PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): o189.
Published online 2007 December 6. doi:  10.1107/S1600536807063842
PMCID: PMC2915252

9,10-Bis{2-[1-(2-pyridylmeth­yl)imidazolium-3-yl]eth­oxy}anthracene bis(hexa­fluoridophosphate)

Abstract

The cation of the title compound, C36H34N6O2 2+·2PF6 , lies across a crystallographic inversion centre. The imidazole and pyridine rings form dihedral angles of 82.28 (5)° and 11.87 (7)°, respectively, with the anthracene ring system. The crystal packing is stabilized by π–π inter­actions between the pyridine ring and the central ring of anthracene, with a ring centroid–centroid distance of 3.684 (3) Å. The PF6 anion is disordered over three different positions with occupancies of 0.284 (6), 0.354 (8) and 0.362 (9).

Related literature

For the synthesis, see: Liu et al. (2003 [triangle]). For related structures, see: Liu et al. (2007 [triangle]); Pei et al. (2005 [triangle]); Qin et al. (2006 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-0o189-scheme1.jpg

Experimental

Crystal data

  • C36H34N6O2 2+·2PF6
  • M r = 872.63
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0o189-efi1.jpg
  • a = 8.829 (4) Å
  • b = 9.811 (4) Å
  • c = 12.586 (5) Å
  • α = 72.382 (7)°
  • β = 78.759 (7)°
  • γ = 65.598 (7)°
  • V = 943.2 (7) Å3
  • Z = 1
  • Mo Kα radiation
  • μ = 0.22 mm−1
  • T = 294 (2) K
  • 0.24 × 0.20 × 0.18 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.950, T max = 0.962
  • 4911 measured reflections
  • 3307 independent reflections
  • 1792 reflections with I > 2σ(I)
  • R int = 0.027

Refinement

  • R[F 2 > 2σ(F 2)] = 0.055
  • wR(F 2) = 0.159
  • S = 1.01
  • 3307 reflections
  • 373 parameters
  • 319 restraints
  • H-atom parameters constrained
  • Δρmax = 0.33 e Å−3
  • Δρmin = −0.24 e Å−3

Data collection: SMART (Bruker, 1998 [triangle]); cell refinement: SAINT (Bruker, 1999 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 [triangle]); molecular graphics: SHELXTL (Bruker, 1999 [triangle]); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536807063842/ci2523sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807063842/ci2523Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors thank the Scientific Research Fund Projects of China West Normal University (grant No. 06B003) and the Youth Fund Projects of Sichuan Educational Department (grant No. 2006B039).

supplementary crystallographic information

Comment

Imidazolium salts or its derivatives or analogs are used as ionic liquids, and as catalysts in many organic transformation processes. They are also used to obtain N-heterocyclic carbene complexes. We report here the crystal structure of the title compound.

The asymmetric unit of the title compound contains one-half of the organic cation and a PF6 counter ion. The cation lies on a crystallographic inversion center. Bond lengths and angles in the title molecule (Fig. 1) are within normal ranges. The imidazole ring is almost perpendicular to the anthracene ring system, with a dihedral angle of 82.28 (5)°, and the pyridine ring is almost parallel to the anthracene ring system, with a dihedral angle of 11.87 (7)°. The crystal packing is stabilized by π-π interactions between pyridine ring and central ring of anthracene [centroid-centroid distance is 3.684 (3) %A.

Experimental

The title compound was prepared according to the reported procedure of Liu et al. (2003). Yellow single crystals suitable for X-ray diffraction were obtained by recrystallization from acetonitrile.

Refinement

The PF6 group is disordered over three different positions with refined occupancies of 0.284 (6), 0.354 (8) and 0.362 (9). The P—F distances were restrained to 1.56 (1) Å, and the displacement parameters of disordered F atoms were restrained to an approximate isotropic behaviour, and also restrained to have the same Uij components. H atoms were placed in calculated positions with C—H = 0.93–0.97 Å, and refined using a riding model approximation, with Uiso(H) = 1.2eq(C).

Figures

Fig. 1.
View of the cationic unit in the title compound. Displacement ellipsoids are drawn at the 30% probability level. Unlabelled atoms are related to labelled atoms by the symmetry operation (1 - x, 1 - y, 2 - z).

Crystal data

C36H34N6O22+·2PF6Z = 1
Mr = 872.63F000 = 446
Triclinic, P1Dx = 1.536 Mg m3
Hall symbol: -P 1Mo Kα radiation λ = 0.71073 Å
a = 8.829 (4) ÅCell parameters from 1209 reflections
b = 9.811 (4) Åθ = 2.7–21.5º
c = 12.586 (5) ŵ = 0.22 mm1
α = 72.382 (7)ºT = 294 (2) K
β = 78.759 (7)ºBlock, yellow
γ = 65.598 (7)º0.24 × 0.20 × 0.18 mm
V = 943.2 (7) Å3

Data collection

Bruker SMART CCD area-detector diffractometer3307 independent reflections
Radiation source: fine-focus sealed tube1792 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.027
T = 294(2) Kθmax = 25.0º
[var phi] and ω scansθmin = 1.7º
Absorption correction: multi-scan(SADABS; Sheldrick, 1996)h = −10→10
Tmin = 0.950, Tmax = 0.962k = −11→6
4911 measured reflectionsl = −14→14

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.055H-atom parameters constrained
wR(F2) = 0.159  w = 1/[σ2(Fo2) + (0.0713P)2 + 0.3109P] where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max = 0.015
3307 reflectionsΔρmax = 0.33 e Å3
373 parametersΔρmin = −0.24 e Å3
319 restraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods

Special details

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.
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)

xyzUiso*/UeqOcc. (<1)
O10.3505 (3)0.6951 (3)0.80589 (19)0.0542 (7)
N1−0.1667 (4)1.0465 (4)0.9161 (3)0.0759 (11)
N2−0.1181 (4)1.0404 (4)0.6845 (3)0.0594 (9)
N30.0945 (4)0.8468 (4)0.6444 (2)0.0537 (9)
C1−0.2180 (7)1.0165 (6)1.0243 (4)0.0824 (14)
H1−0.13850.95121.07490.099*
C2−0.3809 (7)1.0760 (6)1.0655 (4)0.0786 (14)
H2−0.41051.05231.14200.094*
C3−0.4988 (6)1.1708 (5)0.9918 (5)0.0741 (13)
H3−0.61071.21261.01680.089*
C4−0.4483 (5)1.2030 (5)0.8795 (4)0.0665 (12)
H4−0.52601.26610.82730.080*
C5−0.2824 (5)1.1410 (5)0.8457 (4)0.0623 (11)
C6−0.2179 (5)1.1793 (5)0.7253 (4)0.0747 (13)
H6A−0.31151.24280.67990.090*
H6B−0.15011.23890.71720.090*
C7−0.1765 (6)0.9587 (6)0.6444 (4)0.0714 (13)
H7−0.28760.98200.63620.086*
C8−0.0454 (6)0.8389 (6)0.6192 (3)0.0690 (13)
H8−0.04840.76370.58990.083*
C90.0470 (5)0.9692 (5)0.6840 (3)0.0571 (11)
H90.11761.00090.70790.069*
C100.2667 (5)0.7415 (5)0.6272 (3)0.0697 (13)
H10A0.33750.80070.60070.084*
H10B0.27360.69160.56970.084*
C110.3307 (5)0.6199 (5)0.7318 (3)0.0616 (11)
H11A0.25210.57020.76600.074*
H11B0.43680.54180.71430.074*
C120.4252 (4)0.5939 (4)0.9027 (3)0.0440 (9)
C130.5991 (4)0.5322 (4)0.9005 (3)0.0449 (9)
C140.6758 (4)0.4338 (4)1.0009 (3)0.0438 (9)
C150.8534 (4)0.3686 (5)0.9977 (4)0.0590 (11)
H150.90550.30451.06230.071*
C160.9462 (5)0.3990 (5)0.9021 (4)0.0722 (13)
H161.06200.35380.90100.087*
C170.8715 (5)0.4974 (5)0.8043 (4)0.0749 (14)
H170.93820.51870.73960.090*
C180.7031 (5)0.5624 (5)0.8023 (3)0.0592 (11)
H180.65550.62690.73630.071*
P10.71210 (13)0.71357 (15)0.41845 (9)0.0645 (4)
F10.551 (2)0.702 (3)0.3935 (19)0.114 (6)0.284 (6)
F20.789 (2)0.5628 (17)0.3757 (17)0.092 (4)0.284 (6)
F30.758 (2)0.811 (2)0.3001 (11)0.111 (4)0.284 (6)
F40.6560 (19)0.8681 (17)0.4551 (19)0.134 (5)0.284 (6)
F50.662 (2)0.615 (2)0.5320 (11)0.130 (5)0.284 (6)
F60.8857 (15)0.655 (2)0.4618 (15)0.115 (5)0.284 (6)
F1A0.5497 (16)0.672 (2)0.4454 (14)0.119 (5)0.354 (8)
F2A0.7523 (17)0.631 (2)0.3229 (13)0.093 (4)0.354 (8)
F3A0.590 (2)0.8701 (16)0.3574 (15)0.144 (5)0.354 (8)
F4A0.6405 (16)0.7923 (18)0.5218 (10)0.097 (4)0.354 (8)
F5A0.761 (2)0.5581 (15)0.5135 (13)0.130 (4)0.354 (8)
F6A0.8703 (15)0.7530 (19)0.3841 (15)0.114 (5)0.354 (8)
F1B0.5218 (10)0.776 (2)0.4093 (15)0.112 (4)0.362 (9)
F2B0.7395 (16)0.722 (2)0.2880 (7)0.101 (4)0.362 (9)
F3B0.661 (2)0.8926 (11)0.3589 (17)0.123 (4)0.362 (9)
F4B0.6951 (19)0.712 (2)0.5411 (7)0.108 (4)0.362 (9)
F5B0.8139 (15)0.5346 (9)0.4402 (17)0.109 (4)0.362 (9)
F6B0.8931 (11)0.7078 (15)0.4201 (10)0.066 (3)0.362 (9)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0699 (16)0.0451 (16)0.0411 (14)−0.0139 (13)−0.0158 (12)−0.0056 (12)
N10.070 (2)0.078 (3)0.075 (3)−0.015 (2)−0.029 (2)−0.016 (2)
N20.062 (2)0.056 (2)0.057 (2)−0.0193 (19)−0.0174 (16)−0.0072 (18)
N30.066 (2)0.055 (2)0.0356 (17)−0.0213 (18)−0.0148 (15)−0.0023 (16)
C10.093 (4)0.076 (3)0.079 (4)−0.022 (3)−0.036 (3)−0.016 (3)
C20.112 (4)0.070 (3)0.071 (3)−0.047 (3)−0.011 (3)−0.023 (3)
C30.078 (3)0.061 (3)0.097 (4)−0.032 (3)−0.008 (3)−0.032 (3)
C40.064 (3)0.051 (3)0.086 (3)−0.015 (2)−0.024 (2)−0.017 (2)
C50.064 (3)0.046 (3)0.073 (3)−0.013 (2)−0.021 (2)−0.012 (2)
C60.071 (3)0.058 (3)0.084 (3)−0.014 (2)−0.019 (2)−0.009 (3)
C70.068 (3)0.077 (3)0.075 (3)−0.032 (3)−0.027 (2)−0.006 (3)
C80.090 (3)0.068 (3)0.060 (3)−0.038 (3)−0.032 (2)−0.004 (2)
C90.061 (3)0.059 (3)0.053 (2)−0.022 (2)−0.0181 (19)−0.008 (2)
C100.076 (3)0.076 (3)0.045 (2)−0.015 (2)−0.008 (2)−0.014 (2)
C110.078 (3)0.052 (3)0.047 (2)−0.011 (2)−0.018 (2)−0.014 (2)
C120.057 (2)0.035 (2)0.035 (2)−0.0121 (18)−0.0091 (17)−0.0064 (17)
C130.053 (2)0.042 (2)0.040 (2)−0.0203 (18)−0.0008 (17)−0.0102 (18)
C140.047 (2)0.038 (2)0.045 (2)−0.0141 (17)−0.0026 (17)−0.0126 (18)
C150.051 (2)0.058 (3)0.065 (3)−0.017 (2)−0.007 (2)−0.015 (2)
C160.046 (2)0.070 (3)0.090 (4)−0.015 (2)0.001 (2)−0.018 (3)
C170.065 (3)0.068 (3)0.077 (3)−0.027 (2)0.022 (2)−0.012 (3)
C180.070 (3)0.058 (3)0.045 (2)−0.029 (2)0.006 (2)−0.007 (2)
P10.0483 (6)0.0874 (10)0.0528 (7)−0.0162 (6)−0.0078 (5)−0.0219 (7)
F10.084 (7)0.149 (10)0.128 (9)−0.048 (6)−0.055 (6)−0.025 (8)
F20.114 (7)0.086 (7)0.091 (8)−0.042 (5)−0.007 (6)−0.036 (6)
F30.134 (7)0.097 (7)0.092 (7)−0.060 (6)0.002 (6)0.003 (6)
F40.158 (7)0.100 (7)0.110 (7)−0.007 (6)0.006 (7)−0.051 (6)
F50.126 (7)0.137 (7)0.084 (6)−0.032 (6)0.017 (6)−0.008 (6)
F60.098 (6)0.126 (8)0.114 (8)−0.037 (6)−0.050 (6)−0.003 (6)
F1A0.070 (5)0.154 (8)0.126 (8)−0.060 (5)0.011 (5)−0.010 (7)
F2A0.109 (6)0.085 (7)0.090 (7)−0.026 (6)−0.001 (5)−0.048 (6)
F3A0.118 (8)0.121 (7)0.146 (7)−0.023 (6)−0.030 (7)0.010 (6)
F4A0.116 (6)0.101 (7)0.050 (5)−0.015 (5)−0.001 (5)−0.026 (5)
F5A0.128 (7)0.110 (6)0.099 (6)−0.020 (5)−0.011 (6)0.011 (5)
F6A0.106 (6)0.113 (8)0.127 (9)−0.072 (6)−0.002 (6)0.005 (6)
F1B0.051 (4)0.129 (8)0.128 (7)−0.016 (5)−0.009 (4)−0.019 (7)
F2B0.122 (6)0.108 (8)0.069 (5)−0.030 (6)−0.003 (4)−0.037 (5)
F3B0.108 (7)0.093 (6)0.132 (7)−0.032 (5)−0.023 (6)0.022 (6)
F4B0.142 (7)0.131 (8)0.047 (4)−0.040 (6)−0.019 (4)−0.024 (5)
F5B0.126 (6)0.077 (5)0.113 (7)−0.029 (4)−0.015 (6)−0.020 (5)
F6B0.061 (4)0.075 (7)0.060 (6)−0.040 (4)−0.023 (4)0.019 (5)

Geometric parameters (Å, °)

O1—C121.395 (4)C11—H11A0.97
O1—C111.425 (4)C11—H11B0.97
N1—C51.327 (5)C12—C14i1.385 (5)
N1—C11.332 (6)C12—C131.397 (5)
N2—C91.330 (5)C13—C181.421 (5)
N2—C71.361 (5)C13—C141.429 (5)
N2—C61.467 (5)C14—C12i1.385 (5)
N3—C91.316 (5)C14—C151.425 (5)
N3—C81.370 (5)C15—C161.345 (5)
N3—C101.461 (5)C15—H150.93
C1—C21.370 (6)C16—C171.398 (6)
C1—H10.93C16—H160.93
C2—C31.366 (6)C17—C181.356 (5)
C2—H20.93C17—H170.93
C3—C41.377 (6)C18—H180.93
C3—H30.93P1—F4B1.518 (8)
C4—C51.369 (5)P1—F3A1.533 (9)
C4—H40.93P1—F61.544 (9)
C5—C61.502 (6)P1—F1B1.547 (8)
C6—H6A0.97P1—F6A1.548 (9)
C6—H6B0.97P1—F2A1.554 (8)
C7—C81.335 (5)P1—F51.562 (9)
C7—H70.93P1—F21.565 (9)
C8—H80.93P1—F11.566 (10)
C9—H90.93P1—F5B1.571 (8)
C10—C111.503 (5)P1—F41.572 (9)
C10—H10A0.97P1—F6B1.579 (8)
C10—H10B0.97
C12—O1—C11113.8 (3)O1—C11—H11A110.3
C5—N1—C1116.9 (4)C10—C11—H11A110.3
C9—N2—C7107.9 (4)O1—C11—H11B110.3
C9—N2—C6125.3 (4)C10—C11—H11B110.3
C7—N2—C6126.7 (4)H11A—C11—H11B108.5
C9—N3—C8107.9 (4)C14i—C12—O1118.8 (3)
C9—N3—C10125.7 (4)C14i—C12—C13122.5 (3)
C8—N3—C10126.4 (4)O1—C12—C13118.6 (3)
N1—C1—C2123.9 (4)C12—C13—C18122.7 (3)
N1—C1—H1118.0C12—C13—C14118.7 (3)
C2—C1—H1118.0C18—C13—C14118.6 (3)
C3—C2—C1118.5 (5)C12i—C14—C15122.7 (3)
C3—C2—H2120.8C12i—C14—C13118.8 (3)
C1—C2—H2120.8C15—C14—C13118.5 (3)
C2—C3—C4118.5 (5)C16—C15—C14120.6 (4)
C2—C3—H3120.8C16—C15—H15119.7
C4—C3—H3120.8C14—C15—H15119.7
C5—C4—C3119.3 (4)C15—C16—C17121.0 (4)
C5—C4—H4120.4C15—C16—H16119.5
C3—C4—H4120.4C17—C16—H16119.5
N1—C5—C4123.0 (4)C18—C17—C16121.0 (4)
N1—C5—C6115.1 (4)C18—C17—H17119.5
C4—C5—C6121.9 (4)C16—C17—H17119.5
N2—C6—C5112.2 (3)C17—C18—C13120.3 (4)
N2—C6—H6A109.2C17—C18—H18119.9
C5—C6—H6A109.2C13—C18—H18119.9
N2—C6—H6B109.2F4B—P1—F1B94.3 (8)
C5—C6—H6B109.2F3A—P1—F6A96.6 (10)
H6A—C6—H6B107.9F3A—P1—F2A97.0 (10)
C8—C7—N2107.5 (4)F6A—P1—F2A92.4 (9)
C8—C7—H7126.3F6—P1—F587.0 (10)
N2—C7—H7126.3F6—P1—F283.7 (10)
C7—C8—N3107.5 (4)F5—P1—F287.4 (10)
C7—C8—H8126.2F6—P1—F1156.8 (13)
N3—C8—H8126.2F5—P1—F177.1 (11)
N3—C9—N2109.1 (4)F2—P1—F178.9 (12)
N3—C9—H9125.4F4B—P1—F5B93.5 (8)
N2—C9—H9125.4F1B—P1—F5B118.9 (9)
N3—C10—C11112.8 (3)F6—P1—F491.2 (10)
N3—C10—H10A109.0F5—P1—F497.5 (10)
C11—C10—H10A109.0F2—P1—F4172.8 (9)
N3—C10—H10B109.0F1—P1—F4107.3 (11)
C11—C10—H10B109.0F4B—P1—F6B84.2 (7)
H10A—C10—H10B107.8F1B—P1—F6B161.1 (9)
O1—C11—C10107.3 (3)F5B—P1—F6B79.9 (7)
C5—N1—C1—C20.5 (7)C9—N3—C10—C1183.6 (5)
N1—C1—C2—C30.6 (8)C8—N3—C10—C11−98.5 (4)
C1—C2—C3—C4−0.4 (7)C12—O1—C11—C10−174.0 (3)
C2—C3—C4—C5−0.8 (6)N3—C10—C11—O1−70.3 (4)
C1—N1—C5—C4−1.9 (7)C11—O1—C12—C14i−96.3 (4)
C1—N1—C5—C6176.5 (4)C11—O1—C12—C1387.7 (4)
C3—C4—C5—N12.1 (7)C14i—C12—C13—C18−179.0 (3)
C3—C4—C5—C6−176.2 (4)O1—C12—C13—C18−3.1 (5)
C9—N2—C6—C5−93.4 (5)C14i—C12—C13—C141.5 (6)
C7—N2—C6—C584.1 (5)O1—C12—C13—C14177.3 (3)
N1—C5—C6—N255.0 (5)C12—C13—C14—C12i−1.4 (6)
C4—C5—C6—N2−126.6 (4)C18—C13—C14—C12i179.0 (3)
C9—N2—C7—C8−0.5 (5)C12—C13—C14—C15178.7 (3)
C6—N2—C7—C8−178.3 (4)C18—C13—C14—C15−0.8 (5)
N2—C7—C8—N30.3 (5)C12i—C14—C15—C16−180.0 (4)
C9—N3—C8—C70.1 (4)C13—C14—C15—C16−0.1 (6)
C10—N3—C8—C7−178.1 (3)C14—C15—C16—C171.3 (7)
C8—N3—C9—N2−0.4 (4)C15—C16—C17—C18−1.5 (7)
C10—N3—C9—N2177.8 (3)C16—C17—C18—C130.5 (7)
C7—N2—C9—N30.5 (4)C12—C13—C18—C17−178.9 (4)
C6—N2—C9—N3178.4 (3)C14—C13—C18—C170.6 (6)

Symmetry codes: (i) −x+1, −y+1, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CI2523).

References

  • Bruker (1998). SMART Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (1999). SAINT and SHELXTL Bruker AXS Inc., Madison, Wisconsin, USA.
  • Liu, B., Chen, W. Z. & Jin, S. W. (2007). Organometallics, 26, 3660–3667.
  • Liu, Q. X., Xu, F. B., Li, Q. S., Zeng, X. S., Leng, X. B., Chou, Y. L. & Zhang, Z. Z. (2003). Organometallics, 22, 309–314.
  • Pei, L. C., Chun, L. L., Chiu, F. C., Ching, H. H. & Hon, M. L. (2005). Organometallics, 24, 6169–6178.
  • Qin, D. B., Xu, F. B., Wan, X. J., Zhao, Y. J. & Zhang, Z. Z. (2006). Tetrahedron Lett.47, 5641–5643.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (1997). SHELXS97 and SHELXL97 University of Göttingen, Germany.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography