1,2-Bis{2-[2-(trimethyl­sil­yl)ethyn­yl]phen­yl}ethane-1,2-dione

Abstract

The title compound, C₂₄H₂₆O₂Si₂, has C ₂ crystallographic symmetry. The dihedral angle between the aromatic rings is 84.5 (2)°. The acetyl­ene group is slightly non-linear, with angles at the acetyl­ene C atoms of 175.7 (2) and 177.0 (2)°. In the crystal structure, only van de Waals interactions occur.

Related literature  

For the structure of benzil, see Brown & Sadanaga (1965 ▶); Gabe et al. (1981 ▶); More et al. (1987 ▶). For the synthesis see: Garcia et al. (1995 ▶). For the determination of absolute configuration from Bijvoet pairs, see: Hooft et al. (2008 ▶).

Experimental  

Crystal data  

• C₂₄H₂₆O₂Si₂

• M _r = 402.63

• Trigonal,

• a = 9.2241 (1) Å

• c = 23.7787 (5) Å

• V = 1752.13 (5) ų

• Z = 3

• Mo Kα radiation

• μ = 0.17 mm⁻¹

• T = 120 K

• 0.25 × 0.25 × 0.25 mm

Data collection  

• Nonius KappaCCD diffractometer

• Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997 ▶) T _min = 0.959, T _max = 0.959

• 23012 measured reflections

• 3410 independent reflections

• 2325 reflections with I > 2σ(I)

• R _int = 0.047

Refinement  

• R[F ² > 2σ(F ²)] = 0.043

• wR(F ²) = 0.103

• S = 1.00

• 3410 reflections

• 131 parameters

• H-atom parameters constrained

• Δρ_max = 0.25 e Å⁻³

• Δρ_min = −0.21 e Å⁻³

• Absolute structure: Flack (1983 ▶), 1419 Bijvoet pairs

• Flack parameter: 0.0 (1)

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Supplementary material file. DOI: 10.1107/S160053681203663X/bx2422Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

The title compound (I), (C₁₂H₁₃OSi)₂, lies on a crystallographic twofold axis. The phenyl ring is planar - all six C atoms have δ/σ < 0.2. However, carbonyl carbon C12 is 0.217 (5) Å above the C11—O1—C12' plane, and the C10—C11—C12—O1 torsion angle is 19.5 (3)°. The ethanedione C12(sp²)—C12(sp²)' distance of 1.538 (4) Å is somewhat longer than expected, but is consistent with values reported for benzil, which average 1.536 (10) Å. The acetylenic moiety is non-linear with deviations from a weighted least-squares line of δ(Si1) = 0.0034 (15), δ(C4) = 0.054 (4), δ(C5) = 0.049 (4), and δ(C6) = 0.047 (4) Å. The crystal structure is stablized by van der Waals interactions.

Experimental

The title compound was supplied by J. Gabriel Garcia, having been synthesized from 1,2-bis-(2-bromophenyl)-ethane-1,2-dione and trimethylsilyl acetylene (Garcia et al., 1995).

Refinement

The space group assignment and absolute structure are based on analysis of 1419 Bijvoet pairs, Flack (1983) parameter x = 0.0 (1), Hooft et al. (2008) parameter y = -0.04 (7), and Hooft P2(true) = 1.000.

All H atoms were placed in calculated positions with C—H distances of 0.95 (aromatic) and 0.98 Å (methyl) and U_iso = 1.2 or 1.5 U_eq of the attached sp² or sp³ C atom, and thereafter treated as riding. A torsional parameter was refined for each methyl group.

Figures

Fig. 1.

View of (I) (50% probability displacement ellipsoids)

Crystal data

C24H26O2Si2	Dx = 1.145 Mg m−3
Mr = 402.63	Mo Kα radiation, λ = 0.71073 Å
Trigonal, P3221	Cell parameters from 3424 reflections
Hall symbol: P 32 2"	θ = 2.5–30.0°
a = 9.2241 (1) Å	µ = 0.17 mm−1
c = 23.7787 (5) Å	T = 120 K
V = 1752.13 (5) Å3	Rhombohedron, yellow
Z = 3	0.25 × 0.25 × 0.25 mm
F(000) = 642

Data collection

Nonius KappaCCD diffractometer	3410 independent reflections
Radiation source: sealed tube	2325 reflections with I > 2σ(I)
Horizonally mounted graphite crystal monochromator	Rint = 0.047
Detector resolution: 9 pixels mm-1	θmax = 30.0°, θmin = 2.6°
ω and φ scans	h = −12→12
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −10→10
Tmin = 0.959, Tmax = 0.959	l = −31→33
23012 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.043	H-atom parameters constrained
wR(F2) = 0.103	w = 1/[σ2(Fo2) + (0.0519P)2] where P = (Fo2 + 2Fc2)/3
S = 1.00	(Δ/σ)max < 0.001
3410 reflections	Δρmax = 0.25 e Å−3
131 parameters	Δρmin = −0.21 e Å−3
0 restraints	Absolute structure: Flack (1983), 1419 Bijvoet pairs
0 constraints	Flack parameter: 0.0 (1)
Primary atom site location: structure-invariant direct methods

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.4411 (3)	−0.1681 (3)	0.00979 (9)	0.0487 (6)
H1A	0.5479	−0.0985	−0.0095	0.073*
H1B	0.3539	−0.233	−0.018	0.073*
H1C	0.4522	−0.2447	0.0357	0.073*
C2	0.1985 (3)	−0.1571 (4)	0.09491 (10)	0.0714 (8)
H2A	0.2222	−0.2247	0.1211	0.107*
H2B	0.1022	−0.2309	0.0714	0.107*
H2C	0.1731	−0.0815	0.1162	0.107*
C3	0.3475 (4)	0.1018 (3)	0.00053 (11)	0.0802 (10)
H3A	0.3209	0.1763	0.0219	0.12*
H3B	0.2539	0.0314	−0.0245	0.12*
H3C	0.4487	0.1688	−0.0219	0.12*
C4	0.5616 (2)	0.1008 (2)	0.09647 (7)	0.0310 (4)
C5	0.6750 (2)	0.1814 (2)	0.12846 (7)	0.0282 (4)
C6	0.8026 (2)	0.2815 (2)	0.16901 (6)	0.0283 (4)
C7	0.8414 (2)	0.4474 (2)	0.17783 (8)	0.0346 (5)
H7	0.7881	0.4931	0.1558	0.042*
C8	0.9559 (2)	0.5446 (2)	0.21811 (8)	0.0385 (5)
H8	0.982	0.6572	0.2233	0.046*
C9	1.0332 (2)	0.4800 (2)	0.25096 (7)	0.0381 (5)
H9	1.1116	0.5479	0.2789	0.046*
C10	0.9970 (2)	0.3169 (2)	0.24337 (7)	0.0352 (4)
H10	1.0497	0.2725	0.2664	0.042*
C11	0.8830 (2)	0.2166 (2)	0.20188 (7)	0.0274 (4)
C12	0.8518 (2)	0.0429 (2)	0.19563 (7)	0.0309 (4)
O1	0.88376 (18)	−0.02847 (17)	0.23231 (6)	0.0457 (4)
Si1	0.38331 (7)	−0.03278 (7)	0.04974 (2)	0.03309 (15)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0621 (15)	0.0523 (14)	0.0410 (11)	0.0355 (13)	−0.0166 (11)	−0.0167 (10)
C2	0.0331 (13)	0.092 (2)	0.0657 (15)	0.0134 (14)	−0.0059 (12)	−0.0155 (14)
C3	0.108 (2)	0.0446 (14)	0.0940 (18)	0.0423 (15)	−0.0758 (18)	−0.0214 (13)
C4	0.0351 (10)	0.0292 (10)	0.0311 (9)	0.0178 (9)	−0.0057 (8)	−0.0005 (8)
C5	0.0316 (10)	0.0258 (9)	0.0288 (9)	0.0156 (8)	−0.0008 (8)	0.0041 (8)
C6	0.0246 (9)	0.0290 (10)	0.0243 (8)	0.0083 (8)	0.0013 (7)	0.0042 (8)
C7	0.0346 (11)	0.0295 (11)	0.0344 (10)	0.0120 (9)	−0.0044 (8)	0.0022 (8)
C8	0.0361 (12)	0.0273 (11)	0.0401 (11)	0.0068 (10)	0.0020 (9)	−0.0008 (8)
C9	0.0256 (10)	0.0386 (11)	0.0312 (9)	0.0019 (9)	−0.0042 (8)	−0.0033 (8)
C10	0.0233 (9)	0.0403 (11)	0.0339 (9)	0.0098 (9)	−0.0013 (8)	0.0075 (8)
C11	0.0194 (8)	0.0302 (9)	0.0260 (8)	0.0075 (8)	0.0033 (7)	0.0069 (7)
C12	0.0196 (9)	0.0329 (10)	0.0361 (10)	0.0101 (8)	0.0025 (8)	0.0105 (8)
O1	0.0440 (9)	0.0402 (9)	0.0499 (8)	0.0188 (8)	−0.0108 (7)	0.0125 (7)
Si1	0.0354 (3)	0.0283 (3)	0.0372 (3)	0.0172 (3)	−0.0128 (2)	−0.0072 (2)

Geometric parameters (Å, º)

C1—Si1	1.847 (2)	C5—C6	1.443 (2)
C1—H1A	0.98	C6—C7	1.403 (3)
C1—H1B	0.98	C6—C11	1.401 (3)
C1—H1C	0.98	C7—C8	1.375 (3)
C2—Si1	1.849 (2)	C7—H7	0.95
C2—H2A	0.98	C8—C9	1.378 (3)
C2—H2B	0.98	C8—H8	0.95
C2—H2C	0.98	C9—C10	1.380 (3)
C3—Si1	1.852 (2)	C9—H9	0.95
C3—H3A	0.98	C10—C11	1.401 (2)
C3—H3B	0.98	C10—H10	0.95
C3—H3C	0.98	C11—C12	1.487 (3)
C4—C5	1.203 (2)	C12—O1	1.214 (2)
C4—Si1	1.8522 (19)	C12—C12i	1.538 (4)
Si1—C1—H1A	109.5	C8—C7—H7	119.7
Si1—C1—H1B	109.5	C6—C7—H7	119.7
H1A—C1—H1B	109.5	C9—C8—C7	120.52 (19)
Si1—C1—H1C	109.5	C9—C8—H8	119.7
H1A—C1—H1C	109.5	C7—C8—H8	119.7
H1B—C1—H1C	109.5	C8—C9—C10	120.12 (17)
Si1—C2—H2A	109.5	C8—C9—H9	119.9
Si1—C2—H2B	109.5	C10—C9—H9	119.9
H2A—C2—H2B	109.5	C9—C10—C11	120.31 (17)
Si1—C2—H2C	109.5	C9—C10—H10	119.8
H2A—C2—H2C	109.5	C11—C10—H10	119.8
H2B—C2—H2C	109.5	C6—C11—C10	119.58 (17)
Si1—C3—H3A	109.5	C6—C11—C12	123.09 (16)
Si1—C3—H3B	109.5	C10—C11—C12	117.32 (17)
H3A—C3—H3B	109.5	O1—C12—C11	122.93 (17)
Si1—C3—H3C	109.5	O1—C12—C12i	115.72 (18)
H3A—C3—H3C	109.5	C11—C12—C12i	120.33 (17)
H3B—C3—H3C	109.5	C3—Si1—C1	109.67 (11)
C5—C4—Si1	177.01 (16)	C3—Si1—C2	111.37 (14)
C4—C5—C6	175.7 (2)	C1—Si1—C2	111.58 (13)
C7—C6—C11	118.82 (16)	C3—Si1—C4	109.27 (10)
C7—C6—C5	118.66 (17)	C1—Si1—C4	107.33 (9)
C11—C6—C5	122.44 (17)	C2—Si1—C4	107.49 (9)
C8—C7—C6	120.63 (18)
C11—C6—C7—C8	−0.2 (3)	C9—C10—C11—C6	−1.6 (3)
C5—C6—C7—C8	176.61 (16)	C9—C10—C11—C12	179.24 (16)
C6—C7—C8—C9	−0.7 (3)	C6—C11—C12—O1	−159.64 (18)
C7—C8—C9—C10	0.5 (3)	C10—C11—C12—O1	19.5 (3)
C8—C9—C10—C11	0.7 (3)	C6—C11—C12—C12i	32.4 (2)
C7—C6—C11—C10	1.3 (2)	C10—C11—C12—C12i	−148.44 (13)
C5—C6—C11—C10	−175.35 (16)	C11—C12—C12i—C11i	−132.9 (2)
C7—C6—C11—C12	−179.56 (16)	C11—C12—C12i—O1i	58.36 (11)
C5—C6—C11—C12	3.8 (3)	O1—C12—C12i—O1i	−110.4 (3)

Symmetry code: (i) x−y, −y, −z+1/3.