, and consists of a chair-like [Cu4(bpy)4(µ2-OH)2(µ3-OH)2Cl2]2+ dication (bpy = 2,2'-bipyridine), two nitrate anions, and six lattice water molecules. The coordination geometry around each copper(II) ion can be described as a five-coordinate distorted pyramid. The basal sites are occupied by two N atoms from a bpy ligand and two O atoms from two µ2-bridging hydroxo groups, with mean Cu–N and Cu–O bond distances of 2.011 (4) 1.948 (3) Å, respectively; the apical position is occupied by a chloride anion for atom Cu1 (Cu1–Cl1 = 2.594 (2) Å) and a µ3-bridged OH anion for Cu2 (Cu2–O1i = 2.323 (3) Å; symmetry code: (i) = 1-x, 1-y, -z).

In the crystal packing, the complex molecules are linked into a three-dimensional network by intra- and intermolecular O—H···O, O—H···Cl, C—H···O and C—H···Cl hydrogen bonding interactions involving the solvent water molecules, the hydroxo groups and the chloride and nitrate anions (Table 2). The structure is further stabilized by π–π stacking interactions between adjacent bpy molecules with centroid-to-centroid separations of 3.724 (2) and 3.767 (3) Å (Fig. 2).

Related literature top

For the structures of related complexes, see: Albada et al. (2002); Chandrasekhar et al. (2000); Lu et al. (2007); Sletten et al. (1990); Zheng et al. (2002).

Experimental top

The title compound was obtained as a by-product from the reaction between [Cu(bpy)](NO3)2 (0.398 g, 1 mmol) and D-(+)-1,2,2-trimethylcyclopentane-1,3-diamine dihydrogenchloride salt (0.284 g, 2 mmol) in the presence of NaOH (0.080 g, 2 mmol). Yield: 35 % based on the copper(II) amount. Single crystals suitable for X-ray diffraction were grown from a mixture of methanol/water (1:1 v/v) by slow evaporation in air at room temperature. Elemental Analysis: Calcd. for C40H48Cl2Cu4N10O16: C, 38.44; H, 3.87; N, 11.21 %; found: C,38.66; H,3.67; N, 11.03 %. Main FT-IR absorptions (KBr pellets, cm-1): 3427 (vs), 2372 (m), 2341 (m), 1634 (s), 1383 (m), 1080 (s), 991 (m), 773 (m), and 549 (m).

