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

Journal logoIUCrDATA
ISSN: 2414-3146

N-[(1aR,5aR,8R,9aR)-1,1-Di­chloro-1a,5,5,7-tetra­methyl-1a,2,3,4,5,5a,8,9-octa­hydro-1H-benzo[a]cyclo­propa[b][7]annulen-8-yl]acetamide

aLaboratoire de Chimie des Substances Naturelles, Unité Associé au CNRST (URAC16), Faculté des Sciences Semlalia, BP 2390 Bd My Abdellah, Université Cadi Ayyad, 40000 Marrakech, Morocco, bLaboratoire de Chimie du Solide Appliquée, Faculty of Sciences, Mohammed V University in Rabat, Avenue Ibn Batouta BP 1014 Rabat, Morocco, and cLaboratoire de Chimie Bioorganique et Macromoléculaire, Faculté des Sciences et Techniques, Université Cadi Ayyad, 40000 Marrakech, Morocco
*Correspondence e-mail: benharref@uca.ac.ma

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 21 March 2017; accepted 29 March 2017; online 11 April 2017)

In the title compound, C18H27Cl2NO, the cyclo­hexene ring has an envelope conformation, with the C atom at the 9a position as the flap. The cyclo­heptane ring, to which it is fused, has a boat conformation. The dihedral angle between their mean planes is 60.7 (2)°. The 1,1-di­chloro-cyclo­propane ring is inclined to these two ring mean planes by 88.5 (3) and 28.3 (3)°, respectively. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming 61 helices along the c-axis direction. The absolute configuration of the mol­ecule in the crystal could be fully confirmed from anomalous dispersion effects [Flack parameter = 0.020 (15)].

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

The bicyclic sesquiterpene β-himachalene is the main constituent of the essential oil of the Atlas cedar (Cedrus Atlantica) (El Haib et al., 2010[Haib, A. E., Benharref, A., Parrès-Maynadié, S., Manoury, E., Daran, J. C., Urrutigoïty, M. & Gouygou, M. (2010). Tetrahedron Asymmetry, 21, 1272-1277.]; Loubidi et al., 2014[Loubidi, M., Agustin, D., Benharref, A. & Poli, R. (2014). C. R. Chim. 17, 549-556.]). The reactivity of these sesquiterpenes and their derivatives has been studied extensively by our team (El Jamili et al., 2002[El Jamili, H., Auhmani, A., Dakir, M., Lassaba, E., Benharref, A., Pierrot, M., Chiaroni, A. & Riche, C. (2002). Tetrahedron Lett. 43, 6645-6648.]; El Haib et al., 2011[El Haib, A., Benharref, A., Parrès-Maynadié, S., Manoury, E., Urrutigoïty, M. & Gouygou, M. (2011). Tetrahedron Asymmetry, 22, 101-108.]; Benharref et al., 2015[Benharref, A., Elkarroumi, J., El Ammari, L., Saadi, M. & Berraho, M. (2015). Acta Cryst. E71, o659-o660.], 2016[Benharref, A., Oukhrib, A., Ait Elhad, M., El Ammari, L., Saadi, M. & Berraho, M. (2016). IUCrData, 1, x160703.]) in order to prepare new products with biological properties. Indeed, these compounds have been tested, using the food-poisoning technique, for their potential anti­fungal activity against the phytopathogen Botrytis cinerea (Daoubi et al., 2004[Daoubi, M., Durán-Patrón, R., Hmamouchi, M., Hernández-Galán, R., Benharref, A. & Collado, I. G. (2004). Pest Manag. Sci. 60, 927-932.]). Herein, we report on the synthesis and crystal structure of the title modified β-himachalene compound.

The structure of the title compound, Fig. 1[link], is built up from a cyclo­heptane ring (C1/C3–C8), which is fused to a cyclo­hexene ring (C1/C8–C12), and a cyclo­propane ring (C1–C3). The six-membered ring has an envelope conformation with atom C1 (position 9a) as the flap [puckering parameters are: QT = 0.456 (4) Å, θ = 125.3 (6)° and φ = 173.6 (7)°], whereas the seven-membered ring displays a boat conformation [puckering parameters are: QT = 1.1390 (53) Å, θ = 89.19 (30)°, φ2 = 311.1 (3)°, φ3 = 24 (2)°]. The dihedral angle between their mean planes is 60.7 (2)°. The cyclo­propane ring is normal to the mean plane of the cyclo­hexene ring, making a dihedral angle of 88.5 (3)°.

