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The title compound, C22H20Br2N2S, was synthesized under solvent-free conditions. The mol­ecule shows crystallographic C2 symmetry, with the S atom of the central thio­phene ring lying on a twofold rotation axis. Furthermore, as a consequence of the (S,S) stereochemistry, the mol­ecule has a twisted conformation. The dihedral angle between the thio­phene and benzene rings is 72.7 (2)° and that between the two benzene rings is 55.9 (2)°. In the crystal, mol­ecules are arranged in a chevron-like pattern, without any significant inter­molecular inter­actions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536814003651/is5340sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536814003651/is5340Isup2.hkl
Contains datablock I

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S1600536814003651/is5340Isup3.cml
Supplementary material

CCDC reference: 987496

Key indicators

  • Single-crystal X-ray study
  • T = 298 K
  • Mean [sigma](C-C) = 0.007 Å
  • R factor = 0.036
  • wR factor = 0.072
  • Data-to-parameter ratio = 17.0

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT090_ALERT_3_C Poor Data / Parameter Ratio (Zmax > 18) ........ 9.62 Note PLAT242_ALERT_2_C Low Ueq as Compared to Neighbors for ..... C4 Check PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds ............... 0.0070 Ang.
Alert level G PLAT005_ALERT_5_G No _iucr_refine_instructions_details in the CIF Please Do ! PLAT791_ALERT_4_G The Model has Chirality at C7 ............. S Verify PLAT910_ALERT_3_G Missing # of FCF Reflections Below Th(Min) ..... 2 Why ?
0 ALERT level A = Most likely a serious problem - resolve or explain 0 ALERT level B = A potentially serious problem, consider carefully 3 ALERT level C = Check. Ensure it is not caused by an omission or oversight 3 ALERT level G = General information/check it is not something unexpected 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check

Comment top

In continuation of our work focused on chiral bisimines (Espinosa Leija et al., 2009; Bernès et al., 2013), we have now synthesized the title compound under the solvent-free approach because of the cleaner, safer, and easier aspects to perform in the synthetic work. So, solvent-free conditions are becoming more popular and it is often claimed that the best solvent is no solvent. (Tanaka & Toda, 2000).

The bis-aldimine compound shows an E configuration over every imine bond (Fig. 1). The molecule is an (S,S) diastereoisomer as expected by synthetic procedure. The asymmetric unit contains a half-molecule. The S atom of the molecule is located on a twofold rotation axis of the space group C2. and as a consequence the Br-aldimines groups are placed opposite to the central thiophene ring. Only some previous reports of 2,5-thiophene compounds with achiral or chiral substituents have showed C2 crystallographic symmetry like title compound (Kudyakova et al., 2012, space group C2/c; Bernès et al., 2013, space group P22121). The crystal packing does not feature any particular interactions (intra or intermolecular) and the supramolecular arrangement in the solid state shows a chevron-like pattern viewed along the b axis (Fig. 2).

Related literature top

For the solvent-free organic synthesis, see: Tanaka & Toda (2000). For the structure of a chiral bis-aldimine compound, see: Espinosa Leija et al. (2009). For structures of thiophenes substituted in positions 2 and 5 by imine functionalities, see: Bernès et al. (2013); Kudyakova et al. (2012).

Experimental top

Under solvent-free conditions, a mixture of 2,5-thiophenedicarboxaldehyde (100 mg, 0.71 mmol) and (S)-(–)-1-(4-bromophenyl)ethylamine (285 mg, 1.42 mmol) in a 1:2 molar ratio were mixed at room temperature, giving a white solid. The crude was recrystallized from CH2Cl2, affording colorless crystals of the title compound.

Yield 96%; m.p. 147–149 °C. Spectroscopic data: [a]D25 = +59.6 (c 1, CHCl3). IR (KBr): 1623 cm-1 (C=N). 1H NMR (400 MHz, CDCl3/TMS): δ = 1.51, 1.53 (d, 6H, CHCH3,), 4.44, 4.45, 4.47, 4.49(q, 2H, CH), 7.29–7.45 (m, 10 H, Ar), 8.36 (s, 2 H, HC=N). 13C NMR (100 MHz, CDCl3/TMS) δ = 25.1 (CCH3), 68.7 (CHCH3), 120.6 (Ar), 128.3 (Ar), 130.1 (Ar), 131.4 (Ar), 144.0 (Ar), 145.1 (Ar), 152. 7 (HC=N). MS—EI: m/z= 504 (M+).

Refinement top

The absolute configuration was determined using the anomalous dispersion of the Br atom, and was that expected from the synthesis, carried-out with an enantiomerically pure amine. All H atoms were placed in calculated positions, with C—H bond lengths fixed to 0.96 Å for the methyl group and 0.93 Å for aromatic CH groups. Isotropic displacement parameters were calculated as Uiso(H) = 1.5Ueq(carrier atom) for the methyl group and Uiso(H) = 1.2Ueq(carrier atom) otherwise.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis RED (Agilent, 2013); program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top
[Figure 1] Fig. 1. The molecular structure of title compound, with atom labels and 30% probability displacement ellipsoids for non-H atoms.
[Figure 2] Fig. 2. A packing diagram of the title compound, viewed along the b axis.
2,5-Bis{[(–)-(S)-1-(4-bromophenyl)ethyl]iminomethyl}thiophene top
Crystal data top
C22H20Br2N2SF(000) = 504
Mr = 504.27Dx = 1.521 Mg m3
Monoclinic, C2Melting point: 420 K
Hall symbol: C 2yMo Kα radiation, λ = 0.71073 Å
a = 24.5329 (15) ÅCell parameters from 1609 reflections
b = 5.9762 (5) Åθ = 4.4–25.2°
c = 7.5944 (5) ŵ = 3.79 mm1
β = 98.536 (6)°T = 298 K
V = 1101.11 (14) Å3Prism, colourless
Z = 20.52 × 0.15 × 0.06 mm
Data collection top
Agilent Xcalibur (Atlas, Gemini)
diffractometer
2107 independent reflections
Radiation source: Enhance (Mo) X-ray Source1630 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
Detector resolution: 10.5564 pixels mm-1θmax = 26.1°, θmin = 3.0°
ω scansh = 3030
Absorption correction: numerical
(CrysAlis PRO; Agilent, 2013)
k = 77
Tmin = 0.400, Tmax = 0.815l = 99
6101 measured reflections
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.0288P)2 + 0.0296P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.072(Δ/σ)max < 0.001
S = 1.03Δρmax = 0.20 e Å3
2107 reflectionsΔρmin = 0.35 e Å3
124 parametersAbsolute structure: Flack (1983), 914 Friedel pairs
1 restraintAbsolute structure parameter: 0.011 (8)
0 constraints
Crystal data top
C22H20Br2N2SV = 1101.11 (14) Å3
Mr = 504.27Z = 2
Monoclinic, C2Mo Kα radiation
a = 24.5329 (15) ŵ = 3.79 mm1
b = 5.9762 (5) ÅT = 298 K
c = 7.5944 (5) Å0.52 × 0.15 × 0.06 mm
β = 98.536 (6)°
Data collection top
Agilent Xcalibur (Atlas, Gemini)
diffractometer
2107 independent reflections
Absorption correction: numerical
(CrysAlis PRO; Agilent, 2013)
1630 reflections with I > 2σ(I)
Tmin = 0.400, Tmax = 0.815Rint = 0.035
6101 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.072Δρmax = 0.20 e Å3
S = 1.03Δρmin = 0.35 e Å3
2107 reflectionsAbsolute structure: Flack (1983), 914 Friedel pairs
124 parametersAbsolute structure parameter: 0.011 (8)
1 restraint
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
Br10.15628 (2)0.49000 (18)0.61658 (7)0.1112 (4)
S10.50.2196 (2)0.50.0472 (4)
C90.47486 (16)0.0181 (7)0.6292 (5)0.0427 (10)
C110.4216 (2)0.4840 (10)1.0744 (5)0.0657 (13)
H11A0.41940.62481.01290.099*
H11B0.45950.44991.11750.099*
H11C0.40130.49291.1730.099*
C40.2306 (2)0.4327 (11)0.7169 (6)0.0639 (15)
C10.33894 (18)0.3489 (7)0.8651 (5)0.0441 (11)
C60.3243 (2)0.5418 (9)0.7670 (6)0.0569 (13)
H60.35140.64570.75130.068*
N10.43094 (15)0.2748 (6)0.8052 (5)0.0452 (9)
C50.2703 (2)0.5823 (9)0.6921 (7)0.0674 (16)
H50.26130.7110.62530.081*
C20.2971 (2)0.1997 (9)0.8837 (6)0.0603 (13)
H20.30560.06880.94820.072*
C30.2431 (2)0.2389 (11)0.8092 (7)0.0690 (14)
H30.21570.1350.82180.083*
C70.3974 (2)0.3024 (8)0.9485 (5)0.0501 (12)
H70.3980.16161.01490.06*
C80.44434 (18)0.0769 (7)0.7709 (6)0.0469 (12)
H80.43390.0380.84140.056*
C100.4853 (2)0.1907 (8)0.5728 (7)0.0540 (13)
H100.47430.32050.6250.065*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0529 (4)0.2036 (8)0.0729 (4)0.0279 (5)0.0044 (3)0.0229 (5)
S10.0553 (11)0.0347 (8)0.0547 (10)00.0179 (8)0
C90.043 (2)0.038 (2)0.047 (2)0.001 (2)0.0052 (18)0.005 (2)
C110.058 (3)0.085 (3)0.053 (2)0.009 (3)0.005 (2)0.003 (3)
C40.044 (3)0.106 (5)0.042 (2)0.005 (3)0.006 (2)0.009 (3)
C10.044 (3)0.053 (3)0.037 (2)0.001 (2)0.012 (2)0.002 (2)
C60.052 (3)0.062 (3)0.056 (3)0.002 (3)0.007 (2)0.016 (3)
N10.042 (2)0.052 (2)0.0439 (19)0.0014 (17)0.0134 (17)0.0053 (16)
C50.063 (4)0.084 (4)0.053 (3)0.010 (3)0.003 (3)0.014 (3)
C20.064 (4)0.067 (3)0.053 (3)0.002 (3)0.017 (2)0.011 (3)
C30.051 (3)0.094 (4)0.065 (3)0.019 (3)0.017 (3)0.005 (3)
C70.051 (3)0.060 (3)0.043 (2)0.006 (2)0.017 (2)0.011 (2)
C80.039 (3)0.051 (3)0.051 (3)0.000 (2)0.008 (2)0.013 (2)
C100.057 (3)0.035 (2)0.073 (3)0.001 (2)0.017 (3)0.005 (2)
Geometric parameters (Å, º) top
Br1—C41.899 (5)C1—C71.505 (6)
S1—C9i1.724 (4)C6—H60.93
S1—C91.724 (4)C6—C51.383 (7)
C9—C81.442 (6)N1—C71.468 (5)
C9—C101.356 (6)N1—C81.265 (5)
C11—H11A0.96C5—H50.93
C11—H11B0.96C2—H20.93
C11—H11C0.96C2—C31.382 (7)
C11—C71.509 (7)C3—H30.93
C4—C51.356 (7)C7—H70.98
C4—C31.365 (7)C8—H80.93
C1—C61.391 (6)C10—C10i1.405 (10)
C1—C21.383 (7)C10—H100.93
C9—S1—C9i91.4 (3)C4—C5—H5120.3
C8—C9—S1121.6 (3)C6—C5—H5120.3
C10—C9—S1111.2 (3)C1—C2—H2119
C10—C9—C8127.1 (4)C3—C2—C1122.0 (5)
H11A—C11—H11B109.5C3—C2—H2119
H11A—C11—H11C109.5C4—C3—C2118.9 (5)
H11B—C11—H11C109.5C4—C3—H3120.6
C7—C11—H11A109.5C2—C3—H3120.6
C7—C11—H11B109.5C11—C7—H7108.5
C7—C11—H11C109.5C1—C7—C11113.2 (4)
C5—C4—Br1119.5 (4)C1—C7—H7108.5
C5—C4—C3121.3 (5)N1—C7—C11109.9 (4)
C3—C4—Br1119.2 (4)N1—C7—C1108.2 (3)
C6—C1—C7122.2 (4)N1—C7—H7108.5
C2—C1—C6116.9 (4)C9—C8—H8117.9
C2—C1—C7120.9 (4)N1—C8—C9124.1 (4)
C1—C6—H6119.3N1—C8—H8117.9
C5—C6—C1121.3 (5)C9—C10—C10i113.1 (3)
C5—C6—H6119.3C9—C10—H10123.5
C8—N1—C7116.7 (3)C10i—C10—H10123.5
C4—C5—C6119.5 (5)
Br1—C4—C5—C6179.2 (4)C2—C1—C6—C50.2 (7)
Br1—C4—C3—C2179.2 (4)C2—C1—C7—C11122.6 (5)
S1—C9—C8—N14.2 (6)C2—C1—C7—N1115.3 (4)
S1—C9—C10—C10i1.2 (7)C3—C4—C5—C62.3 (8)
C9i—S1—C9—C8177.3 (4)C7—C1—C6—C5179.6 (4)
C9i—S1—C9—C100.4 (3)C7—C1—C2—C3179.7 (4)
C1—C6—C5—C41.0 (7)C7—N1—C8—C9176.9 (4)
C1—C2—C3—C41.0 (7)C8—C9—C10—C10i177.9 (5)
C6—C1—C2—C30.2 (7)C8—N1—C7—C11131.9 (4)
C6—C1—C7—C1157.3 (5)C8—N1—C7—C1104.0 (4)
C6—C1—C7—N164.8 (5)C10—C9—C8—N1172.2 (5)
C5—C4—C3—C22.3 (7)
Symmetry code: (i) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaC22H20Br2N2S
Mr504.27
Crystal system, space groupMonoclinic, C2
Temperature (K)298
a, b, c (Å)24.5329 (15), 5.9762 (5), 7.5944 (5)
β (°) 98.536 (6)
V3)1101.11 (14)
Z2
Radiation typeMo Kα
µ (mm1)3.79
Crystal size (mm)0.52 × 0.15 × 0.06
Data collection
DiffractometerAgilent Xcalibur (Atlas, Gemini)
diffractometer
Absorption correctionNumerical
(CrysAlis PRO; Agilent, 2013)
Tmin, Tmax0.400, 0.815
No. of measured, independent and
observed [I > 2σ(I)] reflections
6101, 2107, 1630
Rint0.035
(sin θ/λ)max1)0.618
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.072, 1.03
No. of reflections2107
No. of parameters124
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.20, 0.35
Absolute structureFlack (1983), 914 Friedel pairs
Absolute structure parameter0.011 (8)

Computer programs: CrysAlis PRO (Agilent, 2013), CrysAlis RED (Agilent, 2013), SHELXS2013 (Sheldrick, 2008), SHELXL2013 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), WinGX (Farrugia, 2012).

 

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