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

Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 67| Part 5| May 2011| Page o1257

(S)-(+)-N-Benzyl­­idene-1-(1-naphth­yl)ethyl­amine

aDEP Facultad de Ciencias Químicas, UANL, Guerrero y Progreso S/N, Col. Treviño, 64570 Monterrey, N.L., Mexico, bLaboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico, and cUniversidad de la Cañada, Cd. Universitaria, 68540, Teotitlán de Flores Magón, Oax., Mexico
*Correspondence e-mail: sylvain_bernes@Hotmail.com

(Received 1 April 2011; accepted 7 April 2011; online 29 April 2011)

In the title chiral aldimine, C19H17N, the azomethine group is not fully conjugated with the phenyl substituent: the dihedral angle between phenyl and C*—N=C mean planes is φ3 = 23.0 (2)°. Compared with the earlier DFT-B3LYP/6–31 G(d) computations from the literature, the C=N—C*—C(naph­thyl) torsion angle, found at φ2 = −118.0 (2)° in the X-ray structure, does not match the angle calculated for the potential minimum energy at φ2 = 0°. However, this angle is close to the second potential energy minimum at φ2 = −120° which is ca. 8.5 kJ mol−1 above the global energy minimum. Thus, the reported X-ray structure corresponds to the second most likely (according to DFT) conformer, allowing the existence of other polymorphs to be anti­cipated.

Related literature

For a typical synthesis of the title compound, see: Lee & Ahn (2002[Lee, T. & Ahn, Y. (2002). Bull. Korean Chem. Soc. 23, 1490-1492.]). For general background to solvent-free synthesis, see: Tanaka & Toda (2000[Tanaka, K. & Toda, F. (2000). Chem. Rev. 100, 1025-1074.]). For the structures of related imines, see: Espinosa Leija et al. (2009[Espinosa Leija, A., Hernández, G., Portillo, R., Gutiérrez, R. & Bernès, S. (2009). Acta Cryst. E65, o1651.]); Bernès et al. (2010[Bernès, S., Hernández, G., Portillo, R., Cruz, S. & Gutiérrez, R. (2010). Acta Cryst. E66, o1322-o1323.]). For the DFT study of the title compound (R enanti­omer), see: Fukuda et al. (2007[Fukuda, K., Suzuki, H., Tokita, M., Watanabe, J. & Kawauchi, S. (2007). J. Mol. Struct. (Theochem), 821, 95-100.]).

[Scheme 1]

Experimental

Crystal data
  • C19H17N

  • Mr = 259.34

  • Monoclinic, P 21

  • a = 8.0761 (8) Å

  • b = 7.7874 (8) Å

  • c = 11.7760 (11) Å

  • β = 95.033 (7)°

  • V = 737.76 (13) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 298 K

  • 0.4 × 0.2 × 0.2 mm

Data collection
  • Siemens P4 diffractometer

  • 2470 measured reflections

  • 1595 independent reflections

  • 1276 reflections with I > 2σ(I)

  • Rint = 0.017

  • 3 standard reflections every 97 reflections intensity decay: 1%

Refinement
  • R[F2 > 2σ(F2)] = 0.034

  • wR(F2) = 0.094

  • S = 1.02

  • 1595 reflections

  • 183 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.09 e Å−3

  • Δρmin = −0.08 e Å−3

Data collection: XSCANS (Siemens, 1996[Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); cell refinement: XSCANS; data reduction: XSCANS; 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: Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Schiff base compounds are widely studied and used, attracting much attention in both organic synthesis and metal ion complexation. Recently, we have focused our attention on the synthesis of chiral and achiral Schiff bases (Espinosa Leija et al., 2009; Bernès et al., 2010). In continuation of this work, we synthesized the title compound using the solvent-free approach (Tanaka & Toda, 2000). The reaction occurs under mild conditions and requires easier workup procedures and simpler equipment, compared to similar reactions carried out in solution, for example - in refluxing CH2Cl2 (Lee & Ahn, 2002).

In the title molecule (Fig. 1), all distances and bond angles have expected values. The imine group has a sterically favored E conformation, and it is rotated by 23.0 (2)° relative to the phenyl group (the dihedral angle between planes of N1/C2/C9 and C3···C8 groups). The dihedral angle between aromatic phenyl and naphthyl groups is 70.7 (1)°. This molecular conformation is significantly different from one observed in the solid-state for a related imine bearing a thiophene group instead of the phenyl (Espinosa Leija et al., 2009), in which corresponding angles are 5.1 (8) and 83.79 (13)°.

Interestingly, there is a study on conformational flexibility of the title compound that has been published on the basis of DFT calculations at B3LYP/6–31 G(d) level (Fukuda et al., 2007). The potential energies for internal rotations around σ bonds C9*—C11 (ϕ1), C9*—N1 (ϕ2) and C2—C3 (ϕ3) were computed (see Fig. 1 for the angle notations, hereafter assumed for the S enantiomer). The dihedral angle ϕ1 related to the orientation of the naphthyl group has two energy minima, with the global minimum at ϕ1 = 40°, close to that found by X-ray diffraction (ϕ1 = N1—C9—C11—C12 = -25.3 (3)°). Similarly, the orientations for the phenyl ring are consistent between DFT and X-ray data: ϕ3 = 0° vs. ϕ3 = N1—C2—C3—C8 = 19.9 (4)°. In contrast, internal rotation ϕ2 computed by DFT presents a minimum at ϕ2 = 0°, far different from the angle observed in the crystal structure: ϕ2 = C2—N1—C9—C11 = -118.0 (2)°. However, on the ϕ2 potential curve published by Fukuda et al., there are two lesser minima, at ϕ2 = -120° and ϕ2 = 110°. The first one is consistent with the conformer observed in the solid-state (ϕ2 = -118°) and is placed only 2 kcal/mol above the ϕ2 = 0° minimum. It may thus be expected that the title molecule could be crystallized in different polymorphic phases, derived from conformers with different values for the angle ϕ2.

Related literature top

For a typical synthesis of the title compound, see: Lee & Ahn (2002). For general background to solvent-free synthesis, see: Tanaka & Toda (2000). For the structures of related imines, see: Espinosa Leija et al. (2009); Bernès et al. (2010). For the DFT study of the title compound (R enantiomer), see: Fukuda et al. (2007).

Experimental top

The title compound was prepared by reacting (S)-(–)-(1-naphthyl)ethylamine and benzaldehyde (Lee & Ahn, 2002), but at room temperature and using no solvent. The crude was recrystallized from EtOH affording colorless crystals of the title compound. Yield 94%; mp 79–81 oC. Analysis: [α]D25 = +233 (c 1, CHCl3). FT—IR (KBr): 1641 cm-1 (C=N). 1H NMR (400 MHz, CDCl3/TMS) δ = 1.71 (d, 3H, CH—CH3,), 5.31 (q, 1H, Ar—CH), 7.34–8.24 (m, 12H, Ar), 8.36 (s, 1H, H-C=N). 13C NMR (100 MHz, CDCl3/TMS) δ = 24.51 (CCH3), 65.51 (CHCH3), 123.56 (Ar), 123.97 (Ar), 125.26 (Ar), 125.64(Ar), 125.74 (Ar), 127.28 (Ar), 128.21 (Ar), 128.46 (Ar), 128.88 (Ar), 130.52 (Ar), 130.60 (Ar), 133.94 (Ar), 136.43 (Ar),141.12 (Ar), 159.55 (HC=N). MS—EI: m/z= 259 (M+).

Refinement top

All C-bonded H atoms were placed in idealized positions and refined as riding to their carrier C atoms, with bond lengths fixed to 0.93 (aromatic CH), 0.96 (methyl CH3), and 0.98 Å (methine CH). Isotropic displacement parameters were calculated as Uiso(H) = 1.5Ueq(C10) for the methyl group and Uiso(H) = 1.2Ueq(carrier atom) otherwise. The methyl group C10 was considered as a rigid group but was allowed to rotate about C9—C10 bond. The absolute configuration was assigned from the known configuration of the chiral amine used as the starting material and confirmed by measring the optical rotation and comparing with rotations reported in the litterature for both enantiomers. All measured Friedel pairs (223) were merged.

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS (Siemens, 1996); data reduction: XSCANS (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The title molecule with displacement ellipsoids for non-H atoms shown at the 30% probability level. The scheme indicates the torsion angles used in the DFT study of Fukuda et al. (2007).
(S)-(+)-N-Benzylidene-1-(1-naphthyl)ethylamine top
Crystal data top
C19H17NF(000) = 276
Mr = 259.34Dx = 1.167 Mg m3
Monoclinic, P21Melting point: 352 K
Hall symbol: P 2ybMo Kα radiation, λ = 0.71073 Å
a = 8.0761 (8) ÅCell parameters from 80 reflections
b = 7.7874 (8) Åθ = 4.9–12.3°
c = 11.7760 (11) ŵ = 0.07 mm1
β = 95.033 (7)°T = 298 K
V = 737.76 (13) Å3Irregular, colourless
Z = 20.4 × 0.2 × 0.2 mm
Data collection top
Siemens P4
diffractometer
Rint = 0.017
Radiation source: fine-focus sealed tubeθmax = 26.2°, θmin = 2.5°
Graphite monochromatorh = 103
2θ/ω scansk = 19
2470 measured reflectionsl = 1414
1595 independent reflections3 standard reflections every 97 reflections
1276 reflections with I > 2σ(I) intensity decay: 1%
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)] = 0.034H-atom parameters constrained
wR(F2) = 0.094 w = 1/[σ2(Fo2) + (0.0477P)2 + 0.0347P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
1595 reflectionsΔρmax = 0.09 e Å3
183 parametersΔρmin = 0.08 e Å3
1 restraintExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 constraintsExtinction coefficient: 0.063 (8)
Primary atom site location: structure-invariant direct methodsAbsolute structure: 223 Friedel pairs merged
Crystal data top
C19H17NV = 737.76 (13) Å3
Mr = 259.34Z = 2
Monoclinic, P21Mo Kα radiation
a = 8.0761 (8) ŵ = 0.07 mm1
b = 7.7874 (8) ÅT = 298 K
c = 11.7760 (11) Å0.4 × 0.2 × 0.2 mm
β = 95.033 (7)°
Data collection top
Siemens P4
diffractometer
Rint = 0.017
2470 measured reflections3 standard reflections every 97 reflections
1595 independent reflections intensity decay: 1%
1276 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0341 restraint
wR(F2) = 0.094H-atom parameters constrained
S = 1.02Δρmax = 0.09 e Å3
1595 reflectionsΔρmin = 0.08 e Å3
183 parametersAbsolute structure: 223 Friedel pairs merged
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.3971 (2)0.6059 (3)0.71942 (14)0.0646 (5)
C20.4226 (3)0.6094 (3)0.61588 (18)0.0643 (6)
H2A0.33630.64320.56310.077*
C30.5833 (3)0.5624 (3)0.57416 (18)0.0662 (6)
C40.6202 (4)0.6121 (4)0.4665 (2)0.0906 (8)
H4A0.54400.67610.42030.109*
C50.7722 (5)0.5659 (5)0.4274 (3)0.1090 (11)
H5A0.79890.60280.35610.131*
C60.8809 (4)0.4676 (5)0.4930 (3)0.1058 (12)
H6A0.98130.43560.46600.127*
C70.8442 (3)0.4155 (5)0.5982 (3)0.0977 (10)
H7A0.91880.34680.64230.117*
C80.6973 (3)0.4640 (4)0.6394 (2)0.0748 (7)
H8A0.67450.43010.71210.090*
C90.2278 (2)0.6405 (3)0.74826 (16)0.0583 (5)
H9A0.15470.65580.67810.070*
C100.1713 (3)0.4844 (3)0.8128 (2)0.0747 (7)
H10A0.17430.38440.76540.112*
H10B0.05990.50250.83280.112*
H10C0.24420.46810.88090.112*
C110.2202 (3)0.7992 (3)0.82185 (16)0.0538 (5)
C120.3561 (3)0.8538 (3)0.88883 (18)0.0648 (6)
H12A0.45670.79680.88560.078*
C130.3473 (3)0.9946 (3)0.9628 (2)0.0760 (7)
H13A0.44121.02711.00920.091*
C140.2046 (3)1.0830 (3)0.96724 (19)0.0729 (7)
H14A0.20111.17651.01610.087*
C150.0608 (3)1.0349 (3)0.89846 (17)0.0595 (5)
C160.0910 (3)1.1256 (3)0.90111 (19)0.0729 (7)
H16A0.09501.22150.94780.088*
C170.2301 (3)1.0758 (4)0.8373 (2)0.0776 (7)
H17A0.32851.13690.84070.093*
C180.2257 (3)0.9330 (4)0.7667 (2)0.0731 (7)
H18A0.32170.89870.72330.088*
C190.0826 (2)0.8434 (3)0.76058 (18)0.0618 (6)
H19A0.08220.74900.71220.074*
C200.0660 (2)0.8899 (3)0.82582 (16)0.0529 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0602 (10)0.0696 (13)0.0646 (10)0.0073 (10)0.0089 (8)0.0043 (10)
C20.0694 (13)0.0571 (13)0.0670 (12)0.0072 (12)0.0095 (11)0.0043 (11)
C30.0726 (14)0.0565 (12)0.0718 (12)0.0021 (11)0.0185 (11)0.0127 (11)
C40.121 (2)0.0679 (16)0.0887 (16)0.0076 (18)0.0422 (16)0.0017 (14)
C50.139 (3)0.084 (2)0.116 (2)0.017 (2)0.074 (2)0.023 (2)
C60.0783 (18)0.100 (2)0.145 (3)0.0151 (19)0.0411 (19)0.059 (2)
C70.0638 (15)0.112 (3)0.117 (2)0.0058 (16)0.0057 (15)0.052 (2)
C80.0638 (14)0.0823 (17)0.0782 (13)0.0047 (14)0.0061 (11)0.0211 (13)
C90.0544 (11)0.0602 (12)0.0606 (11)0.0038 (11)0.0073 (9)0.0060 (11)
C100.0847 (16)0.0558 (14)0.0842 (15)0.0062 (13)0.0114 (12)0.0021 (13)
C110.0571 (11)0.0528 (12)0.0530 (10)0.0038 (10)0.0127 (9)0.0041 (9)
C120.0600 (13)0.0637 (13)0.0708 (12)0.0029 (12)0.0060 (11)0.0000 (12)
C130.0773 (17)0.0729 (17)0.0765 (14)0.0175 (15)0.0008 (12)0.0106 (14)
C140.0912 (17)0.0565 (14)0.0723 (13)0.0121 (13)0.0155 (12)0.0119 (11)
C150.0730 (14)0.0493 (11)0.0587 (11)0.0047 (11)0.0209 (10)0.0048 (10)
C160.0884 (18)0.0584 (13)0.0768 (14)0.0041 (14)0.0341 (13)0.0024 (13)
C170.0715 (16)0.0747 (17)0.0901 (15)0.0131 (14)0.0269 (13)0.0072 (14)
C180.0605 (13)0.0809 (17)0.0794 (14)0.0022 (13)0.0145 (11)0.0021 (13)
C190.0601 (13)0.0612 (13)0.0655 (11)0.0024 (11)0.0139 (10)0.0031 (11)
C200.0591 (11)0.0495 (11)0.0520 (9)0.0052 (9)0.0166 (8)0.0045 (9)
Geometric parameters (Å, º) top
N1—C21.255 (2)C10—H10C0.9600
N1—C91.462 (3)C11—C121.362 (3)
C2—C31.473 (3)C11—C201.436 (3)
C2—H2A0.9300C12—C131.405 (3)
C3—C81.379 (3)C12—H12A0.9300
C3—C41.383 (3)C13—C141.348 (3)
C4—C51.395 (4)C13—H13A0.9300
C4—H4A0.9300C14—C151.407 (3)
C5—C61.355 (5)C14—H14A0.9300
C5—H5A0.9300C15—C161.418 (3)
C6—C71.361 (5)C15—C201.420 (3)
C6—H6A0.9300C16—C171.352 (3)
C7—C81.373 (3)C16—H16A0.9300
C7—H7A0.9300C17—C181.391 (4)
C8—H8A0.9300C17—H17A0.9300
C9—C111.514 (3)C18—C191.358 (3)
C9—C101.525 (3)C18—H18A0.9300
C9—H9A0.9800C19—C201.414 (3)
C10—H10A0.9600C19—H19A0.9300
C10—H10B0.9600
C2—N1—C9117.30 (18)H10A—C10—H10C109.5
N1—C2—C3122.9 (2)H10B—C10—H10C109.5
N1—C2—H2A118.5C12—C11—C20118.99 (19)
C3—C2—H2A118.5C12—C11—C9121.04 (19)
C8—C3—C4118.6 (2)C20—C11—C9119.90 (18)
C8—C3—C2121.2 (2)C11—C12—C13121.4 (2)
C4—C3—C2120.2 (2)C11—C12—H12A119.3
C3—C4—C5119.8 (3)C13—C12—H12A119.3
C3—C4—H4A120.1C14—C13—C12120.8 (2)
C5—C4—H4A120.1C14—C13—H13A119.6
C6—C5—C4120.2 (3)C12—C13—H13A119.6
C6—C5—H5A119.9C13—C14—C15120.5 (2)
C4—C5—H5A119.9C13—C14—H14A119.8
C5—C6—C7120.4 (3)C15—C14—H14A119.8
C5—C6—H6A119.8C14—C15—C16121.8 (2)
C7—C6—H6A119.8C14—C15—C20119.5 (2)
C6—C7—C8120.2 (3)C16—C15—C20118.7 (2)
C6—C7—H7A119.9C17—C16—C15121.5 (2)
C8—C7—H7A119.9C17—C16—H16A119.2
C7—C8—C3120.8 (3)C15—C16—H16A119.2
C7—C8—H8A119.6C16—C17—C18119.9 (2)
C3—C8—H8A119.6C16—C17—H17A120.1
N1—C9—C11111.65 (18)C18—C17—H17A120.1
N1—C9—C10107.2 (2)C19—C18—C17120.6 (2)
C11—C9—C10109.68 (15)C19—C18—H18A119.7
N1—C9—H9A109.4C17—C18—H18A119.7
C11—C9—H9A109.4C18—C19—C20121.7 (2)
C10—C9—H9A109.4C18—C19—H19A119.2
C9—C10—H10A109.5C20—C19—H19A119.2
C9—C10—H10B109.5C19—C20—C15117.57 (19)
H10A—C10—H10B109.5C19—C20—C11123.62 (18)
C9—C10—H10C109.5C15—C20—C11118.81 (18)
C9—N1—C2—C3174.6 (2)C11—C12—C13—C141.9 (4)
N1—C2—C3—C819.9 (4)C12—C13—C14—C150.6 (4)
N1—C2—C3—C4162.2 (3)C13—C14—C15—C16179.9 (2)
C8—C3—C4—C51.6 (4)C13—C14—C15—C201.4 (3)
C2—C3—C4—C5179.5 (2)C14—C15—C16—C17178.0 (2)
C3—C4—C5—C62.3 (5)C20—C15—C16—C170.7 (3)
C4—C5—C6—C71.1 (5)C15—C16—C17—C180.3 (4)
C5—C6—C7—C80.8 (5)C16—C17—C18—C190.4 (4)
C6—C7—C8—C31.6 (4)C17—C18—C19—C200.6 (3)
C4—C3—C8—C70.3 (4)C18—C19—C20—C150.1 (3)
C2—C3—C8—C7177.6 (3)C18—C19—C20—C11179.8 (2)
C2—N1—C9—C11118.0 (2)C14—C15—C20—C19178.3 (2)
C2—N1—C9—C10121.9 (2)C16—C15—C20—C190.5 (3)
N1—C9—C11—C1225.3 (3)C14—C15—C20—C112.0 (3)
C10—C9—C11—C1293.4 (2)C16—C15—C20—C11179.16 (18)
N1—C9—C11—C20157.71 (17)C12—C11—C20—C19179.5 (2)
C10—C9—C11—C2083.6 (2)C9—C11—C20—C192.5 (3)
C20—C11—C12—C131.1 (3)C12—C11—C20—C150.8 (3)
C9—C11—C12—C13175.92 (19)C9—C11—C20—C15177.88 (17)

