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

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(5R)-5-[(1R)-2,2-Di­chloro-1-methyl­cyclo­prop­yl]-2-methyl­cyclo­hex-2-en-1-one

aLaboratoire de Chimie de Coordination, Université Cadi Ayyad, Faculté des Sciences-Semlalia, BP 2390, 40001 Marrakech, Morocco, and bDipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universitá degli Studi di Parma, Viale G. P. Usberti 17/A, I-43124 Parma, Italy
*Correspondence e-mail: corrado.rizzoli@unipr.it

(Received 3 June 2011; accepted 7 June 2011; online 11 June 2011)

The title compound, C11H14Cl2O, was synthesized by the reaction of a dichloro­methane solution of (R)-carvone and potassium tert-butano­late in the presence of a catalytic amount of benzyl­triethyl­ammonium chloride in chloro­form. The cyclo­hexene ring adopts a half-boat conformation. The cyclo­propyl ring is unsymmetrical, the shortest C—C bond being distal to the alkyl-substituted C atom. The crystal packing is stabilized only by van der Waals inter­actions.

Related literature

For background to and applications of dichloro­cyclo­propane derivatives, see: Hirota et al. (1996[Hirota, H., Tomono, Y. & Fusetani, N. (1996). Tetrahedron, 52, 2359-2368.]); Künzer et al. (1996[Künzer, H., Thiel, M. & Peschke, B. (1996). Tetrahedron Lett. 37, 1771-1772.]); Ziyat et al. (2004[Ziyat, H., El Houssame, S., Ait Ali, M., Ait Itto, M. Y., Karim, A., Wartchow, R. & Butenschen, H. (2004). Z. Naturforsch. Teil B, 59, 1177-1179.]); Fedorynski (2003[Fedorynski, M. (2003). Chem. Rev. 103, 1099-1132.]). For the synthesis and structures of optically active dihalogenocylopropanes reported by our group, see: Ziyat et al. (2002[Ziyat, H., Ait Itto, M. Y., Ait Ali, M., Karim, A., Riahi, A. & Daran, J.-C. (2002). Acta Cryst. C58, o90-o93.]); Boualy et al. (2009[Boualy, B., El Firdoussi, L., Ait Ali, M., Karim, A. & Spannenberg, A. (2009). Z. Kristallogr. New Cryst. Struct. 224, 1-2.]); Ziyat et al. (2006[Ziyat, H., Ait Itto, M. Y., Ait Ali, M., Riahi, A., Karim, A. & Daran, J.-C. (2006). ARKIVOC, XII, 152-160.]). For puckering parameters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]).

[Scheme 1]

Experimental

Crystal data
  • C11H14Cl2O

  • Mr = 233.12

  • Monoclinic, P 21

  • a = 6.5722 (3) Å

  • b = 8.4802 (4) Å

  • c = 10.8022 (5) Å

  • β = 104.435 (4)°

  • V = 583.04 (5) Å3

  • Z = 2

  • Cu Kα radiation

  • μ = 4.73 mm−1

  • T = 294 K

  • 0.25 × 0.20 × 0.14 mm

Data collection
  • Siemens AED diffractometer

  • Absorption correction: refined from ΔF (DIFABS; Walker & Stuart, 1983[Walker, N. & Stuart, D. (1983). Acta Cryst. A39, 158-166.]) Tmin = 0.327, Tmax = 0.519

  • 2295 measured reflections

  • 1576 independent reflections

  • 1554 reflections with I > 2σ(I)

  • Rint = 0.057

  • 3 standard reflections every 100 reflections intensity decay: 0.3%

Refinement
  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.126

  • S = 1.09

  • 1576 reflections

  • 130 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.43 e Å−3

  • Δρmin = −0.30 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 394 Friedel pairs

  • Flack parameter: 0.00 (2)

Data collection: AED (Belletti et al., 1993[Belletti, D., Cantoni, A. & Pasquinelli, G. (1993). AED. Internal Report 1/93. Centro di Studio per la Strutturistica Diffrattometrica del CNR, Parma, Italy.]); cell refinement: AED; data reduction: AED; program(s) used to solve structure: SIR97 (Altomare et al., 1999[Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.]); 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 SCHAKAL97 (Keller, 1997[Keller, E. (1997). SCHAKAL97. University of Freiburg, Germany.]); software used to prepare material for publication: SHELXL97 and PARST95 (Nardelli, 1995[Nardelli, M. (1995). J. Appl. Cryst. 28, 659.]).

Supporting information


Comment top

Dichlorocyclopropanes play an important role in organic synthesis, due to the widespread occurrence of these structures in biologically active compounds (Hirota et al., 1996; Künzer et al., 1996). These compounds have found wide applications as substrates for the synthesis of many class of compounds such as pyrethroides (Ziyat et al., 2004), benzocyclopropenes or cyclopentadiene derivatives (Fedorynski, 2003), which are not easily obtained using other starting materials. As a part of our ongoing research aimed at the synthesis of optically active dihalogenocylopropanes from terpenes (Ziyat et al., 2002; Ziyat et al., 2004; Boualy et al., 2009; Ziyat et al., 2006), the title compound has been prepared and its crystal structure is reported herein.

In the title compound (Fig. 1), the cyclohexene ring adopts a half-boat conformation [puckering parameters for ring C6/C1/C2/C3/C4/C5: Q = 0.478 (4) Å, θ = 126.7 (4)°, ϕ = -171.0 (6)°; Cremer & Pople, 1975] with atom C6 displaced by 0.645 (3) Å from the mean plane through the C1–C5 atoms. The cyclopropyl ring (C7–C9) is tilted by 57.64 (19)° with respect to this plane. As already observed in related compounds (Ziyat et al., 2002), the geometry of the cyclopropyl ring is unsymmetrical, the distal bond to the alkyl-substituted C7 carbon atom (C8—C9 = 1.477 (6) Å) being significantly shorter than the vicinal bonds (C7—C8 = 1.518 (6) Å; C7—C9 = 1.500 (4) Å). The crystal packing (Fig. 2) is governed only by van der Waals interactions. The shortest intermolecular halogen···halogen separation is Cl1···Cl2i = 3.990 (3) Å (symmetry code: (i) 2 - x, -1/2 + y, 1 - z).

Related literature top

For background to and applications of dichlorocyclopropane derivatives, see: Hirota et al. (1996); Künzer et al. (1996); Ziyat et al. (2004); Fedorynski (2003). For the synthesis and structures of optically active dihalogenocylopropanes reported by our group, see: Ziyat et al. (2002); Boualy et al. (2009); Ziyat et al. (2006). For puckering parameters, see: Cremer & Pople (1975).

Experimental top

Potassium tert-butanolate (4.00 g, 19.8 mmol) was added to (R)-carvone (1.47 g, 9.8 mmol) and benzyltriethylammonium chloride (0.02 g, 0.1 mmol) in dichloromethane (60 ml). The mixture was stirred for 10 min, then chloroform (0.8 ml, 9.8 mmol) was added dropwise over a period of 30 min. The mixture was stirred for 8 h at 25°C, and then hydrolyzed by addition of water (20 ml). The organic layer was separated and the aqueous layer was extracted with dichloromethane (3 × 10 ml). The combined organic extracts were dried over Na2SO4 and the solvent was removed under reduced pressure. Column chromatography on silica gel (hexane/ethyl acetate, 5:1 v/v) of the residue gave 1.24 g (5.3 mmol, 54% yield) of the title compound as colourless crystals. Slow evaporation of a chloroform solution of the title compound at 25°C afforded crystals suitable for X-ray crystallographic analysis. M.p. 392 K. [α]20D = +7.72° (c 1, chloroform). 1H NMR (300 MHz, CDCl3, δp.p.m.): 1.18 (s, 2H), 1.3 (s, 3H), 1.78 (d, J = 0.9 Hz, 3H), 2.1 (m, 1H), 2.3–2.5 (m, 4H), 6.77 (m, 1H). 13C NMR (75 MHz, CDCl3, δp.p.m.): 15.6 (CH3), 16.0 (CH3), 28.5 (CH2), 32.5 (CH2), 40.8 (Cq), 41.4 (CH2), 41.8 (CH), 65.8 (Cq), 135.5 ( Cq), 144.5 (CH), 199 (CO). MS (70 eV) m/z (%): 233 [M+].

Refinement top

All H atoms were fixed geometrically and treated as riding, with C–H = 0.93–0.98 Å, and with Uiso(H) = 1.2 Ueq(C) or 1.5 Ueq(C) for methyl H atoms. The absolute configuration of the molecule was established by the known chirality of the (R)-carvone starting material and, in spite of the low Friedel pair coverage (40%), the value of the resulting Flack (1983) parameter was in accordance with this configuration. For the inverted structure, the Flack parameter refined to 0.71 (3), and the values of R[F2>2σ(F2)] and wR(F2) increased to 0.0583 and 0.1695, respectively.

Computing details top

Data collection: AED (Belletti et al., 1993); cell refinement: AED (Belletti et al., 1993); data reduction: AED (Belletti et al., 1993); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and SCHAKAL97 (Keller, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PARST95 (Nardelli, 1995)'.

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 40% probability level.
[Figure 2] Fig. 2. Crystal packing of the title compound approximately viewed along the a axis.
(5R)-5-[(1R)-2,2-Dichloro-1-methylcyclopropyl]-2-methylcyclohex- 2-en-1-one top
Crystal data top
C11H14Cl2OF(000) = 244
Mr = 233.12Dx = 1.328 Mg m3
Monoclinic, P21Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ybCell parameters from 48 reflections
a = 6.5722 (3) Åθ = 22.5–35.9°
b = 8.4802 (4) ŵ = 4.73 mm1
c = 10.8022 (5) ÅT = 294 K
β = 104.435 (4)°Irregular block, colourless
V = 583.04 (5) Å30.25 × 0.20 × 0.14 mm
Z = 2
Data collection top
Siemens AED
diffractometer
1554 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.057
Graphite monochromatorθmax = 69.8°, θmin = 4.2°
θ/2θ scansh = 76
Absorption correction: part of the refinement model (ΔF)
(DIFABS; Walker & Stuart, 1983)
k = 106
Tmin = 0.327, Tmax = 0.519l = 1213
2295 measured reflections3 standard reflections every 100 reflections
1576 independent reflections intensity decay: 0.3%
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.046 w = 1/[σ2(Fo2) + (0.083P)2 + 0.0912P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.126(Δ/σ)max < 0.001
S = 1.09Δρmax = 0.43 e Å3
1576 reflectionsΔρmin = 0.30 e Å3
130 parametersExtinction correction: SHELXL
1 restraintExtinction coefficient: 0.014 (3)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 394 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.00 (2)
Crystal data top
C11H14Cl2OV = 583.04 (5) Å3
Mr = 233.12Z = 2
Monoclinic, P21Cu Kα radiation
a = 6.5722 (3) ŵ = 4.73 mm1
b = 8.4802 (4) ÅT = 294 K
c = 10.8022 (5) Å0.25 × 0.20 × 0.14 mm
β = 104.435 (4)°
Data collection top
Siemens AED
diffractometer
1554 reflections with I > 2σ(I)
Absorption correction: part of the refinement model (ΔF)
(DIFABS; Walker & Stuart, 1983)
Rint = 0.057
Tmin = 0.327, Tmax = 0.5193 standard reflections every 100 reflections
2295 measured reflections intensity decay: 0.3%
1576 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.046H-atom parameters constrained
wR(F2) = 0.126Δρmax = 0.43 e Å3
S = 1.09Δρmin = 0.30 e Å3
1576 reflectionsAbsolute structure: Flack (1983), 394 Friedel pairs
130 parametersAbsolute structure parameter: 0.00 (2)
1 restraint
Special details top

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
Cl11.34023 (13)0.77757 (15)0.58246 (8)0.0824 (4)
Cl20.90330 (12)0.84462 (16)0.47313 (8)0.0858 (4)
O10.7651 (5)0.7920 (6)0.1253 (3)0.0987 (12)
C11.0031 (5)0.7536 (6)0.0774 (3)0.0693 (10)
H1A1.05230.85970.06770.083*
H1B1.10990.68050.06520.083*
C20.8020 (5)0.7244 (5)0.0244 (3)0.0636 (8)
C30.6586 (5)0.6053 (4)0.0053 (3)0.0554 (7)
C40.7023 (5)0.5357 (4)0.1185 (3)0.0571 (7)
H40.60910.45900.13220.069*
C50.8894 (4)0.5702 (4)0.2264 (3)0.0548 (7)
H5A0.99820.49270.22700.066*
H5B0.84990.56270.30690.066*
C60.9740 (4)0.7342 (4)0.2127 (3)0.0496 (6)
H60.86680.81010.22270.059*
C71.1744 (4)0.7717 (5)0.3144 (3)0.0584 (7)
C81.2112 (6)0.9436 (6)0.3526 (4)0.0799 (11)
H8A1.35470.98220.37310.096*
H8B1.10621.01970.31080.096*
C91.1528 (4)0.8301 (5)0.4415 (3)0.0614 (7)
C100.4642 (6)0.5669 (7)0.0993 (4)0.0791 (11)
H10A0.39660.66300.13440.119*
H10B0.36920.50550.06440.119*
H10C0.50370.50790.16550.119*
C111.3618 (5)0.6704 (8)0.3127 (4)0.0909 (15)
H11A1.38160.66730.22760.136*
H11B1.33860.56540.33950.136*
H11C1.48480.71380.36990.136*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0728 (5)0.0887 (7)0.0691 (5)0.0062 (4)0.0133 (3)0.0101 (5)
Cl20.0610 (4)0.1189 (9)0.0741 (5)0.0072 (5)0.0107 (3)0.0351 (6)
O10.115 (2)0.115 (3)0.0616 (14)0.024 (2)0.0147 (13)0.028 (2)
C10.0660 (16)0.081 (3)0.0632 (17)0.0162 (17)0.0201 (13)0.007 (2)
C20.0756 (17)0.066 (2)0.0503 (15)0.0062 (16)0.0182 (13)0.0030 (17)
C30.0608 (14)0.0537 (16)0.0500 (14)0.0017 (14)0.0104 (11)0.0062 (15)
C40.0616 (15)0.0554 (17)0.0544 (16)0.0067 (13)0.0146 (12)0.0029 (15)
C50.0571 (14)0.0535 (17)0.0515 (15)0.0014 (12)0.0091 (11)0.0047 (14)
C60.0467 (12)0.0490 (16)0.0512 (14)0.0010 (10)0.0087 (10)0.0009 (13)
C70.0443 (12)0.0613 (18)0.0666 (17)0.0028 (13)0.0083 (11)0.0043 (17)
C80.075 (2)0.064 (2)0.090 (3)0.0173 (18)0.0005 (17)0.001 (2)
C90.0511 (13)0.0621 (19)0.0632 (15)0.0017 (13)0.0003 (11)0.0075 (17)
C100.081 (2)0.086 (3)0.0612 (18)0.019 (2)0.0007 (15)0.007 (2)
C110.0462 (15)0.124 (4)0.097 (3)0.015 (2)0.0073 (16)0.027 (3)
Geometric parameters (Å, º) top
Cl1—C91.760 (3)C6—C71.523 (4)
Cl2—C91.761 (3)C6—H60.9800
O1—C21.202 (4)C7—C91.500 (4)
C1—C21.514 (4)C7—C111.506 (5)
C1—C61.529 (4)C7—C81.518 (6)
C1—H1A0.9700C8—C91.477 (6)
C1—H1B0.9700C8—H8A0.9700
C2—C31.470 (5)C8—H8B0.9700
C3—C41.323 (4)C10—H10A0.9600
C3—C101.515 (4)C10—H10B0.9600
C4—C51.497 (4)C10—H10C0.9600
C4—H40.9300C11—H11A0.9600
C5—C61.519 (5)C11—H11B0.9600
C5—H5A0.9700C11—H11C0.9600
C5—H5B0.9700
C2—C1—C6112.4 (2)C11—C7—C8118.4 (3)
C2—C1—H1A109.1C9—C7—C6117.9 (2)
C6—C1—H1A109.1C11—C7—C6115.8 (3)
C2—C1—H1B109.1C8—C7—C6116.5 (3)
C6—C1—H1B109.1C9—C8—C760.1 (3)
H1A—C1—H1B107.8C9—C8—H8A117.8
O1—C2—C3122.0 (3)C7—C8—H8A117.8
O1—C2—C1121.5 (3)C9—C8—H8B117.8
C3—C2—C1116.5 (3)C7—C8—H8B117.8
C4—C3—C2120.3 (3)H8A—C8—H8B114.9
C4—C3—C10122.8 (3)C8—C9—C761.3 (3)
C2—C3—C10116.9 (3)C8—C9—Cl1119.2 (2)
C3—C4—C5125.4 (3)C7—C9—Cl1120.2 (2)
C3—C4—H4117.3C8—C9—Cl2119.1 (3)
C5—C4—H4117.3C7—C9—Cl2120.4 (2)
C4—C5—C6110.7 (3)Cl1—C9—Cl2109.55 (18)
C4—C5—H5A109.5C3—C10—H10A109.5
C6—C5—H5A109.5C3—C10—H10B109.5
C4—C5—H5B109.5H10A—C10—H10B109.5
C6—C5—H5B109.5C3—C10—H10C109.5
H5A—C5—H5B108.1H10A—C10—H10C109.5
C5—C6—C7113.1 (3)H10B—C10—H10C109.5
C5—C6—C1109.1 (3)C7—C11—H11A109.5
C7—C6—C1112.1 (2)C7—C11—H11B109.5
C5—C6—H6107.4H11A—C11—H11B109.5
C7—C6—H6107.4C7—C11—H11C109.5
C1—C6—H6107.4H11A—C11—H11C109.5
C9—C7—C11117.6 (3)H11B—C11—H11C109.5
C9—C7—C858.6 (3)

Experimental details

Crystal data
Chemical formulaC11H14Cl2O
Mr233.12
Crystal system, space groupMonoclinic, P21
Temperature (K)294
a, b, c (Å)6.5722 (3), 8.4802 (4), 10.8022 (5)
β (°) 104.435 (4)
V3)583.04 (5)
Z2
Radiation typeCu Kα
µ (mm1)4.73
Crystal size (mm)0.25 × 0.20 × 0.14
Data collection
DiffractometerSiemens AED
diffractometer
Absorption correctionPart of the refinement model (ΔF)
(DIFABS; Walker & Stuart, 1983)
Tmin, Tmax0.327, 0.519
No. of measured, independent and
observed [I > 2σ(I)] reflections
2295, 1576, 1554
Rint0.057
(sin θ/λ)max1)0.609
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.126, 1.09
No. of reflections1576
No. of parameters130
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.43, 0.30
Absolute structureFlack (1983), 394 Friedel pairs
Absolute structure parameter0.00 (2)

Computer programs: AED (Belletti et al., 1993), SIR97 (Altomare et al., 1999), ORTEP-3 for Windows (Farrugia, 1997) and SCHAKAL97 (Keller, 1997), SHELXL97 (Sheldrick, 2008) and PARST95 (Nardelli, 1995)'.

 

Acknowledgements

Financial support from the Universitá degli Studi di Parma is gratefully acknowledged.

References

First citationAltomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119.  Web of Science CrossRef CAS IUCr Journals
First citationBelletti, D., Cantoni, A. & Pasquinelli, G. (1993). AED. Internal Report 1/93. Centro di Studio per la Strutturistica Diffrattometrica del CNR, Parma, Italy.
First citationBoualy, B., El Firdoussi, L., Ait Ali, M., Karim, A. & Spannenberg, A. (2009). Z. Kristallogr. New Cryst. Struct. 224, 1–2.
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals
First citationFedorynski, M. (2003). Chem. Rev. 103, 1099–1132.  Web of Science PubMed CAS
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals
First citationHirota, H., Tomono, Y. & Fusetani, N. (1996). Tetrahedron, 52, 2359–2368.  CrossRef CAS
First citationKeller, E. (1997). SCHAKAL97. University of Freiburg, Germany.
First citationKünzer, H., Thiel, M. & Peschke, B. (1996). Tetrahedron Lett. 37, 1771–1772.
First citationNardelli, M. (1995). J. Appl. Cryst. 28, 659.  CrossRef IUCr Journals
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationWalker, N. & Stuart, D. (1983). Acta Cryst. A39, 158–166.  CrossRef CAS Web of Science IUCr Journals
First citationZiyat, H., Ait Itto, M. Y., Ait Ali, M., Karim, A., Riahi, A. & Daran, J.-C. (2002). Acta Cryst. C58, o90–o93.  Web of Science CSD CrossRef CAS IUCr Journals
First citationZiyat, H., Ait Itto, M. Y., Ait Ali, M., Riahi, A., Karim, A. & Daran, J.-C. (2006). ARKIVOC, XII, 152–160.  CrossRef
First citationZiyat, H., El Houssame, S., Ait Ali, M., Ait Itto, M. Y., Karim, A., Wartchow, R. & Butenschen, H. (2004). Z. Naturforsch. Teil B, 59, 1177–1179.  CAS

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