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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

(2E)-1-Phenyl-2-[1-(2-phenyl­prop-2-en-1-yl)pyrrolidin-2-yl­­idene]ethanone

aMolecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, PO WITS, 2050, Johannesburg, South Africa
*Correspondence e-mail: joseph.michael@wits.ac.za

(Received 17 October 2012; accepted 26 October 2012; online 3 November 2012)

The title compound, C21H21NO, is a vinyl­ogous amide (enaminone) produced by reaction of 1-(2-phenyl­prop-2-en-1-yl)pyrrolidine-2-thione with phenacyl bromide. In the mol­ecule, the phenyl rings are twisted from the mean plane of the pyrrolidine ring by 11.2 (1) and 67.3 (1)°. In the crystal, weak C—H⋯O hydrogen bonds link the mol­ecules related by translation along the b axis into chains.

Related literature

For details of the synthesis of enamino­nes, see: Roth et al. (1971[Roth, M., Dubs, P., Götschi, E. & Eschenmoser, A. (1971). Helv. Chim. Acta, 54, 710-734.]). For applications of enamino­nes in alkaloid synthesis, see: Michael et al. (1999[Michael, J. P., de Koning, C. B., Gravestock, D., Hosken, G. D., Howard, A. S., Jungmann, C. M., Krause, R. W. M., Parsons, A. S., Pelly, S. C. & Stanbury, T. V. (1999). Pure Appl. Chem. 71, 979-988.]). For a related enaminone structure, see: Lemmerer et al. (2007[Lemmerer, A., Michael, J. P., Pienaar, D. P. & Sannasy, D. (2007). Acta Cryst. E63, o98-o99.]).

[Scheme 1]

Experimental

Crystal data
  • C21H21NO

  • Mr = 303.39

  • Triclinic, P 1

  • a = 5.7806 (6) Å

  • b = 7.9407 (7) Å

  • c = 9.6089 (9) Å

  • α = 82.579 (7)°

  • β = 76.793 (7)°

  • γ = 83.510 (7)°

  • V = 424.21 (7) Å3

  • Z = 1

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 293 K

  • 0.4 × 0.2 × 0.19 mm

Data collection
  • Bruker APEXII CCD area-detector diffractometer

  • 5222 measured reflections

  • 1563 independent reflections

  • 970 reflections with I > 2σ(I)

  • Rint = 0.040

Refinement
  • R[F2 > 2σ(F2)] = 0.044

  • wR(F2) = 0.119

  • S = 0.98

  • 1563 reflections

  • 208 parameters

  • 3 restraints

  • H-atom parameters constrained

  • Δρmax = 0.11 e Å−3

  • Δρmin = −0.13 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C3—H3⋯O1i 0.93 2.45 3.368 (5) 170
Symmetry code: (i) x, y+1, z.

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2004[Bruker (2004). SAINT-Plus and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus and XPREP (Bruker, 2004[Bruker (2004). SAINT-Plus and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.]); 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, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and DIAMOND (Brandenburg, 1999[Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

The title compound, (2E)-1-phenyl-2-[1-(2-phenylprop-2-en-1-yl)pyrrolidin-2-ylidene] ethanone, (I), was prepared as part of an ongoing project dealing with the use of enaminones as intermediates for alkaloid synthesis (Michael et al., 1999).

In (I) (Fig. 1), two phenyl rings are twisted from the mean plane of the central pyrrolidine ring by 11.2 (1) and 67.3 (1)°, respectively. The (E) configuration and s-cis conformation of the exocyclic CC bond of the enaminone are similar to those found in a related enaminone (Lemmerer et al., 2007). In the crystal, weak intermolecular C—H···O hydrogen bonds (Table 1) link the molecules related by translation along the b axis into chains (Fig. 2).

Related literature top

For details of the synthesis of enaminones, see: Roth et al. (1971). For applications of enaminones in alkaloid synthesis, see: Michael et al. (1999). For a related enaminone structure, see: Lemmerer et al. (2007).

Experimental top

The synthesis employed followed the Eschenmoser procedure (Roth et al., 1971). A solution of phenacyl bromide (4.30 g, 21.6 mmol) and 1-(2-phenylprop-2-en-1-yl)pyrrolidine-2-thione (4.27 g, 19.6 mmol) in dry acetonitrile (20 ml) was stirred at room temperature under an argon atmosphere until precipitation of the adduct as a gum was complete. The mixture was briefly warmed to solubilize the precipitate, after which a solution of triphenylphosphine (5.66 g, 21.6 mmol) and triethylamine (3.31 ml, 23.6 mmol) in dry MeCN (20 ml) was added dropwise to induce extrusion of sulfur, and stirring was maintained for 18 h. The solvent was evaporated and the residue was taken up into ethyl acetate (200 ml) and washed with water (3 × 100 ml) and brine (50 ml). The organic phase was dried over MgSO4, filtered and evaporated to give an orange gum. Column chromatography on silica gel with hexane:ethyl acetate (3:2 v/v) afforded the title compound (5.42 g, 91%) as very pale yellow needles, m.p. 325—326 K.

Refinement top

The C-bound H atoms were geometrically positioned [C—H = 0.93 Å (alkenyl- and aromatic-H) and 0.97 Å (methylene-H)] and refined as riding with Uiso(H) = 1.2Ueq(C). In the absence of significant anomalous scatterers in the molecule, 1562 Friedel pairs were merged before the final refinement.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); 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, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atomic numbering scheme. Displacement ellipsoids are shown at the 50% probability level.
[Figure 2] Fig. 2. A portion of the crystal packing showing C—H···O hydrogen bonds as dashed red lines. H atoms not involved in hydrogen bonding are omitted for clarity.
(2E)-1-Phenyl-2-[1-(2-phenylprop-2-en-1-yl)pyrrolidin-2-ylidene]ethanone top
Crystal data top
C21H21NOZ = 1
Mr = 303.39F(000) = 162
Triclinic, P1Dx = 1.188 Mg m3
Hall symbol: P 1Mo Kα radiation, λ = 0.71073 Å
a = 5.7806 (6) ÅCell parameters from 1287 reflections
b = 7.9407 (7) Åθ = 2.2–24.8°
c = 9.6089 (9) ŵ = 0.07 mm1
α = 82.579 (7)°T = 293 K
β = 76.793 (7)°Prism, colourless
γ = 83.510 (7)°0.4 × 0.2 × 0.19 mm
V = 424.21 (7) Å3
Data collection top
Bruker APEXII CCD area-detector
diffractometer
Rint = 0.040
ω scansθmax = 25.5°, θmin = 2.2°
5222 measured reflectionsh = 66
1563 independent reflectionsk = 99
970 reflections with I > 2σ(I)l = 1111
Refinement top
Refinement on F23 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.044 w = 1/[σ2(Fo2) + (0.0653P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.119(Δ/σ)max < 0.001
S = 0.98Δρmax = 0.11 e Å3
1563 reflectionsΔρmin = 0.13 e Å3
208 parameters
Crystal data top
C21H21NOγ = 83.510 (7)°
Mr = 303.39V = 424.21 (7) Å3
Triclinic, P1Z = 1
a = 5.7806 (6) ÅMo Kα radiation
b = 7.9407 (7) ŵ = 0.07 mm1
c = 9.6089 (9) ÅT = 293 K
α = 82.579 (7)°0.4 × 0.2 × 0.19 mm
β = 76.793 (7)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer
970 reflections with I > 2σ(I)
5222 measured reflectionsRint = 0.040
1563 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0443 restraints
wR(F2) = 0.119H-atom parameters constrained
S = 0.98Δρmax = 0.11 e Å3
1563 reflectionsΔρmin = 0.13 e Å3
208 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.6399 (6)0.8328 (4)1.0527 (4)0.0522 (9)
C20.5691 (7)1.0058 (4)1.0341 (4)0.0653 (11)
H20.4461.04330.98690.078*
C30.6799 (8)1.1226 (5)1.0850 (5)0.0752 (12)
H30.63161.23821.07180.09*
C40.8608 (8)1.0687 (6)1.1548 (5)0.0785 (13)
H40.93711.14721.18810.094*
C50.9283 (7)0.8981 (6)1.1751 (5)0.0789 (13)
H51.05010.86041.22330.095*
C60.8181 (7)0.7835 (5)1.1250 (4)0.0659 (11)
H60.86560.6681.14060.079*
C70.5255 (7)0.6979 (4)1.0017 (4)0.0636 (11)
C80.3853 (7)0.7440 (4)0.8977 (4)0.0585 (10)
H80.37370.85740.85910.07*
C90.2666 (7)0.6322 (5)0.8508 (4)0.0636 (11)
C100.2782 (9)0.4424 (5)0.8878 (5)0.0838 (13)
H10A0.21240.41370.98930.101*
H10B0.44190.39290.86530.101*
C110.1326 (11)0.3781 (7)0.7980 (7)0.1127 (19)
H11A0.23470.31090.72670.135*
H11B0.01480.30680.85820.135*
C120.0139 (10)0.5276 (7)0.7269 (6)0.1016 (17)
H12A0.15750.53330.76330.122*
H12B0.04770.52340.62380.122*
C130.0360 (8)0.8452 (6)0.7109 (4)0.0773 (12)
H13A0.04210.92110.78110.093*
H13B0.12940.84690.70460.093*
C140.1767 (8)0.9137 (6)0.5674 (4)0.0778 (12)
C150.0892 (8)1.0875 (6)0.5101 (4)0.0751 (12)
C160.1450 (9)1.1520 (6)0.5513 (6)0.0909 (14)
H160.25061.08660.61850.109*
C170.2279 (11)1.3117 (8)0.4954 (7)0.1099 (17)
H170.38731.35180.52370.132*
C180.0743 (16)1.4078 (8)0.3995 (7)0.1170 (19)
H180.12941.51440.36140.14*
C190.1563 (17)1.3526 (10)0.3579 (6)0.121 (2)
H190.26121.4220.29420.145*
C200.2381 (9)1.1892 (8)0.4114 (5)0.1007 (17)
H200.39651.14920.37920.121*
C210.3663 (10)0.8275 (8)0.4994 (6)0.1161 (19)
H21A0.45270.87410.41170.139*
H21B0.41470.71970.53890.139*
O10.5650 (7)0.5495 (3)1.0546 (4)0.0998 (11)
N10.1148 (6)0.6753 (4)0.7626 (3)0.0725 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.067 (2)0.0394 (18)0.049 (2)0.0063 (17)0.0088 (18)0.0052 (16)
C20.081 (3)0.041 (2)0.076 (3)0.004 (2)0.019 (2)0.0123 (18)
C30.094 (3)0.048 (2)0.086 (3)0.011 (2)0.016 (3)0.018 (2)
C40.086 (3)0.078 (3)0.077 (3)0.024 (3)0.012 (3)0.027 (2)
C50.074 (3)0.089 (3)0.079 (3)0.004 (3)0.022 (2)0.019 (3)
C60.080 (3)0.052 (2)0.065 (3)0.003 (2)0.015 (2)0.0099 (19)
C70.089 (3)0.044 (2)0.058 (3)0.007 (2)0.012 (2)0.0082 (19)
C80.074 (2)0.044 (2)0.057 (2)0.0108 (19)0.009 (2)0.0080 (18)
C90.074 (3)0.063 (2)0.054 (2)0.017 (2)0.002 (2)0.017 (2)
C100.111 (3)0.058 (2)0.088 (3)0.024 (2)0.015 (3)0.023 (2)
C110.135 (5)0.097 (4)0.118 (5)0.047 (4)0.020 (4)0.034 (4)
C120.107 (4)0.113 (4)0.097 (4)0.035 (3)0.019 (3)0.043 (3)
C130.069 (3)0.101 (3)0.065 (3)0.009 (2)0.015 (2)0.017 (2)
C140.072 (3)0.106 (3)0.055 (2)0.022 (2)0.011 (2)0.001 (2)
C150.077 (3)0.108 (3)0.048 (2)0.032 (3)0.015 (2)0.014 (2)
C160.091 (4)0.091 (3)0.094 (3)0.023 (3)0.022 (3)0.004 (3)
C170.125 (5)0.108 (4)0.112 (5)0.010 (4)0.052 (4)0.021 (4)
C180.172 (7)0.113 (5)0.083 (4)0.042 (5)0.049 (4)0.009 (4)
C190.179 (7)0.126 (5)0.064 (4)0.078 (5)0.019 (4)0.010 (3)
C200.107 (4)0.145 (5)0.055 (3)0.051 (4)0.005 (3)0.015 (3)
C210.108 (4)0.129 (4)0.085 (3)0.000 (3)0.025 (3)0.007 (3)
O10.165 (3)0.0361 (15)0.114 (3)0.0150 (15)0.065 (2)0.0006 (14)
N10.082 (2)0.075 (2)0.067 (2)0.0187 (19)0.018 (2)0.0181 (18)
Geometric parameters (Å, º) top
C1—C61.365 (5)C11—H11B0.97
C1—C21.389 (4)C12—N11.478 (6)
C1—C71.507 (5)C12—H12A0.97
C2—C31.380 (5)C12—H12B0.97
C2—H20.93C13—N11.437 (5)
C3—C41.368 (6)C13—C141.501 (6)
C3—H30.93C13—H13A0.97
C4—C51.368 (6)C13—H13B0.97
C4—H40.93C14—C211.309 (6)
C5—C61.360 (6)C14—C151.495 (6)
C5—H50.93C15—C201.371 (6)
C6—H60.93C15—C161.379 (6)
C7—O11.239 (4)C16—C171.390 (7)
C7—C81.413 (5)C16—H160.93
C8—C91.358 (5)C17—C181.348 (8)
C8—H80.93C17—H170.93
C9—N11.342 (5)C18—C191.341 (8)
C9—C101.500 (5)C18—H180.93
C10—C111.503 (7)C19—C201.404 (8)
C10—H10A0.97C19—H190.93
C10—H10B0.97C20—H200.93
C11—C121.472 (7)C21—H21A0.93
C11—H11A0.97C21—H21B0.93
C6—C1—C2117.7 (3)C11—C12—N1104.6 (4)
C6—C1—C7118.8 (3)C11—C12—H12A110.8
C2—C1—C7123.5 (3)N1—C12—H12A110.8
C3—C2—C1120.5 (4)C11—C12—H12B110.8
C3—C2—H2119.7N1—C12—H12B110.8
C1—C2—H2119.7H12A—C12—H12B108.9
C4—C3—C2120.2 (4)N1—C13—C14115.3 (4)
C4—C3—H3119.9N1—C13—H13A108.5
C2—C3—H3119.9C14—C13—H13A108.5
C3—C4—C5119.4 (4)N1—C13—H13B108.5
C3—C4—H4120.3C14—C13—H13B108.5
C5—C4—H4120.3H13A—C13—H13B107.5
C6—C5—C4120.2 (4)C21—C14—C15122.8 (4)
C6—C5—H5119.9C21—C14—C13121.7 (5)
C4—C5—H5119.9C15—C14—C13115.5 (4)
C5—C6—C1122.0 (4)C20—C15—C16116.7 (5)
C5—C6—H6119C20—C15—C14121.3 (4)
C1—C6—H6119C16—C15—C14122.0 (4)
O1—C7—C8123.9 (3)C15—C16—C17122.0 (5)
O1—C7—C1116.2 (4)C15—C16—H16119
C8—C7—C1119.9 (3)C17—C16—H16119
C9—C8—C7123.8 (3)C18—C17—C16119.1 (6)
C9—C8—H8118.1C18—C17—H17120.5
C7—C8—H8118.1C16—C17—H17120.5
N1—C9—C8124.8 (3)C19—C18—C17121.3 (6)
N1—C9—C10108.2 (3)C19—C18—H18119.3
C8—C9—C10127.0 (4)C17—C18—H18119.3
C9—C10—C11105.7 (4)C18—C19—C20119.5 (6)
C9—C10—H10A110.6C18—C19—H19120.3
C11—C10—H10A110.6C20—C19—H19120.3
C9—C10—H10B110.6C15—C20—C19121.3 (6)
C11—C10—H10B110.6C15—C20—H20119.4
H10A—C10—H10B108.7C19—C20—H20119.4
C12—C11—C10107.5 (4)C14—C21—H21A120
C12—C11—H11A110.2C14—C21—H21B120
C10—C11—H11A110.2H21A—C21—H21B120
C12—C11—H11B110.2C9—N1—C13126.6 (3)
C10—C11—H11B110.2C9—N1—C12113.4 (4)
H11A—C11—H11B108.5C13—N1—C12119.8 (4)
C6—C1—C2—C31.3 (5)N1—C13—C14—C15177.5 (3)
C7—C1—C2—C3179.2 (4)C21—C14—C15—C2021.8 (7)
C1—C2—C3—C40.2 (6)C13—C14—C15—C20156.6 (4)
C2—C3—C4—C50.8 (6)C21—C14—C15—C16156.8 (5)
C3—C4—C5—C60.6 (7)C13—C14—C15—C1624.7 (5)
C4—C5—C6—C10.5 (6)C20—C15—C16—C170.4 (6)
C2—C1—C6—C51.5 (6)C14—C15—C16—C17178.3 (4)
C7—C1—C6—C5179.5 (4)C15—C16—C17—C181.0 (7)
C6—C1—C7—O114.8 (5)C16—C17—C18—C190.4 (8)
C2—C1—C7—O1163.2 (4)C17—C18—C19—C202.2 (8)
C6—C1—C7—C8164.4 (4)C16—C15—C20—C191.5 (6)
C2—C1—C7—C817.7 (5)C14—C15—C20—C19179.8 (4)
O1—C7—C8—C94.2 (6)C18—C19—C20—C152.8 (8)
C1—C7—C8—C9176.7 (3)C8—C9—N1—C135.1 (6)
C7—C8—C9—N1173.4 (4)C10—C9—N1—C13174.4 (4)
C7—C8—C9—C106.0 (6)C8—C9—N1—C12179.0 (4)
N1—C9—C10—C115.6 (5)C10—C9—N1—C121.5 (5)
C8—C9—C10—C11174.9 (4)C14—C13—N1—C994.1 (4)
C9—C10—C11—C127.5 (5)C14—C13—N1—C1290.3 (5)
C10—C11—C12—N16.6 (5)C11—C12—N1—C93.3 (5)
N1—C13—C14—C214.0 (6)C11—C12—N1—C13179.5 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O1i0.932.453.368 (5)170
Symmetry code: (i) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC21H21NO
Mr303.39
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)5.7806 (6), 7.9407 (7), 9.6089 (9)
α, β, γ (°)82.579 (7), 76.793 (7), 83.510 (7)
V3)424.21 (7)
Z1
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.4 × 0.2 × 0.19
Data collection
DiffractometerBruker APEXII CCD area-detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
5222, 1563, 970
Rint0.040
(sin θ/λ)max1)0.605
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.119, 0.98
No. of reflections1563
No. of parameters208
No. of restraints3
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.11, 0.13

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2004), SAINT-Plus and XPREP (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O1i0.932.453.368 (5)170
Symmetry code: (i) x, y+1, z.
 

Acknowledgements

This research was supported by the University of the Witwatersrand and the Mol­ecular Sciences Institute, which are thanked for providing the infrastructure required to do this work.

References

First citationBrandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.
First citationBruker (2004). SAINT-Plus and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals
First citationLemmerer, A., Michael, J. P., Pienaar, D. P. & Sannasy, D. (2007). Acta Cryst. E63, o98–o99.  Web of Science CSD CrossRef IUCr Journals
First citationMichael, J. P., de Koning, C. B., Gravestock, D., Hosken, G. D., Howard, A. S., Jungmann, C. M., Krause, R. W. M., Parsons, A. S., Pelly, S. C. & Stanbury, T. V. (1999). Pure Appl. Chem. 71, 979–988.  Web of Science CrossRef CAS
First citationRoth, M., Dubs, P., Götschi, E. & Eschenmoser, A. (1971). Helv. Chim. Acta, 54, 710–734.  CrossRef CAS Web of Science
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals

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 logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds