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

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ISSN: 2056-9890

1-Meth­­oxy-4-({[(4-meth­­oxy­phen­yl)­sulfan­yl](phen­yl)meth­yl}sulfan­yl)benzene

aKey Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People's Republic of China, bChemistry Division, School of Advanced Sciences, VIT University, Vellore 632 014, India, and cBioinformatics Infrastructure Facility, Department of Biotechnology, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India
*Correspondence e-mail: hongqili@dhu.edu.cn

(Received 12 February 2012; accepted 13 February 2012; online 17 February 2012)

The title compound, C21H20O2S2, forms a propeller-shaped structure with the tetra­hedral C atom as the central hub and meth­oxy­benzene and phenyl residues as radiating blades. Short C—H⋯π contacts are observed.

Related literature

For related structures, see: Farrugia et al. (2000[Farrugia, L. J., Hartley, R. C. & Guthrie, E. (2000). Private communication [refcodes QITPEO, QITPOY, QITPUE and QITQAL (CCDC 149307-CCDC 149310l, respectively)]. CCDC, Union Road, Cambridge, England.]). For details on the Cambridge Structural Database, see: Allen (2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]).

[Scheme 1]

Experimental

Crystal data
  • C21H20O2S2

  • Mr = 368.49

  • Monoclinic, P 21 /c

  • a = 21.1506 (15) Å

  • b = 5.6114 (3) Å

  • c = 17.1219 (11) Å

  • β = 110.336 (2)°

  • V = 1905.4 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.29 mm−1

  • T = 298 K

  • 0.42 × 0.20 × 0.18 mm

Data collection
  • Bruker APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2004[Bruker (2004). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.888, Tmax = 0.950

  • 12756 measured reflections

  • 4154 independent reflections

  • 2725 reflections with I > 2σ(I)

  • Rint = 0.024

Refinement
  • R[F2 > 2σ(F2)] = 0.043

  • wR(F2) = 0.128

  • S = 1.02

  • 4154 reflections

  • 228 parameters

  • H-atom parameters constrained

  • Δρmax = 0.51 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 rings, respectively.

D—H⋯A D—H H⋯A DA D—H⋯A
C4—H4⋯Cg2i 0.93 2.99 3.713 (3) 136
C10—H10⋯Cg2ii 0.93 2.96 3.610 (2) 128
C21—H21BCg1iii 0.96 2.98 3.914 (5) 165
Symmetry codes: (i) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]; (ii) [-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iii) [-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2; data reduction: SAINT-Plus (Bruker, 2004[Bruker (2004). APEX2, SAINT-Plus and SADABS. 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 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

A search in Cambridge Structural Database (CCDC; version 5.31; Allen, 2002) revealed four similar crystal structures (Farrugia et al., 2000). The title compound, Fig. 1, forms a propeller-shaped structure with the tetrahedral carbon of the phenylmethyl moiety as the central hub and methoxybenzene and phenyl moieties as radiating blades. Short C—H···π contacts stabilize the structure, Table 1.

Related literature top

For related structures, see: Farrugia et al. (2000). For details on the Cambridge Structural Database, see: Allen (2002).

Experimental top

In a dry 100 ml Erlenmeyer flask were placed benzaldehyde (10 mmol), 4-methoxythiophenol (10 mmol), iodine (15 mol %) and dichloromethane (DCM; 15 ml). The reaction mixture was stirred at room temperature for an hour. The reaction was monitored by TLC and after the completion of reaction the iodine utilized was removed from the product by treating it with aqueous sodium thiosulfate solution. The final product was extracted into DCM (2 x 20 ml). The crude reaction mixture was purified by column chromatography on silica gel using ethyl acetate/hexane as the eluents. Final yields: 93%; M.pt: 322 (1) °K. Suitable single crystals of the title compound were grown from its ethanol/tetrahydrofuran mixture (1:1).

Refinement top

H atoms were placed in their geometrically expected positions and refined in the riding-model approximation [Csp2—H = 0.93 Å, C(methine)—H = 0.98 Å and C(methyl)—H = 0.96 Å, and with Uiso(H) = 1.2Ueq(parent) or 1.5Ueq(Cmethyl)]. The torsion angles for the methyl group H atoms were set with reference to a local difference Fourier calculation. The reflection (100), truncated by the beam stop, was omitted during the final cycles of refinement.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 (Bruker, 2004); data reduction: SAINT-Plus (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. A view of the title compound with non-H atoms shown with 30% probability ellipsoids.
1-Methoxy-4-({[(4-methoxyphenyl)sulfanyl](phenyl)methyl}sulfanyl)benzene top
Crystal data top
C21H20O2S2F(000) = 776
Mr = 368.49Dx = 1.285 Mg m3
Monoclinic, P21/cMelting point: 322(1) K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 21.1506 (15) ÅCell parameters from 4040 reflections
b = 5.6114 (3) Åθ = 2.5–25.1°
c = 17.1219 (11) ŵ = 0.29 mm1
β = 110.336 (2)°T = 298 K
V = 1905.4 (2) Å3Rectangular, colourless
Z = 40.42 × 0.20 × 0.18 mm
Data collection top
Bruker APEXII CCD area-detector
diffractometer
4154 independent reflections
Radiation source: fine-focus sealed tube2725 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
ϕ and ω scansθmax = 27.3°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
h = 2726
Tmin = 0.888, Tmax = 0.950k = 67
12756 measured reflectionsl = 2121
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)] = 0.043Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0584P)2 + 0.5757P]
where P = (Fo2 + 2Fc2)/3
4154 reflections(Δ/σ)max < 0.001
228 parametersΔρmax = 0.51 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C21H20O2S2V = 1905.4 (2) Å3
Mr = 368.49Z = 4
Monoclinic, P21/cMo Kα radiation
a = 21.1506 (15) ŵ = 0.29 mm1
b = 5.6114 (3) ÅT = 298 K
c = 17.1219 (11) Å0.42 × 0.20 × 0.18 mm
β = 110.336 (2)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer
4154 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
2725 reflections with I > 2σ(I)
Tmin = 0.888, Tmax = 0.950Rint = 0.024
12756 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.128H-atom parameters constrained
S = 1.02Δρmax = 0.51 e Å3
4154 reflectionsΔρmin = 0.27 e Å3
228 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.

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
C10.28208 (12)0.3397 (4)0.08333 (15)0.0582 (6)
H10.29560.23000.12670.070*
C20.30050 (14)0.3069 (5)0.01429 (17)0.0682 (7)
H20.32690.17640.01180.082*
C30.28023 (12)0.4651 (5)0.05079 (14)0.0582 (6)
H30.29230.44120.09750.070*
C40.24238 (12)0.6575 (4)0.04643 (14)0.0579 (6)
H40.22860.76560.09030.069*
C50.22434 (11)0.6929 (4)0.02289 (14)0.0553 (6)
H50.19880.82550.02550.066*
C60.24388 (10)0.5330 (4)0.08852 (12)0.0437 (5)
C70.22303 (10)0.5625 (4)0.16395 (13)0.0472 (5)
H70.23310.41440.19630.057*
C80.11543 (10)0.5823 (4)0.22356 (13)0.0465 (5)
C90.07731 (10)0.7557 (4)0.24299 (13)0.0498 (5)
H90.06500.89140.20990.060*
C100.05727 (10)0.7304 (4)0.31070 (13)0.0497 (5)
H100.03060.84720.32230.060*
C110.07636 (10)0.5324 (4)0.36186 (13)0.0463 (5)
C120.11566 (11)0.3596 (4)0.34425 (15)0.0534 (6)
H120.12970.22750.37880.064*
C130.13406 (11)0.3849 (4)0.27413 (15)0.0561 (6)
H130.15940.26600.26120.067*
C140.06989 (14)0.3243 (5)0.48056 (16)0.0749 (8)
H14A0.05150.18330.44910.112*
H14B0.05140.34390.52400.112*
H14C0.11800.30950.50470.112*
C150.34680 (11)0.6870 (4)0.27962 (13)0.0504 (5)
C160.35770 (14)0.5044 (6)0.33572 (17)0.0822 (9)
H160.32160.44380.34860.099*
C170.42130 (16)0.4077 (6)0.37378 (19)0.0917 (10)
H170.42760.28040.41050.110*
C180.47508 (14)0.5028 (6)0.35644 (17)0.0741 (8)
C190.46437 (15)0.6859 (6)0.3018 (2)0.0877 (9)
H190.50070.75110.29060.105*
C200.40113 (13)0.7771 (5)0.26288 (17)0.0718 (7)
H200.39490.90080.22480.086*
C210.5537 (2)0.2212 (8)0.4413 (3)0.1463 (19)
H21A0.53980.24630.48840.220*
H21B0.60110.18660.46030.220*
H21C0.52910.08960.40900.220*
O10.05333 (8)0.5258 (3)0.42700 (10)0.0633 (4)
O20.54066 (11)0.4281 (5)0.39166 (15)0.1103 (8)
S10.13305 (3)0.61593 (13)0.12994 (4)0.0614 (2)
S20.26527 (3)0.80951 (11)0.23220 (3)0.05424 (19)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0697 (15)0.0523 (15)0.0573 (14)0.0096 (11)0.0281 (12)0.0104 (11)
C20.0824 (18)0.0560 (16)0.0804 (18)0.0158 (13)0.0463 (15)0.0015 (14)
C30.0652 (15)0.0657 (16)0.0505 (13)0.0064 (12)0.0287 (11)0.0081 (12)
C40.0617 (14)0.0656 (16)0.0474 (13)0.0037 (12)0.0203 (11)0.0117 (11)
C50.0600 (14)0.0544 (14)0.0561 (13)0.0129 (11)0.0262 (11)0.0068 (11)
C60.0443 (11)0.0451 (12)0.0425 (11)0.0031 (9)0.0160 (9)0.0024 (9)
C70.0485 (11)0.0502 (13)0.0447 (11)0.0023 (10)0.0183 (9)0.0008 (10)
C80.0387 (10)0.0504 (13)0.0508 (12)0.0041 (9)0.0162 (9)0.0030 (10)
C90.0435 (11)0.0502 (14)0.0541 (13)0.0018 (10)0.0149 (9)0.0050 (10)
C100.0452 (11)0.0468 (13)0.0590 (13)0.0059 (9)0.0206 (10)0.0026 (11)
C110.0388 (11)0.0511 (13)0.0502 (12)0.0024 (9)0.0169 (9)0.0016 (10)
C120.0497 (12)0.0449 (13)0.0688 (15)0.0040 (10)0.0250 (11)0.0089 (11)
C130.0490 (12)0.0469 (14)0.0801 (16)0.0039 (10)0.0322 (12)0.0059 (12)
C140.0818 (19)0.082 (2)0.0701 (17)0.0028 (15)0.0380 (15)0.0216 (15)
C150.0551 (13)0.0552 (14)0.0423 (11)0.0060 (10)0.0186 (9)0.0050 (10)
C160.0661 (17)0.102 (2)0.0743 (17)0.0057 (16)0.0187 (14)0.0297 (17)
C170.086 (2)0.096 (2)0.077 (2)0.0070 (18)0.0083 (16)0.0303 (17)
C180.0609 (16)0.088 (2)0.0660 (16)0.0093 (15)0.0134 (13)0.0180 (15)
C190.0616 (17)0.101 (3)0.109 (2)0.0023 (16)0.0406 (17)0.006 (2)
C200.0687 (17)0.0734 (18)0.0814 (18)0.0002 (14)0.0362 (14)0.0113 (15)
C210.115 (3)0.132 (4)0.138 (4)0.051 (3)0.025 (3)0.013 (3)
O10.0678 (10)0.0719 (12)0.0588 (9)0.0083 (9)0.0329 (8)0.0075 (9)
O20.0726 (14)0.136 (2)0.1071 (17)0.0291 (14)0.0116 (12)0.0111 (16)
S10.0485 (3)0.0866 (5)0.0493 (3)0.0027 (3)0.0174 (2)0.0004 (3)
S20.0579 (3)0.0549 (4)0.0504 (3)0.0013 (3)0.0195 (3)0.0066 (3)
Geometric parameters (Å, º) top
C1—C61.374 (3)C12—C131.392 (3)
C1—C21.379 (3)C12—H120.9300
C1—H10.9300C13—H130.9300
C2—C31.372 (3)C14—O11.421 (3)
C2—H20.9300C14—H14A0.9600
C3—C41.361 (3)C14—H14B0.9600
C3—H30.9300C14—H14C0.9600
C4—C51.381 (3)C15—C161.368 (3)
C4—H40.9300C15—C201.374 (3)
C5—C61.384 (3)C15—S21.770 (2)
C5—H50.9300C16—C171.385 (4)
C6—C71.512 (3)C16—H160.9300
C7—S11.811 (2)C17—C181.379 (4)
C7—S21.833 (2)C17—H170.9300
C7—H70.9800C18—C191.354 (4)
C8—C91.376 (3)C18—O21.372 (3)
C8—C131.377 (3)C19—C201.370 (4)
C8—S11.778 (2)C19—H190.9300
C9—C101.373 (3)C20—H200.9300
C9—H90.9300C21—O21.408 (5)
C10—C111.385 (3)C21—H21A0.9600
C10—H100.9300C21—H21B0.9600
C11—O11.364 (2)C21—H21C0.9600
C11—C121.377 (3)
C6—C1—C2120.6 (2)C13—C12—H12120.4
C6—C1—H1119.7C8—C13—C12121.3 (2)
C2—C1—H1119.7C8—C13—H13119.3
C3—C2—C1120.5 (2)C12—C13—H13119.3
C3—C2—H2119.7O1—C14—H14A109.5
C1—C2—H2119.7O1—C14—H14B109.5
C4—C3—C2119.5 (2)H14A—C14—H14B109.5
C4—C3—H3120.3O1—C14—H14C109.5
C2—C3—H3120.3H14A—C14—H14C109.5
C3—C4—C5120.3 (2)H14B—C14—H14C109.5
C3—C4—H4119.9C16—C15—C20118.2 (2)
C5—C4—H4119.9C16—C15—S2120.83 (19)
C4—C5—C6120.7 (2)C20—C15—S2120.9 (2)
C4—C5—H5119.6C15—C16—C17121.5 (3)
C6—C5—H5119.6C15—C16—H16119.2
C1—C6—C5118.41 (19)C17—C16—H16119.2
C1—C6—C7119.62 (19)C18—C17—C16119.1 (3)
C5—C6—C7121.96 (19)C18—C17—H17120.5
C6—C7—S1109.22 (13)C16—C17—H17120.5
C6—C7—S2113.90 (14)C19—C18—O2115.9 (3)
S1—C7—S2107.73 (11)C19—C18—C17119.3 (3)
C6—C7—H7108.6O2—C18—C17124.8 (3)
S1—C7—H7108.6C18—C19—C20121.4 (3)
S2—C7—H7108.6C18—C19—H19119.3
C9—C8—C13118.7 (2)C20—C19—H19119.3
C9—C8—S1117.84 (17)C19—C20—C15120.5 (3)
C13—C8—S1123.28 (17)C19—C20—H20119.8
C10—C9—C8120.6 (2)C15—C20—H20119.8
C10—C9—H9119.7O2—C21—H21A109.5
C8—C9—H9119.7O2—C21—H21B109.5
C9—C10—C11120.6 (2)H21A—C21—H21B109.5
C9—C10—H10119.7O2—C21—H21C109.5
C11—C10—H10119.7H21A—C21—H21C109.5
O1—C11—C12125.0 (2)H21B—C21—H21C109.5
O1—C11—C10115.50 (19)C11—O1—C14118.12 (18)
C12—C11—C10119.5 (2)C18—O2—C21118.2 (3)
C11—C12—C13119.2 (2)C8—S1—C7102.63 (9)
C11—C12—H12120.4C15—S2—C7100.37 (10)
C6—C1—C2—C30.8 (4)C20—C15—C16—C171.4 (4)
C1—C2—C3—C40.8 (4)S2—C15—C16—C17179.6 (2)
C2—C3—C4—C50.2 (4)C15—C16—C17—C182.0 (5)
C3—C4—C5—C60.5 (4)C16—C17—C18—C190.9 (5)
C2—C1—C6—C50.1 (3)C16—C17—C18—O2178.1 (3)
C2—C1—C6—C7178.7 (2)O2—C18—C19—C20179.7 (3)
C4—C5—C6—C10.5 (3)C17—C18—C19—C200.6 (5)
C4—C5—C6—C7178.0 (2)C18—C19—C20—C151.2 (5)
C1—C6—C7—S1129.59 (19)C16—C15—C20—C190.2 (4)
C5—C6—C7—S148.9 (2)S2—C15—C20—C19178.0 (2)
C1—C6—C7—S2109.9 (2)C12—C11—O1—C141.1 (3)
C5—C6—C7—S271.6 (2)C10—C11—O1—C14178.5 (2)
C13—C8—C9—C101.1 (3)C19—C18—O2—C21172.7 (3)
S1—C8—C9—C10174.58 (16)C17—C18—O2—C218.2 (5)
C8—C9—C10—C111.5 (3)C9—C8—S1—C7131.85 (17)
C9—C10—C11—O1179.77 (18)C13—C8—S1—C752.7 (2)
C9—C10—C11—C120.2 (3)C6—C7—S1—C8168.12 (15)
O1—C11—C12—C13178.0 (2)S2—C7—S1—C867.69 (13)
C10—C11—C12—C131.5 (3)C16—C15—S2—C770.3 (2)
C9—C8—C13—C120.6 (3)C20—C15—S2—C7111.6 (2)
S1—C8—C13—C12176.06 (17)C6—C7—S2—C1573.83 (16)
C11—C12—C13—C81.9 (3)S1—C7—S2—C15164.86 (11)
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg2i0.932.993.713 (3)136
C10—H10···Cg2ii0.932.963.610 (2)128
C21—H21B···Cg1iii0.962.983.914 (5)165
Symmetry codes: (i) x, y+3/2, z1/2; (ii) x, y+1/2, z+1/2; (iii) x+1, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC21H20O2S2
Mr368.49
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)21.1506 (15), 5.6114 (3), 17.1219 (11)
β (°) 110.336 (2)
V3)1905.4 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.29
Crystal size (mm)0.42 × 0.20 × 0.18
Data collection
DiffractometerBruker APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2004)
Tmin, Tmax0.888, 0.950
No. of measured, independent and
observed [I > 2σ(I)] reflections
12756, 4154, 2725
Rint0.024
(sin θ/λ)max1)0.646
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.128, 1.02
No. of reflections4154
No. of parameters228
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.51, 0.27

Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2004), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg2i0.932.993.713 (3)136
C10—H10···Cg2ii0.932.963.610 (2)128
C21—H21B···Cg1iii0.962.983.914 (5)165
Symmetry codes: (i) x, y+3/2, z1/2; (ii) x, y+1/2, z+1/2; (iii) x+1, y1/2, z+1/2.
 

Acknowledgements

RSR thanks CSIR, New Delhi, for funding under the Scientist's Pool Scheme and BIF, University of Hyderabad, for computational resources.

References

First citationAllen, F. H. (2002). Acta Cryst. B58, 380–388.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationBruker (2004). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J., Hartley, R. C. & Guthrie, E. (2000). Private communication [refcodes QITPEO, QITPOY, QITPUE and QITQAL (CCDC 149307–CCDC 149310l, respectively)]. CCDC, Union Road, Cambridge, England.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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