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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 67| Part 7| July 2011| Pages o1648-o1649

1,3-Bis[(−)-(S)-(1-phenyl­eth­yl)imino­meth­yl]benzene

aDEP Facultad de Ciencias Químicas, UANL, Guerrero y Progreso S/N, Col. Treviño, 64570 Monterrey, N.L., Mexico, bFacultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico, and cLaboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico
*Correspondence e-mail: sylvain_bernes@Hotmail.com

(Received 19 May 2011; accepted 3 June 2011; online 11 June 2011)

The title compound, C24H24N2, is an enanti­omerically pure bis-aldimine, which displays twofold crystallographic symmetry, with two C atoms of the central benzene ring lying on the symmetry axis. The imine group is slightly twisted from the benzene core, with a dihedral angle of 12.72 (16)° between the benzene ring and the C=N—C* plane. The terminal phenyl rings make an angle of 66.44 (4)° and are oriented in opposite directions with respect to the benzene ring. In the crystal, mol­ecules inter­act weakly through a C—H⋯π inter­action involving the phenyl rings, and form chains along the 21 screw-axis in the [100] direction.

Related literature

For the structure of the analogous mol­ecule with naphthyl in place of phenyl, see: Espinosa Leija et al. (2009[Espinosa Leija, A., Hernández, G., Cruz, S., Bernès, S. & Gutiérrez, R. (2009). Acta Cryst. E65, o1316.]). For the structure of the isoformular mol­ecule with a 1,4-disubstituted benzene ring, see: García et al. (2010[García, T., Bernès, S., Hernández, G., Gutiérrez, R. & Vázquez, J. (2010). Quím. Hoy Chem. Sci. 1, 10-13.]). For the Pd(II) and Pt(II) coordination complexes formed using the title ligand, see: Fossey et al. (2007[Fossey, J. S., Russell, M. L., Abdul Malik, K. M. & Richards, C. J. (2007). J. Organomet. Chem. 692, 4843-4848.]). For background to the synthesis carried out in solvent-free conditions, see: Tanaka & Toda (2000[Tanaka, K. & Toda, F. (2000). Chem. Rev. 100, 1025-1074.]); Jeon et al. (2005[Jeon, S.-J., Li, H. & Walsh, P. J. (2005). J. Am. Chem. Soc. 127, 16416-16425.]).

[Scheme 1]

Experimental

Crystal data
  • C24H24N2

  • Mr = 340.45

  • Orthorhombic, P 21 21 2

  • a = 21.1309 (7) Å

  • b = 5.6572 (2) Å

  • c = 8.2290 (3) Å

  • V = 983.71 (6) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 130 K

  • 0.33 × 0.26 × 0.14 mm

Data collection
  • Oxford Diffraction Xcalibur Atlas Gemini diffractometer

  • Absorption correction: analytical [CrysAlis PRO (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]) based on expressions derived by Clark & Reid (1995[Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897.])] Tmin = 0.980, Tmax = 0.991

  • 6971 measured reflections

  • 1161 independent reflections

  • 1027 reflections with I > 2σ(I)

  • Rint = 0.025

Refinement
  • R[F2 > 2σ(F2)] = 0.029

  • wR(F2) = 0.073

  • S = 1.06

  • 1161 reflections

  • 154 parameters

  • Only H-atom coordinates refined

  • Δρmax = 0.09 e Å−3

  • Δρmin = −0.17 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C1–C6 ring.

D—H⋯A D—H H⋯A DA D—H⋯A
C3—H3⋯Cgi 0.92 (2) 2.97 (2) 3.7265 (18) 140.7 (18)
Symmetry code: (i) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+1].

Data collection: CrysAlis CCD (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]); cell refinement: CrysAlis RED (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]); data reduction: CrysAlis RED; 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and 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: SHELXTL.

Supporting information


Comment top

The title compound was synthesized in an almost quantitative yield, using a one-step solvent-free route. Such procedures are becoming primordial in organic synthetic methods, in order to minimize the quantity of toxic waste and byproducts and to decrease the amount of solvents in the reaction media and/or during the following workups. Indeed, solvent-free reactions or solid-state reactions have been particularly developed these last years. (Jeon et al., 2005; Tanaka & Toda, 2000).

The molecular structure of the title compound is as expected. The imine groups N1C8 are found in the E configuration, which is known to be more stable than Z. The molecule is placed on a crystallographic twofold axis, passing through benzene atoms C10 and C11 (Fig. 1). Imine groups are not fully conjugated with the benzene core: the dihedral angle between C7—N1 C8 and benzene mean-planes is 12.72 (16)°. The benzene ring makes an angle of 69.35 (5)° with the phenyl group, and terminal phenyl rings make an angle of 66.44 (4)°. Although the analogous bis-imine bearing a naphthyl group in place of phenyl crystallizes in the same space group, P21212, and with identical molecular symmetry, it is stabilized in a different conformation compared to the title molecule. For instance, imine groups are almost perfectly conjugated with the benzene ring (dihedral angle between benzene and C*—NC planes less than 0.6°; Espinosa Leija et al., 2009). The title molecule and the naphthyl analogue are also differentiated by the fact that the latter crystallized with lattice solvent, CH2Cl2. The title molecule also shows a different conformation to that of the isoformular compound with a central 1,4-disubsituted benzene ring (García et al., 2010): in that case, the molecule crystallizes in P212121 and is placed in general position (C1 point group).

The crystal structure (Fig. 2) features chains of molecules placed along the 21 screw-axis in the [100] direction, which interact trough rather weak C3—H3···π contacts involving phenyl groups C1···C6. The H3···π separation is 2.97 (2) Å, and the C3—H3···π angle 140.7 (18)°.

Interestingly, (Fossey et al. 2007) reported on the synthesis of chiral bis-aldimine NCN–pincer complexes, where the NCN ligand is derived from the title compound by deprotonation at C10. These authors probed the catalytic activity of Pd(II) and Pt(II) complexes, where the ancillary ligand is an halide ion, Br- or Cl-, for Pd and Pt complexes, respectively. The studied reaction, a classical Michael addition between methyl 2-cyanopropanoate and methyl vinyl ketone, showed that addition was not stereocontrolled. This poor selectivity was related to conformational flexibility of the chiral phenylethyl moiety of the ligand. Indeed, that point is confirmed by our structure, since a poor overlay is observed for this part of the molecule, when attempting to fit the title molecule and the main ligand in the complexes. However, differences in point symmetry also deserve to be considered regarding the catalytic activity: the title molecule belongs to C2 point-group, while complexes prepared by Fossey et al. crystallize in space group P212121, the whole complexes being placed in general positions. The complexes used for the Michael addition thus actually displayed the non-crystallographic C2 symmetry.

Related literature top

For the structure of the analogous molecule with naphthyl in place of phenyl, see: Espinosa Leija et al. (2009). For the structure of the isoformular molecule with a 1,4-disubstituted benzene ring, see: García et al. (2010). For the Pd(II) and Pt(II) coordination complexes formed using the title ligand, see: Fossey et al. (2007). For background to the synthesis carried out in solvent-free conditions, see: Tanaka & Toda (2000); Jeon et al. (2005).

Experimental top

Under solvent-free conditions, (S)-(–)-1-phenylethylamine (0.45 g, 3.72 mmol) and benzene-1,3-dicarboxaldehyde (0.25 g, 1.86 mmol) in a 2:1 molar ratio were mixed at room temperature, obtaining a white solid. The crude was recrystallized twice from CH2Cl2, affording colorless crystals of the title compound. Yield: 92%; m.p. 80–82 °C. Analysis: [α]25D = -71.4 (c=1, CHCl3). FT—IR (KBr): 1645 cm-1 (C=N). 1H-NMR (400 MHz, CDCl3/TMS) δ = 1.58 (d, 6H, CHCH3), 4.53 (q, 2H, CH), 7.22–8.11 (m, 14H, Ar—CH), 8.36 (s, 2H, HC=N). 13C-NMR (100 MHz, CDCl3/TMS) δ = 24.7 (CCH3), 69.6 (CHCH3), 126.5 (Ar), 126.8 (Ar), 128.2 (Ar), 128.3 (Ar), 128.7 (Ar), 130.0 (Ar), 136.6 (Ar), 144.8 (Ar), 158.9 (HC=N). MS—EI: m/z= 340 (M+).

Refinement top

All H atoms were found in a difference map and refined with free coordinates and isotropic displacement parameters fixed to Uiso = 1.2Ueq(carrier C atom). C—H bond lengths are in the range 0.92 (2)–1.023 (18) Å. The absolute configuration at C7 was assigned from the known configuration of the chiral amine used as starting material, and measured Friedel pairs (775) were merged.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis RED (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006)'; software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The title molecule with displacement ellipsoids for non-H atoms shown at the 60% probability level. Non-labeled atoms are generated by symmetry operation -x, 1 - y, z.
[Figure 2] Fig. 2. A part of the crystal structure of the title compound. The purple molecules are related by the 21 symmetry along the a axis, and dashed lines represent C—H···π contacts.
1,3-Bis[(-)-(S)-(1-phenylethyl)iminomethyl]benzene top
Crystal data top
C24H24N2Dx = 1.149 Mg m3
Mr = 340.45Melting point: 353 K
Orthorhombic, P21212Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2abCell parameters from 4133 reflections
a = 21.1309 (7) Åθ = 3.6–26.0°
b = 5.6572 (2) ŵ = 0.07 mm1
c = 8.2290 (3) ÅT = 130 K
V = 983.71 (6) Å3Prism, colourless
Z = 20.33 × 0.26 × 0.14 mm
F(000) = 364
Data collection top
Oxford Diffraction Xcalibur Atlas Gemini
diffractometer
1161 independent reflections
Radiation source: Enhance (Mo) X-ray Source1027 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
Detector resolution: 10.4685 pixels mm-1θmax = 26.0°, θmin = 3.7°
ω scansh = 2624
Absorption correction: analytical
[CrysAlis PRO (Oxford Diffraction, 2009) based on expressions derived by Clark & Reid (1995)]
k = 66
Tmin = 0.980, Tmax = 0.991l = 109
6971 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)] = 0.029Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.073Only H-atom coordinates refined
S = 1.06 w = 1/[σ2(Fo2) + (0.0497P)2 + 0.0095P]
where P = (Fo2 + 2Fc2)/3
1161 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 0.09 e Å3
0 restraintsΔρmin = 0.17 e Å3
0 constraints
Crystal data top
C24H24N2V = 983.71 (6) Å3
Mr = 340.45Z = 2
Orthorhombic, P21212Mo Kα radiation
a = 21.1309 (7) ŵ = 0.07 mm1
b = 5.6572 (2) ÅT = 130 K
c = 8.2290 (3) Å0.33 × 0.26 × 0.14 mm
Data collection top
Oxford Diffraction Xcalibur Atlas Gemini
diffractometer
1161 independent reflections
Absorption correction: analytical
[CrysAlis PRO (Oxford Diffraction, 2009) based on expressions derived by Clark & Reid (1995)]
1027 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.991Rint = 0.025
6971 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0290 restraints
wR(F2) = 0.073Only H-atom coordinates refined
S = 1.06Δρmax = 0.09 e Å3
1161 reflectionsΔρmin = 0.17 e Å3
154 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.08171 (5)0.8507 (2)0.09804 (15)0.0334 (3)
C10.18464 (7)0.9616 (3)0.20948 (18)0.0320 (3)
C20.19358 (8)0.7590 (3)0.3015 (2)0.0444 (4)
H20.1570 (9)0.669 (3)0.330 (2)0.053*
C30.25402 (9)0.6851 (3)0.3437 (2)0.0517 (5)
H30.2581 (9)0.549 (4)0.405 (3)0.062*
C40.30581 (8)0.8153 (4)0.2952 (2)0.0504 (5)
H40.3488 (10)0.765 (4)0.326 (2)0.060*
C50.29724 (8)1.0147 (4)0.2039 (2)0.0543 (5)
H50.3325 (10)1.099 (4)0.164 (3)0.065*
C60.23701 (8)1.0880 (3)0.1605 (2)0.0420 (4)
H60.2300 (8)1.226 (4)0.100 (2)0.050*
C70.11876 (7)1.0481 (3)0.16569 (19)0.0346 (4)
H70.1234 (8)1.176 (3)0.0885 (19)0.042*
C80.06895 (6)0.8605 (3)0.05179 (18)0.0320 (4)
H80.0837 (7)0.997 (3)0.1224 (19)0.038*
C90.03271 (6)0.6758 (3)0.13695 (17)0.0313 (3)
C100.00000.50000.0535 (2)0.0299 (5)
H100.00000.50000.068 (3)0.036*
C110.00000.50000.3906 (3)0.0441 (6)
H110.00000.50000.506 (3)0.053*
C120.03173 (7)0.6752 (3)0.30697 (18)0.0398 (4)
H120.0545 (8)0.797 (3)0.363 (2)0.048*
C130.08354 (8)1.1472 (3)0.3116 (2)0.0427 (4)
H13A0.1078 (8)1.284 (4)0.365 (2)0.051*
H13B0.0793 (9)1.021 (4)0.393 (2)0.051*
H13C0.0397 (9)1.208 (3)0.279 (2)0.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0258 (6)0.0373 (7)0.0370 (7)0.0034 (5)0.0025 (5)0.0064 (6)
C10.0324 (8)0.0313 (7)0.0325 (7)0.0046 (6)0.0019 (6)0.0027 (7)
C20.0393 (9)0.0360 (8)0.0580 (11)0.0068 (7)0.0027 (8)0.0085 (8)
C30.0564 (10)0.0411 (10)0.0578 (11)0.0074 (9)0.0127 (9)0.0024 (9)
C40.0371 (9)0.0653 (12)0.0489 (10)0.0111 (9)0.0053 (8)0.0156 (10)
C50.0322 (9)0.0736 (13)0.0571 (11)0.0111 (9)0.0038 (8)0.0015 (11)
C60.0361 (9)0.0460 (10)0.0440 (9)0.0079 (7)0.0035 (7)0.0063 (8)
C70.0322 (8)0.0310 (7)0.0407 (8)0.0052 (7)0.0028 (7)0.0081 (7)
C80.0252 (7)0.0355 (8)0.0351 (8)0.0052 (6)0.0063 (6)0.0079 (7)
C90.0233 (6)0.0406 (8)0.0301 (7)0.0105 (7)0.0020 (6)0.0036 (7)
C100.0216 (9)0.0413 (12)0.0268 (10)0.0084 (9)0.0000.000
C110.0454 (13)0.0633 (16)0.0236 (11)0.0175 (12)0.0000.000
C120.0347 (8)0.0520 (10)0.0326 (8)0.0119 (8)0.0048 (7)0.0090 (8)
C130.0360 (8)0.0424 (9)0.0496 (10)0.0023 (8)0.0046 (8)0.0012 (9)
Geometric parameters (Å, º) top
N1—C81.2633 (19)C7—H70.967 (17)
N1—C71.4727 (19)C8—C91.473 (2)
C1—C61.378 (2)C8—H81.014 (18)
C1—C21.387 (2)C9—C101.3920 (17)
C1—C71.519 (2)C9—C121.399 (2)
C2—C31.388 (2)C10—C9i1.3920 (17)
C2—H20.96 (2)C10—H101.00 (2)
C3—C41.378 (3)C11—C12i1.380 (2)
C3—H30.92 (2)C11—C121.380 (2)
C4—C51.367 (3)C11—H110.95 (2)
C4—H40.98 (2)C12—H120.959 (19)
C5—C61.385 (2)C13—H13A1.02 (2)
C5—H50.94 (2)C13—H13B0.98 (2)
C6—H60.94 (2)C13—H13C1.023 (18)
C7—C131.520 (2)
C8—N1—C7116.69 (13)C1—C7—H7107.7 (10)
C6—C1—C2118.64 (15)C13—C7—H7107.0 (9)
C6—C1—C7119.96 (14)N1—C8—C9122.96 (14)
C2—C1—C7121.38 (13)N1—C8—H8121.8 (9)
C1—C2—C3120.71 (17)C9—C8—H8115.3 (9)
C1—C2—H2117.7 (12)C10—C9—C12118.95 (16)
C3—C2—H2121.5 (11)C10—C9—C8122.03 (13)
C4—C3—C2119.84 (17)C12—C9—C8119.01 (15)
C4—C3—H3121.9 (12)C9—C10—C9i120.90 (18)
C2—C3—H3118.2 (12)C9—C10—H10119.55 (9)
C5—C4—C3119.65 (16)C9i—C10—H10119.55 (9)
C5—C4—H4120.0 (12)C12i—C11—C12120.2 (2)
C3—C4—H4120.4 (12)C12i—C11—H11119.90 (10)
C4—C5—C6120.69 (17)C12—C11—H11119.90 (10)
C4—C5—H5120.4 (12)C11—C12—C9120.48 (17)
C6—C5—H5118.8 (12)C11—C12—H12121.4 (11)
C1—C6—C5120.45 (16)C9—C12—H12118.1 (11)
C1—C6—H6117.4 (11)C7—C13—H13A111.8 (10)
C5—C6—H6122.1 (11)C7—C13—H13B108.4 (11)
N1—C7—C1109.44 (12)H13A—C13—H13B107.4 (14)
N1—C7—C13108.55 (12)C7—C13—H13C111.2 (9)
C1—C7—C13112.35 (13)H13A—C13—H13C108.1 (13)
N1—C7—H7111.8 (10)H13B—C13—H13C109.8 (15)
C6—C1—C2—C30.1 (2)C2—C1—C7—N149.69 (19)
C7—C1—C2—C3178.53 (16)C6—C1—C7—C13107.63 (17)
C1—C2—C3—C40.6 (3)C2—C1—C7—C1370.97 (19)
C2—C3—C4—C50.9 (3)C7—N1—C8—C9179.55 (12)
C3—C4—C5—C60.4 (3)N1—C8—C9—C1012.2 (2)
C2—C1—C6—C50.6 (2)N1—C8—C9—C12167.04 (14)
C7—C1—C6—C5178.06 (16)C12—C9—C10—C9i0.71 (10)
C4—C5—C6—C10.3 (3)C8—C9—C10—C9i178.53 (14)
C8—N1—C7—C1110.27 (15)C12i—C11—C12—C90.73 (10)
C8—N1—C7—C13126.80 (15)C10—C9—C12—C111.4 (2)
C6—C1—C7—N1131.72 (14)C8—C9—C12—C11177.83 (10)
Symmetry code: (i) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C1–C6 ring.
D—H···AD—HH···AD···AD—H···A
C3—H3···Cgii0.92 (2)2.97 (2)3.7265 (18)140.7 (18)
Symmetry code: (ii) x+1/2, y1/2, z+1.

Experimental details

Crystal data
Chemical formulaC24H24N2
Mr340.45
Crystal system, space groupOrthorhombic, P21212
Temperature (K)130
a, b, c (Å)21.1309 (7), 5.6572 (2), 8.2290 (3)
V3)983.71 (6)
Z2
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.33 × 0.26 × 0.14
Data collection
DiffractometerOxford Diffraction Xcalibur Atlas Gemini
diffractometer
Absorption correctionAnalytical
[CrysAlis PRO (Oxford Diffraction, 2009) based on expressions derived by Clark & Reid (1995)]
Tmin, Tmax0.980, 0.991
No. of measured, independent and
observed [I > 2σ(I)] reflections
6971, 1161, 1027
Rint0.025
(sin θ/λ)max1)0.618
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.073, 1.06
No. of reflections1161
No. of parameters154
H-atom treatmentOnly H-atom coordinates refined
Δρmax, Δρmin (e Å3)0.09, 0.17

Computer programs: CrysAlis CCD (Oxford Diffraction, 2009), CrysAlis RED (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006)', SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C1–C6 ring.
D—H···AD—HH···AD···AD—H···A
C3—H3···Cgi0.92 (2)2.97 (2)3.7265 (18)140.7 (18)
Symmetry code: (i) x+1/2, y1/2, z+1.
 

Acknowledgements

Support from VIEP-UAP: GUPJ-NAT10-G (2011) is acknowledged.

References

First citationClark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887–897.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationEspinosa Leija, A., Hernández, G., Cruz, S., Bernès, S. & Gutiérrez, R. (2009). Acta Cryst. E65, o1316.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationFossey, J. S., Russell, M. L., Abdul Malik, K. M. & Richards, C. J. (2007). J. Organomet. Chem. 692, 4843–4848.  CrossRef CAS Google Scholar
First citationGarcía, T., Bernès, S., Hernández, G., Gutiérrez, R. & Vázquez, J. (2010). Quím. Hoy Chem. Sci. 1, 10–13.  Google Scholar
First citationJeon, S.-J., Li, H. & Walsh, P. J. (2005). J. Am. Chem. Soc. 127, 16416–16425.  Web of Science CrossRef PubMed 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 citationOxford Diffraction (2009). CrysAlis CCD, CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals 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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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 67| Part 7| July 2011| Pages o1648-o1649
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