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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

2,5-Bis­(tri­methyl­silyl­ethynyl)­thieno­[3,2-b]­thio­phene

CROSSMARK_Color_square_no_text.svg

aDepartment of Chemistry, College of Science, Sultan Qaboos University, PO Box 36, Al Khod 123, Sultanate of Oman, bDepartment of Chemistry, University of Bath, Bath BA2 7AY, England, and cDepartment of Chemistry, University of Bath, Bath BA2 7AY, England, and CCLRC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, England
*Correspondence e-mail: p.r.raithby@bath.ac.uk

(Received 7 June 2004; accepted 10 June 2004; online 19 June 2004)

2,5-Bis­(tri­methyl­silyl­ethynyl)­thieno­[3,2-b]­thio­phene, C16H20S2Si2, is a tri­methyl­silyl-protected diyne. It is a precursor in the formation of platinum and gold diyne complexes and and polyyne polymers. These materials are of interest because of the π-conjugation that extends through the fused oligothienyl linker unit along the rigid backbone of the polymer. In the structure of the title compound, the oligothienyl group is planar, by crystallographic symmetry, and the tri­methyl­silyl-alkyne groups are essentially linear.

Comment

We report here the structural characterization of the title compound, 2,5-bis­(tri­methyl­silyl­ethynyl)­thieno­[3,2-b]­thio­phene, (I[link]), which is a tri­methyl­silyl-protected diyne. It is a precursor in the formation of the following series of compounds: the terminal diyne, H—C≡C—R—C≡C—H, the dinuclear platinum(II) diyne, [(Ph)(PEt3)2Pt—C≡C—R—C≡C—Pt(PEt3)2(Ph)], and the platinum(II) polyyne, trans-[(nBu3P)2Pt—C≡C—R—C≡C—] (R = thieno­[3,2-b]­thio­phene-2,5-diyl). Rigid-rod platinum(II) polyynes with the general formula trans-[(nBu3P)2Pt—C≡C—R—C≡C—] (R = conjugated aromatic/hetero-aromatic linker group) are considered to be good model systems to study the triplet excited state in polymers and provide important information on the photophysical processes that occur within them (Khan, Al-Mandhary, Al-Suti, Hisham et al., 2002[Khan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Hisham, A. K., Raithby, P. R., Ahrens, B., Mahon, M. F., Male, L., Marseglia, E. A., Tedesco, E., Friend, R. H., Köhler, Feeder, N. & Teat, S. J. (2002). J. Chem. Soc. Dalton Trans. pp. 1358-1368.]; Khan, Al-Mandhary, Al-Suti, Feeder et al., 2002[Khan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Feeder, N., Nahar, S., Köhler, A., Friend, R. H., Wilson, P. J. & Raithby, P. R. (2002). J. Chem. Soc. Dalton Trans. pp. 2441-2448.]; Khan et al., 2003[Khan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Raithby, P. R., Ahrens, B., Male. L., Friend, R. H., Köhler, A. & Wilson, J. S. (2003). Dalton Trans. pp. 65-73.E]). The incorporation of heavy transition metals, such as platinum, at regular intervals along the rigid polymer backbone introduces a large component of spin-orbit coupling that allows emission from the triplet excited state of the system via spin cross-over processes (Wittmann et al., 1994[Wittmann, H. F., Friend, R. H., Khan, M. S. & Lewis, J. (1994). J. Chem. Phys. 101, 2693-2698.]; Beljonne et al., 1996[Beljonne, D. Wittmann, H. F. Köhler, A., Graham, S., Younus, M., Lewis, J., Raithby, P. R., Khan, M. S., Friend, R. H. & Bredas, J. L. (1996). J. Chem. Phys. 105, 3868-3877.]; Younus et al., 1998[Younus, M., Köhler, A. Cron, Chawdhury, N., Al-Mandhary, M. R. A., Khan, M. S., Lewis, J., Long, N. J., Friend, R. H. & Raithby, P. R. (1998). Angew. Chem. Int. Ed. 37, 3036-3039.]; Chawdhury et al., 1999[Chawdhury, N., Köhler, A., Friend, R. H., Wong, W.-Y., Younus, M., Raithby, P. R., Lewis, J. Corcoran, T. C., Al-Mandhary, M. R. A. & Khan, M. S. (1999). J. Chem. Phys. 110, 4963-4970.]). The novel photophysics of the platinum(II) polyynes leads to materials that are useful for applications in modern opto-electronic devices such as light emitting diodes (LEDs), lasers, photocells and field-effect transistors (FETs) (Wilson et al., 2000[Wilson, J. S., Köhler, A. Friend, R. H., Al-Suti, M. K., Khan, M. S. & Raithby, P. R. (2000). J. Chem. Phys. 113, 7627-7634.]; Wilson, Chawdhury et al., 2001[Wilson, J. S., Chawdhury, N., Köhler, A., Friend, R. H., Al-Mandhary, M. R. A., Khan, M. S., Younus, M. & P. R. Raithby (2001). J. Am. Chem. Soc. 123, 9412-9417.]; Wilson, Dhoot et al., 2001[Wilson, J. S., Dhoot, A. S., Seeley, A. J. A. B., Khan, M. S., Köhler, A. & Friend, R. H. (2001). Nature (London), 413, 828-831.]).[link]

[Scheme 1]

The title compound, (I[link]), crystallizes in the monoclinic space group P21/c, with two mol­ecules in the unit cell, such that each mol­ecule sits on a crystallographic centre of symmetry at the centre of the bi­thio­phene unit, at the mid-point of the C8—C8a bond (Fig. 1[link]), and the asymmetric unit contains half of one mol­ecule. The bi­thio­phene unit is planar. Within the bi­thio­phene unit, the S—C bond lengths average 1.730 Å, and the C6—C7 and C8—C8a bond lengths (average 1.395 Å) are significantly shorter than the C7—C8 bond, 1.444 (3) Å, consistent with the normal bonding picture for bi­thio­phene, and similar to those found in a binuclear platinum(II) complex bridged by a thieno­[3,2-b]­thio­phene group (Sato et al., 2002[Sato, M., Asami, A., Maruyama, G., Kosuge, M., Nakayama, J., Kumakura, S., Fujihara, T. & Unoura, K. (2002). J. Organomet. Chem. 654, 56-65.]). The bond parameters associated with the acetyl­enic units and the tri­methyl­silyl groups are similar to those in a number of other bis(tri­methyl­silyl) substituted diyne compounds (Khan, Ahrens et al., 2002[Khan, M. S., Ahrens, B., Male, L. & Raithby, P. R. (2002). Acta Cryst. E58, o1220-o1221.], 2004[Khan, M. S., Ahrens, B., Male, L. & Raithby, P. R. (2004). Acta Cryst. E60, o915-o916.]).

There are no short intermolecular contacts within the crystal structure.

[Figure 1]
Figure 1
View of (I[link]) (50% probability displacement ellipsoids). Atoms with the suffix A are the symmetry equivalents, related by 1 − x, −y, 1 − z

Experimental

To a solution of 2,5-di­bromo­thieno­[3,2-b]­thio­phene (2.0 g, 6.71 mmol) in iPr2NH–THF (70 ml, 1:1 v/v) under nitro­gen was added a catalytic mixture of CuI (20 mg), Pd(OAc)2 (20 mg) and PPh3 (60 mg). The solution was stirred for 20 min at 323 K and then tri­methyl­silyl­ethyne (1.64 g, 16.7 mmol) was added. The reaction mixture was left, with stirring, for 20 h at 348 K. The solution was allowed to cool down to room temperature, filtered and the solvent mixture removed under reduced pressure. The residue was subjected to silica column chromatography using hexane to afford the title compound as a colourless solid in 85% yield (1.78 g).

Crystal data
  • C16H20S2Si2

  • Mr = 332.62

  • Monoclinic, P21/c

  • a = 15.173 (3) Å

  • b = 5.7317 (12) Å

  • c = 10.9836 (18) Å

  • β = 108.220 (9)°

  • V = 907.3 (3) Å3

  • Z = 2

  • Dx = 1.217 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 3713 reflections

  • θ = 2.9–25.0°

  • μ = 0.42 mm−1

  • T = 170 (2) K

  • Needle, colourless

  • 0.23 × 0.07 × 0.04 mm

Data collection
  • Nonius KappaCCD diffractometer

  • φ and ω scans

  • Absorption correction: none

  • 2820 measured reflections

  • 1596 independent reflections

  • 1336 reflections with I > 2σ(I)

  • Rint = 0.022

  • θmax = 25.1°

  • h = −17 → 18

  • k = −6 → 6

  • l = −13 → 12

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.100

  • S = 1.05

  • 1596 reflections

  • 94 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0404P)2 + 0.7998P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.39 e Å−3

  • Δρmin = −0.26 e Å−3

All the aromatic and methyl H atoms were constrained as riding atoms, fixed to the parent atoms with distances of 0.95 and 0.98 Å, respectively, with Uiso(H) set at 1.2 (aromatic H atoms) or 1.5 (methyl H atoms) times Ueq(parent atom).

Data collection: COLLECT (Nonius, 1998[Nonius. (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999).

(I) top
Crystal data top
C16H20S2Si2F(000) = 352
Mr = 332.62Dx = 1.217 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 15.173 (3) ÅCell parameters from 3713 reflections
b = 5.7317 (12) Åθ = 2.9–25.0°
c = 10.9836 (18) ŵ = 0.42 mm1
β = 108.220 (9)°T = 170 K
V = 907.3 (3) Å3Plate, colourless
Z = 20.23 × 0.07 × 0.04 mm
Data collection top
Nonius KappaCCD
diffractometer
Rint = 0.022
88 2° φ and 32 2° ω scansθmax = 25.1°, θmin = 3.8°
2820 measured reflectionsh = 1718
1596 independent reflectionsk = 66
1336 reflections with I > 2σ(I)l = 1312
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.037 w = 1/[σ2(Fo2) + (0.0404P)2 + 0.7998P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.100(Δ/σ)max < 0.001
S = 1.05Δρmax = 0.39 e Å3
1596 reflectionsΔρmin = 0.26 e Å3
94 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
S10.55976 (4)0.07228 (11)0.35782 (6)0.0324 (2)
Si10.82072 (4)0.56440 (11)0.30149 (6)0.0245 (2)
C10.88762 (18)0.3625 (5)0.2313 (3)0.0378 (6)
H1A0.91530.23910.29320.057*
H1B0.93680.44930.21080.057*
H1C0.8460.29270.15290.057*
C20.75124 (18)0.7738 (5)0.1809 (2)0.0370 (6)
H2A0.70530.68840.11270.055*
H2B0.79230.86140.14410.055*
H2C0.71940.88220.2220.055*
C30.89848 (18)0.7245 (5)0.4417 (2)0.0403 (7)
H3A0.8630.84580.46860.06*
H3B0.94920.79670.41770.06*
H3C0.92410.61520.51260.06*
C40.73868 (16)0.3931 (4)0.3582 (2)0.0290 (6)
C50.68058 (15)0.2953 (4)0.3936 (2)0.0269 (5)
C60.61124 (15)0.1820 (4)0.4346 (2)0.0259 (5)
C70.57692 (14)0.2577 (4)0.5332 (2)0.0235 (5)
H70.59560.3940.5840.028*
C80.50819 (15)0.0909 (4)0.5434 (2)0.0250 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0330 (4)0.0353 (4)0.0331 (4)0.0076 (3)0.0165 (3)0.0039 (3)
Si10.0244 (4)0.0256 (4)0.0260 (4)0.0033 (3)0.0113 (3)0.0012 (3)
C10.0400 (15)0.0373 (15)0.0427 (15)0.0019 (12)0.0226 (13)0.0000 (12)
C20.0428 (15)0.0325 (14)0.0362 (14)0.0019 (12)0.0132 (12)0.0056 (12)
C30.0372 (15)0.0473 (17)0.0367 (14)0.0116 (13)0.0119 (12)0.0053 (13)
C40.0293 (13)0.0317 (14)0.0273 (12)0.0017 (11)0.0105 (10)0.0005 (10)
C50.0255 (12)0.0291 (13)0.0262 (12)0.0006 (11)0.0083 (10)0.0012 (10)
C60.0215 (12)0.0268 (13)0.0277 (12)0.0033 (10)0.0055 (10)0.0041 (10)
C70.0188 (11)0.0307 (13)0.0218 (11)0.0074 (10)0.0076 (9)0.0041 (10)
C80.0230 (12)0.0271 (12)0.0244 (11)0.0010 (10)0.0069 (10)0.0014 (9)
Geometric parameters (Å, º) top
S1—C8i1.718 (2)C8—S1i1.718 (2)
S1—C61.742 (2)C1—H1A0.98
Si1—C41.840 (2)C1—H1B0.98
Si1—C21.853 (3)C1—H1C0.98
Si1—C11.858 (3)C2—H2A0.98
Si1—C31.863 (3)C2—H2B0.98
C4—C51.207 (3)C2—H2C0.98
C5—C61.424 (3)C3—H3A0.98
C6—C71.409 (3)C3—H3B0.98
C7—C81.444 (3)C3—H3C0.98
C8—C8i1.381 (4)C7—H70.95
C8i—S1—C690.76 (11)Si1—C1—H1C109.47
C4—Si1—C2107.07 (11)H1A—C1—H1B109.51
C4—Si1—C1108.86 (12)H1A—C1—H1C109.49
C2—Si1—C1111.67 (12)H1B—C1—H1C109.46
C4—Si1—C3107.67 (11)Si1—C2—H2A109.43
C2—Si1—C3110.11 (13)Si1—C2—H2B109.49
C1—Si1—C3111.28 (13)Si1—C2—H2C109.50
C5—C4—Si1175.1 (2)H2A—C2—H2B109.42
C4—C5—C6179.3 (3)H2A—C2—H2C109.49
C7—C6—C5126.2 (2)H2B—C2—H2C109.49
C7—C6—S1114.33 (16)Si1—C3—H3A109.46
C5—C6—S1119.50 (17)Si1—C3—H3B109.48
C6—C7—C8107.8 (2)Si1—C3—H3C109.47
C8i—C8—C7115.1 (2)H3A—C3—H3B109.47
C8i—C8—S1i112.0 (2)H3A—C3—H3C109.44
C7—C8—S1i132.87 (18)H3B—C3—H3C109.51
Si1—C1—H1A109.44C6—C7—H7126.19
Si1—C1—H1B109.46C8—C7—H7126.05
Symmetry code: (i) x+1, y, z+1.
 

Acknowledgements

We thank the Sultan Qaboos University, Oman, the Royal Society of Chemistry for a Journals Grant for International Authors (to MSK), and the DAAD for funding (to BA).

References

First citationBeljonne, D. Wittmann, H. F. Köhler, A., Graham, S., Younus, M., Lewis, J., Raithby, P. R., Khan, M. S., Friend, R. H. & Bredas, J. L. (1996). J. Chem. Phys. 105, 3868–3877.  CrossRef CAS Web of Science Google Scholar
First citationChawdhury, N., Köhler, A., Friend, R. H., Wong, W.-Y., Younus, M., Raithby, P. R., Lewis, J. Corcoran, T. C., Al-Mandhary, M. R. A. & Khan, M. S. (1999). J. Chem. Phys. 110, 4963–4970.  Web of Science CrossRef CAS Google Scholar
First citationKhan, M. S., Ahrens, B., Male, L. & Raithby, P. R. (2002). Acta Cryst. E58, o1220–o1221.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationKhan, M. S., Ahrens, B., Male, L. & Raithby, P. R. (2004). Acta Cryst. E60, o915–o916.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationKhan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Feeder, N., Nahar, S., Köhler, A., Friend, R. H., Wilson, P. J. & Raithby, P. R. (2002). J. Chem. Soc. Dalton Trans. pp. 2441–2448.  Web of Science CSD CrossRef Google Scholar
First citationKhan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Hisham, A. K., Raithby, P. R., Ahrens, B., Mahon, M. F., Male, L., Marseglia, E. A., Tedesco, E., Friend, R. H., Köhler, Feeder, N. & Teat, S. J. (2002). J. Chem. Soc. Dalton Trans. pp. 1358–1368.  Web of Science CSD CrossRef Google Scholar
First citationKhan, M. S., Al-Mandhary, M. R. A., Al-Suti, M. K., Raithby, P. R., Ahrens, B., Male. L., Friend, R. H., Köhler, A. & Wilson, J. S. (2003). Dalton Trans. pp. 65–73.E  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationNonius. (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSato, M., Asami, A., Maruyama, G., Kosuge, M., Nakayama, J., Kumakura, S., Fujihara, T. & Unoura, K. (2002). J. Organomet. Chem. 654, 56–65.  Web of Science CSD CrossRef CAS Google Scholar
First citationSheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.  Google Scholar
First citationWilson, J. S., Chawdhury, N., Köhler, A., Friend, R. H., Al-Mandhary, M. R. A., Khan, M. S., Younus, M. & P. R. Raithby (2001). J. Am. Chem. Soc. 123, 9412–9417.  Google Scholar
First citationWilson, J. S., Dhoot, A. S., Seeley, A. J. A. B., Khan, M. S., Köhler, A. & Friend, R. H. (2001). Nature (London), 413, 828–831.  Web of Science CrossRef PubMed CAS Google Scholar
First citationWilson, J. S., Köhler, A. Friend, R. H., Al-Suti, M. K., Khan, M. S. & Raithby, P. R. (2000). J. Chem. Phys. 113, 7627–7634.  Web of Science CrossRef CAS Google Scholar
First citationWittmann, H. F., Friend, R. H., Khan, M. S. & Lewis, J. (1994). J. Chem. Phys. 101, 2693–2698.  CrossRef CAS Web of Science Google Scholar
First citationYounus, M., Köhler, A. Cron, Chawdhury, N., Al-Mandhary, M. R. A., Khan, M. S., Lewis, J., Long, N. J., Friend, R. H. & Raithby, P. R. (1998). Angew. Chem. Int. Ed. 37, 3036–3039.  Web of Science CrossRef CAS Google Scholar

© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds