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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 10| October 2009| Page o2528
doi:10.1107/S1600536809037349

Di­ethyl 2,6-di­methyl­pyridine-3,5-di­carboxyl­ate at 100 K

Wassima Ghalem,a Ratiba Belhouas,b* Raouf Boulcina,a Sofiane Bouacidac and Abdelmadjid Debachea

aLaboratoire des Produits Naturels d'Origine Végétale et de Synthèse Organique, PHYSYNOR, Université Mentouri-Constantine, 25000 Constantine, Algeria, bFaculté de Chimie, USTHB, BP32, El-Alia, Bab-Ezzouar, Alger, Algeria, and cUnité de Recherche de Chimie de l'Environnement et Moléculaire Structurale, CHEMS, Université Mentouri-Constantine, 25000 Algeria.
*Correspondence e-mail: belhouas.ratiba@yahoo.fr

(Received 14 September 2009; accepted 15 September 2009; online 26 September 2009)

In the structure of the title compound, C13H17NO4, the packing is stabilized by weak C—H⋯O and C—H⋯π inter­actions, resulting in the formation of a three-dimensional network.

Related literature

For our studies on nitro­gen heterocycles, see: Debache et al. (2008a[Debache, A., Boulcina, R., Tafer, R., Belfaitah, A., Rhouati, S. & Carboni, B. (2008a). Chin. J. Chem. 26, 2112-2116.],b[Debache, A., Boulcina, R., Belfaitah, A., Rhouati, S. & Carboni, B. (2008b). Synlett, 4, 509-512.]); Boulcina et al. (2007[Boulcina, R., Bouacida, S., Roisnel, T. & Debache, A. (2007). Acta Cryst. E63, o3635-o3636.]).

[Scheme 1]

Experimental

Crystal data

  • C13H17NO4

  • Mr = 251.28

  • Monoclinic, P 21 /c

  • a = 4.5380 (6) Å

  • b = 15.440 (2) Å

  • c = 18.722 (2) Å

  • β = 90.502 (6)°

  • V = 1311.7 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 100 K

  • 0.58 × 0.34 × 0.25 mm
Data collection

  • Bruker APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2002[Sheldrick, G. M. (2002). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.942, Tmax = 0.977

  • 9968 measured reflections

  • 2977 independent reflections

  • 2442 reflections with I > 2σ(I)

  • Rint = 0.038
Refinement

  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.128

  • S = 1.04

  • 2977 reflections

  • 170 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.35 e Å−3

  • Δρmin = −0.23 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C9—H9A⋯O3i 0.97 2.51 3.2478 (18) 133
C6—H6B⋯Cgii 0.96 2.67 3.4279 (16) 136
Symmetry codes: (i) [-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) x-1, y, z. Cg is the centroid of the N1,C1–C5 ring.

Data collection: APEX2 (Bruker, 2003[Bruker (2003). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2003[Bruker (2003). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2003[Burla, M. C., Camalli, M., Carrozzini, B., Cascarano, G. L., Giacovazzo, C., Polidori, G. & Spagna, R. (2003). J. Appl. Cryst. 36, 1103.]); 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, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and DIAMOND (Brandenburg & Berndt, 2001[Brandenburg, K. & Berndt, M. (2001). DIAMOND. Crystal Impact, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809037349/hb5104sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809037349/hb5104Isup2.hkl

checkCIF report


Comment top

In continuation of our interest in the synthesis and structure determination of nitrogen heterocyclic compounds (e.g. Boulcina et al., 2007; Debache et al., 2008a; Debache et al., 2008b), herein, we report synthesis and crystallographic study of the title compound, (I), (Fig. 1), obtained from the oxidation of the corresponding 1,4-DHP.

The asymmetric unit of title compound contains a pyridine four times substituted by two dimethyl and two diethoxycarbonyl groups. As expected, The molecule is are approximately planar, the r.m.s. deviation for non-H atoms = 0.130Å with a maximum deviation from the mean plane = -0.3409 (19)Å for C13 atom.

The crystal structure can be described by two crossed layers which dihydropyridine ring is parallel to (-110) and (110) planes respectively (Fig.2).

The packing is stabilized by weak intermolecular interactions of C—H···O type (Figure 3) and the layers of dihydropyridine are linked together by C—H···π interactions (figure 4) involving the nitrogen heterocyclic ring (Cg), resulting in the formation of three dimensional network and reinforcing a cohesion of structure. Hydrogen-bonding parameters are listed in (table 1).

Related literature top

For our studies on nitrogen heterocycles, see: Debache et al. (2008a,b); Boulcina et al. (2007). Cg is the centroid of the N1,C1–C5 ring.

Experimental top

A 25-ml round-bottomed flask was charged with ethyl acetoacetate (2.0 mmol), 2-chloroquinoline-3-carboxaldehyde (1.0 mmol) and ammonium acetate (1.0 mmol), followed by 5 ml of water. The mixture was then refluxed until the reaction was completed (monitored by TLC). The reaction mixture was treated with brine solution, then extracted with ethyl acetate. After evaporation of the solvent, the crude yellow product was recrystallized from ethanol to give DHP in 85% yields. A solution of FeCl3.6H2O (0.1 mmol) in H2O (5 ml) was added to the obtained 1,4-dihydropyridines (1 mmol). The reaction mixture was stirred under refluxing until no starting material is detected. After the reaction was completed, the mixture was cooled to room temperature, quenched with 20 ml of H2O, neutralized with saturated aqueous solution of NaHCO3, and then extracted with ethyl acetate. The combined organic layer was dried over anhydrous sodium sulfate, and concentrated under a reduced pressure. Colourless blocks of (I) were obtained by a slow recrystallization from toluene.

Refinement top

In the final stages of refinement, all H atoms were localized in Fourier maps but introduced in calculated positions, with C—H distances of 0.96 and 0.97 for methylene and methyl H atoms, respectively, and refined using a riding model with Uiso(H) values of 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) for methylene H atoms. Except for H3 atom were located in a difference Fourier map and refined isotropically. All non-H atoms were refined with anisotropic atomic displacement parameters.

Computing details top

Data collection: APEX2 (Bruker,2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I): displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. A diagram of the layered crystal packing of (I) viewed down the c axis.
[Figure 3] Fig. 3. Unit cell of (I) showing hydrogen bond [C—H···O] as dashed line. Cg: is the controid of the nitrogen heterocyclic ring [N1—C5]
[Figure 4] Fig. 4. Part of crystal packing of (I) showing interactions between layers [C—H···π] as dashed line. Cg: is the controid of the nitrogen heterocyclic ring [N1—C5]
Diethyl 2,6-dimethylpyridine-3,5-dicarboxylate top
Crystal data top
C13H17NO4F(000) = 536
Mr = 251.28Dx = 1.272 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4103 reflections
a = 4.5380 (6) Åθ = 2.5–27.4°
b = 15.440 (2) ŵ = 0.09 mm−1
c = 18.722 (2) ÅT = 100 K
β = 90.502 (6)°Block, white
V = 1311.7 (3) Å30.58 × 0.34 × 0.25 mm
Z = 4
Data collection top
Bruker APEXII
diffractometer		2977 independent reflections
Radiation source: fine-focus sealed tube2442 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.038
Detector resolution: 10.0 pixels mm-1θmax = 27.6°, θmin = 2.5°
CCD rotation images, thin slices scansh = −4→5
Absorption correction: multi-scan
(SADABS; Sheldrick, 2002)		k = −19→19
Tmin = 0.942, Tmax = 0.977l = −24→24
9968 measured reflections
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)] = 0.048Hydrogen site location: difference Fourier map
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0665P)2 + 0.4357P]
where P = (Fo2 + 2Fc2)/3
2977 reflections(Δ/σ)max < 0.001
170 parametersΔρmax = 0.35 e Å−3
0 restraintsΔρmin = −0.23 e Å−3
Crystal data top
C13H17NO4V = 1311.7 (3) Å3
Mr = 251.28Z = 4
Monoclinic, P21/cMo Kα radiation
a = 4.5380 (6) ŵ = 0.09 mm−1
b = 15.440 (2) ÅT = 100 K
c = 18.722 (2) Å0.58 × 0.34 × 0.25 mm
β = 90.502 (6)°
Data collection top
Bruker APEXII
diffractometer		2977 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2002)		2442 reflections with I > 2σ(I)
Tmin = 0.942, Tmax = 0.977Rint = 0.038
9968 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.35 e Å−3
2977 reflectionsΔρmin = −0.23 e Å−3
170 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
C10.4395 (3)0.39005 (9)0.40522 (8)0.0176 (3)
C20.5062 (3)0.39184 (8)0.33193 (7)0.0167 (3)
C30.7120 (3)0.33252 (8)0.30658 (8)0.0161 (3)
H30.761 (5)0.3320 (13)0.2570 (12)0.05*
C40.8450 (3)0.27347 (8)0.35269 (7)0.0163 (3)
C50.7627 (3)0.27417 (9)0.42501 (7)0.0179 (3)
C60.2267 (3)0.45056 (9)0.44050 (8)0.0224 (3)
H6A0.19270.43170.48860.034*
H6B0.04370.45060.41440.034*
H6C0.30740.5080.44110.034*
C70.8829 (4)0.21296 (10)0.48038 (8)0.0248 (3)
H7A0.78550.22280.5250.037*
H7B1.09070.22260.48640.037*
H7C0.84950.15440.46520.037*
C81.0669 (3)0.21071 (8)0.32422 (7)0.0166 (3)
C91.3018 (3)0.16026 (9)0.21932 (8)0.0206 (3)
H9A1.24780.10050.22860.025*
H9B1.49940.170.23780.025*
C101.2891 (4)0.17865 (12)0.14082 (9)0.0396 (5)
H10A1.09320.16790.12310.059*
H10B1.42550.14170.11650.059*
H10C1.34030.23810.13250.059*
C110.3604 (3)0.45328 (9)0.28148 (8)0.0185 (3)
C120.2762 (4)0.49029 (10)0.16025 (8)0.0268 (4)
H12A0.35230.54880.16430.032*
H12B0.06480.49180.16740.032*
C130.3448 (6)0.45354 (13)0.08850 (10)0.0491 (6)
H13A0.55440.45270.0820.074*
H13B0.25490.48870.05210.074*
H13C0.26920.39560.08530.074*
N10.5655 (3)0.33183 (7)0.44964 (6)0.0189 (3)
O11.2043 (2)0.15896 (6)0.35969 (6)0.0236 (3)
O21.0940 (2)0.21896 (6)0.25334 (5)0.0201 (2)
O30.2067 (2)0.51374 (7)0.29916 (6)0.0286 (3)
O40.4163 (2)0.43422 (6)0.21325 (5)0.0238 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0130 (6)0.0164 (7)0.0233 (7)−0.0039 (5)0.0008 (5)−0.0038 (5)
C20.0142 (6)0.0138 (6)0.0219 (7)−0.0025 (5)0.0003 (5)−0.0023 (5)
C30.0144 (6)0.0148 (6)0.0190 (7)−0.0036 (5)0.0008 (5)−0.0025 (5)
C40.0136 (6)0.0144 (6)0.0208 (7)−0.0039 (5)0.0004 (5)−0.0019 (5)
C50.0162 (7)0.0161 (6)0.0213 (7)−0.0045 (5)−0.0002 (5)−0.0007 (5)
C60.0198 (7)0.0206 (7)0.0269 (8)0.0005 (6)0.0046 (6)−0.0056 (6)
C70.0285 (8)0.0245 (7)0.0215 (8)0.0017 (6)0.0030 (6)0.0034 (6)
C80.0152 (7)0.0129 (6)0.0218 (7)−0.0030 (5)−0.0001 (5)−0.0018 (5)
C90.0178 (7)0.0164 (6)0.0276 (8)0.0033 (5)0.0031 (6)−0.0047 (5)
C100.0495 (11)0.0414 (10)0.0280 (9)0.0200 (9)0.0102 (8)−0.0003 (7)
C110.0143 (6)0.0149 (6)0.0264 (8)−0.0032 (5)0.0008 (5)−0.0020 (5)
C120.0327 (9)0.0193 (7)0.0281 (8)0.0036 (6)−0.0081 (6)0.0023 (6)
C130.0827 (16)0.0362 (10)0.0283 (10)0.0183 (10)−0.0110 (10)0.0008 (8)
N10.0156 (6)0.0184 (6)0.0227 (6)−0.0039 (5)0.0021 (5)−0.0022 (5)
O10.0253 (6)0.0200 (5)0.0255 (6)0.0054 (4)−0.0004 (4)0.0016 (4)
O20.0209 (5)0.0190 (5)0.0205 (5)0.0047 (4)0.0036 (4)−0.0014 (4)
O30.0287 (6)0.0220 (5)0.0351 (6)0.0089 (5)0.0045 (5)−0.0002 (5)
O40.0301 (6)0.0188 (5)0.0225 (6)0.0076 (4)−0.0033 (4)0.0004 (4)
Geometric parameters (Å, º) top
C1—N11.3483 (19)C8—O21.3397 (17)
C1—C21.408 (2)C9—O21.4584 (16)
C1—C61.5011 (19)C9—C101.497 (2)
C2—C31.3945 (19)C9—H9A0.97
C2—C111.489 (2)C9—H9B0.97
C3—C41.3899 (19)C10—H10A0.96
C3—H30.96 (2)C10—H10B0.96
C4—C51.4079 (19)C10—H10C0.96
C4—C81.4986 (19)C11—O31.2132 (17)
C5—N11.3466 (18)C11—O41.3374 (18)
C5—C71.502 (2)C12—O41.4586 (18)
C6—H6A0.96C12—C131.493 (2)
C6—H6B0.96C12—H12A0.97
C6—H6C0.96C12—H12B0.97
C7—H7A0.96C13—H13A0.96
C7—H7B0.96C13—H13B0.96
C7—H7C0.96C13—H13C0.96
C8—O11.2089 (17)
N1—C1—C2121.38 (12)O2—C9—C10106.94 (12)
N1—C1—C6114.49 (12)O2—C9—H9A110.3
C2—C1—C6124.13 (13)C10—C9—H9A110.3
C3—C2—C1117.97 (13)O2—C9—H9B110.3
C3—C2—C11119.84 (12)C10—C9—H9B110.3
C1—C2—C11122.18 (12)H9A—C9—H9B108.6
C4—C3—C2120.54 (13)C9—C10—H10A109.5
C4—C3—H3119.5 (13)C9—C10—H10B109.5
C2—C3—H3119.9 (13)H10A—C10—H10B109.5
C3—C4—C5118.34 (12)C9—C10—H10C109.5
C3—C4—C8119.52 (12)H10A—C10—H10C109.5
C5—C4—C8122.13 (12)H10B—C10—H10C109.5
N1—C5—C4121.15 (13)O3—C11—O4122.98 (13)
N1—C5—C7114.72 (12)O3—C11—C2124.78 (13)
C4—C5—C7124.13 (13)O4—C11—C2112.24 (11)
C1—C6—H6A109.5O4—C12—C13107.06 (13)
C1—C6—H6B109.5O4—C12—H12A110.3
H6A—C6—H6B109.5C13—C12—H12A110.3
C1—C6—H6C109.5O4—C12—H12B110.3
H6A—C6—H6C109.5C13—C12—H12B110.3
H6B—C6—H6C109.5H12A—C12—H12B108.6
C5—C7—H7A109.5C12—C13—H13A109.5
C5—C7—H7B109.5C12—C13—H13B109.5
H7A—C7—H7B109.5H13A—C13—H13B109.5
C5—C7—H7C109.5C12—C13—H13C109.5
H7A—C7—H7C109.5H13A—C13—H13C109.5
H7B—C7—H7C109.5H13B—C13—H13C109.5
O1—C8—O2123.74 (12)C5—N1—C1120.60 (12)
O1—C8—C4125.24 (13)C8—O2—C9116.03 (11)
O2—C8—C4111.02 (11)C11—O4—C12115.71 (11)
C1—C2—C3—C40.29 (19)C9—C10—C11—C12−176.91 (12)
C2—C3—C4—C51.11 (19)C10—C11—C12—C1313.4 (2)
C3—C4—C5—C6−1.65 (14)C11—C12—C13—N12.46 (9)
C4—C5—C6—C7−179.72 (18)C12—C13—N1—O1−162.64 (16)
C5—C6—C7—C80.52 (11)C13—N1—O1—O23.02 (4)
C6—C7—C8—C9−172.90 (18)N1—O1—O2—O33.67 (3)
C7—C8—C9—C10167.30 (19)O1—O2—O3—O4−169.36 (7)
C8—C9—C10—C112.37 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O3i0.972.513.2478 (18)133
C6—H6B···Cgii0.962.673.4279 (16)136
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) x−1, y, z.

Experimental details

Crystal data
Chemical formulaC13H17NO4
Mr251.28
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)4.5380 (6), 15.440 (2), 18.722 (2)
β (°) 90.502 (6)
V (Å3)1311.7 (3)
Z4
Radiation typeMo Kα
µ (mm−1)0.09
Crystal size (mm)0.58 × 0.34 × 0.25
Data collection
DiffractometerBruker APEXII
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2002)
Tmin, Tmax0.942, 0.977
No. of measured, independent and
observed [I > 2σ(I)] reflections		9968, 2977, 2442
Rint0.038
(sin θ/λ)max (Å−1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.128, 1.04
No. of reflections2977
No. of parameters170
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.35, −0.23

Computer programs: APEX2 (Bruker,2003), SAINT (Bruker, 2003), SIR2002 (Burla et al., 2003), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Berndt, 2001), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O3i0.972.513.2478 (18)133
C6—H6B···Cgii0.962.673.4279 (16)136
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) x−1, y, z.
 

Acknowledgements

The authors are grateful to Dr Thierry Roisnel, Centre de Diffractométrie X (CDIFX) de Rennes, Université de Rennes 1, France, for data-collection facilities.

References

First citationBoulcina, R., Bouacida, S., Roisnel, T. & Debache, A. (2007). Acta Cryst. E63, o3635–o3636.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationBrandenburg, K. & Berndt, M. (2001). DIAMOND. Crystal Impact, Bonn, Germany.  Google Scholar
 First citationBruker (2003). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationBurla, M. C., Camalli, M., Carrozzini, B., Cascarano, G. L., Giacovazzo, C., Polidori, G. & Spagna, R. (2003). J. Appl. Cryst. 36, 1103.  CrossRef IUCr Journals Google Scholar
 First citationDebache, A., Boulcina, R., Belfaitah, A., Rhouati, S. & Carboni, B. (2008b). Synlett, 4, 509–512.  Web of Science CrossRef Google Scholar
 First citationDebache, A., Boulcina, R., Tafer, R., Belfaitah, A., Rhouati, S. & Carboni, B. (2008a). Chin. J. Chem. 26, 2112–2116.  CrossRef CAS Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2002). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 65| Part 10| October 2009| Page o2528
doi:10.1107/S1600536809037349
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