Refinement top

All H atoms were placed in geometrically idealized positions and refined as riding, with C—H = 0.93 Å, O—H = 0.85 Å, and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(O).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Unlabeled atoms are related to the labeled atoms by (1-x, 1-y, -z).
[Figure 2] Fig. 2. Perspective view of the crystal packing the title compound showing the the hydrogen bonds and π–π stacking interactions as dashed lines.
Tetrakis(2,2'-bipyridyl)dichloridodi-µ3-hydroxido-di-µ2-hydroxido- tetracopper(II) dinitrate hexahydrate top
Crystal data top
[Cu4Cl2(OH)4(C10H8N2)4](NO3)2·6H2OZ = 1
Mr = 1249.94F(000) = 636
Triclinic, P1Dx = 1.728 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 9.389 (3) ÅCell parameters from 2700 reflections
b = 10.622 (3) Åθ = 2.3–27.2°
c = 12.950 (4) ŵ = 1.94 mm−1
α = 86.909 (4)°T = 291 K
β = 77.263 (3)°Block, blue
γ = 72.512 (4)°0.16 × 0.12 × 0.10 mm
V = 1201.4 (6) Å3
Data collection top
Bruker SMART CCD area-detector
diffractometer		4181 independent reflections
Radiation source: fine-focus sealed tube3156 reflections with I > 2σ(I)
graphiteRint = 0.025
φ and ω scansθmax = 25.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2000)		h = −10→11
Tmin = 0.747, Tmax = 0.830k = −12→12
6088 measured reflectionsl = −15→13
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.047Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.153H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0958P)2]
where P = (Fo2 + 2Fc2)/3
4181 reflections(Δ/σ)max < 0.001
319 parametersΔρmax = 0.94 e Å−3
0 restraintsΔρmin = −1.04 e Å−3
Crystal data top
[Cu4Cl2(OH)4(C10H8N2)4](NO3)2·6H2Oγ = 72.512 (4)°
Mr = 1249.94V = 1201.4 (6) Å3
Triclinic, P1Z = 1
a = 9.389 (3) ÅMo Kα radiation
b = 10.622 (3) ŵ = 1.94 mm−1
c = 12.950 (4) ÅT = 291 K
α = 86.909 (4)°0.16 × 0.12 × 0.10 mm
β = 77.263 (3)°
Data collection top
Bruker SMART CCD area-detector
diffractometer		4181 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2000)		3156 reflections with I > 2σ(I)
Tmin = 0.747, Tmax = 0.830Rint = 0.025
6088 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.047H-atom parameters constrained
wR(F2) = 0.153Δρmax = 0.94 e Å−3
S = 1.08Δρmin = −1.04 e Å−3
4181 reflectionsAbsolute structure: ?
319 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. The structure was solved by direct methods (Bruker, 2000) and successive difference Fourier syntheses.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.46249 (6)0.44695 (6)0.22215 (4)0.03567 (19)
Cu20.36457 (6)0.43378 (5)0.02528 (4)0.03328 (18)
C10.6144 (5)0.5218 (5)0.3666 (3)0.0348 (10)
C20.6642 (6)0.5990 (6)0.4245 (4)0.0490 (13)
H20.72940.56030.46960.059*
C30.6160 (7)0.7337 (6)0.4146 (4)0.0528 (14)
H30.64910.78720.45260.063*
C40.5183 (6)0.7893 (6)0.3479 (4)0.0509 (13)
H40.48270.88040.34140.061*
C50.4755 (6)0.7075 (5)0.2917 (4)0.0453 (12)
H50.41160.74470.24550.054*
C60.6549 (5)0.3764 (5)0.3726 (3)0.0366 (11)
C70.7526 (6)0.3022 (6)0.4334 (4)0.0507 (13)
H70.79740.34240.47400.061*
C80.7825 (7)0.1664 (6)0.4324 (5)0.0602 (15)
H80.84850.11430.47250.072*
C90.7158 (7)0.1094 (6)0.3732 (4)0.0547 (14)
H90.73480.01830.37240.066*
C100.6195 (6)0.1888 (5)0.3144 (4)0.0458 (12)
H100.57340.15000.27370.055*
C110.1473 (5)0.5060 (5)−0.1073 (4)0.0372 (11)
C120.0421 (6)0.5816 (6)−0.1627 (4)0.0481 (13)
H12−0.00760.5418−0.19970.058*
C130.0117 (6)0.7171 (6)−0.1622 (4)0.0537 (14)
H13−0.05960.7695−0.19850.064*
C140.0865 (6)0.7741 (6)−0.1082 (4)0.0499 (13)
H140.06700.8653−0.10720.060*
C150.1916 (6)0.6937 (5)−0.0553 (4)0.0432 (12)
H150.24420.7321−0.01980.052*
C160.1902 (5)0.3603 (5)−0.1028 (3)0.0350 (10)
C170.1309 (6)0.2829 (6)−0.1531 (4)0.0474 (13)
H170.05680.3218−0.19180.057*
C180.1819 (6)0.1486 (6)−0.1455 (4)0.0518 (14)
H180.14220.0953−0.17850.062*
C190.2941 (6)0.0924 (5)−0.0878 (4)0.0507 (13)
H190.33140.0012−0.08240.061*
C200.3483 (6)0.1740 (5)−0.0393 (4)0.0448 (12)
H200.42280.1365−0.00070.054*
Cl10.18510 (17)0.49867 (15)0.33336 (11)0.059
N10.5207 (4)0.5767 (4)0.3000 (3)0.0360 (9)
N20.5897 (4)0.3206 (4)0.3135 (3)0.0372 (9)
N30.2209 (4)0.5615 (4)−0.0532 (3)0.0351 (9)
N40.2985 (4)0.3057 (4)−0.0451 (3)0.0362 (9)
N50.1809 (5)0.8933 (4)0.1658 (4)0.0347 (10)
O10.4182 (4)0.5621 (3)0.1006 (2)0.0344 (7)
H1A0.33050.61400.12710.052*
O20.4539 (4)0.3165 (3)0.1278 (2)0.0408 (8)
H2A0.48210.23270.13020.061*
O30.0821 (8)0.9740 (6)0.2427 (6)0.130 (2)
O40.1649 (6)0.7823 (6)0.1809 (5)0.1076 (18)
O50.2665 (11)0.9185 (7)0.1204 (6)0.140 (3)
O60.3529 (6)0.1021 (5)0.2300 (4)0.0985 (17)
H6A0.38470.01860.22230.148*
H6B0.29230.12040.18760.148*
O70.8224 (8)0.7897 (8)0.5938 (5)0.156 (3)
H7A0.84450.74490.53700.235*
H7B0.75210.76590.63570.235*
O8−0.0164 (7)0.7957 (7)0.3929 (5)0.124 (2)
H8A0.01250.71200.38710.185*
H8B0.06060.82440.37410.185*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0413 (4)0.0418 (4)0.0281 (3)−0.0113 (3)−0.0174 (2)0.0003 (2)
Cu20.0359 (3)0.0396 (3)0.0297 (3)−0.0123 (3)−0.0165 (2)0.0008 (2)
C10.033 (2)0.051 (3)0.026 (2)−0.017 (2)−0.0108 (18)0.001 (2)
C20.053 (3)0.068 (4)0.036 (3)−0.023 (3)−0.023 (2)0.002 (2)
C30.066 (4)0.063 (4)0.044 (3)−0.032 (3)−0.022 (3)−0.002 (3)
C40.060 (3)0.049 (3)0.048 (3)−0.019 (3)−0.015 (3)0.000 (2)
C50.045 (3)0.050 (3)0.043 (3)−0.009 (2)−0.020 (2)−0.002 (2)
C60.032 (2)0.048 (3)0.028 (2)−0.006 (2)−0.0087 (19)0.000 (2)
C70.051 (3)0.061 (4)0.046 (3)−0.014 (3)−0.028 (3)0.004 (3)
C80.054 (4)0.067 (4)0.056 (4)−0.003 (3)−0.030 (3)0.014 (3)
C90.062 (4)0.047 (3)0.053 (3)−0.007 (3)−0.022 (3)0.007 (3)
C100.051 (3)0.044 (3)0.040 (3)−0.006 (2)−0.015 (2)−0.007 (2)
C110.028 (2)0.051 (3)0.031 (2)−0.009 (2)−0.0067 (19)0.000 (2)
C120.036 (3)0.071 (4)0.041 (3)−0.016 (3)−0.019 (2)0.005 (3)
C130.040 (3)0.062 (4)0.053 (3)0.000 (3)−0.020 (2)0.014 (3)
C140.049 (3)0.047 (3)0.052 (3)−0.008 (3)−0.017 (2)0.009 (2)
C150.046 (3)0.045 (3)0.036 (3)−0.009 (2)−0.011 (2)0.002 (2)
C160.029 (2)0.049 (3)0.029 (2)−0.015 (2)−0.0062 (18)0.000 (2)
C170.044 (3)0.065 (4)0.042 (3)−0.023 (3)−0.015 (2)−0.006 (3)
C180.053 (3)0.061 (4)0.053 (3)−0.028 (3)−0.016 (3)−0.010 (3)
C190.062 (4)0.043 (3)0.052 (3)−0.019 (3)−0.016 (3)−0.003 (2)
C200.044 (3)0.046 (3)0.044 (3)−0.008 (2)−0.015 (2)−0.001 (2)
Cl10.0590.0670.055−0.021−0.019−0.008
N10.039 (2)0.041 (2)0.031 (2)−0.0119 (18)−0.0130 (16)0.0004 (17)
N20.036 (2)0.046 (2)0.029 (2)−0.0080 (18)−0.0118 (16)−0.0009 (17)
N30.030 (2)0.045 (2)0.032 (2)−0.0100 (18)−0.0110 (16)−0.0012 (17)
N40.037 (2)0.042 (2)0.033 (2)−0.0127 (18)−0.0127 (17)0.0019 (17)
N50.029 (2)0.0156 (19)0.066 (3)−0.0057 (17)−0.026 (2)0.0040 (19)
O10.0386 (18)0.0388 (18)0.0292 (16)−0.0108 (14)−0.0145 (13)−0.0016 (13)
O20.053 (2)0.0387 (19)0.0348 (18)−0.0112 (16)−0.0226 (15)0.0014 (14)
O30.139 (6)0.086 (4)0.152 (6)−0.031 (4)−0.007 (5)−0.010 (4)
O40.085 (4)0.118 (5)0.110 (5)−0.015 (3)−0.019 (3)−0.019 (4)
O50.184 (8)0.117 (6)0.110 (6)−0.033 (6)−0.031 (5)0.004 (4)
O60.088 (4)0.093 (4)0.132 (5)−0.043 (3)−0.046 (3)0.039 (3)
O70.159 (6)0.232 (9)0.119 (5)−0.129 (6)−0.004 (5)−0.040 (5)
O80.112 (5)0.149 (6)0.101 (5)−0.018 (4)−0.031 (4)−0.008 (4)
Geometric parameters (Å, °) top
Cu1—O21.927 (3)C11—C121.382 (7)
Cu1—O11.980 (3)C11—C161.479 (7)
Cu1—N12.016 (4)C12—C131.381 (8)
Cu1—N22.029 (4)C12—H120.9300
Cu1—Cl12.5942 (17)C13—C141.366 (8)
Cu2—O21.924 (3)C13—H130.9300
Cu2—O11.959 (3)C14—C151.379 (7)
Cu2—N41.989 (4)C14—H140.9300
Cu2—N32.012 (4)C15—N31.347 (6)
Cu2—O1i2.323 (3)C15—H150.9300
C1—N11.352 (5)C16—N41.364 (6)
C1—C21.380 (6)C16—C171.380 (6)
C1—C61.478 (7)C17—C181.367 (8)
C2—C31.373 (8)C17—H170.9300
C2—H20.9300C18—C191.396 (7)
C3—C41.381 (7)C18—H180.9300
C3—H30.9300C19—C201.367 (7)
C4—C51.361 (7)C19—H190.9300
C4—H40.9300C20—N41.338 (6)
C5—N11.331 (6)C20—H200.9300
C5—H50.9300N5—O50.983 (8)
C6—N21.336 (6)N5—O41.233 (7)
C6—C71.378 (7)N5—O31.339 (7)
C7—C81.384 (8)O1—Cu2i2.323 (3)
C7—H70.9300O1—H1A0.8500
C8—C91.357 (8)O2—H2A0.8501
C8—H80.9300O6—H6A0.8501
C9—C101.373 (7)O6—H6B0.8498
C9—H90.9300O7—H7A0.8499
C10—N21.342 (6)O7—H7B0.8501
C10—H100.9300O8—H8A0.8499
C11—N31.349 (6)O8—H8B0.8500
O2—Cu1—O181.23 (13)C13—C12—H12120.5
O2—Cu1—N1166.66 (15)C11—C12—H12120.5
O1—Cu1—N196.22 (14)C14—C13—C12119.9 (5)
O2—Cu1—N297.19 (15)C14—C13—H13120.1
O1—Cu1—N2157.97 (15)C12—C13—H13120.1
N1—Cu1—N280.23 (15)C13—C14—C15118.6 (5)
O2—Cu1—Cl198.14 (11)C13—C14—H14120.7
O1—Cu1—Cl198.03 (10)C15—C14—H14120.7
N1—Cu1—Cl195.17 (12)N3—C15—C14122.5 (5)
N2—Cu1—Cl1103.92 (11)N3—C15—H15118.8
O2—Cu2—O181.86 (13)C14—C15—H15118.8
O2—Cu2—N497.99 (15)N4—C16—C17121.4 (5)
O1—Cu2—N4176.65 (14)N4—C16—C11114.1 (4)
O2—Cu2—N3165.08 (15)C17—C16—C11124.5 (4)
O1—Cu2—N398.37 (14)C18—C17—C16119.4 (5)
N4—Cu2—N380.91 (15)C18—C17—H17120.3
O2—Cu2—O1i100.99 (13)C16—C17—H17120.3
O1—Cu2—O1i83.97 (12)C17—C18—C19119.3 (5)
N4—Cu2—O1i99.33 (13)C17—C18—H18120.3
N3—Cu2—O1i93.86 (13)C19—C18—H18120.3
N1—C1—C2121.1 (5)C20—C19—C18118.6 (5)
N1—C1—C6114.9 (4)C20—C19—H19120.7
C2—C1—C6124.0 (4)C18—C19—H19120.7
C3—C2—C1119.0 (5)N4—C20—C19122.8 (5)
C3—C2—H2120.5N4—C20—H20118.6
C1—C2—H2120.5C19—C20—H20118.6
C2—C3—C4119.6 (5)C5—N1—C1118.9 (4)
C2—C3—H3120.2C5—N1—Cu1126.2 (3)
C4—C3—H3120.2C1—N1—Cu1114.9 (3)
C5—C4—C3118.4 (5)C6—N2—C10118.9 (4)
C5—C4—H4120.8C6—N2—Cu1115.1 (3)
C3—C4—H4120.8C10—N2—Cu1125.9 (3)
N1—C5—C4123.0 (5)C15—N3—C11118.5 (4)
N1—C5—H5118.5C15—N3—Cu2126.6 (3)
C4—C5—H5118.5C11—N3—Cu2114.9 (3)
N2—C6—C7121.8 (5)C20—N4—C16118.4 (4)
N2—C6—C1114.7 (4)C20—N4—Cu2126.2 (3)
C7—C6—C1123.5 (4)C16—N4—Cu2115.4 (3)
C6—C7—C8118.4 (5)O5—N5—O4128.5 (7)
C6—C7—H7120.8O5—N5—O3121.4 (6)
C8—C7—H7120.8O4—N5—O3108.1 (5)
C9—C8—C7120.1 (5)Cu2—O1—Cu195.59 (13)
C9—C8—H8119.9Cu2—O1—Cu2i96.03 (12)
C7—C8—H8119.9Cu1—O1—Cu2i113.66 (14)
C8—C9—C10118.7 (5)Cu2—O1—H1A101.5
C8—C9—H9120.7Cu1—O1—H1A101.5
C10—C9—H9120.7Cu2i—O1—H1A138.7
N2—C10—C9122.2 (5)Cu2—O2—Cu198.51 (15)
N2—C10—H10118.9Cu2—O2—H2A130.7
C9—C10—H10118.9Cu1—O2—H2A130.8
N3—C11—C12121.5 (5)H6A—O6—H6B99.3
N3—C11—C16114.6 (4)H7A—O7—H7B106.7
C12—C11—C16123.9 (4)H8A—O8—H8B109.5
C13—C12—C11119.0 (5)
Symmetry codes: (i) −x+1, −y+1, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O40.852.022.835 (7)160
O2—H2A···O60.852.282.874 (6)127
O7—H7A···O8ii0.852.172.714 (9)121
O8—H8A···Cl10.852.393.187 (7)157
C2—H2···Cl1iii0.932.823.692 (5)156
C5—H5···O40.932.553.394 (7)152
C10—H10···O60.932.463.318 (7)154
C12—H12···Cl1iv0.932.783.679 (5)162
C15—H15···O40.932.583.185 (8)123
Symmetry codes: (ii) x+1, y, z; (iii) −x+1, −y+1, −z+1; (iv) −x, −y+1, −z.
Table 1
Selected geometric parameters (Å) top
Cu1—O21.927 (3)Cu2—O21.924 (3)
Cu1—O11.980 (3)Cu2—O11.959 (3)
Cu1—N12.016 (4)Cu2—N41.989 (4)
Cu1—N22.029 (4)Cu2—N32.012 (4)
Cu1—Cl12.5942 (17)Cu2—O1i2.323 (3)
Symmetry codes: (i) −x+1, −y+1, −z.
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O40.852.022.835 (7)160
O2—H2A···O60.852.282.874 (6)127
O7—H7A···O8ii0.852.172.714 (9)121
O8—H8A···Cl10.852.393.187 (7)157
C2—H2···Cl1iii0.932.823.692 (5)156
C5—H5···O40.932.553.394 (7)152
C10—H10···O60.932.463.318 (7)154
C12—H12···Cl1iv0.932.783.679 (5)162
C15—H15···O40.932.583.185 (8)123
Symmetry codes: (ii) x+1, y, z; (iii) −x+1, −y+1, −z+1; (iv) −x, −y+1, −z.
Acknowledgements top

WH acknowledges the National Natural Science Foundation of China (No. 20871065) and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry, for financial aid.

references
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