Crystal structure of ({4-[(4-bromo­phen­yl)ethyn­yl]-3,5-di­ethyl­phen­yl}ethyn­yl)triiso­propyl­silane

Caiyun Shu; Graeme J Moxey; Adam Barlow; Mahbod Morshedi

doi:10.1107/S2056989015007252

. 2015 Apr 18;71(Pt 5):o321–o322. doi: 10.1107/S2056989015007252

Crystal structure of ({4-[(4-bromophenyl)ethynyl]-3,5-diethylphenyl}ethynyl)triisopropylsilane

Caiyun Shu ^a, Graeme J Moxey ^a,^b,^*, Adam Barlow ^b, Mahbod Morshedi ^b

PMCID: PMC4420139 PMID: 25995927

Abstract

The title compound, C₂₉H₃₇BrSi, was synthesized by the Sonogashira coupling of [(3,5-diethyl-4-ethynylphenyl)ethynyl]triisopropylsilane with 4-bromo-1-iodobenzene. In the structure, the two phenyl rings are nearly parallel to each other with a dihedral angle of 4.27 (4)°. In the crystal, π–π interactions between the terminal and central phenyl rings of adjacent molecules link them in the a-axis direction [perpendicular distance = 3.5135 (14); centroid–centroid distance = 3.7393 (11) Å]. In addition, there are weak C—H⋯π interactions between the isopropyl H atoms and the phenyl rings of adjacent molecules.

Keywords: crystal structure, trialkylsilylacetylene, bromoarene, oligo(phenyleneethynylene)

Related literature

For the syntheses of arylalkynes by Sonogashira coupling, see: Takahashi et al. (1980 ▸). For the use of related oligo(phenyleneethynylene)s in the construction of metal alkynyl complexes exhibiting non-linear optical properties, see: Garcia et al. (2002 ▸); Hurst et al. (2002 ▸; 2003 ▸); McDonagh et al. (2003 ▸). For the synthesis of [(3,5-diethyl-4-iodophenyl)ethynyl]triisopropylsilane, see: Ehlers et al. (2011 ▸). For related structures, see: Lehnherr et al. (2008 ▸, 2009 ▸); Błaszczyk et al. (2007 ▸). graphic file with name e-71-0o321-scheme1.jpg

Experimental

Crystal data

C₂₉H₃₇BrSi
M _r = 493.58
Monoclinic,
a = 14.9043 (2) Å
b = 8.50185 (11) Å
c = 22.6111 (3) Å
β = 108.2791 (16)°
V = 2720.56 (7) Å³
Z = 4
Cu Kα radiation
μ = 2.56 mm⁻¹
T = 150 K
0.19 × 0.06 × 0.05 mm

Data collection

Agilent SuperNova (Dual, Cu at zero, EosS2) diffractometer
Absorption correction: analytical [CrysAlis PRO (Agilent, 2014 ▸), based on expressions derived by Clark & Reid (1995 ▸)] T _min = 0.910, T _max = 0.973
17549 measured reflections
5355 independent reflections
4677 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.093
S = 1.03
5355 reflections
288 parameters
H-atom parameters constrained
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.64 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2014 ▸); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015 ▸); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▸); software used to prepare material for publication: OLEX2.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015007252/hg5438sup1.cif

e-71-0o321-sup1.cif^{(618.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015007252/hg5438Isup2.hkl

e-71-0o321-Isup2.hkl^{(293.6KB, hkl)}

Click here for additional data file.^{(8.7KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015007252/hg5438Isup3.cml

Click here for additional data file.^{(1.3MB, tif)}

. DOI: 10.1107/S2056989015007252/hg5438fig1.tif

Molecular structure of ((4-((4-bromophenyl)ethynyl)-3,5-diethylphenyl)ethynyl)triisopropylsilane, with thermal ellipsoids set at the 40% probability level.

Click here for additional data file.^{(1.7MB, tif)}

. DOI: 10.1107/S2056989015007252/hg5438fig2.tif

Packing diagram of ((4-((4-bromophenyl)ethynyl)-3,5-diethylphenyl)ethynyl)triisopropylsilane.

Click here for additional data file.^{(99.3KB, tif)}

1 13 . DOI: 10.1107/S2056989015007252/hg5438fig3.tif

Atom numbering scheme of ((2,6-diethyl-4-((triisopropylsilyl)ethynyl)phenyl)ethynyl)trimethylsilane for ¹H and ¹³C NMR assignments.

Click here for additional data file.^{(106.3KB, tif)}

1 13 . DOI: 10.1107/S2056989015007252/hg5438fig4.tif

Atom numbering scheme of ((3,5-diethyl-4-ethynylphenyl)ethynyl)triisopropylsilane for ¹H and ¹³C NMR assignments.

Click here for additional data file.^{(91.7KB, tif)}

1 13 . DOI: 10.1107/S2056989015007252/hg5438fig5.tif

Atom numbering scheme of ((4-((4-bromophenyl)ethynyl)-3,5-diethylphenyl)ethynyl)triisopropylsilane for ¹H and ¹³C NMR assignments.

CCDC reference: 1059001

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

Cg is the centroid of the C9C14 ring.

DHA	DH	HA	D A	DHA
C25H25B Cg ⁱ	0.96	2.98	3.699(3)	132

Open in a new tab

Symmetry code: (i) Inline graphic .

Acknowledgments

We gratefully acknowledge support from the Australian Research Council (LE130100057) to purchase Agilent Technologies SuperNova and XCalibur diffractometers. We thank Professors C. Zhang (Jiangnan University), M. P. Cifuentes (Australian National University) and M. G. Humphrey (Australian National University) for assistance.

supplementary crystallographic information

S1. Synthesis and crystallization

As described herein, the title compound was prepared in three steps from ((3,5-diethyl-4-iodophenyl)ethynyl)triisopropylsilane; the synthesis of ((3,5-diethyl-4-iodophenyl)ethynyl)triisopropylsilane is described in: Ehlers et al. (2011).

1. Synthesis of ((2,6-diethyl-4-((triisopropylsilyl)ethynyl)phenyl)ethynyl)trimethylsilane

((3,5-Diethyl-4-iodophenyl)ethynyl)triisopropylsilane (325 mg, 0.740 mmol) was added to triethylamine (15 mL) and the solvent was deoxygenated. Triisopropylsilylacetylene (0.2 mL, 1.45 mmol) was then added, followed by Pd(PPh₃)₄ (30 mg, 0.025 mmol) and CuI (5.0 mg, 0.025 mmol) and the mixture was stirred at room temperature for 24 h. The solvent was removed under reduced pressure and the residue was purified using column chromatography on silica, eluting with petrol. The solvent was removed from the eluate to give

((2,6-diethyl-4-((triisopropylsilyl)ethynyl)phenyl)ethynyl)trimethylsilane as a pale yellow liquid (0.194 g, 64%). ¹H NMR (δ, 400MHz, CDCl₃): 0.26 (s, 9H, H_(Si(CH3)3), 1.13 (s, 21H, H₂₁, H₂₂), 1.23 (t, J_HH = 7.5Hz, 6H, H₁₆), 2.77 (q, J_HH = 7.5Hz, 4H, H₁₅), 7.14 (s, 2H, H₁₁). ¹³C NMR (δ, 101MHz, CDCl₃): 146.9 (C₁₀), 128.9 (C₁₁), 123.1 (C₉), 121.9 (C₁₂), 107.4 (C₁₉), 103.6 (C₈), 102.0 (C₇), 91.4 (C₂₀), 28.0 (C₁₅), 18.8 (C₂₂), 14.5 (C₁₆), 11.4 (C₂₁), 0.12 (C_(SiCH3)3). MS—EI: m/z (fragment, relative intensity): 410.2 ([M]⁺, 8).

2. Synthesis of ((3,5-diethyl-4-ethynylphenyl)ethynyl)triisopropylsilane

((2,6-Diethyl-4-((triisopropylsilyl)ethynyl)phenyl)ethynyl)trimethylsilane (0.947 g, 2.31 mmol) was added to a mixture of THF and ethanol (1:1, 50 mL). An aqueous solution of NaOH (2.5 mL, 0.1 M) was then added, and the mixture was stirred for 30 min. The solvent was removed under reduced pressure and the residue was purified using column chromatography on silica, eluting with petrol. The solvent was removed to give ((3,5-diethyl-4-ethynylphenyl)ethynyl)triisopropylsilane as a pale yellow liquid (0.706 g, 90%). ¹H NMR (δ, 400MHz, CDCl₃): 1.13 (s, 21H, H₂₁, H₂₂), 1.24 (t, J_HH = 7.5Hz, 6H, H₁₆), 2.80 (q, J_HH = 7.5Hz, 4H, H₁₅), 3.50 (s, 1H, H₇), 7.17 (s, 2H, H₁₁). ¹³C NMR (δ, 101MHz, CDCl₃): 147.2 (C₁₀), 128.9 (C₁₁), 123.5 (C₉), 120.7 (C₁₂), 107.2 (C₁₉), 91.6 (C₂₀), 85.8 (C₇), 80.3 (C₈), 27.8 (C₁₅), 18.7 (C₂₂), 14.7 (C₁₆), 11.4 (C₂₁). MS—EI: m/z (fragment, relative intensity): 338.3 ([M]⁺, 26).

3. Synthesis of ((4-((4-bromophenyl)ethynyl)-3,5-diethylphenyl)ethynyl)triisopropylsilane

((3,5-Diethyl-4-ethynylphenyl)ethynyl)triisopropylsilane (0.140 g, 0.415 mmol) and 4-bromo-1-iodobenzene (0.139 g, 0.491 mmol) was added to deoxygenated triethylamine (40 mL). PdCl₂(PPh₃)₂ (9.0 mg, 0.12 mmol) and CuI (4 mg, 0.02 mmol) were then added, and the resultant solution was stirred at room temperature for 16 h. The solvent was then removed under vacuum and the residue was passed through a silica column, eluting with petrol. The solvent was reduced in volume to give ((4-((4-bromophenyl)ethynyl)-3,5-diethylphenyl)ethynyl)triisopropylsilane as a white solid (0.192 g, 96%). Anal. Calc. for C₂₉H₃₇BrSi: C, 70.57; H, 7.56. Found: C, 70.53; H, 7.61%. ¹H NMR (δ, 400MHz, CDCl₃): 1.14 (s, 21H, H₂₁, H₂₂), 1.28 (t, J_HH = 7.5Hz, 6H, H₁₆), 2.84 (q, J_HH = 7.5Hz, 4H, H₁₅), 7.20 (s, 2H, H₁₁), 7.37 (d, J_HH = 7.5Hz, 2H, H₃), 7.49 (d, J_HH = 7.5Hz, 2H, H₂). ¹³C NMR (δ, 101MHz, CDCl₃): 146.9 (C₁₀), 132.8 (C₃), 131.8 (C₂), 128.9 (C₁₁), 123.1 (C₉), 122.8 (C_{1 or 4}), 122.6 (C_{1 or 4}), 121.9 (C₁₂), 107.4 (C₁₉), 97.2 (C₇), 91.9 (C₂₀), 87.8 (C₈), 28.1 (C₁₅), 18.8 (C₂₂), 14.8 (C₁₆), 11.5 (C₂₁). MS—EI: m/z (fragment, relative intensity): 494.2 ([M]⁺, 10). Colorless crystals of the title compound were obtained by slow evaporation of a hexane solution at room temperature.

S2. Refinement

Crystal data, data collection and structure refinement details are summarized below.