organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

2,3-Bis(4-bromo­phen­yl)quinoxaline

aNew Materials and Function Coordination Chemistry Laboratory, Qingdao University of Science and Technology, Qingdao 266042, People's Republic of China
*Correspondence e-mail: ffj2003@163169.net

(Received 23 October 2007; accepted 1 November 2007; online 6 December 2007)

The title compound, C20H12Br2N2, was prepared by the reaction of 1-(3-bromo­phen­yl)-2-(4-bromo­phen­yl)ethane-1,2-dione with o-phenyl­enediamine in refluxing ethanol. In the mol­ecule, all bond lengths and angles are within normal ranges. The dihedral angle between the two benzene rings is 34.89 (1)°. The dihedral angles between the benzene rings and the quinoxaline system are 57.23 (1) and 36.75 (1)°. The crystal packing is stabilized by van der Waals forces.

Related literature

For related literature, see: Brock et al. (1999[Brock, E. D., Lewis, D. M., Yousaf, T. I. & Harper, H. H. (1999). (The Procter & Gamble Company, USA.) World Patent WO 9 951 688.]); Dailey et al. (2001[Dailey, S., Feast, J. W., Peace, R. J., Sage, I. C., Till, S. & Wood, E. L. (2001). J. Mater. Chem. 11, 2238-2243.]); Guillon et al. (1998[Guillon, J., Dallemagne, P., Pfeiffer, B., Renard, P., Manechez, D., Kervran, A. & Rault, S. (1998). Eur. J. Med. Chem. 33, 293-308.]); Kim et al. (1993[Kim, K. S., Qian, L., Bird, J. E., Dickinson, K. E. J., Moreland, S., Schaeffer, T. R., Waldron, T. L., Delaney, C. L., Weller, H. N. & Miller, A. V. (1993). J. Med. Chem. 36, 2335-2342.]); Patel et al. (2000[Patel, M., Mc, H. R., Cordova, B. C., Klabe, R. M., Erickson, V. S., Trainor, G. L. & Rodgers, J. D. (2000). Bioorg. Med. Chem. Lett. 10, 1729-1731.]); Rong et al. (2006[Rong, L.-C., Li, X.-Y., Yao, C.-S., Wang, H.-Y. & Shi, D.-Q. (2006). Acta Cryst. E62, o1959-o1960.]).

[Scheme 1]

Experimental

Crystal data
  • C20H12Br2N2

  • Mr = 440.14

  • Triclinic, [P \overline 1]

  • a = 6.0830 (12) Å

  • b = 12.018 (2) Å

  • c = 12.323 (3) Å

  • α = 105.47 (3)°

  • β = 91.89 (3)°

  • γ = 97.47 (3)°

  • V = 858.7 (3) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 4.72 mm−1

  • T = 293 (2) K

  • 0.20 × 0.18 × 0.15 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.404, Tmax = 0.492

  • 3338 measured reflections

  • 2888 independent reflections

  • 1824 reflections with I > 2σ(I)

  • Rint = 0.027

  • 3 standard reflections every 100 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.128

  • S = 1.06

  • 2888 reflections

  • 217 parameters

  • H-atom parameters constrained

  • Δρmax = 0.56 e Å−3

  • Δρmin = −0.74 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: NRCVAX (Gabe et al., 1989[Gabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384-387.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.]); molecular graphics: SHELXTL/PC (Sheldrick, 1990[Sheldrick, G. M. (1990). SHELXTL/PC. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Quinoxaline derivatives are an important class of nitrogen containing heterocycles and constitute useful intermediates in organic synthesis which have been reported for their applications in the fields of dyes (Brock et al., 1999) and have also been used as building blocks for the synthesis of organic semiconductors (Dailey et al., 2001). Tetrahydroquinoxaline derivatives are important from a therapeutic point of view since promising anti HIV agents (Patel et al., 2000), glucogen receptor antagonists (Guillon et al., 1998) and angiotens in receptor antagonists (Kim et al., 1993) possess this ring system. The title compound (I) was synthesized as part of our study of these ligands. Here we report the crystal structure of (I).

The structure of (I) is represented in Fig. 1. The bond lengths and angles are usual for this type of compound (Rong et al., 2006). The mean planes p1(C1 - C6) and p2 (N1,N2,C7 - C14) make a dihedral angle of 57.23 (1)°. The dihedral angles formed by phenyl ring(C8 –C13) and phenyl ring (C15 - C20) with p1 are 55.48 (1) and 64.80 (1)°, respectively. The dihedral angles between the benzene rings is 34.89 (1)°. The crystal packing (Fig. 2) is stabilized by van der Waals forces.

Related literature top

For related literature, see: Brock et al. (1999); Dailey et al. (2001); Guillon et al. (1998); Kim et al. (1993); Patel et al. (2000); Rong et al. (2006).

Experimental top

A mixture of 1-(3-bromophenyl)-2-(4-bromophenyl)ethane-1,2-dione (5.77 g, 0.02 mol) and o-phenylene diamine (2.16 g, 0.02 mol) was stirred in refluxing ethanol (30 ml) for 5 h to afford the title compound (3.25 g, yield 74%). Single crystals suitable for X-ray measurements were obtained by recrystallization from THF at room temperature.

Refinement top

H atoms were fixed geometrically and allowed to ride on their parent atoms, with N—H and C—H distances of 0.86 and 0.93–0.96 Å, respectively, and with Uiso=1.2–1.5Ueq of the parent atoms.

Structure description top

Quinoxaline derivatives are an important class of nitrogen containing heterocycles and constitute useful intermediates in organic synthesis which have been reported for their applications in the fields of dyes (Brock et al., 1999) and have also been used as building blocks for the synthesis of organic semiconductors (Dailey et al., 2001). Tetrahydroquinoxaline derivatives are important from a therapeutic point of view since promising anti HIV agents (Patel et al., 2000), glucogen receptor antagonists (Guillon et al., 1998) and angiotens in receptor antagonists (Kim et al., 1993) possess this ring system. The title compound (I) was synthesized as part of our study of these ligands. Here we report the crystal structure of (I).

The structure of (I) is represented in Fig. 1. The bond lengths and angles are usual for this type of compound (Rong et al., 2006). The mean planes p1(C1 - C6) and p2 (N1,N2,C7 - C14) make a dihedral angle of 57.23 (1)°. The dihedral angles formed by phenyl ring(C8 –C13) and phenyl ring (C15 - C20) with p1 are 55.48 (1) and 64.80 (1)°, respectively. The dihedral angles between the benzene rings is 34.89 (1)°. The crystal packing (Fig. 2) is stabilized by van der Waals forces.

For related literature, see: Brock et al. (1999); Dailey et al. (2001); Guillon et al. (1998); Kim et al. (1993); Patel et al. (2000); Rong et al. (2006).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: NRCVAX (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick, 1990); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure and atom-labeling scheme for (I), with displacement ellipsoids drawn at the 30% probability level.
[Figure 2] Fig. 2. The crystal packing of (I), viewed down the a axis.
2,3-Bis(4-bromophenyl)quinoxaline top
Crystal data top
C20H12Br2N2Z = 2
Mr = 440.14F(000) = 432
Triclinic, P1Dx = 1.702 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.0830 (12) ÅCell parameters from 25 reflections
b = 12.018 (2) Åθ = 4–14°
c = 12.323 (3) ŵ = 4.72 mm1
α = 105.47 (3)°T = 293 K
β = 91.89 (3)°Block, yellow
γ = 97.47 (3)°0.20 × 0.18 × 0.15 mm
V = 858.7 (3) Å3
Data collection top
Enraf–Nonius CAD-4
diffractometer
1824 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.027
Graphite monochromatorθmax = 25.0°, θmin = 1.7°
ω scansh = 07
Absorption correction: ψ scan
(North et al., 1968)
k = 1414
Tmin = 0.404, Tmax = 0.492l = 1414
3338 measured reflections3 standard reflections every 100 reflections
2888 independent reflections intensity decay: none
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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0589P)2 + 0.7939P]
where P = (Fo2 + 2Fc2)/3
2888 reflections(Δ/σ)max < 0.001
217 parametersΔρmax = 0.56 e Å3
0 restraintsΔρmin = 0.74 e Å3
Crystal data top
C20H12Br2N2γ = 97.47 (3)°
Mr = 440.14V = 858.7 (3) Å3
Triclinic, P1Z = 2
a = 6.0830 (12) ÅMo Kα radiation
b = 12.018 (2) ŵ = 4.72 mm1
c = 12.323 (3) ÅT = 293 K
α = 105.47 (3)°0.20 × 0.18 × 0.15 mm
β = 91.89 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
1824 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.027
Tmin = 0.404, Tmax = 0.4923 standard reflections every 100 reflections
3338 measured reflections intensity decay: none
2888 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0460 restraints
wR(F2) = 0.128H-atom parameters constrained
S = 1.06Δρmax = 0.56 e Å3
2888 reflectionsΔρmin = 0.74 e Å3
217 parameters
Special details top

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
Br10.47031 (12)0.83130 (5)0.45247 (6)0.0741 (3)
Br20.24223 (11)0.30938 (6)0.14438 (6)0.0753 (3)
N10.7857 (7)0.2921 (4)0.3229 (4)0.0493 (11)
N20.4951 (8)0.1176 (4)0.1656 (4)0.0542 (12)
C10.3718 (9)0.4705 (5)0.3533 (5)0.0526 (14)
H1B0.25640.41160.35320.063*
C20.3425 (9)0.5854 (5)0.3977 (5)0.0529 (14)
H2B0.21120.60410.42970.064*
C30.5130 (10)0.6720 (5)0.3936 (5)0.0522 (14)
C40.7127 (10)0.6469 (5)0.3496 (5)0.0589 (15)
H4A0.82550.70650.34800.071*
C50.7412 (9)0.5309 (5)0.3078 (5)0.0544 (14)
H5A0.87550.51290.27890.065*
C60.5720 (9)0.4407 (4)0.3082 (4)0.0461 (13)
C70.6106 (9)0.3173 (4)0.2700 (4)0.0462 (13)
C80.8169 (9)0.1783 (5)0.2990 (5)0.0493 (13)
C90.9999 (10)0.1469 (6)0.3534 (5)0.0652 (17)
H9A1.10070.20460.40250.078*
C101.0281 (12)0.0335 (6)0.3342 (6)0.0709 (18)
H10A1.14800.01300.36950.085*
C110.8729 (12)0.0534 (6)0.2597 (6)0.0735 (19)
H11A0.89040.13140.24790.088*
C120.7000 (11)0.0263 (5)0.2052 (6)0.0694 (18)
H12A0.60310.08520.15510.083*
C130.6657 (9)0.0901 (5)0.2238 (5)0.0505 (13)
C140.4677 (8)0.2285 (4)0.1856 (5)0.0472 (13)
C150.2918 (9)0.2540 (5)0.1121 (4)0.0477 (13)
C160.3189 (10)0.3520 (5)0.0707 (5)0.0584 (15)
H16A0.44550.40710.09400.070*
C170.1619 (10)0.3685 (5)0.0041 (5)0.0611 (16)
H17A0.18360.43300.03260.073*
C180.0301 (9)0.2875 (5)0.0366 (5)0.0545 (14)
C190.0638 (10)0.1897 (5)0.0024 (5)0.0576 (15)
H19A0.19270.13620.02000.069*
C200.0981 (9)0.1728 (5)0.0755 (5)0.0516 (14)
H20A0.07830.10620.10100.062*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0889 (5)0.0564 (4)0.0746 (5)0.0182 (3)0.0012 (4)0.0107 (3)
Br20.0645 (4)0.0854 (5)0.0725 (5)0.0068 (3)0.0241 (3)0.0212 (4)
N10.044 (3)0.053 (3)0.049 (3)0.009 (2)0.002 (2)0.009 (2)
N20.048 (3)0.056 (3)0.057 (3)0.001 (2)0.002 (2)0.016 (2)
C10.040 (3)0.056 (3)0.057 (4)0.001 (3)0.004 (3)0.011 (3)
C20.039 (3)0.065 (4)0.052 (3)0.011 (3)0.002 (3)0.010 (3)
C30.059 (4)0.051 (3)0.045 (3)0.010 (3)0.006 (3)0.012 (3)
C40.050 (4)0.056 (3)0.066 (4)0.004 (3)0.001 (3)0.014 (3)
C50.039 (3)0.061 (3)0.061 (4)0.007 (3)0.002 (3)0.013 (3)
C60.041 (3)0.053 (3)0.041 (3)0.004 (2)0.008 (2)0.010 (2)
C70.041 (3)0.053 (3)0.044 (3)0.004 (2)0.001 (2)0.013 (2)
C80.044 (3)0.058 (3)0.047 (3)0.009 (3)0.007 (3)0.014 (3)
C90.059 (4)0.073 (4)0.064 (4)0.022 (3)0.010 (3)0.016 (3)
C100.076 (5)0.075 (4)0.072 (4)0.033 (4)0.001 (4)0.027 (4)
C110.084 (5)0.059 (4)0.087 (5)0.027 (4)0.018 (4)0.027 (4)
C120.065 (4)0.054 (3)0.087 (5)0.003 (3)0.000 (4)0.019 (3)
C130.047 (3)0.052 (3)0.054 (3)0.007 (3)0.010 (3)0.017 (3)
C140.037 (3)0.051 (3)0.050 (3)0.000 (2)0.004 (2)0.011 (3)
C150.042 (3)0.058 (3)0.041 (3)0.005 (2)0.001 (2)0.011 (3)
C160.051 (4)0.061 (4)0.057 (4)0.008 (3)0.010 (3)0.015 (3)
C170.063 (4)0.059 (3)0.061 (4)0.002 (3)0.009 (3)0.021 (3)
C180.043 (3)0.071 (4)0.045 (3)0.008 (3)0.011 (3)0.011 (3)
C190.049 (3)0.070 (4)0.048 (3)0.002 (3)0.004 (3)0.013 (3)
C200.047 (3)0.057 (3)0.049 (3)0.002 (3)0.002 (3)0.014 (3)
Geometric parameters (Å, º) top
Br1—C31.913 (5)C9—C101.355 (8)
Br2—C181.913 (5)C9—H9A0.9300
N1—C71.339 (6)C10—C111.414 (9)
N1—C81.360 (7)C10—H10A0.9300
N2—C141.322 (7)C11—C121.350 (9)
N2—C131.367 (7)C11—H11A0.9300
C1—C21.380 (8)C12—C131.400 (8)
C1—C61.404 (8)C12—H12A0.9300
C1—H1B0.9300C14—C151.493 (7)
C2—C31.383 (8)C15—C161.397 (8)
C2—H2B0.9300C15—C201.405 (7)
C3—C41.383 (8)C16—C171.374 (8)
C4—C51.388 (8)C16—H16A0.9300
C4—H4A0.9300C17—C181.392 (8)
C5—C61.395 (7)C17—H17A0.9300
C5—H5A0.9300C18—C191.378 (8)
C6—C71.484 (7)C19—C201.384 (7)
C7—C141.443 (7)C19—H19A0.9300
C8—C131.412 (7)C20—H20A0.9300
C8—C91.424 (7)
C7—N1—C8117.5 (4)C11—C10—H10A120.4
C14—N2—C13118.5 (4)C12—C11—C10121.8 (6)
C2—C1—C6121.4 (5)C12—C11—H11A119.1
C2—C1—H1B119.3C10—C11—H11A119.1
C6—C1—H1B119.3C11—C12—C13120.4 (6)
C1—C2—C3118.5 (5)C11—C12—H12A119.8
C1—C2—H2B120.8C13—C12—H12A119.8
C3—C2—H2B120.8N2—C13—C12120.2 (5)
C2—C3—C4122.1 (5)N2—C13—C8120.9 (5)
C2—C3—Br1118.5 (4)C12—C13—C8118.8 (5)
C4—C3—Br1119.3 (4)N2—C14—C7120.4 (5)
C3—C4—C5118.6 (5)N2—C14—C15115.8 (4)
C3—C4—H4A120.7C7—C14—C15123.7 (5)
C5—C4—H4A120.7C16—C15—C20118.0 (5)
C4—C5—C6121.2 (5)C16—C15—C14122.4 (5)
C4—C5—H5A119.4C20—C15—C14119.4 (5)
C6—C5—H5A119.4C17—C16—C15121.2 (5)
C5—C6—C1118.1 (5)C17—C16—H16A119.4
C5—C6—C7120.4 (5)C15—C16—H16A119.4
C1—C6—C7121.3 (5)C16—C17—C18119.2 (5)
N1—C7—C14121.5 (5)C16—C17—H17A120.4
N1—C7—C6114.9 (4)C18—C17—H17A120.4
C14—C7—C6123.5 (5)C19—C18—C17121.5 (5)
N1—C8—C13120.9 (5)C19—C18—Br2119.8 (4)
N1—C8—C9119.7 (5)C17—C18—Br2118.6 (5)
C13—C8—C9119.4 (5)C18—C19—C20118.6 (5)
C10—C9—C8120.4 (6)C18—C19—H19A120.7
C10—C9—H9A119.8C20—C19—H19A120.7
C8—C9—H9A119.8C19—C20—C15121.5 (5)
C9—C10—C11119.1 (6)C19—C20—H20A119.3
C9—C10—H10A120.4C15—C20—H20A119.3
C6—C1—C2—C32.2 (8)C11—C12—C13—C81.0 (9)
C1—C2—C3—C41.9 (8)N1—C8—C13—N25.8 (8)
C1—C2—C3—Br1178.8 (4)C9—C8—C13—N2176.5 (5)
C2—C3—C4—C50.4 (9)N1—C8—C13—C12177.5 (5)
Br1—C3—C4—C5179.7 (4)C9—C8—C13—C120.2 (8)
C3—C4—C5—C60.9 (9)C13—N2—C14—C72.2 (8)
C4—C5—C6—C10.6 (8)C13—N2—C14—C15174.7 (5)
C4—C5—C6—C7176.0 (5)N1—C7—C14—N26.1 (8)
C2—C1—C6—C51.0 (8)C6—C7—C14—N2171.5 (5)
C2—C1—C6—C7174.4 (5)N1—C7—C14—C15170.5 (5)
C8—N1—C7—C143.8 (8)C6—C7—C14—C1511.9 (8)
C8—N1—C7—C6174.0 (5)N2—C14—C15—C16140.4 (6)
C5—C6—C7—N154.7 (7)C7—C14—C15—C1636.3 (8)
C1—C6—C7—N1120.5 (6)N2—C14—C15—C2034.6 (7)
C5—C6—C7—C14127.6 (6)C7—C14—C15—C20148.6 (6)
C1—C6—C7—C1457.2 (7)C20—C15—C16—C170.3 (9)
C7—N1—C8—C131.9 (8)C14—C15—C16—C17174.8 (5)
C7—N1—C8—C9179.6 (5)C15—C16—C17—C181.7 (9)
N1—C8—C9—C10177.2 (6)C16—C17—C18—C191.6 (9)
C13—C8—C9—C100.5 (9)C16—C17—C18—Br2178.0 (5)
C8—C9—C10—C110.3 (10)C17—C18—C19—C200.1 (9)
C9—C10—C11—C121.5 (11)Br2—C18—C19—C20176.5 (4)
C10—C11—C12—C131.9 (11)C18—C19—C20—C151.3 (9)
C14—N2—C13—C12179.9 (6)C16—C15—C20—C191.2 (8)
C14—N2—C13—C83.5 (8)C14—C15—C20—C19176.5 (5)
C11—C12—C13—N2177.7 (6)

Experimental details

Crystal data
Chemical formulaC20H12Br2N2
Mr440.14
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.0830 (12), 12.018 (2), 12.323 (3)
α, β, γ (°)105.47 (3), 91.89 (3), 97.47 (3)
V3)858.7 (3)
Z2
Radiation typeMo Kα
µ (mm1)4.72
Crystal size (mm)0.20 × 0.18 × 0.15
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.404, 0.492
No. of measured, independent and
observed [I > 2σ(I)] reflections
3338, 2888, 1824
Rint0.027
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.128, 1.06
No. of reflections2888
No. of parameters217
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.56, 0.74

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), NRCVAX (Gabe et al., 1989), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL/PC (Sheldrick, 1990), WinGX (Farrugia, 1999).

 

Acknowledgements

The authors thank the Natural Science Foundation of Shandong Province (grant No. Y2005B04).

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