[Figure 1]
Figure 1
The mol­ecular structure of the title compound, with the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming helices running along the c-axis direction (Fig. 2[link] and Table 1[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O1i 0.86 2.20 3.059 (4) 175
Symmetry code: (i) [y, -x+y, z-{\script{1\over 6}}].
[Figure 2]
Figure 2
A view along the a axis of the crystal packing of the title compound, showing mol­ecules linked by N—H⋯O hydrogen bonds (dashed lines; see Table 1[link]). For clarity, C-bound H atoms have been omitted.

Synthesis and crystallization

3 g (10 mmol) of 2,2-di­chloro-9,10-ep­oxy-3,7,7,10- tetra­methyl-tri­cyclo­[6.4.0.01,3]dodecane (Sbai et al., 2002[Sbai, F., Dakir, M., Auhmani, A., El Jamili, H., Akssira, M., Benharref, A., Kenz, A. & Pierrot, M. (2002). Acta Cryst. C58, o518-o520.]) was dissolved in 30 ml of CH3CN and stirred at 273 K under argon. BF3OEt (3% mmol) was added and the reaction mixture was stirred and monitored by TLC. After the completion of reaction, the solvent was removed and the residue obtained was chromatographed on silica, eluting with hexa­ne–ethyl­acetate (90:10), which allowed the isolation of the title compound (yield 70%). It was recrystallized from ethyl acetate solution and yielded colourless prismatic crystals on slow evaporation of the solvent.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. Owing to the presence of the Cl atoms, the absolute configuration could be fully confirmed from anomalous dispersion effects [Flack parameter = 0.020 (15)].

Table 2
Experimental details

Crystal data
Chemical formula C18H27Cl2NO
Mr 344.30
Crystal system, space group Hexagonal, P61
Temperature (K) 296
a, c (Å) 10.5372 (4), 29.9710 (11)
V3) 2881.9 (2)
Z 6
Radiation type Mo Kα
μ (mm−1) 0.34
Crystal size (mm) 0.24 × 0.2 × 0.15
 
Data collection
Diffractometer Bruker X8 APEX Diffractometer
Absorption correction Multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.666, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 53780, 3934, 3513
Rint 0.042
(sin θ/λ)max−1) 0.625
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.109, 1.08
No. of reflections 3934
No. of parameters 204
No. of restraints 1
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.45, −0.22
Absolute structure Flack x determined using 1571 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.])
Absolute structure parameter 0.020 (15)
Computer programs: APEX2 and SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT2014/7 (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]), SHELXL2014/7 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT2014/7 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014/7 (Sheldrick, 2015b) and publCIF (Westrip, 2010).

N-[(1aR,5aR,8R,9aR)-1,1-Dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-yl]acetamide top
Crystal data top
C18H27Cl2NODx = 1.190 Mg m3
Mr = 344.30Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P61Cell parameters from 3934 reflections
a = 10.5372 (4) Åθ = 2.3–26.4°
c = 29.9710 (11) ŵ = 0.34 mm1
V = 2881.9 (2) Å3T = 296 K
Z = 6Prismatic, colourless
F(000) = 11040.24 × 0.2 × 0.15 mm
Data collection top
Bruker X8 APEX Diffractometer3513 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.042
φ and ω scansθmax = 26.4°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 1313
Tmin = 0.666, Tmax = 0.746k = 1313
53780 measured reflectionsl = 3737
3934 independent 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)] = 0.039H-atom parameters constrained
wR(F2) = 0.109 w = 1/[σ2(Fo2) + (0.0665P)2 + 0.3403P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max < 0.001
3934 reflectionsΔρmax = 0.45 e Å3
204 parametersΔρmin = 0.22 e Å3
1 restraintAbsolute structure: Flack x determined using 1571 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.020 (15)
Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C180.5450 (7)0.7825 (6)0.1505 (3)0.128 (3)
H18A0.50000.78840.12330.192*
H18B0.60770.74290.14430.192*
H18C0.60190.87870.16310.192*
C170.5129 (8)0.6699 (7)0.2229 (2)0.123 (3)
H17A0.57350.63180.21260.184*
H17B0.44470.60440.24470.184*
H17C0.57320.76440.23620.184*
Cl10.09118 (10)0.37089 (13)0.08694 (3)0.0641 (3)
Cl20.10316 (9)0.19825 (11)0.15688 (3)0.0607 (3)
N10.1265 (4)0.1158 (3)0.21087 (9)0.0511 (7)
H10.10800.08280.18400.061*
C20.0507 (4)0.3694 (4)0.14440 (11)0.0469 (7)
C100.3586 (4)0.3202 (4)0.18513 (12)0.0530 (8)
C90.3998 (4)0.4388 (4)0.16039 (12)0.0520 (8)
H90.47940.46610.14150.062*
C10.1732 (4)0.4450 (3)0.17758 (10)0.0430 (7)
C110.2348 (4)0.2701 (4)0.21848 (11)0.0498 (8)
H110.27770.27480.24790.060*
O10.0812 (4)0.0650 (4)0.28373 (10)0.0747 (9)
C120.1652 (4)0.3679 (4)0.22130 (10)0.0466 (7)
H12A0.06340.30830.23000.056*
H12B0.21480.44100.24430.056*
C80.3304 (4)0.5331 (4)0.15991 (11)0.0494 (8)
H80.32270.55420.12850.059*
C30.0687 (4)0.5032 (4)0.16756 (12)0.0565 (9)
C140.0566 (4)0.0260 (4)0.24435 (12)0.0510 (8)
C130.4342 (6)0.2307 (7)0.18241 (17)0.0803 (13)
H13A0.36950.13770.16890.120*
H13B0.45960.21550.21190.120*
H13C0.52140.28210.16470.120*
C150.0558 (6)0.1280 (5)0.23115 (18)0.0775 (13)
H15A0.03200.19590.24480.116*
H15B0.05580.13760.19930.116*
H15C0.15100.14870.24090.116*
C40.1314 (7)0.6467 (6)0.14176 (18)0.0827 (15)
H4A0.05150.66160.13250.099*
H4B0.17950.63960.11510.099*
C160.0474 (6)0.4854 (6)0.20148 (16)0.0751 (12)
H16A0.13330.47130.18600.113*
H16B0.00950.57180.21960.113*
H16C0.07230.40200.22010.113*
C70.4279 (5)0.6846 (5)0.18313 (17)0.0756 (13)
C50.2408 (8)0.7790 (6)0.1690 (2)0.1000 (19)
H5A0.18720.81520.18600.120*
H5B0.30490.85600.14860.120*
C60.3382 (8)0.7484 (6)0.2021 (3)0.113 (2)
H6A0.40510.83990.21670.136*
H6B0.27440.68200.22500.136*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C180.098 (4)0.062 (3)0.151 (6)0.014 (3)0.053 (4)0.003 (4)
C170.117 (5)0.088 (4)0.106 (5)0.008 (3)0.042 (4)0.035 (4)
Cl10.0514 (5)0.1048 (8)0.0286 (4)0.0334 (5)0.0005 (3)0.0010 (4)
Cl20.0445 (4)0.0679 (6)0.0495 (5)0.0128 (4)0.0036 (4)0.0046 (4)
N10.0697 (19)0.0473 (15)0.0320 (13)0.0262 (14)0.0014 (12)0.0003 (11)
C20.0447 (16)0.061 (2)0.0299 (15)0.0226 (15)0.0048 (13)0.0045 (13)
C100.0502 (18)0.062 (2)0.0375 (16)0.0212 (16)0.0087 (14)0.0015 (15)
C90.0430 (16)0.062 (2)0.0359 (17)0.0150 (15)0.0008 (13)0.0028 (15)
C10.0501 (17)0.0399 (15)0.0299 (14)0.0157 (14)0.0044 (13)0.0001 (12)
C110.062 (2)0.0530 (18)0.0273 (14)0.0233 (16)0.0061 (13)0.0004 (13)
O10.091 (2)0.093 (2)0.0381 (14)0.0438 (18)0.0096 (13)0.0121 (13)
C120.059 (2)0.0438 (16)0.0258 (13)0.0172 (15)0.0029 (13)0.0016 (12)
C80.0501 (17)0.0469 (17)0.0328 (15)0.0105 (14)0.0066 (14)0.0014 (13)
C30.070 (2)0.062 (2)0.043 (2)0.0369 (19)0.0142 (16)0.0122 (16)
C140.062 (2)0.055 (2)0.0431 (19)0.0338 (17)0.0100 (15)0.0097 (15)
C130.089 (3)0.106 (4)0.061 (3)0.060 (3)0.001 (2)0.012 (2)
C150.089 (3)0.056 (2)0.080 (3)0.031 (2)0.027 (2)0.013 (2)
C40.117 (4)0.078 (3)0.069 (3)0.061 (3)0.027 (3)0.029 (2)
C160.095 (3)0.086 (3)0.064 (3)0.059 (3)0.024 (2)0.010 (2)
C70.068 (3)0.047 (2)0.072 (3)0.0012 (19)0.010 (2)0.0086 (19)
C50.139 (5)0.057 (3)0.106 (4)0.050 (3)0.030 (4)0.021 (3)
C60.121 (5)0.060 (3)0.121 (5)0.016 (3)0.033 (4)0.022 (3)
Geometric parameters (Å, º) top
C18—C71.506 (7)C12—H12A0.9700
C18—H18A0.9600C12—H12B0.9700
C18—H18B0.9600C8—C71.565 (5)
C18—H18C0.9600C8—H80.9800
C17—C71.544 (9)C3—C41.524 (6)
C17—H17A0.9600C3—C161.529 (5)
C17—H17B0.9600C14—C151.506 (6)
C17—H17C0.9600C13—H13A0.9600
Cl1—C21.772 (3)C13—H13B0.9600
Cl2—C21.760 (4)C13—H13C0.9600
N1—C141.322 (5)C15—H15A0.9600
N1—C111.464 (5)C15—H15B0.9600
N1—H10.8600C15—H15C0.9600
C2—C31.495 (5)C4—C51.528 (9)
C2—C11.504 (5)C4—H4A0.9700
C10—C91.326 (6)C4—H4B0.9700
C10—C131.510 (7)C16—H16A0.9600
C10—C111.514 (5)C16—H16B0.9600
C9—C81.500 (6)C16—H16C0.9600
C9—H90.9300C7—C61.518 (9)
C1—C121.522 (4)C5—C61.572 (11)
C1—C81.532 (4)C5—H5A0.9700
C1—C31.533 (5)C5—H5B0.9700
C11—C121.537 (5)C6—H6A0.9700
C11—H110.9800C6—H6B0.9700
O1—C141.234 (5)
C7—C18—H18A109.5C2—C3—C4119.2 (3)
C7—C18—H18B109.5C2—C3—C16118.5 (3)
H18A—C18—H18B109.5C4—C3—C16112.4 (4)
C7—C18—H18C109.5C2—C3—C159.5 (2)
H18A—C18—H18C109.5C4—C3—C1117.1 (3)
H18B—C18—H18C109.5C16—C3—C1120.7 (3)
C7—C17—H17A109.5O1—C14—N1122.6 (4)
C7—C17—H17B109.5O1—C14—C15122.1 (4)
H17A—C17—H17B109.5N1—C14—C15115.4 (4)
C7—C17—H17C109.5C10—C13—H13A109.5
H17A—C17—H17C109.5C10—C13—H13B109.5
H17B—C17—H17C109.5H13A—C13—H13B109.5
C14—N1—C11121.5 (3)C10—C13—H13C109.5
C14—N1—H1119.2H13A—C13—H13C109.5
C11—N1—H1119.2H13B—C13—H13C109.5
C3—C2—C161.5 (2)C14—C15—H15A109.5
C3—C2—Cl2119.0 (2)C14—C15—H15B109.5
C1—C2—Cl2120.6 (2)H15A—C15—H15B109.5
C3—C2—Cl1121.7 (3)C14—C15—H15C109.5
C1—C2—Cl1119.9 (2)H15A—C15—H15C109.5
Cl2—C2—Cl1108.06 (19)H15B—C15—H15C109.5
C9—C10—C13122.2 (4)C3—C4—C5112.9 (4)
C9—C10—C11121.1 (4)C3—C4—H4A109.0
C13—C10—C11116.7 (4)C5—C4—H4A109.0
C10—C9—C8126.3 (3)C3—C4—H4B109.0
C10—C9—H9116.9C5—C4—H4B109.0
C8—C9—H9116.9H4A—C4—H4B107.8
C2—C1—C12118.9 (3)C3—C16—H16A109.5
C2—C1—C8118.3 (3)C3—C16—H16B109.5
C12—C1—C8112.0 (3)H16A—C16—H16B109.5
C2—C1—C359.0 (2)C3—C16—H16C109.5
C12—C1—C3121.5 (3)H16A—C16—H16C109.5
C8—C1—C3117.7 (3)H16B—C16—H16C109.5
N1—C11—C10110.0 (3)C18—C7—C6114.7 (5)
N1—C11—C12112.7 (3)C18—C7—C17104.6 (6)
C10—C11—C12114.8 (3)C6—C7—C17106.0 (5)
N1—C11—H11106.2C18—C7—C8107.8 (4)
C10—C11—H11106.2C6—C7—C8112.4 (4)
C12—C11—H11106.2C17—C7—C8111.1 (4)
C1—C12—C11113.2 (3)C4—C5—C6115.0 (4)
C1—C12—H12A108.9C4—C5—H5A108.5
C11—C12—H12A108.9C6—C5—H5A108.5
C1—C12—H12B108.9C4—C5—H5B108.5
C11—C12—H12B108.9C6—C5—H5B108.5
H12A—C12—H12B107.8H5A—C5—H5B107.5
C9—C8—C1109.5 (3)C7—C6—C5118.0 (5)
C9—C8—C7112.5 (3)C7—C6—H6A107.8
C1—C8—C7115.1 (3)C5—C6—H6A107.8
C9—C8—H8106.4C7—C6—H6B107.8
C1—C8—H8106.4C5—C6—H6B107.8
C7—C8—H8106.4H6A—C6—H6B107.1
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.862.203.059 (4)175
Symmetry code: (i) y, x+y, z1/6.
 

