7,7′,8,8′-Tetra­meth­oxy-4,4′-dimethyl-3,3′-bicoumarin

Fun, H.-K.; Jebas, S.R.; Parveen, M.; Khanam, Z.; Ghalib, R.M.

doi:10.1107/S1600536809017334

organic compounds

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ISSN: 2056-9890

Volume 65| Part 6| June 2009| Pages o1294-o1295

doi:10.1107/S1600536809017334

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7,7′,8,8′-Tetramethoxy-4,4′-dimethyl-3,3′-bicoumarin

Hoong-Kun Fun,^a ^*‡ Samuel Robinson Jebas,^a § Mehtab Parveen,^b Zakia Khanam ^b and Raza Murad Ghalib ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 Universiti Sains Malaysia, Penang, Malaysia, and ^bDepartment of Chemistry, Aligarh Muslim University, Aligarh 202002 (UP), India
^*Correspondence e-mail: hkfun@usm.my

(Received 5 May 2009; accepted 8 May 2009; online 14 May 2009)

In the crystal structure, the title compound, C₂₄H₂₂O₈, lies on a twofold rotation axis and the asymmetric unit comprises one half-molecule. The dihedral angle formed by the coumarin unit with the symmetry-related part is 74.78 (14)°. One of the methoxy groups attached to the coumarin unit is considerably twisted, making an angle of 87.17 (17)° with respect to the coumarin unit; the other is twisted by 0.66 (19)°. No classical hydrogen bonds are found in the sturcture; only a weak C—H⋯π interaction and short intramolecular O⋯O contacts [2.683 (2)–2.701 (2) Å] are observed.

Related literature

For the biological activity of coumarins, see: El-Agrody et al. (2001 ); El-Farargy (1991 ); Emmanuel-Giota et al. (2001 ); Ghate et al. (2005 ); Laakso et al. (1994 ); Nofal et al. (2000 ); Pratibha & Shreeya (1999 ); Shaker (1996 ); Yang et al. (2005 ). For the pharmaceutical properties of coumarin derivatives, see: Kennedy & Thornes (1997 ). For natural and synthetic coumarins, see: Carlton et al. (1996 ); Zhou et al. (2000 ). For related bond-length data, see: Allen et al. (1987 ). For stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

C₂₄H₂₂O₈
M_r = 438.42
Monoclinic, C 2/c
a = 21.715 (9) Å
b = 7.138 (3) Å
c = 15.511 (6) Å
β = 121.801 (5)°
V = 2043.3 (14) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 100 K
0.28 × 0.19 × 0.06 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.971, T_max = 0.994
27961 measured reflections
3527 independent reflections
2710 reflections with I > 2σ(I)
R_int = 0.065

Refinement

R[F² > 2σ(F²)] = 0.059
wR(F²) = 0.155
S = 1.08
3527 reflections
189 parameters
All H-atom parameters refined
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯Cg1ⁱ	0.96 (2)	2.86 (2)	3.676 (2)	143.5 (18)
Symmetry code: (i) $[x, -y, z-{\script{1\over 2}}]$ . Cg1 is the centroid of the C4–C9 ring.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809017334/is2417sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809017334/is2417Isup2.hkl

checkCIF report

Comment top

Coumarins are a large group of naturally occurring oxygen heterocycles representing 2H-1-benzopyran-2-one derivative. Many natural coumarins are reputed for their wide range of biological activites such as antibacterial (El-Agrody et al., 2001; Pratibha & Shreeya, 1999), antifungal (Shaker, 1996; El-Farargy, 1991), antioxidant (Yang et al., 2005), analgesic (Ghate et al., 2005), anti-inflammatory (Emmanuel-Giota et al., 2001) and antitumor (Nofal et al., 2000) properties. Bi and tri-coumarins are comparatively new groups which are widely spread in nature and their biological properties are also well known (Laakso et al., 1994). One of the characteristic pharmacological properties of coumarin derivatives is the anticoagulant action (Kennedy & Thornes, 1997). A large number of natural and semisynthetic coumarin and bicoumarin derivatives have been reported to demonstrate chemopreventive (Carlton et al., 1996) and anti-HIV (Zhou et al., 2000) activities. Keeping in view of these biological importance of coumarins and their dimers, we have synthesized the title compound (I) and report here its structure.

The asymmetric unit of (I) (Fig. 1), contains half of the 7,7',8,8'-4,4'-dimethyl-3,3'-bicoumarin molecule. The other half is symmetry generated [symmetry code: -x, y, -z + 1/2]. The coumarin unit is planar with the maximum deviation from the mean plane of 0.0295 (15) Å for atom C2. One of the methyl group attached to the coumarin unit is twisted as evidenced by the torsion angle of C10—O3—C8—C9 = 87.17 (17)°. The dihedral angle formed by the coumarin unit (O1/C1—C9) with the symmetry related coumarin unit (O1A/C1A—C9A) is 74.78 (14)°, indicating that they are almost perpendicular to each other. The bond lengths (Allen et al., 1987) and bond angles are normal.

The crystal packing (Fig. 2) (Table 1) is stabilized by weak C—H···π interactions and intramolecular O···O = 2.683 (2) to 2.701 (2) Å short contacts.

Related literature top

For thebiological activity of coumarin, see: El-Agrody et al. (2001); El-Farargy (1991); Emmanuel-Giota et al. (2001); Ghate et al. (2005); Laakso et al. (1994); Nofal et al. (2000); Pratibha & Shreeya (1999); Shaker (1996); Yang et al. (2005). For the pharmaceutical properties of coumarin derivatives, see: Kennedy & Thornes (1997). For natural and synthetic coumarins, see: Carlton et al. (1996); Zhou et al. (2000). For related bond-length data, see: Allen et al. (1987). For stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986). Cg1 is the centroid of the C4–C9 ring.

Experimental top

A mixture of 7,8-dimethoxy-4-methyl coumarin (2.20 g, 10 mmol) and manganese(III) acetate (0.774 g, 1 mmol) was stirred at room temperature, then 70% perchloric acid (0.8 g, 6 mmol) was added. The reaction mixture was heated under reflux at 114°C with stirring in the atmosphere of nitrogen for 3 h. The reaction mixture was cooled and diluted with 50 ml of benzene. The benzene solution was washed with water and aq. NaHCO₃, dried over anhydrous Na₂SO₄ and left to evaporate. The residue showed two major compounds which were separated by column chromatography followed by preparative thin layer chromatography (Benzene: EtOAc, 9:1) into the title compound (I) (260 mg, 12%).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); 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) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom numbering scheme. [Symmetry code: -x, y, -z + 1/2 to generate equivalent atoms].
	Fig. 2. The crystal packing of (I). Molecules are stacked along the b axis.

(I) top

Crystal data top

C₂₄H₂₂O₈	F(000) = 920
M_r = 438.42	D_x = 1.425 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 6562 reflections
a = 21.715 (9) Å	θ = 2.7–31.8°
b = 7.138 (3) Å	µ = 0.11 mm⁻¹
c = 15.511 (6) Å	T = 100 K
β = 121.801 (5)°	Plate, colourless
V = 2043.3 (14) Å³	0.28 × 0.19 × 0.06 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3527 independent reflections
Radiation source: fine-focus sealed tube	2710 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.065
ϕ and ω scans	θ_max = 32.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −32→32
T_min = 0.971, T_max = 0.994	k = −10→10
27961 measured reflections	l = −23→23

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.155	All H-atom parameters refined
S = 1.08	w = 1/[σ²(F_o²) + (0.0752P)² + 1.2567P] where P = (F_o² + 2F_c²)/3
3527 reflections	(Δ/σ)_max < 0.001
189 parameters	Δρ_max = 0.50 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₂₄H₂₂O₈	V = 2043.3 (14) Å³
M_r = 438.42	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 21.715 (9) Å	µ = 0.11 mm⁻¹
b = 7.138 (3) Å	T = 100 K
c = 15.511 (6) Å	0.28 × 0.19 × 0.06 mm
β = 121.801 (5)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3527 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2710 reflections with I > 2σ(I)
T_min = 0.971, T_max = 0.994	R_int = 0.065
27961 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.059	0 restraints
wR(F²) = 0.155	All H-atom parameters refined
S = 1.08	Δρ_max = 0.50 e Å⁻³
3527 reflections	Δρ_min = −0.21 e Å⁻³
189 parameters

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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

	x	y	z	U_iso*/U_eq
O1	0.15443 (5)	0.04445 (13)	0.38705 (7)	0.0178 (2)
O2	0.05473 (6)	−0.06775 (15)	0.37300 (8)	0.0242 (2)
O3	0.30066 (5)	0.03278 (14)	0.48961 (7)	0.0212 (2)
O4	0.37511 (5)	0.26053 (15)	0.43926 (8)	0.0221 (2)
C1	0.08045 (7)	0.05014 (19)	0.34517 (10)	0.0175 (3)
C2	0.03949 (7)	0.19639 (19)	0.27048 (10)	0.0163 (3)
C3	0.07228 (7)	0.32194 (19)	0.24158 (10)	0.0168 (3)
C4	0.15015 (7)	0.31354 (18)	0.28870 (10)	0.0161 (3)
C5	0.19034 (8)	0.44106 (19)	0.26927 (10)	0.0185 (3)
C6	0.26498 (8)	0.42852 (19)	0.31768 (11)	0.0194 (3)
C7	0.30199 (7)	0.28719 (19)	0.38881 (10)	0.0174 (3)
C8	0.26401 (7)	0.15966 (18)	0.41265 (9)	0.0164 (3)
C9	0.18892 (7)	0.17416 (18)	0.36139 (10)	0.0154 (2)
C10	0.30773 (13)	−0.1493 (2)	0.45770 (15)	0.0362 (4)
C11	0.41539 (8)	0.3869 (2)	0.41549 (13)	0.0267 (3)
C12	0.02974 (8)	0.4697 (2)	0.16315 (12)	0.0247 (3)
H5	0.1654 (10)	0.540 (3)	0.2226 (15)	0.024 (5)*
H6	0.2908 (11)	0.516 (3)	0.3016 (16)	0.033 (5)*
H10A	0.3396 (14)	−0.139 (4)	0.429 (2)	0.063 (8)*
H10B	0.3324 (13)	−0.224 (3)	0.514 (2)	0.046 (6)*
H10C	0.2573 (16)	−0.202 (4)	0.410 (2)	0.067 (8)*
H11A	0.3985 (12)	0.382 (3)	0.3405 (19)	0.044 (6)*
H11B	0.4125 (11)	0.519 (3)	0.4338 (15)	0.028 (5)*
H11C	0.4642 (10)	0.340 (3)	0.4535 (14)	0.022 (4)*
H12A	0.0472 (11)	0.483 (3)	0.1149 (17)	0.035 (5)*
H12B	0.0359 (12)	0.591 (3)	0.1955 (18)	0.041 (6)*
H12C	−0.0217 (12)	0.440 (3)	0.1264 (17)	0.036 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0162 (5)	0.0193 (5)	0.0163 (4)	0.0013 (3)	0.0074 (4)	0.0050 (4)
O2	0.0213 (5)	0.0253 (5)	0.0244 (5)	−0.0003 (4)	0.0111 (4)	0.0083 (4)
O3	0.0217 (5)	0.0219 (5)	0.0134 (4)	0.0047 (4)	0.0048 (4)	0.0029 (4)
O4	0.0144 (5)	0.0250 (5)	0.0230 (5)	−0.0015 (4)	0.0071 (4)	−0.0020 (4)
C1	0.0167 (6)	0.0199 (6)	0.0149 (6)	0.0003 (5)	0.0076 (5)	0.0008 (5)
C2	0.0155 (6)	0.0179 (6)	0.0140 (6)	0.0004 (4)	0.0067 (5)	−0.0003 (4)
C3	0.0166 (6)	0.0176 (6)	0.0145 (6)	0.0013 (4)	0.0071 (5)	0.0018 (4)
C4	0.0166 (6)	0.0174 (6)	0.0133 (5)	0.0013 (4)	0.0072 (5)	0.0009 (4)
C5	0.0199 (6)	0.0185 (6)	0.0165 (6)	0.0007 (5)	0.0091 (5)	0.0027 (5)
C6	0.0202 (6)	0.0200 (6)	0.0186 (6)	−0.0016 (5)	0.0106 (5)	−0.0002 (5)
C7	0.0142 (6)	0.0211 (6)	0.0143 (6)	−0.0007 (4)	0.0058 (5)	−0.0037 (5)
C8	0.0168 (6)	0.0176 (6)	0.0108 (5)	0.0018 (4)	0.0045 (5)	−0.0003 (4)
C9	0.0175 (6)	0.0155 (6)	0.0125 (5)	−0.0012 (4)	0.0075 (5)	−0.0006 (4)
C10	0.0564 (12)	0.0239 (8)	0.0302 (9)	0.0173 (8)	0.0241 (9)	0.0093 (7)
C11	0.0188 (7)	0.0267 (8)	0.0339 (8)	−0.0059 (6)	0.0134 (6)	−0.0047 (6)
C12	0.0183 (7)	0.0265 (7)	0.0254 (7)	0.0030 (5)	0.0089 (6)	0.0112 (6)

Geometric parameters (Å, º) top

O1—C9	1.3750 (16)	C5—H5	0.952 (19)
O1—C1	1.3801 (17)	C6—C7	1.395 (2)
O2—C1	1.2085 (17)	C6—H6	0.96 (2)
O3—C8	1.3701 (16)	C7—C8	1.4025 (19)
O3—C10	1.428 (2)	C8—C9	1.3912 (19)
O4—C7	1.3640 (17)	C10—H10A	1.01 (3)
O4—C11	1.4334 (19)	C10—H10B	0.92 (3)
C1—C2	1.4618 (19)	C10—H10C	1.02 (3)
C2—C3	1.3592 (19)	C11—H11A	1.02 (2)
C2—C2ⁱ	1.482 (3)	C11—H11B	1.00 (2)
C3—C4	1.4472 (19)	C11—H11C	0.963 (19)
C3—C12	1.5036 (19)	C12—H12A	1.01 (2)
C4—C5	1.3993 (19)	C12—H12B	0.97 (2)
C4—C9	1.4034 (18)	C12—H12C	0.97 (2)
C5—C6	1.384 (2)

C9—O1—C1	121.36 (10)	O3—C8—C9	121.00 (12)
C8—O3—C10	114.77 (12)	O3—C8—C7	120.42 (12)
C7—O4—C11	116.63 (12)	C9—C8—C7	118.42 (12)
O2—C1—O1	116.99 (12)	O1—C9—C8	115.95 (11)
O2—C1—C2	125.28 (13)	O1—C9—C4	121.49 (12)
O1—C1—C2	117.72 (11)	C8—C9—C4	122.56 (12)
C3—C2—C1	121.77 (12)	O3—C10—H10A	108.3 (16)
C3—C2—C2ⁱ	123.20 (11)	O3—C10—H10B	108.3 (15)
C1—C2—C2ⁱ	115.03 (10)	H10A—C10—H10B	106 (2)
C2—C3—C4	118.80 (12)	O3—C10—H10C	108.6 (16)
C2—C3—C12	121.60 (13)	H10A—C10—H10C	115 (2)
C4—C3—C12	119.59 (12)	H10B—C10—H10C	110 (2)
C5—C4—C9	117.13 (12)	O4—C11—H11A	111.7 (13)
C5—C4—C3	124.03 (12)	O4—C11—H11B	112.6 (11)
C9—C4—C3	118.80 (12)	H11A—C11—H11B	108.8 (17)
C6—C5—C4	121.74 (13)	O4—C11—H11C	104.2 (11)
C6—C5—H5	119.7 (11)	H11A—C11—H11C	107.7 (16)
C4—C5—H5	118.6 (11)	H11B—C11—H11C	111.8 (16)
C5—C6—C7	119.83 (13)	C3—C12—H12A	111.0 (12)
C5—C6—H6	119.7 (13)	C3—C12—H12B	110.3 (14)
C7—C6—H6	120.5 (13)	H12A—C12—H12B	107.2 (17)
O4—C7—C6	124.46 (12)	C3—C12—H12C	110.3 (12)
O4—C7—C8	115.26 (12)	H12A—C12—H12C	110.5 (18)
C6—C7—C8	120.28 (13)	H12B—C12—H12C	107.4 (17)

C9—O1—C1—O2	−179.03 (12)	C5—C6—C7—O4	178.75 (12)
C9—O1—C1—C2	1.45 (18)	C5—C6—C7—C8	−1.0 (2)
O2—C1—C2—C3	−178.65 (14)	C10—O3—C8—C9	87.17 (17)
O1—C1—C2—C3	0.83 (19)	C10—O3—C8—C7	−97.47 (17)
O2—C1—C2—C2ⁱ	1.3 (2)	O4—C7—C8—O3	6.82 (18)
O1—C1—C2—C2ⁱ	−179.20 (11)	C6—C7—C8—O3	−173.39 (12)
C1—C2—C3—C4	−2.0 (2)	O4—C7—C8—C9	−177.70 (11)
C2ⁱ—C2—C3—C4	178.01 (13)	C6—C7—C8—C9	2.09 (19)
C1—C2—C3—C12	178.72 (13)	C1—O1—C9—C8	176.73 (11)
C2ⁱ—C2—C3—C12	−1.3 (2)	C1—O1—C9—C4	−2.48 (18)
C2—C3—C4—C5	−176.43 (13)	O3—C8—C9—O1	−5.18 (18)
C12—C3—C4—C5	2.8 (2)	C7—C8—C9—O1	179.37 (11)
C2—C3—C4—C9	1.01 (19)	O3—C8—C9—C4	174.02 (12)
C12—C3—C4—C9	−179.71 (13)	C7—C8—C9—C4	−1.42 (19)
C9—C4—C5—C6	1.4 (2)	C5—C4—C9—O1	178.84 (11)
C3—C4—C5—C6	178.94 (13)	C3—C4—C9—O1	1.22 (19)
C4—C5—C6—C7	−0.8 (2)	C5—C4—C9—C8	−0.32 (19)
C11—O4—C7—C6	−0.66 (19)	C3—C4—C9—C8	−177.94 (12)
C11—O4—C7—C8	179.12 (12)

Symmetry code: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···Cg1ⁱⁱ	0.96 (2)	2.86 (2)	3.676 (2)	143.5 (18)

Symmetry code: (ii) x, −y, z−1/2.

Experimental details

Crystal data
Chemical formula	C₂₄H₂₂O₈
M_r	438.42
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	100
a, b, c (Å)	21.715 (9), 7.138 (3), 15.511 (6)
β (°)	121.801 (5)
V (Å³)	2043.3 (14)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.28 × 0.19 × 0.06

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.971, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	27961, 3527, 2710
R_int	0.065
(sin θ/λ)_max (Å⁻¹)	0.745

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.059, 0.155, 1.08
No. of reflections	3527
No. of parameters	189
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.21

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···Cg1ⁱ	0.96 (2)	2.86 (2)	3.676 (2)	143.5 (18)

Symmetry code: (i) x, −y, z−1/2.

Footnotes

‡Thomson Reuters Researcher ID: A-3561-2009.

§Thomson Reuters Researcher ID: A-5473-2009. Permanent address: Department of Physics, Karunya University, Karunya Nagar, Coimbatore 641 114, India.

Acknowledgements

HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post–doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

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