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ISSN: 2056-9890

4-Di­methyl­amino-1-(4-meth­­oxy­phen­yl)-2,5-dioxo-2,5-di­hydro-1H-pyrrole-3-carbo­nitrile

aApplied Organic Chemistry Department, National Research Centre, Dokki, 12622 Giza, Egypt, bDepartment of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt, cDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, and dChemistry Department, Faculty of Science, King Abdulaziz University, PO Box 80203 Jeddah, Saudi Arabia
*Correspondence e-mail: edward.tiekink@gmail.com

(Received 14 February 2013; accepted 19 February 2013; online 23 February 2013)

In the title compound, C14H13N3O3, a twist occurs, as seen in the dihedral angle of 53.60 (12)° between the pyrrole and benzene rings. A three-dimensional architecture is formed in the crystal whereby layers of mol­ecules in the ac plane are connected by C—H⋯O and C—H⋯π inter­actions.

Related literature

For background to the biological activity exhibited by pyrroles and pyran­opyrroles, see: Amer et al. (2008[Amer, F. A.-K., Hammouda, M., El-Ahl, A.-A. S. & Abdel-Wahab, B. F. (2008). J. Heterocycl. Chem. 45, 1549-1569.], 2009[Amer, F. A.-K., Hammouda, M., El-Ahl, A. A. S. & Abdel-Wahab, B. F. (2009). Synth. Commun. 39, 416-425.]).

[Scheme 1]

Experimental

Crystal data
  • C14H13N3O3

  • Mr = 271.27

  • Monoclinic, P 21 /c

  • a = 12.7408 (14) Å

  • b = 7.8520 (9) Å

  • c = 14.4194 (18) Å

  • β = 115.163 (14)°

  • V = 1305.6 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 295 K

  • 0.40 × 0.20 × 0.10 mm

Data collection
  • Agilent SuperNova Dual diffractometer with an Atlas detector

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.]) Tmin = 0.869, Tmax = 1.000

  • 8113 measured reflections

  • 3020 independent reflections

  • 1772 reflections with I > 2σ(I)

  • Rint = 0.040

Refinement
  • R[F2 > 2σ(F2)] = 0.054

  • wR(F2) = 0.153

  • S = 1.04

  • 3020 reflections

  • 184 parameters

  • H-atom parameters constrained

  • Δρmax = 0.20 e Å−3

  • Δρmin = −0.17 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C8–C13 benzene ring.

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6A⋯O2i 0.96 2.54 3.397 (3) 149
C12—H12⋯O1ii 0.93 2.54 3.384 (3) 151
C5—H5BCg1iii 0.96 2.94 3.848 (3) 158
C6—H6BCg1iv 0.96 3.00 3.781 (3) 140
Symmetry codes: (i) [-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) [-x+2, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (iii) [x, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]; (iv) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].

Data collection: CrysAlis PRO (Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and DIAMOND (Brandenburg, 2006[Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

The title compound (I) was investigated owing to the biological activities exhibited pyrroles and pyranopyrrole analogues (Amer et al. 2009; Amer et al. 2008). Herein, its crystal structure determination is described.

Crystallography shows that fusion of 1-(4-methoxyphenyl)-4-oxopyrrolidine-3-carbonitrile with excess 1,1-dimethoxy-N,N-dimethylmethanamine afforded 4-(dimethylamino)-1-(4-methoxyphenyl)-2,5-dioxo-2,5-dihydro-1H-pyrrole-3-carbonitrile (I) not the expected 2-((dimethylamino)methylene)-1-(4-methoxyphenyl)-4-oxopyrrolidine-3-carbonitrile (II).

In (I), Fig. 1, the dihedral angle of 53.60 (12)° between the pyrrole (r.m.s. deviation = 0.005 Å) and benzene rings indicates a significant twist in the molecule. The methoxy substituent is twisted out of the plane of the ring to which it is attached as seen in the value of the C14—O3—C11—C10 torsion angle of -13.9 (4)°. The dimethylamino group is also slightly twisted out of the plane through the pyrrole ring to which it is attached; the C5—N2—C2—C1 torsion angle is 8.7 (3)°.

The three-dimensional architecture of (I) is consolidated by C—H···O interactions, involving both carbonyl-O atoms, as well as C—H···π interactions whereby the benzene ring serves as a bridge between molecules, Fig. 2 and Table 1.

Related literature top

For background to the biological activity exhibited by pyrroles and pyranopyrroles, see: Amer et al. (2008, 2009).

Experimental top

A mixture of 1-(4-methoxyphenyl)-4-oxopyrrolidine-3-carbonitrile (0.22 g, 0.001 M) and excess 1,1-dimethoxy-N,N-dimethylmethanamine (0.2 ml) was heated under reflux for about 1.5 h on water bath. The resultant solid was filtered and dried. Re-crystallization was by slow evaporation of its DMF solution which yielded yellow prisms in 28% yield. M.pt. 482–483 K.

Refinement top

Carbon-bound H-atoms were placed in calculated positions (C—H 0.93 to 0.96 Å) and were included in the refinement in the riding model approximation, with Uiso(H) = 1.2Uequiv(C).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 35% probability level.
[Figure 2] Fig. 2. A view of the crystal packing in projection down the a axis. The C—H···O and C—H···π interactions are shown as orange and purple dashed lines, respectively.
4-Dimethylamino-1-(4-methoxyphenyl)-2,5-dioxo-2,5-dihydro-1H-pyrrole-3-carbonitrile top
Crystal data top
C14H13N3O3F(000) = 568
Mr = 271.27Dx = 1.380 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1717 reflections
a = 12.7408 (14) Åθ = 2.9–27.5°
b = 7.8520 (9) ŵ = 0.10 mm1
c = 14.4194 (18) ÅT = 295 K
β = 115.163 (14)°Prism, yellow
V = 1305.6 (3) Å30.40 × 0.20 × 0.10 mm
Z = 4
Data collection top
Agilent SuperNova Dual
diffractometer with an Atlas detector
3020 independent reflections
Radiation source: SuperNova (Mo) X-ray Source1772 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.040
Detector resolution: 10.4041 pixels mm-1θmax = 27.6°, θmin = 2.9°
ω scanh = 1616
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
k = 910
Tmin = 0.869, Tmax = 1.000l = 1718
8113 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.054H-atom parameters constrained
wR(F2) = 0.153 w = 1/[σ2(Fo2) + (0.0573P)2 + 0.268P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
3020 reflectionsΔρmax = 0.20 e Å3
184 parametersΔρmin = 0.17 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0065 (17)
Crystal data top
C14H13N3O3V = 1305.6 (3) Å3
Mr = 271.27Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.7408 (14) ŵ = 0.10 mm1
b = 7.8520 (9) ÅT = 295 K
c = 14.4194 (18) Å0.40 × 0.20 × 0.10 mm
β = 115.163 (14)°
Data collection top
Agilent SuperNova Dual
diffractometer with an Atlas detector
3020 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
1772 reflections with I > 2σ(I)
Tmin = 0.869, Tmax = 1.000Rint = 0.040
8113 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0540 restraints
wR(F2) = 0.153H-atom parameters constrained
S = 1.04Δρmax = 0.20 e Å3
3020 reflectionsΔρmin = 0.17 e Å3
184 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
O10.87550 (12)0.4211 (2)0.83764 (12)0.0638 (5)
O20.54480 (12)0.7013 (2)0.63309 (13)0.0643 (5)
O30.86456 (14)0.6113 (3)0.40226 (13)0.0700 (5)
N10.72098 (13)0.5628 (2)0.71557 (13)0.0457 (5)
N20.74285 (15)0.4605 (3)0.96511 (14)0.0517 (5)
N30.43202 (18)0.7134 (3)0.82506 (18)0.0764 (7)
C10.78270 (17)0.4912 (3)0.81026 (17)0.0461 (5)
C20.71002 (16)0.5147 (3)0.87029 (16)0.0448 (5)
C30.60974 (16)0.5976 (3)0.80526 (16)0.0463 (6)
C40.61362 (16)0.6288 (3)0.70794 (17)0.0471 (6)
C50.85888 (19)0.3921 (4)1.03016 (18)0.0665 (8)
H5A0.90240.37970.99010.100*
H5B0.85110.28311.05670.100*
H5C0.89870.46891.08590.100*
C60.6647 (2)0.4773 (4)1.01516 (18)0.0644 (7)
H6A0.58850.43970.96930.097*
H6B0.66150.59441.03290.097*
H6C0.69290.40891.07610.097*
C70.51255 (19)0.6588 (3)0.81992 (18)0.0551 (6)
C80.75727 (16)0.5680 (3)0.63493 (16)0.0445 (5)
C90.68625 (17)0.5068 (3)0.53895 (17)0.0501 (6)
H90.61570.45700.52780.060*
C100.71847 (18)0.5185 (3)0.45933 (18)0.0528 (6)
H100.66940.47820.39470.063*
C110.82415 (18)0.5903 (3)0.47577 (18)0.0522 (6)
C120.89700 (18)0.6489 (3)0.57264 (18)0.0558 (6)
H120.96870.69520.58430.067*
C130.86383 (17)0.6389 (3)0.65152 (17)0.0518 (6)
H130.91270.67960.71610.062*
C140.8062 (2)0.5219 (4)0.3082 (2)0.0729 (8)
H14A0.84200.54790.26320.109*
H14B0.72630.55590.27660.109*
H14C0.81110.40160.32130.109*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0468 (9)0.0708 (13)0.0703 (11)0.0171 (8)0.0215 (8)0.0120 (9)
O20.0497 (9)0.0694 (13)0.0663 (10)0.0130 (8)0.0174 (8)0.0112 (10)
O30.0740 (11)0.0761 (14)0.0704 (11)0.0066 (9)0.0409 (9)0.0007 (10)
N10.0349 (9)0.0490 (12)0.0492 (10)0.0021 (8)0.0143 (8)0.0038 (9)
N20.0497 (10)0.0507 (13)0.0499 (11)0.0038 (9)0.0165 (8)0.0009 (9)
N30.0643 (13)0.0814 (19)0.0946 (17)0.0171 (12)0.0445 (12)0.0116 (14)
C10.0391 (11)0.0387 (13)0.0550 (13)0.0014 (9)0.0146 (9)0.0004 (11)
C20.0408 (11)0.0387 (13)0.0486 (12)0.0057 (9)0.0131 (9)0.0051 (10)
C30.0373 (11)0.0429 (14)0.0555 (13)0.0018 (9)0.0167 (9)0.0026 (11)
C40.0358 (11)0.0446 (14)0.0558 (13)0.0010 (9)0.0145 (9)0.0002 (11)
C50.0574 (14)0.070 (2)0.0572 (14)0.0056 (12)0.0102 (11)0.0095 (13)
C60.0663 (15)0.071 (2)0.0569 (15)0.0048 (13)0.0276 (12)0.0023 (13)
C70.0495 (13)0.0514 (16)0.0641 (15)0.0005 (11)0.0240 (11)0.0017 (12)
C80.0389 (11)0.0400 (13)0.0520 (13)0.0016 (9)0.0168 (9)0.0016 (10)
C90.0388 (11)0.0452 (14)0.0610 (14)0.0034 (9)0.0162 (10)0.0007 (12)
C100.0474 (12)0.0538 (16)0.0530 (13)0.0010 (10)0.0174 (10)0.0009 (12)
C110.0524 (13)0.0473 (15)0.0604 (14)0.0034 (10)0.0273 (11)0.0045 (12)
C120.0428 (12)0.0532 (16)0.0731 (16)0.0064 (10)0.0262 (11)0.0014 (13)
C130.0385 (11)0.0518 (15)0.0586 (14)0.0045 (10)0.0144 (10)0.0051 (12)
C140.0936 (19)0.065 (2)0.0674 (17)0.0095 (15)0.0411 (15)0.0042 (15)
Geometric parameters (Å, º) top
O1—C11.208 (2)C5—H5C0.9600
O2—C41.206 (3)C6—H6A0.9600
O3—C111.371 (3)C6—H6B0.9600
O3—C141.424 (3)C6—H6C0.9600
N1—C11.373 (3)C8—C91.378 (3)
N1—C81.423 (3)C8—C131.391 (3)
N1—C41.422 (3)C9—C101.377 (3)
N2—C21.319 (3)C9—H90.9300
N2—C61.463 (3)C10—C111.384 (3)
N2—C51.475 (3)C10—H100.9300
N3—C71.143 (3)C11—C121.386 (3)
C1—C21.524 (3)C12—C131.374 (3)
C2—C31.384 (3)C12—H120.9300
C3—C71.425 (3)C13—H130.9300
C3—C41.446 (3)C14—H14A0.9600
C5—H5A0.9600C14—H14B0.9600
C5—H5B0.9600C14—H14C0.9600
C11—O3—C14117.5 (2)N2—C6—H6C109.5
C1—N1—C8125.20 (17)H6A—C6—H6C109.5
C1—N1—C4110.58 (18)H6B—C6—H6C109.5
C8—N1—C4124.21 (17)N3—C7—C3175.1 (3)
C2—N2—C6119.99 (19)C9—C8—C13119.2 (2)
C2—N2—C5124.6 (2)C9—C8—N1120.52 (18)
C6—N2—C5115.32 (19)C13—C8—N1120.23 (19)
O1—C1—N1125.4 (2)C10—C9—C8120.9 (2)
O1—C1—C2128.0 (2)C10—C9—H9119.6
N1—C1—C2106.60 (17)C8—C9—H9119.6
N2—C2—C3130.4 (2)C9—C10—C11119.8 (2)
N2—C2—C1123.25 (19)C9—C10—H10120.1
C3—C2—C1106.32 (19)C11—C10—H10120.1
C2—C3—C7131.9 (2)O3—C11—C12115.4 (2)
C2—C3—C4109.54 (18)O3—C11—C10125.0 (2)
C7—C3—C4118.50 (18)C12—C11—C10119.6 (2)
O2—C4—N1123.4 (2)C13—C12—C11120.4 (2)
O2—C4—C3129.56 (19)C13—C12—H12119.8
N1—C4—C3106.97 (17)C11—C12—H12119.8
N2—C5—H5A109.5C12—C13—C8120.1 (2)
N2—C5—H5B109.5C12—C13—H13119.9
H5A—C5—H5B109.5C8—C13—H13119.9
N2—C5—H5C109.5O3—C14—H14A109.5
H5A—C5—H5C109.5O3—C14—H14B109.5
H5B—C5—H5C109.5H14A—C14—H14B109.5
N2—C6—H6A109.5O3—C14—H14C109.5
N2—C6—H6B109.5H14A—C14—H14C109.5
H6A—C6—H6B109.5H14B—C14—H14C109.5
C8—N1—C1—O10.9 (4)C2—C3—C4—O2177.8 (2)
C4—N1—C1—O1177.9 (2)C7—C3—C4—O20.2 (4)
C8—N1—C1—C2179.66 (19)C2—C3—C4—N10.4 (3)
C4—N1—C1—C20.9 (2)C7—C3—C4—N1177.2 (2)
C6—N2—C2—C33.3 (4)C1—N1—C8—C9126.3 (2)
C5—N2—C2—C3172.2 (2)C4—N1—C8—C952.3 (3)
C6—N2—C2—C1175.7 (2)C1—N1—C8—C1355.3 (3)
C5—N2—C2—C18.7 (3)C4—N1—C8—C13126.1 (2)
O1—C1—C2—N21.2 (4)C13—C8—C9—C101.4 (4)
N1—C1—C2—N2179.9 (2)N1—C8—C9—C10177.0 (2)
O1—C1—C2—C3178.1 (2)C8—C9—C10—C110.9 (4)
N1—C1—C2—C30.6 (2)C14—O3—C11—C12166.8 (2)
N2—C2—C3—C73.6 (4)C14—O3—C11—C1013.9 (4)
C1—C2—C3—C7177.2 (2)C9—C10—C11—O3178.9 (2)
N2—C2—C3—C4179.3 (2)C9—C10—C11—C120.4 (4)
C1—C2—C3—C40.1 (2)O3—C11—C12—C13178.1 (2)
C1—N1—C4—O2178.4 (2)C10—C11—C12—C131.3 (4)
C8—N1—C4—O22.8 (4)C11—C12—C13—C80.8 (4)
C1—N1—C4—C30.8 (2)C9—C8—C13—C120.6 (4)
C8—N1—C4—C3179.62 (19)N1—C8—C13—C12177.8 (2)
Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the C8–C13 benzene ring.
D—H···AD—HH···AD···AD—H···A
C6—H6A···O2i0.962.543.397 (3)149
C12—H12···O1ii0.932.543.384 (3)151
C5—H5B···Cg1iii0.962.943.848 (3)158
C6—H6B···Cg1iv0.963.003.781 (3)140
Symmetry codes: (i) x+1, y1/2, z+3/2; (ii) x+2, y+1/2, z+3/2; (iii) x, y1/2, z1/2; (iv) x, y+1/2, z1/2.

Experimental details

Crystal data
Chemical formulaC14H13N3O3
Mr271.27
Crystal system, space groupMonoclinic, P21/c
Temperature (K)295
a, b, c (Å)12.7408 (14), 7.8520 (9), 14.4194 (18)
β (°) 115.163 (14)
V3)1305.6 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.40 × 0.20 × 0.10
Data collection
DiffractometerAgilent SuperNova Dual
diffractometer with an Atlas detector
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2011)
Tmin, Tmax0.869, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
8113, 3020, 1772
Rint0.040
(sin θ/λ)max1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.054, 0.153, 1.04
No. of reflections3020
No. of parameters184
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.20, 0.17

Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the C8–C13 benzene ring.
D—H···AD—HH···AD···AD—H···A
C6—H6A···O2i0.962.543.397 (3)149
C12—H12···O1ii0.932.543.384 (3)151
C5—H5B···Cg1iii0.962.943.848 (3)158
C6—H6B···Cg1iv0.963.003.781 (3)140
Symmetry codes: (i) x+1, y1/2, z+3/2; (ii) x+2, y+1/2, z+3/2; (iii) x, y1/2, z1/2; (iv) x, y+1/2, z1/2.
 

Footnotes

Additional correspondence author, e-mail: bakrfatehy@yahoo.com.

Acknowledgements

We thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR-MOHE/SC/12).

References

First citationAgilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.  Google Scholar
First citationAmer, F. A.-K., Hammouda, M., El-Ahl, A.-A. S. & Abdel-Wahab, B. F. (2008). J. Heterocycl. Chem. 45, 1549–1569.  CrossRef CAS Google Scholar
First citationAmer, F. A.-K., Hammouda, M., El-Ahl, A. A. S. & Abdel-Wahab, B. F. (2009). Synth. Commun. 39, 416–425.  Web of Science CrossRef CAS Google Scholar
First citationBrandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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