Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807050398/dn2244sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807050398/dn2244Isup2.hkl |
CCDC reference: 640132
A mixture consisting of 67.0 mg (0.30 mmol) of palladium(II) acetate, 157.2 mg (0.6 mmol) of triphenylphosphine, 1.70 g of silver nitrate (10 mmol), 5 mmol of 1,4-diiodobenzene, 10 mmol (1.72 g) of 1,1-bis(trimethylsilyl)ethene, 2.80 ml (20 mmol) of triethylamine and 30 ml of acetonitrile was placed in 50 ml, two-necked, round-bottomed flask equipped with a magnetic stirring bar and reflux condenser. The suspension was heated in an oil bath at 80°C for 2 h. After cooling to room temperature, the reaction mixture was added to water (50 ml) and extracted twice with 30 ml of pentane. The combined organic layers were dried (MgSO4) and the crude product obtained was then purified by column chromatography (silica gel/pentane) to give pure product. (2.01 g, 96%, white crystals) 1H NMR (CDCl3,) δ(p.p.m.): -0.01 (s, 18H, SiCH3), 0.18 (s, 18H, SiCH3), 7.12 (s, 4H, Ar), 7.72 (s, 2H, ═CH—). 13C NMR (CDCl3,) δ(p.p.m.): 0.5 (SiCH3), 2.1 (SiCH3), 127.4, 141.4 (Ar), 146.3 (—CH═), 154.7 (>C═). MS (EI) m/z (rel. int.): 418 (M+ 10%), 345 (15), 257 (10), 171 (100), 131 (10), 73 (15). HRMS calcd for C22H42Si4: 418.2363, found: 418.2348.
Hydrogen atoms were found in the difference Fourier maps; the positional parameters of all hydrogen atoms were freely refined, Uiso parameters for C—H H atoms were refined, for CH3 groups one common Uiso for each group was refined.
1,1-Bis(silyl)-2-arylalkenes constitute an important class of organosilicon reagents which are currently widely used as potential intermediates in the organic and organometallic syntheses. Their use as precursors for the preparation of ketones (Inoue et al., 2002), dibromostyrenes (Pawluć et al., 2007) as well as a variety of important organosilicon intermediates such as acylsilanes (Inoue et al., 2001), epoxysilanes (Hodgson et al., 1997) silyl enol ethers (Cuadrado et al., 2004) etc, greatly stimulates their synthetic advancements. Although considerable effort has been made to the characterization of 1,1-bis(silyl)-2-arylalkenes, determination of their crystal structures remains almost unexplored. Here we report the crystal structure of 1,4-bis(2,2-bis(trimethylsilyl)ethenyl)benzene (1). To the best of our knowledge, this is the first example of structurally characterized 1,1-bis(silyl)-2-arylalkene without additional substituent in 2-position. The closest structure known contains t-butyl-Al instead of one SiMe3 group: 1,4-bis{2-di(tert-butyl)aluminium-2-trimethylsilyl-ethenyl}benzene (Uhl & Breher, 2000).
The overall conformation of the molecule 1 (Fig. 1) can be characterized by the dihedral angle between the benzene ring (planar within 0.0051 (7) Å) and approximately planar C11, C12, Si1, Si2 fragment (maximum deviation of 0.017 (1) Å); this angle is equal 51.75 (6)°.
The Si—C bonds differ in their lengths depending on the hybridization of the carbon atom; the mean values are 1.871 (4) Å for C(sp3) and 1.892 (2) Å for C(sp2). The silylethenyl substiuent changes the intraannular angles in benzene ring: the ipso angle is sharpened to 117.96 (11)°, while the neighbouring angle is widened to 121.19 (12)°.
Crystal packing (Fig. 2) is determined mainly by van der Waals interactions.
For related literature, see: Cuadrado et al. (2004); Hodgson et al. (1997); Inoue et al. (2001); Inoue et al. (2002); Pawluć et al. (2007); Uhl & Breher (2000).
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1989); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
C22H42Si4 | F(000) = 920 |
Mr = 418.92 | Dx = 1.034 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 6578 reflections |
a = 31.050 (2) Å | θ = 2–29° |
b = 6.5882 (7) Å | µ = 0.23 mm−1 |
c = 13.1661 (14) Å | T = 100 K |
β = 92.293 (7)° | Needle, colourless |
V = 2691.2 (4) Å3 | 0.5 × 0.05 × 0.05 mm |
Z = 4 |
Kuma KM-4-CCD four-circle diffractometer | 3547 independent reflections |
Radiation source: fine-focus sealed tube | 2579 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
Detector resolution: 8.1929 pixels mm-1 | θmax = 29.8°, θmin = 2.6° |
ω scan | h = −41→43 |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006) | k = −8→9 |
Tmin = 0.804, Tmax = 0.989 | l = −17→16 |
13212 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.083 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | w = 1/[σ2(Fo2) + (0.05P)2] where P = (Fo2 + 2Fc2)/3 |
3547 reflections | (Δ/σ)max = 0.018 |
190 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C22H42Si4 | V = 2691.2 (4) Å3 |
Mr = 418.92 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 31.050 (2) Å | µ = 0.23 mm−1 |
b = 6.5882 (7) Å | T = 100 K |
c = 13.1661 (14) Å | 0.5 × 0.05 × 0.05 mm |
β = 92.293 (7)° |
Kuma KM-4-CCD four-circle diffractometer | 3547 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006) | 2579 reflections with I > 2σ(I) |
Tmin = 0.804, Tmax = 0.989 | Rint = 0.033 |
13212 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.083 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | Δρmax = 0.37 e Å−3 |
3547 reflections | Δρmin = −0.20 e Å−3 |
190 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.79450 (4) | 0.2370 (2) | −0.01884 (9) | 0.0181 (3) | |
C2 | 0.77151 (4) | 0.0671 (2) | 0.01147 (9) | 0.0206 (3) | |
H2 | 0.7860 (4) | −0.065 (2) | 0.0170 (10) | 0.018 (3)* | |
C3 | 0.72761 (4) | 0.0789 (2) | 0.02898 (9) | 0.0210 (3) | |
H3 | 0.7131 (5) | −0.043 (2) | 0.0477 (12) | 0.028 (4)* | |
C11 | 0.84141 (4) | 0.2199 (2) | −0.03543 (9) | 0.0199 (3) | |
H11 | 0.8558 (4) | 0.144 (2) | 0.0183 (10) | 0.019 (3)* | |
C12 | 0.86443 (4) | 0.29150 (19) | −0.11281 (9) | 0.0175 (3) | |
Si1 | 0.924800 (11) | 0.25655 (6) | −0.09758 (3) | 0.02064 (10) | |
C1A | 0.95192 (5) | 0.5073 (3) | −0.11380 (15) | 0.0386 (4) | |
H1A1 | 0.9816 (6) | 0.485 (3) | −0.1030 (15) | 0.056 (3)* | |
H1A2 | 0.9454 (6) | 0.563 (3) | −0.1826 (16) | 0.056 (3)* | |
H1A3 | 0.9424 (6) | 0.602 (3) | −0.0683 (15) | 0.056 (3)* | |
C1B | 0.94583 (5) | 0.0721 (3) | −0.19101 (12) | 0.0312 (3) | |
H1B1 | 0.9482 (6) | 0.128 (3) | −0.2592 (16) | 0.054 (3)* | |
H1B2 | 0.9737 (6) | 0.034 (3) | −0.1695 (14) | 0.054 (3)* | |
H1B3 | 0.9279 (6) | −0.046 (3) | −0.1950 (15) | 0.054 (3)* | |
C1C | 0.94025 (5) | 0.1578 (3) | 0.03236 (12) | 0.0325 (4) | |
H1C1 | 0.9299 (5) | 0.023 (3) | 0.0403 (14) | 0.046 (3)* | |
H1C2 | 0.9694 (6) | 0.151 (3) | 0.0407 (13) | 0.046 (3)* | |
H1C3 | 0.9291 (6) | 0.245 (3) | 0.0857 (15) | 0.046 (3)* | |
Si2 | 0.839681 (11) | 0.40940 (6) | −0.23262 (3) | 0.01909 (10) | |
C2A | 0.83715 (5) | 0.6925 (2) | −0.22308 (13) | 0.0302 (3) | |
H2A1 | 0.8175 (7) | 0.738 (3) | −0.1752 (16) | 0.062 (4)* | |
H2A2 | 0.8630 (7) | 0.743 (3) | −0.2031 (16) | 0.062 (4)* | |
H2A3 | 0.8276 (7) | 0.750 (3) | −0.2808 (18) | 0.062 (4)* | |
C2B | 0.78577 (5) | 0.2995 (2) | −0.26891 (11) | 0.0245 (3) | |
H2B1 | 0.7631 (6) | 0.338 (3) | −0.2245 (13) | 0.046 (3)* | |
H2B2 | 0.7769 (5) | 0.341 (3) | −0.3307 (14) | 0.046 (3)* | |
H2B3 | 0.7883 (5) | 0.160 (3) | −0.2726 (13) | 0.046 (3)* | |
C2C | 0.87442 (5) | 0.3473 (3) | −0.34196 (11) | 0.0315 (3) | |
H2C1 | 0.9030 (6) | 0.400 (3) | −0.3346 (14) | 0.044 (3)* | |
H2C2 | 0.8765 (5) | 0.192 (3) | −0.3489 (13) | 0.044 (3)* | |
H2C3 | 0.8622 (5) | 0.404 (3) | −0.3989 (15) | 0.044 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0164 (6) | 0.0255 (7) | 0.0124 (5) | 0.0011 (5) | 0.0006 (4) | −0.0016 (5) |
C2 | 0.0223 (7) | 0.0216 (7) | 0.0179 (6) | 0.0049 (6) | 0.0025 (5) | 0.0013 (5) |
C3 | 0.0212 (6) | 0.0228 (7) | 0.0193 (6) | −0.0007 (6) | 0.0042 (5) | 0.0001 (5) |
C11 | 0.0176 (6) | 0.0239 (8) | 0.0182 (6) | 0.0035 (5) | −0.0009 (5) | −0.0007 (5) |
C12 | 0.0152 (6) | 0.0175 (7) | 0.0199 (6) | 0.0010 (5) | 0.0004 (4) | −0.0029 (5) |
Si1 | 0.01415 (17) | 0.0229 (2) | 0.02477 (19) | 0.00000 (14) | −0.00017 (13) | 0.00310 (15) |
C1A | 0.0259 (8) | 0.0347 (10) | 0.0544 (11) | −0.0080 (7) | −0.0075 (7) | 0.0049 (8) |
C1B | 0.0210 (7) | 0.0345 (9) | 0.0387 (8) | 0.0073 (7) | 0.0067 (6) | 0.0015 (7) |
C1C | 0.0204 (7) | 0.0448 (10) | 0.0318 (8) | 0.0042 (7) | −0.0035 (6) | 0.0075 (7) |
Si2 | 0.01679 (17) | 0.0216 (2) | 0.01887 (17) | 0.00176 (14) | 0.00090 (12) | 0.00212 (14) |
C2A | 0.0252 (8) | 0.0256 (8) | 0.0395 (9) | 0.0005 (6) | −0.0020 (6) | 0.0056 (7) |
C2B | 0.0233 (7) | 0.0291 (9) | 0.0208 (7) | −0.0009 (6) | −0.0032 (5) | −0.0015 (6) |
C2C | 0.0291 (8) | 0.0434 (10) | 0.0222 (7) | 0.0088 (7) | 0.0049 (6) | 0.0078 (7) |
C1—C2 | 1.3944 (18) | C1B—H1B2 | 0.934 (19) |
C1—C3i | 1.3976 (18) | C1B—H1B3 | 0.96 (2) |
C1—C11 | 1.4855 (17) | C1C—H1C1 | 0.954 (18) |
C2—C3 | 1.3938 (17) | C1C—H1C2 | 0.907 (18) |
C2—H2 | 0.982 (14) | C1C—H1C3 | 0.979 (19) |
C3—C1i | 1.3976 (18) | Si2—C2B | 1.8683 (14) |
C3—H3 | 0.957 (15) | Si2—C2A | 1.8709 (17) |
C11—C12 | 1.3527 (18) | Si2—C2C | 1.8781 (15) |
C11—H11 | 0.962 (14) | C2A—H2A1 | 0.94 (2) |
C12—Si1 | 1.8914 (12) | C2A—H2A2 | 0.90 (2) |
C12—Si2 | 1.8933 (13) | C2A—H2A3 | 0.89 (2) |
Si1—C1B | 1.8656 (16) | C2B—H2B1 | 0.966 (18) |
Si1—C1A | 1.8702 (18) | C2B—H2B2 | 0.891 (18) |
Si1—C1C | 1.8748 (15) | C2B—H2B3 | 0.922 (19) |
C1A—H1A1 | 0.94 (2) | C2C—H2C1 | 0.953 (18) |
C1A—H1A2 | 0.99 (2) | C2C—H2C2 | 1.030 (19) |
C1A—H1A3 | 0.92 (2) | C2C—H2C3 | 0.907 (19) |
C1B—H1B1 | 0.97 (2) | ||
C2—C1—C3i | 117.96 (11) | H1B2—C1B—H1B3 | 109.3 (17) |
C2—C1—C11 | 119.81 (12) | Si1—C1C—H1C1 | 110.5 (11) |
C3i—C1—C11 | 122.18 (12) | Si1—C1C—H1C2 | 110.1 (11) |
C1—C2—C3 | 121.19 (12) | H1C1—C1C—H1C2 | 106.3 (15) |
C1—C2—H2 | 119.7 (8) | Si1—C1C—H1C3 | 111.5 (10) |
C3—C2—H2 | 119.1 (8) | H1C1—C1C—H1C3 | 109.7 (15) |
C2—C3—C1i | 120.83 (12) | H1C2—C1C—H1C3 | 108.6 (15) |
C2—C3—H3 | 118.1 (9) | C2B—Si2—C2A | 111.32 (7) |
C1i—C3—H3 | 121.1 (9) | C2B—Si2—C2C | 104.82 (7) |
C12—C11—C1 | 129.40 (12) | C2A—Si2—C2C | 107.18 (8) |
C12—C11—H11 | 119.5 (8) | C2B—Si2—C12 | 112.57 (6) |
C1—C11—H11 | 111.1 (8) | C2A—Si2—C12 | 111.70 (7) |
C11—C12—Si1 | 115.40 (9) | C2C—Si2—C12 | 108.84 (6) |
C11—C12—Si2 | 124.17 (10) | Si2—C2A—H2A1 | 113.1 (11) |
Si1—C12—Si2 | 120.38 (6) | Si2—C2A—H2A2 | 110.3 (12) |
C1B—Si1—C1A | 109.21 (8) | H2A1—C2A—H2A2 | 106.3 (17) |
C1B—Si1—C1C | 106.97 (8) | Si2—C2A—H2A3 | 112.5 (12) |
C1A—Si1—C1C | 108.11 (8) | H2A1—C2A—H2A3 | 103.5 (18) |
C1B—Si1—C12 | 112.39 (6) | H2A2—C2A—H2A3 | 110.8 (18) |
C1A—Si1—C12 | 109.22 (7) | Si2—C2B—H2B1 | 114.3 (10) |
C1C—Si1—C12 | 110.82 (6) | Si2—C2B—H2B2 | 110.9 (11) |
Si1—C1A—H1A1 | 106.8 (11) | H2B1—C2B—H2B2 | 105.4 (14) |
Si1—C1A—H1A2 | 110.7 (11) | Si2—C2B—H2B3 | 108.7 (11) |
H1A1—C1A—H1A2 | 111.1 (16) | H2B1—C2B—H2B3 | 111.0 (15) |
Si1—C1A—H1A3 | 111.5 (12) | H2B2—C2B—H2B3 | 106.3 (16) |
H1A1—C1A—H1A3 | 110.2 (16) | Si2—C2C—H2C1 | 113.8 (11) |
H1A2—C1A—H1A3 | 106.6 (16) | Si2—C2C—H2C2 | 108.9 (9) |
Si1—C1B—H1B1 | 113.9 (11) | H2C1—C2C—H2C2 | 108.0 (14) |
Si1—C1B—H1B2 | 108.6 (11) | Si2—C2C—H2C3 | 108.1 (11) |
H1B1—C1B—H1B2 | 106.0 (15) | H2C1—C2C—H2C3 | 107.0 (15) |
Si1—C1B—H1B3 | 110.3 (11) | H2C2—C2C—H2C3 | 111.2 (15) |
H1B1—C1B—H1B3 | 108.7 (16) | ||
C3i—C1—C2—C3 | 1.42 (19) | Si2—C12—Si1—C1A | 56.09 (10) |
C11—C1—C2—C3 | 179.12 (11) | C11—C12—Si1—C1C | −7.46 (13) |
C1—C2—C3—C1i | −1.5 (2) | Si2—C12—Si1—C1C | 175.09 (8) |
C2—C1—C11—C12 | 134.75 (15) | C11—C12—Si2—C2B | −31.27 (13) |
C3i—C1—C11—C12 | −47.6 (2) | Si1—C12—Si2—C2B | 145.95 (8) |
C1—C11—C12—Si1 | 174.44 (11) | C11—C12—Si2—C2A | 94.83 (12) |
C1—C11—C12—Si2 | −8.2 (2) | Si1—C12—Si2—C2A | −87.95 (9) |
C11—C12—Si1—C1B | 112.18 (11) | C11—C12—Si2—C2C | −147.03 (12) |
Si2—C12—Si1—C1B | −65.27 (10) | Si1—C12—Si2—C2C | 30.19 (10) |
C11—C12—Si1—C1A | −126.46 (11) |
Symmetry code: (i) −x+3/2, −y+1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C22H42Si4 |
Mr | 418.92 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 100 |
a, b, c (Å) | 31.050 (2), 6.5882 (7), 13.1661 (14) |
β (°) | 92.293 (7) |
V (Å3) | 2691.2 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.23 |
Crystal size (mm) | 0.5 × 0.05 × 0.05 |
Data collection | |
Diffractometer | Kuma KM-4-CCD four-circle |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2006) |
Tmin, Tmax | 0.804, 0.989 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13212, 3547, 2579 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.698 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.083, 1.00 |
No. of reflections | 3547 |
No. of parameters | 190 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.37, −0.20 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP (Siemens, 1989).
1,1-Bis(silyl)-2-arylalkenes constitute an important class of organosilicon reagents which are currently widely used as potential intermediates in the organic and organometallic syntheses. Their use as precursors for the preparation of ketones (Inoue et al., 2002), dibromostyrenes (Pawluć et al., 2007) as well as a variety of important organosilicon intermediates such as acylsilanes (Inoue et al., 2001), epoxysilanes (Hodgson et al., 1997) silyl enol ethers (Cuadrado et al., 2004) etc, greatly stimulates their synthetic advancements. Although considerable effort has been made to the characterization of 1,1-bis(silyl)-2-arylalkenes, determination of their crystal structures remains almost unexplored. Here we report the crystal structure of 1,4-bis(2,2-bis(trimethylsilyl)ethenyl)benzene (1). To the best of our knowledge, this is the first example of structurally characterized 1,1-bis(silyl)-2-arylalkene without additional substituent in 2-position. The closest structure known contains t-butyl-Al instead of one SiMe3 group: 1,4-bis{2-di(tert-butyl)aluminium-2-trimethylsilyl-ethenyl}benzene (Uhl & Breher, 2000).
The overall conformation of the molecule 1 (Fig. 1) can be characterized by the dihedral angle between the benzene ring (planar within 0.0051 (7) Å) and approximately planar C11, C12, Si1, Si2 fragment (maximum deviation of 0.017 (1) Å); this angle is equal 51.75 (6)°.
The Si—C bonds differ in their lengths depending on the hybridization of the carbon atom; the mean values are 1.871 (4) Å for C(sp3) and 1.892 (2) Å for C(sp2). The silylethenyl substiuent changes the intraannular angles in benzene ring: the ipso angle is sharpened to 117.96 (11)°, while the neighbouring angle is widened to 121.19 (12)°.
Crystal packing (Fig. 2) is determined mainly by van der Waals interactions.