Experimental details

Crystal data
Chemical formulaC19H17N
Mr259.34
Crystal system, space groupMonoclinic, P21
Temperature (K)298
a, b, c (Å)8.0761 (8), 7.7874 (8), 11.7760 (11)
β (°) 95.033 (7)
V3)737.76 (13)
Z2
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.4 × 0.2 × 0.2
Data collection
DiffractometerSiemens P4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2470, 1595, 1276
Rint0.017
(sin θ/λ)max1)0.621
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.094, 1.02
No. of reflections1595
No. of parameters183
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.09, 0.08
Absolute structure223 Friedel pairs merged

Computer programs: XSCANS (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006).

 

Acknowledgements

Support from VIEP-UAP (GUPJ-NAT10-G) is acknowledged.

References

First citationBernès, S., Hernández, G., Portillo, R., Cruz, S. & Gutiérrez, R. (2010). Acta Cryst. E66, o1322–o1323.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationEspinosa Leija, A., Hernández, G., Portillo, R., Gutiérrez, R. & Bernès, S. (2009). Acta Cryst. E65, o1651.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationFukuda, K., Suzuki, H., Tokita, M., Watanabe, J. & Kawauchi, S. (2007). J. Mol. Struct. (Theochem), 821, 95–100.  CrossRef CAS Google Scholar
First citationLee, T. & Ahn, Y. (2002). Bull. Korean Chem. Soc. 23, 1490–1492.  CAS Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  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 citationSiemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.  Google Scholar
First citationTanaka, K. & Toda, F. (2000). Chem. Rev. 100, 1025–1074.  Web of Science CrossRef PubMed CAS Google Scholar

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Volume 67| Part 5| May 2011| Page o1257
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