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

References

First citationBenharref, A., Elkarroumi, J., El Ammari, L., Saadi, M. & Berraho, M. (2015). Acta Cryst. E71, o659–o660.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationBenharref, A., Oukhrib, A., Ait Elhad, M., El Ammari, L., Saadi, M. & Berraho, M. (2016). IUCrData, 1, x160703.  Google Scholar
First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDaoubi, M., Durán-Patrón, R., Hmamouchi, M., Hernández-Galán, R., Benharref, A. & Collado, I. G. (2004). Pest Manag. Sci. 60, 927–932.  Web of Science CrossRef PubMed CAS Google Scholar
First citationEl Haib, A., Benharref, A., Parrès-Maynadié, S., Manoury, E., Urrutigoïty, M. & Gouygou, M. (2011). Tetrahedron Asymmetry, 22, 101–108.  Web of Science CrossRef CAS Google Scholar
First citationEl Jamili, H., Auhmani, A., Dakir, M., Lassaba, E., Benharref, A., Pierrot, M., Chiaroni, A. & Riche, C. (2002). Tetrahedron Lett. 43, 6645–6648.  CAS Google Scholar
First citationHaib, A. E., Benharref, A., Parrès-Maynadié, S., Manoury, E., Daran, J. C., Urrutigoïty, M. & Gouygou, M. (2010). Tetrahedron Asymmetry, 21, 1272–1277.  Web of Science CSD CrossRef Google Scholar
First citationLoubidi, M., Agustin, D., Benharref, A. & Poli, R. (2014). C. R. Chim. 17, 549–556.  Web of Science CrossRef CAS Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSbai, F., Dakir, M., Auhmani, A., El Jamili, H., Akssira, M., Benharref, A., Kenz, A. & Pierrot, M. (2002). Acta Cryst. C58, o518–o520.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoIUCrDATA
ISSN: 2414-3146
Follow IUCr Journals
Sign up for e-alerts
Follow IUCr on Twitter
Follow us on facebook
Sign up for RSS feeds