Triclinic polymorph of bis­(triphenyl­sil­yl) oxide toluene disolvate

Purdy, A.P.; Smoot, E.; Butcher, R.J.; Kerr, A.

doi:10.1107/S160053681200356X

organic compounds

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Volume 68| Part 3| March 2012| Page o588

doi:10.1107/S160053681200356X

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Triclinic polymorph of bis(triphenylsilyl) oxide toluene disolvate

Andrew P. Purdy,^a ^* Emily Smoot,^a ‡ Ray J. Butcher ^b and Andrew Kerr ^c

^aNaval Research Laboratory, Chemistry Division, Code 6100, 4555 Overlook Avenue SW, Washington, DC 20375, USA, ^bDepartment of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA, and ^cGeorge Washington University, Chemistry Department, Washington, DC, USA
^*Correspondence e-mail: andrew.purdy@nrl.navy.mil

(Received 23 November 2011; accepted 26 January 2012; online 4 February 2012)

A new polymorph of the title compound, C₃₆H₃₀OSi₂·2C₇H₈, is reported, which is triclinic (P-1) instead of possessing the previously reported rhombohedral symmetry [Hönle et al. (1990). Acta Cryst. C46, 1982–1984]. Each of the –SiPh₃ units are related by the inversion center. The Si—O—Si moiety is linear with the O atom sitting on an inversion center, and the O—Si—(toluene ring centroid) angle is 3.69 (15)°. Each toluene molecule is 5.622 (2) Å from the Si atom and has its closest contacts with the phenyl rings outside of the van der Waals radii.

Related literature

For the rhombohedral polymorph of the title compound and its benzene analog, see: Hönle et al. (1990 ). For the structures of related compounds, see: Glidewell & Liles (1978 ); Morosin & Harrah (1981 ); Suwińska et al. (1986 ). For the determination by IR spectroscopy of silylcarbonate in the reaction product, see: Yildirimyan & Gattow (1984 ).

Experimental

Crystal data

C₃₆H₃₀OSi₂·2C₇H₈
M_r = 719.05
Triclinic, $[P \overline 1]$
a = 10.756 (3) Å
b = 11.062 (3) Å
c = 11.156 (3) Å
α = 62.638 (4)°
β = 61.356 (4)°
γ = 61.795 (4)°
V = 978.8 (4) Å³
Z = 1
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 123 K
0.33 × 0.25 × 0.12 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.605, T_max = 0.746
16663 measured reflections
4819 independent reflections
3344 reflections with I > 2σ(I)
R_int = 0.057

Refinement

R[F² > 2σ(F²)] = 0.088
wR(F²) = 0.259
S = 1.06
4819 reflections
242 parameters
H-atom parameters constrained
Δρ_max = 1.38 e Å⁻³ (near atom Si1)
Δρ_min = −0.52 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Si1—O1	1.6251 (9)
Si1—C7	1.863 (4)
Si1—C1	1.865 (4)
Si1—C13	1.867 (4)

O1—Si1—C7	107.86 (11)
O1—Si1—C1	108.74 (12)
C7—Si1—C1	110.50 (16)
O1—Si1—C13	108.28 (11)
C7—Si1—C13	111.99 (16)
C1—Si1—C13	109.38 (16)
Si1—O1—Si1ⁱ	180
Symmetry code: (i) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681200356X/rz2678sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681200356X/rz2678Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681200356X/rz2678Isup3.cml

checkCIF report

Comment top

A rhombohedral polymorph of the title compound and its benzene analog have been reported by Hönle et al. (1990). The triclinic unsolvated molecule was reported by Glidewell & Liles (1978) and repeated by Morosin & Harrah (1981), who also determined the entire series of Ge and Sn analogs. A benzene and a piperidine adduct of (Ph₃Si)₂O were also determined by Suwińska et al. (1986).

The core geometry (Table 1) of the title compound is almost identical to the previously reported rhombohedral polymorph. The main difference is the rhombohedral form was collected at room temperature, and has rotational disorder in the toluene. Our structure was collected at -150°C, and the toluene is not disordered. This difference could account for the lower symmetry of our structure. In our structure, the centroid of the toluene is slightly offset (3.69 (15)° versus 0°) from the linear Si—O—Si axis, and slightly closer (5.622 (5) versus 5.672 (2) Å) than it is in the rhombohedral form.

Related literature top

For the rhombohedral polymorph of the title compound and its benzene analog, see: Hönle et al. (1990). For the structures of related compounds, see: Glidewell & Liles (1978); Morosin & Harrah (1981); Suwińska et al. (1986). For the determination by IR spectroscopy of silylcarbonate in the reaction product, see: Yildirimyan & Gattow (1984).

Experimental top

All chemicals were handled inside a dry box under Ar or N₂. A Ph₃SiOK solution was prepared by dissolving KH (0.28 g) with Ph₃SiOH (2.0 g) in 30 g of dry ether, and filtering to remove the small amount of undissolved solids. The solution was put in a 1" diameter test tube which was inserted into a Newport Scientific 2" OD pressure vessel and pressurized with CO₂ at tank pressure. After 1 day, the pressure was released and the resulting voluminous white solid (presumably Ph₃SiOCO₂K) was isolated by filtration and washing with ether, and pumped dry under vacuum. An infrared spectrum of the white solid shows a broad peak at 1660 cm^-1 and is consistent (Yildirimyan & Gattow, 1984) with the presence of silylcarbonate. Attempts were made to crystallize the silylcarbonate from numerous solvents. In one attempt, a portion of the white solid was mixed in a vial with toluene and 18-crown-6. Over several weeks small crystals formed on the walls of the vial. One crystal was mounted in Cargill #2 oil and frozen in the diffractometer.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. Structural diagram of the title compound. Atomic displacement parameters are at the 30% probability level. Unlabelled atoms are related to the labelled atoms by the symmetry operation 1-x, 1-y, 1-z.

triphenyl[(triphenylsilyl)oxy]silane toluene disolvate top

Crystal data top

C₃₆H₃₀OSi₂·2C₇H₈	Z = 1
M_r = 719.05	F(000) = 382
Triclinic, P1	D_x = 1.220 Mg m⁻³
a = 10.756 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.062 (3) Å	Cell parameters from 8183 reflections
c = 11.156 (3) Å	θ = 2.3–28.3°
α = 62.638 (4)°	µ = 0.13 mm⁻¹
β = 61.356 (4)°	T = 123 K
γ = 61.795 (4)°	Prism, colorless
V = 978.8 (4) Å³	0.33 × 0.25 × 0.12 mm

Data collection top

Bruker APEXII CCD diffractometer	4819 independent reflections
Radiation source: fine-focus sealed tube	3344 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.057
ϕ and ω scans	θ_max = 28.5°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −14→14
T_min = 0.605, T_max = 0.746	k = −14→14
16663 measured reflections	l = −14→14

Refinement top

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)] = 0.088	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.259	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.1084P)² + 2.5305P] where P = (F_o² + 2F_c²)/3
4819 reflections	(Δ/σ)_max < 0.001
242 parameters	Δρ_max = 1.38 e Å⁻³
0 restraints	Δρ_min = −0.52 e Å⁻³

Crystal data top

C₃₆H₃₀OSi₂·2C₇H₈	γ = 61.795 (4)°
M_r = 719.05	V = 978.8 (4) Å³
Triclinic, P1	Z = 1
a = 10.756 (3) Å	Mo Kα radiation
b = 11.062 (3) Å	µ = 0.13 mm⁻¹
c = 11.156 (3) Å	T = 123 K
α = 62.638 (4)°	0.33 × 0.25 × 0.12 mm
β = 61.356 (4)°

Data collection top

Bruker APEXII CCD diffractometer	4819 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3344 reflections with I > 2σ(I)
T_min = 0.605, T_max = 0.746	R_int = 0.057
16663 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.088	0 restraints
wR(F²) = 0.259	H-atom parameters constrained
S = 1.06	Δρ_max = 1.38 e Å⁻³
4819 reflections	Δρ_min = −0.52 e Å⁻³
242 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.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Si1	0.43554 (11)	0.43924 (10)	0.44133 (11)	0.0247 (3)
O1	0.5000	0.5000	0.5000	0.0275 (8)
C1	0.5919 (4)	0.3631 (4)	0.2956 (4)	0.0269 (7)
C2	0.5652 (4)	0.3559 (4)	0.1875 (4)	0.0294 (8)
H2	0.4654	0.3901	0.1888	0.035*
C3	0.6820 (5)	0.2998 (4)	0.0797 (4)	0.0316 (8)
H3	0.6619	0.2960	0.0076	0.038*
C4	0.8287 (5)	0.2491 (4)	0.0760 (4)	0.0323 (8)
H4	0.9085	0.2110	0.0014	0.039*
C5	0.8585 (5)	0.2541 (4)	0.1816 (4)	0.0332 (8)
H5	0.9587	0.2187	0.1799	0.040*
C6	0.7411 (4)	0.3110 (4)	0.2898 (4)	0.0294 (8)
H6	0.7623	0.3148	0.3613	0.035*
C7	0.3593 (4)	0.2968 (4)	0.5940 (4)	0.0262 (7)
C8	0.3663 (4)	0.1750 (4)	0.5763 (4)	0.0285 (7)
H8	0.4073	0.1664	0.4827	0.034*
C9	0.3140 (4)	0.0672 (4)	0.6935 (4)	0.0325 (8)
H9	0.3201	−0.0140	0.6792	0.039*
C10	0.2535 (4)	0.0779 (4)	0.8303 (4)	0.0309 (8)
H10	0.2192	0.0036	0.9101	0.037*
C11	0.2428 (4)	0.1985 (4)	0.8507 (4)	0.0319 (8)
H11	0.1996	0.2074	0.9443	0.038*
C12	0.2958 (4)	0.3052 (4)	0.7335 (4)	0.0301 (8)
H12	0.2887	0.3864	0.7487	0.036*
C13	0.2885 (4)	0.5928 (4)	0.3676 (4)	0.0266 (7)
C14	0.1678 (4)	0.5759 (4)	0.3677 (4)	0.0302 (8)
H14	0.1561	0.4836	0.4105	0.036*
C15	0.0640 (4)	0.6927 (4)	0.3057 (4)	0.0325 (8)
H15	−0.0171	0.6793	0.3060	0.039*
C16	0.0790 (4)	0.8284 (4)	0.2436 (4)	0.0316 (8)
H16	0.0074	0.9081	0.2028	0.038*
C17	0.1988 (5)	0.8474 (4)	0.2413 (4)	0.0330 (8)
H17	0.2103	0.9399	0.1974	0.040*
C18	0.3021 (4)	0.7311 (4)	0.3031 (4)	0.0296 (8)
H18	0.3833	0.7453	0.3017	0.035*
C19	0.2596 (7)	0.3594 (5)	0.0656 (6)	0.0559 (14)
H19	0.2725	0.4353	−0.0217	0.067*
C20	0.1304 (7)	0.3834 (6)	0.1816 (6)	0.0571 (14)
H20	0.0550	0.4750	0.1735	0.068*
C21	0.1120 (6)	0.2751 (5)	0.3072 (5)	0.0450 (11)
H21	0.0239	0.2922	0.3869	0.054*
C22	0.2219 (5)	0.1381 (5)	0.3207 (5)	0.0378 (9)
C23	0.3501 (5)	0.1166 (5)	0.2024 (5)	0.0437 (10)
H23	0.4255	0.0249	0.2091	0.052*
C24	0.3695 (6)	0.2270 (6)	0.0751 (6)	0.0528 (13)
H24	0.4578	0.2116	−0.0050	0.063*
C25	0.2010 (6)	0.0204 (5)	0.4542 (5)	0.0469 (11)
H25A	0.1330	0.0600	0.5345	0.070*
H25B	0.2979	−0.0403	0.4682	0.070*
H25C	0.1582	−0.0375	0.4492	0.070*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si1	0.0311 (5)	0.0208 (4)	0.0317 (5)	−0.0106 (4)	−0.0141 (4)	−0.0089 (4)
O1	0.0334 (19)	0.0253 (17)	0.036 (2)	−0.0116 (14)	−0.0158 (17)	−0.0114 (14)
C1	0.0346 (18)	0.0219 (15)	0.0316 (19)	−0.0113 (13)	−0.0137 (16)	−0.0087 (13)
C2	0.0345 (19)	0.0269 (17)	0.035 (2)	−0.0122 (14)	−0.0147 (17)	−0.0102 (14)
C3	0.042 (2)	0.0286 (17)	0.035 (2)	−0.0145 (15)	−0.0152 (18)	−0.0118 (15)
C4	0.039 (2)	0.0276 (17)	0.033 (2)	−0.0119 (15)	−0.0097 (17)	−0.0131 (15)
C5	0.0340 (19)	0.0305 (18)	0.041 (2)	−0.0106 (15)	−0.0154 (18)	−0.0121 (16)
C6	0.0358 (19)	0.0255 (16)	0.035 (2)	−0.0111 (14)	−0.0159 (17)	−0.0100 (14)
C7	0.0297 (17)	0.0244 (16)	0.0332 (19)	−0.0098 (13)	−0.0155 (16)	−0.0089 (13)
C8	0.0347 (19)	0.0236 (16)	0.035 (2)	−0.0106 (14)	−0.0147 (17)	−0.0106 (14)
C9	0.037 (2)	0.0214 (16)	0.045 (2)	−0.0112 (14)	−0.0167 (19)	−0.0103 (15)
C10	0.0355 (19)	0.0235 (16)	0.038 (2)	−0.0135 (14)	−0.0174 (18)	−0.0033 (14)
C11	0.037 (2)	0.0336 (19)	0.031 (2)	−0.0172 (16)	−0.0101 (17)	−0.0103 (15)
C12	0.0354 (19)	0.0262 (17)	0.037 (2)	−0.0128 (14)	−0.0130 (17)	−0.0124 (14)
C13	0.0323 (18)	0.0230 (16)	0.0314 (19)	−0.0098 (13)	−0.0130 (16)	−0.0102 (13)
C14	0.0360 (19)	0.0242 (16)	0.038 (2)	−0.0115 (14)	−0.0164 (17)	−0.0091 (14)
C15	0.036 (2)	0.0335 (19)	0.039 (2)	−0.0138 (16)	−0.0182 (18)	−0.0100 (16)
C16	0.0348 (19)	0.0298 (18)	0.035 (2)	−0.0072 (15)	−0.0169 (17)	−0.0115 (15)
C17	0.043 (2)	0.0244 (17)	0.039 (2)	−0.0115 (15)	−0.0210 (19)	−0.0079 (15)
C18	0.0347 (19)	0.0245 (16)	0.039 (2)	−0.0123 (14)	−0.0170 (17)	−0.0089 (14)
C19	0.099 (4)	0.046 (3)	0.052 (3)	−0.044 (3)	−0.036 (3)	−0.005 (2)
C20	0.086 (4)	0.043 (3)	0.061 (3)	−0.023 (3)	−0.037 (3)	−0.015 (2)
C21	0.050 (3)	0.045 (2)	0.055 (3)	−0.011 (2)	−0.022 (2)	−0.026 (2)
C22	0.049 (2)	0.043 (2)	0.039 (2)	−0.0232 (19)	−0.016 (2)	−0.0157 (17)
C23	0.040 (2)	0.052 (3)	0.054 (3)	−0.0162 (19)	−0.018 (2)	−0.024 (2)
C24	0.060 (3)	0.072 (3)	0.050 (3)	−0.044 (3)	−0.009 (3)	−0.022 (2)
C25	0.059 (3)	0.044 (2)	0.044 (3)	−0.017 (2)	−0.020 (2)	−0.016 (2)

Geometric parameters (Å, º) top

Si1—O1	1.6251 (9)	C13—C14	1.396 (5)
Si1—C7	1.863 (4)	C13—C18	1.407 (5)
Si1—C1	1.865 (4)	C14—C15	1.396 (5)
Si1—C13	1.867 (4)	C14—H14	0.9500
O1—Si1ⁱ	1.6251 (9)	C15—C16	1.387 (5)
C1—C6	1.404 (5)	C15—H15	0.9500
C1—C2	1.409 (5)	C16—C17	1.387 (5)
C2—C3	1.382 (5)	C16—H16	0.9500
C2—H2	0.9500	C17—C18	1.390 (5)
C3—C4	1.388 (6)	C17—H17	0.9500
C3—H3	0.9500	C18—H18	0.9500
C4—C5	1.391 (5)	C19—C24	1.376 (8)
C4—H4	0.9500	C19—C20	1.385 (8)
C5—C6	1.391 (5)	C19—H19	0.9500
C5—H5	0.9500	C20—C21	1.361 (7)
C6—H6	0.9500	C20—H20	0.9500
C7—C12	1.397 (5)	C21—C22	1.409 (6)
C7—C8	1.413 (4)	C21—H21	0.9500
C8—C9	1.394 (5)	C22—C23	1.391 (6)
C8—H8	0.9500	C22—C25	1.462 (6)
C9—C10	1.381 (6)	C23—C24	1.384 (7)
C9—H9	0.9500	C23—H23	0.9500
C10—C11	1.398 (5)	C24—H24	0.9500
C10—H10	0.9500	C25—H25A	0.9800
C11—C12	1.390 (5)	C25—H25B	0.9800
C11—H11	0.9500	C25—H25C	0.9800
C12—H12	0.9500

O1—Si1—C7	107.86 (11)	C14—C13—C18	117.9 (3)
O1—Si1—C1	108.74 (12)	C14—C13—Si1	122.9 (3)
C7—Si1—C1	110.50 (16)	C18—C13—Si1	119.2 (3)
O1—Si1—C13	108.28 (11)	C15—C14—C13	121.0 (3)
C7—Si1—C13	111.99 (16)	C15—C14—H14	119.5
C1—Si1—C13	109.38 (16)	C13—C14—H14	119.5
Si1—O1—Si1ⁱ	180	C16—C15—C14	120.2 (3)
C6—C1—C2	117.6 (3)	C16—C15—H15	119.9
C6—C1—Si1	120.9 (3)	C14—C15—H15	119.9
C2—C1—Si1	121.5 (3)	C15—C16—C17	119.8 (3)
C3—C2—C1	121.0 (3)	C15—C16—H16	120.1
C3—C2—H2	119.5	C17—C16—H16	120.1
C1—C2—H2	119.5	C16—C17—C18	120.0 (3)
C2—C3—C4	120.5 (3)	C16—C17—H17	120.0
C2—C3—H3	119.8	C18—C17—H17	120.0
C4—C3—H3	119.8	C17—C18—C13	121.2 (3)
C3—C4—C5	119.9 (4)	C17—C18—H18	119.4
C3—C4—H4	120.1	C13—C18—H18	119.4
C5—C4—H4	120.1	C24—C19—C20	121.0 (5)
C4—C5—C6	119.7 (4)	C24—C19—H19	119.5
C4—C5—H5	120.1	C20—C19—H19	119.5
C6—C5—H5	120.1	C21—C20—C19	119.7 (5)
C5—C6—C1	121.3 (3)	C21—C20—H20	120.2
C5—C6—H6	119.3	C19—C20—H20	120.2
C1—C6—H6	119.3	C20—C21—C22	121.0 (5)
C12—C7—C8	117.0 (3)	C20—C21—H21	119.5
C12—C7—Si1	120.3 (2)	C22—C21—H21	119.5
C8—C7—Si1	122.6 (3)	C23—C22—C21	118.2 (4)
C9—C8—C7	121.2 (3)	C23—C22—C25	120.6 (4)
C9—C8—H8	119.4	C21—C22—C25	121.2 (4)
C7—C8—H8	119.4	C24—C23—C22	120.9 (5)
C10—C9—C8	120.3 (3)	C24—C23—H23	119.6
C10—C9—H9	119.8	C22—C23—H23	119.6
C8—C9—H9	119.8	C19—C24—C23	119.3 (5)
C9—C10—C11	119.7 (3)	C19—C24—H24	120.3
C9—C10—H10	120.2	C23—C24—H24	120.3
C11—C10—H10	120.2	C22—C25—H25A	109.5
C12—C11—C10	119.7 (4)	C22—C25—H25B	109.5
C12—C11—H11	120.1	H25A—C25—H25B	109.5
C10—C11—H11	120.1	C22—C25—H25C	109.5
C11—C12—C7	122.0 (3)	H25A—C25—H25C	109.5
C11—C12—H12	119.0	H25B—C25—H25C	109.5
C7—C12—H12	119.0

O1—Si1—C1—C6	25.8 (3)	C10—C11—C12—C7	0.5 (6)
C7—Si1—C1—C6	−92.4 (3)	C8—C7—C12—C11	0.6 (5)
C13—Si1—C1—C6	143.9 (3)	Si1—C7—C12—C11	−177.6 (3)
O1—Si1—C1—C2	−154.1 (3)	O1—Si1—C13—C14	−150.6 (3)
C7—Si1—C1—C2	87.7 (3)	C7—Si1—C13—C14	−31.8 (4)
C13—Si1—C1—C2	−36.0 (3)	C1—Si1—C13—C14	91.1 (3)
C6—C1—C2—C3	−0.2 (5)	O1—Si1—C13—C18	32.4 (3)
Si1—C1—C2—C3	179.7 (3)	C7—Si1—C13—C18	151.2 (3)
C1—C2—C3—C4	0.1 (5)	C1—Si1—C13—C18	−86.0 (3)
C2—C3—C4—C5	0.2 (6)	C18—C13—C14—C15	−0.1 (6)
C3—C4—C5—C6	−0.5 (6)	Si1—C13—C14—C15	−177.1 (3)
C4—C5—C6—C1	0.5 (6)	C13—C14—C15—C16	−0.4 (6)
C2—C1—C6—C5	−0.1 (5)	C14—C15—C16—C17	1.0 (6)
Si1—C1—C6—C5	180.0 (3)	C15—C16—C17—C18	−1.1 (6)
O1—Si1—C7—C12	31.8 (3)	C16—C17—C18—C13	0.6 (6)
C1—Si1—C7—C12	150.6 (3)	C14—C13—C18—C17	0.0 (6)
C13—Si1—C7—C12	−87.2 (3)	Si1—C13—C18—C17	177.2 (3)
O1—Si1—C7—C8	−146.2 (3)	C24—C19—C20—C21	0.5 (7)
C1—Si1—C7—C8	−27.5 (3)	C19—C20—C21—C22	−0.7 (7)
C13—Si1—C7—C8	94.7 (3)	C20—C21—C22—C23	0.4 (6)
C12—C7—C8—C9	−1.0 (5)	C20—C21—C22—C25	−178.5 (4)
Si1—C7—C8—C9	177.2 (3)	C21—C22—C23—C24	0.2 (6)
C7—C8—C9—C10	0.2 (6)	C25—C22—C23—C24	179.0 (4)
C8—C9—C10—C11	0.9 (6)	C20—C19—C24—C23	0.1 (7)
C9—C10—C11—C12	−1.2 (6)	C22—C23—C24—C19	−0.4 (6)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₃₆H₃₀OSi₂·2C₇H₈
M_r	719.05
Crystal system, space group	Triclinic, P1
Temperature (K)	123
a, b, c (Å)	10.756 (3), 11.062 (3), 11.156 (3)
α, β, γ (°)	62.638 (4), 61.356 (4), 61.795 (4)
V (Å³)	978.8 (4)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.33 × 0.25 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.605, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	16663, 4819, 3344
R_int	0.057
(sin θ/λ)_max (Å⁻¹)	0.672

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.088, 0.259, 1.06
No. of reflections	4819
No. of parameters	242
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.38, −0.52

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top

Si1—O1	1.6251 (9)	Si1—C1	1.865 (4)
Si1—C7	1.863 (4)	Si1—C13	1.867 (4)

O1—Si1—C7	107.86 (11)	C7—Si1—C13	111.99 (16)
O1—Si1—C1	108.74 (12)	C1—Si1—C13	109.38 (16)
C7—Si1—C1	110.50 (16)	Si1—O1—Si1ⁱ	180
O1—Si1—C13	108.28 (11)

Symmetry code: (i) −x+1, −y+1, −z+1.

Footnotes

‡SEAP student at NRL.

Acknowledgements

We thank the Office of Naval Research for financial support.

References

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