Download citation
Download citation
link to html
The crystal structure of the red polymorph of tetrahexylsexithiophene (THST) is solved from X-ray powder diffraction data by a direct-space Monte Carlo simulated-annealing approach. First-principles density functional theory (DFT) calculations are used to distinguish between three nearly identical solutions in the space groups C2/m, C2 and P\bar{1} and to improve the overall accuracy of the crystal structure. The correct space group is found to be C2/m. In all space groups, the thiophene backbone is planar and the hexyl side chains assume an all-trans conformation except for two terminal methyl residues, which adopt a gauche orientation. The ability of first-principles DFT calculations to provide atomic coordinates of single-crystal quality is demonstrated by lattice-energy minimization of the known crystal structure of the yellow polymorph of THST. The combination of Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement presented in this paper is generally applicable. It provides a powerful alternative to standard approaches in cases where the information content of the powder diffraction pattern alone is insufficient to distinguish between different structure solutions. DFT calculations can also provide invaluable guidance in Rietveld refinement.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889802002844/ks0106sup1.cif
Contains datablock C2m_best_0k03shift

CCDC reference: 214226

Computing details top

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
(C2m_best_0k03shift) top
Crystal data top
?β = 117.2444°
Mr = ?V = ? Å3
Monoclinic, C2/MZ = ?
a = 24.9512 Å? radiation, λ = ? Å
b = 7.5153 Å × × mm
c = 13.8689 Å
Data collection top
h = ??l = ??
k = ??
Refinement top
Crystal data top
?β = 117.2444°
Mr = ?V = ? Å3
Monoclinic, C2/MZ = ?
a = 24.9512 Å? radiation, λ = ? Å
b = 7.5153 Å × × mm
c = 13.8689 Å
Data collection top
Refinement top
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.088560.006910.927010.00000*
H20.160030.112310.784730.00000*
C30.046000.004470.579100.00000*
C40.464790.010740.302470.00000*
C50.108660.003950.543960.00000*
H60.066220.124270.761290.00000*
S70.256690.000000.416140.00000*
H80.157410.063550.972910.00000*
H90.167160.120800.599500.00000*
H100.423530.110680.522830.00000*
H110.361310.062770.900810.00000*
C120.361050.002650.472020.00000*
H130.064480.110830.760040.00000*
H140.059710.087911.143260.00000*
H150.315670.237720.908010.00000*
H160.539470.014380.135240.00000*
S170.439740.005160.143130.00000*
C180.319170.000000.288040.00000*
C190.137210.004590.618190.00000*
H200.215000.006860.198460.00000*
H210.330960.001330.122830.00000*
H220.106660.073881.159270.00000*
H230.316670.108940.683970.00000*
H240.261700.085780.997930.00000*
C250.392760.003640.543400.00000*
H260.063270.118650.952490.00000*
H270.331860.115660.493030.00000*
C280.299850.002070.208940.00000*
C290.491930.011230.191560.00000*
C300.377710.008690.737440.00000*
C310.129430.002650.805220.00000*
S320.093610.003230.371080.00000*
C330.029420.003980.496720.00000*
C340.141800.003660.430970.00000*
C350.205510.002920.362610.00000*
C360.237070.003880.250000.00000*
C370.379650.003070.274670.00000*
C380.400960.005890.351650.00000*
C390.094670.004720.739300.00000*
C400.122440.038880.992790.00000*
C410.081550.041521.114420.00000*
C420.347560.005010.663590.00000*
C430.334640.038350.857440.00000*
C440.291140.114460.912120.00000*
H450.013050.006060.664100.00000*
H460.490140.014030.348220.00000*
H470.167030.111860.600050.00000*
H480.158340.121580.781500.00000*
H490.054690.112290.945570.00000*
H500.146770.165940.967650.00000*
H510.045740.141021.136030.00000*
H520.330030.116870.495340.00000*
H530.420310.124470.527510.00000*
H540.319650.125080.678400.00000*
H550.402550.116460.727700.00000*
H560.411450.115680.709800.00000*
H570.308960.161270.866140.00000*
H580.262010.139900.874030.00000*
Bond lengths (Å) top
C1—C311.522C18—C281.386
C1—C401.520C18—C371.434
C1—H491.099C19—H471.101
C1—H261.100C19—C391.522
H2—C311.101H20—C361.084
C3—C51.409H21—C281.086
C3—C331.382H22—C411.093
C3—H451.086H23—C421.099
C4—H461.082H24—C441.096
C4—C291.368C25—H531.099
C4—C381.417C25—C421.528
C5—C191.496C28—C361.401
C5—C341.397C30—C431.529
H6—C391.098C30—C421.524
S7—C351.747C30—H551.100
S7—C181.747C30—H561.099
H8—C401.100C31—H481.100
H9—C191.100C31—C391.522
H10—C251.099S32—C341.746
H11—C431.098S32—C331.745
C12—C381.502C34—C351.430
C12—H271.101C35—C361.390
C12—H521.101C37—C381.394
C12—C251.524C40—H501.099
H13—C391.098C40—C411.520
H14—C411.097C41—H511.096
H15—C441.097C42—H541.100
H16—C291.081C43—H571.099
S17—C371.753C43—C441.523
S17—C291.717C44—H581.093

Experimental details

Crystal data
Chemical formula?
Mr?
Crystal system, space groupMonoclinic, C2/M
Temperature (K)?
a, b, c (Å)24.9512, 7.5153, 13.8689
β (°) 117.2444
V3)?
Z?
Radiation type?, λ = ? Å
µ (mm1)?
Crystal size (mm) × ×
Data collection
Diffractometer?
Absorption correction?
No. of measured, independent and
observed (?) reflections
?, ?, ?
Rint?
Refinement
R[F2 > 2σ(F2)], wR(F2), S ?, ?, ?
No. of reflections?
No. of parameters?
No. of restraints?
Δρmax, Δρmin (e Å3)?, ?

 

Follow J. Appl. Cryst.
Sign up for e-alerts
Follow J. Appl. Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds