3,3-Dimethyl-1,1,1,5,5,5-hexa­phenyl­trisiloxane

Spek, A.L.; Ellis, D.D.; Hanssen, R.W.J.M.; van Santen, R.A.; Abbenhuis, H.C.L.

doi:10.1107/S1600536805029405

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3,3-Dimethyl-1,1,1,5,5,5-hexaphenyltrisiloxane

A. L. Spek, D. D. Ellis, R. W. J. M. Hanssen, R. A. van Santen and H. C. L. Abbenhuis

The title compound, C₃₈H₃₆O₂Si₃, crystallizes with one crystallographically independent molecule in a general position and one molecule in a special position with twofold rotation symmetry. The approximate twofold rotation axis of the molecule in the general position is also approximately parallel to the monoclinic b axis. The conformations of the two independent molecules are similar.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805029405/cf6456sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536805029405/cf6456Isup2.hkl Contains datablock I

CCDC reference: 287499

checkCIF report

Key indicators

Single-crystal X-ray study
T = 150 K
Mean (C-C) = 0.004 Å
R factor = 0.047
wR factor = 0.112
Data-to-parameter ratio = 19.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Si2
PLAT396_ALERT_2_C Deviating Si-O-Si Angle from 150 Deg for      O1     164.20 Deg.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

Comment top

The symmetrical title compound, (I), was obtained unintentially in an attempt to synthesize the unsymmetrical compound 1,1-dimethyl-3,3,3-triphenyl-1-(2-pyridyl)disiloxane (i.e. with one of the two triphenylsiloxy groups substituted by a covalently bonded pyridyl group).

The unit cell contains eight equivalent molecules of (I) in general positions and four equivalent molecules located in positions with imposed crystallographic twofold rotation symmetry (Fig. 1). The two independent molecules have very similar conformations as illustrated by the quaternion fit (Mackay, 1984; Spek 2003) plot shown in Fig. 2. The approximate molecular twofold axes are approximately parallel to the monoclinic b axis.

The Si—O—Si angles range from 151.51 (10) to 164.17 (10)° (Table 1). Similar values in the range 160–163° have been reported by Graalmann et al. (1984) in the related siloxane structure 1,1,5,5-tetra-tert-butyl-1,5-dihydroxy-3,3-dimethyl-1,3,5-trisiloxane.

Molecules are stacked in planes parallel to (102) with an interplanar distance of approximately 8.3 Å (Fig. 3). Each layer contains the two types of molecules (general and special positions) in a 2:1 ratio.

Experimental top

The crystal used for this study was obtained in low yield (<10%) from dimethylmethoxy(2-pyridyl)silane and triphenylsilanol. A subsequently optimized synthesis is described. Ph₃SiOH (0.915 g, 3.3 mmol) in tetrahydrofuran (20 ml) was treated with SiMe₂Cl₂ (0.21 g, 1.65 mmol) in the presence of pyridine (1 ml). The reaction mixture was dried in vacuo and the residue was extracted with hexanes (20 ml). After concentration of the extract, pure colorless crystals of the title compund were formed (0.51 g, 0.84 mmol, 51%).

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON.

Figures top

	Fig. 1. Views of the two independent molecules of the title compound with the atom-numbering schemes. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. [Symmetry code: (a) −x, y, 1/2 − z.]
	Fig. 2. Quaternion fit of the two crystallographically independent molecules, illustrating their conformational similarity. The molecule with exact rotation symmetry is shown in red. H atoms have been omitted.
	Fig. 3. Molecular packing plot, projected down the b axis. The molecules on special positions are in red. H atoms have been omitted.

3,3-dimethyl-1,1,1,5,5,5-hexaphenyltrisiloxane top

Crystal data top

C₃₈H₃₆O₂Si₃	F(000) = 3864
M_r = 608.94	Least Squares Treatment of 25 SET4 setting angles.
Monoclinic, C2/c	D_x = 1.216 Mg m⁻³
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 47.7051 (5) Å	Cell parameters from 11325 reflections
b = 7.6270 (1) Å	θ = 1.0–27.5°
c = 33.1200 (5) Å	µ = 0.18 mm⁻¹
β = 124.1246 (6)°	T = 150 K
V = 9975.7 (2) Å³	Plate, colorless
Z = 12	0.30 × 0.27 × 0.09 mm

Data collection top

Nonius KappaCCD diffractometer	7490 reflections with I > 2σ(I)
Radiation source: Rotating Anode	R_int = 0.066
Graphite monochromator	θ_max = 27.4°, θ_min = 1.0°
Detector resolution: 18.4 pixels mm^-1	h = −60→61
ω and ϕ scans	k = −9→9
43681 measured reflections	l = −40→42
11325 independent reflections

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.112	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0388P)² + 6.4055P] where P = (F_o² + 2F_c²)/3
11325 reflections	(Δ/σ)_max = 0.001
585 parameters	Δρ_max = 0.36 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

C₃₈H₃₆O₂Si₃	V = 9975.7 (2) Å³
M_r = 608.94	Z = 12
Monoclinic, C2/c	Mo Kα radiation
a = 47.7051 (5) Å	µ = 0.18 mm⁻¹
b = 7.6270 (1) Å	T = 150 K
c = 33.1200 (5) Å	0.30 × 0.27 × 0.09 mm
β = 124.1246 (6)°

Data collection top

Nonius KappaCCD diffractometer	7490 reflections with I > 2σ(I)
43681 measured reflections	R_int = 0.066
11325 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.047	0 restraints
wR(F²) = 0.112	H-atom parameters constrained
S = 1.02	Δρ_max = 0.36 e Å⁻³
11325 reflections	Δρ_min = −0.31 e Å⁻³
585 parameters

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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	0.21757 (1)	0.93704 (7)	0.08503 (2)	0.0288 (2)
Si2	0.16404 (1)	1.20332 (7)	0.08047 (2)	0.0262 (2)
Si3	0.10338 (1)	0.99794 (7)	0.07132 (2)	0.0265 (2)
O1	0.19035 (4)	1.05358 (19)	0.08788 (6)	0.0405 (5)
O2	0.12822 (3)	1.10900 (17)	0.06149 (5)	0.0314 (4)
C1	0.18013 (7)	1.3050 (4)	0.13982 (10)	0.0660 (11)
C2	0.15787 (6)	1.3605 (3)	0.03434 (10)	0.0553 (9)
C11	0.23818 (5)	0.7857 (3)	0.13829 (7)	0.0313 (7)
C12	0.24582 (6)	0.8474 (3)	0.18323 (8)	0.0493 (9)
C13	0.26384 (7)	0.7463 (4)	0.22483 (9)	0.0602 (10)
C14	0.27468 (6)	0.5809 (4)	0.22301 (9)	0.0524 (9)
C15	0.26718 (6)	0.5164 (3)	0.17929 (9)	0.0467 (9)
C16	0.24906 (5)	0.6173 (3)	0.13742 (8)	0.0384 (7)
C21	0.25160 (5)	1.0801 (3)	0.09126 (7)	0.0292 (6)
C22	0.28530 (6)	1.0600 (3)	0.13014 (8)	0.0417 (8)
C23	0.31055 (6)	1.1680 (4)	0.13585 (9)	0.0544 (9)
C24	0.30251 (6)	1.2991 (3)	0.10250 (10)	0.0510 (9)
C25	0.26949 (6)	1.3217 (3)	0.06314 (9)	0.0458 (9)
C26	0.24431 (6)	1.2126 (3)	0.05773 (8)	0.0377 (8)
C31	0.19521 (5)	0.8179 (3)	0.02576 (7)	0.0305 (6)
C32	0.21320 (6)	0.7361 (3)	0.00915 (8)	0.0430 (8)
C33	0.19698 (7)	0.6385 (3)	−0.03342 (9)	0.0534 (9)
C34	0.16230 (7)	0.6228 (3)	−0.06062 (9)	0.0512 (9)
C35	0.14378 (6)	0.7028 (3)	−0.04552 (8)	0.0478 (8)
C36	0.16011 (5)	0.7989 (3)	−0.00266 (8)	0.0374 (7)
C41	0.12807 (5)	0.8911 (3)	0.13269 (7)	0.0295 (6)
C42	0.11778 (6)	0.8993 (3)	0.16466 (8)	0.0403 (8)
C43	0.13575 (7)	0.8163 (3)	0.20936 (8)	0.0489 (9)
C44	0.16432 (6)	0.7211 (3)	0.22331 (8)	0.0471 (8)
C45	0.17532 (6)	0.7106 (3)	0.19272 (8)	0.0414 (7)
C46	0.15741 (5)	0.7956 (3)	0.14791 (8)	0.0351 (7)
C51	0.07199 (5)	1.1542 (3)	0.06818 (7)	0.0276 (6)
C52	0.03746 (5)	1.1471 (3)	0.03205 (7)	0.0295 (6)
C53	0.01501 (5)	1.2697 (3)	0.02989 (8)	0.0344 (7)
C54	0.02687 (6)	1.4013 (3)	0.06419 (8)	0.0369 (8)
C55	0.06100 (6)	1.4117 (3)	0.10064 (8)	0.0398 (8)
C56	0.08329 (6)	1.2892 (3)	0.10257 (8)	0.0360 (7)
C61	0.08224 (5)	0.8321 (3)	0.02176 (7)	0.0268 (6)
C62	0.08465 (5)	0.6517 (3)	0.03032 (8)	0.0357 (7)
C63	0.07039 (6)	0.5320 (3)	−0.00781 (9)	0.0426 (8)
C64	0.05357 (6)	0.5898 (3)	−0.05518 (9)	0.0431 (8)
C65	0.05024 (6)	0.7674 (3)	−0.06489 (8)	0.0412 (8)
C66	0.06459 (5)	0.8860 (3)	−0.02699 (8)	0.0351 (7)
Si4	0.05770 (1)	0.58038 (7)	0.26019 (2)	0.0243 (2)
Si5	0.00000	0.33836 (9)	0.25000	0.0234 (2)
O3	0.02398 (3)	0.46381 (16)	0.24161 (5)	0.0276 (4)
C3	0.02646 (6)	0.2052 (3)	0.30502 (8)	0.0414 (8)
C71	0.07144 (5)	0.6937 (2)	0.31855 (7)	0.0269 (6)
C72	0.04964 (5)	0.7226 (3)	0.33323 (7)	0.0306 (7)
C73	0.06014 (6)	0.8095 (3)	0.37615 (8)	0.0349 (7)
C74	0.09282 (6)	0.8712 (3)	0.40567 (8)	0.0394 (8)
C75	0.11484 (6)	0.8452 (4)	0.39206 (9)	0.0573 (9)
C76	0.10430 (6)	0.7576 (4)	0.34919 (8)	0.0493 (9)
C81	0.09287 (5)	0.4354 (2)	0.27077 (7)	0.0270 (6)
C82	0.10700 (5)	0.3121 (3)	0.30845 (8)	0.0381 (8)
C83	0.13310 (6)	0.2034 (3)	0.31717 (9)	0.0487 (8)
C84	0.14572 (6)	0.2136 (3)	0.28883 (9)	0.0476 (9)
C85	0.13223 (6)	0.3334 (3)	0.25146 (9)	0.0449 (8)
C86	0.10621 (5)	0.4431 (3)	0.24275 (8)	0.0347 (7)
C91	0.04681 (5)	0.7432 (2)	0.21130 (7)	0.0246 (6)
C92	0.05670 (5)	0.9183 (3)	0.22156 (8)	0.0341 (7)
C93	0.04870 (6)	1.0362 (3)	0.18475 (9)	0.0427 (8)
C94	0.03049 (6)	0.9840 (3)	0.13689 (8)	0.0375 (8)
C95	0.02036 (6)	0.8118 (3)	0.12567 (8)	0.0370 (7)
C96	0.02836 (5)	0.6925 (3)	0.16220 (7)	0.0317 (7)
H1A	0.18190	1.21610	0.16250	0.0990*
H1B	0.16460	1.39790	0.13590	0.0990*
H1C	0.20250	1.35540	0.15280	0.0990*
H2A	0.17950	1.41750	0.04550	0.0830*
H2B	0.14130	1.44930	0.02920	0.0830*
H2C	0.14950	1.29890	0.00360	0.0830*
H12	0.23850	0.96110	0.18510	0.0590*
H13	0.26880	0.79100	0.25490	0.0720*
H14	0.28720	0.51200	0.25180	0.0630*
H15	0.27450	0.40210	0.17780	0.0560*
H16	0.24390	0.57050	0.10740	0.0460*
H22	0.29110	0.96970	0.15330	0.0500*
H23	0.33330	1.15180	0.16270	0.0650*
H24	0.31980	1.37450	0.10660	0.0610*
H25	0.26410	1.41130	0.03990	0.0550*
H26	0.22160	1.22850	0.03060	0.0450*
H32	0.23710	0.74790	0.02750	0.0520*
H33	0.20970	0.58280	−0.04380	0.0640*
H34	0.15110	0.55650	−0.09000	0.0610*
H35	0.11980	0.69190	−0.06450	0.0570*
H36	0.14710	0.85300	0.00760	0.0450*
H42	0.09800	0.96340	0.15540	0.0480*
H43	0.12840	0.82510	0.23060	0.0590*
H44	0.17640	0.66270	0.25390	0.0570*
H45	0.19510	0.64540	0.20230	0.0500*
H46	0.16530	0.78880	0.12720	0.0420*
H52	0.02900	1.05650	0.00830	0.0350*
H53	−0.00840	1.26260	0.00480	0.0410*
H54	0.01160	1.48490	0.06280	0.0440*
H55	0.06920	1.50240	0.12430	0.0480*
H56	0.10670	1.29740	0.12780	0.0430*
H62	0.09630	0.61000	0.06290	0.0430*
H63	0.07230	0.40990	−0.00110	0.0510*
H64	0.04430	0.50780	−0.08120	0.0520*
H65	0.03810	0.80770	−0.09770	0.0490*
H66	0.06240	1.00780	−0.03410	0.0420*
H3A	0.04030	0.12490	0.30010	0.0620*
H3B	0.01200	0.13730	0.31150	0.0620*
H3C	0.04120	0.28210	0.33280	0.0620*
H72	0.02700	0.68150	0.31330	0.0370*
H73	0.04470	0.82690	0.38530	0.0420*
H74	0.10000	0.93110	0.43510	0.0470*
H75	0.13740	0.88740	0.41210	0.0690*
H76	0.11990	0.74060	0.34040	0.0590*
H82	0.09860	0.30260	0.32840	0.0460*
H83	0.14240	0.12080	0.34310	0.0580*
H84	0.16360	0.13860	0.29500	0.0570*
H85	0.14070	0.34110	0.23160	0.0540*
H86	0.09730	0.52590	0.21690	0.0420*
H92	0.06920	0.95750	0.25440	0.0410*
H93	0.05590	1.15460	0.19280	0.0510*
H94	0.02490	1.06570	0.11180	0.0450*
H95	0.00780	0.77450	0.09260	0.0440*
H96	0.02120	0.57410	0.15380	0.0380*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si1	0.0251 (3)	0.0311 (3)	0.0320 (3)	0.0042 (2)	0.0172 (3)	0.0021 (3)
Si2	0.0247 (3)	0.0244 (3)	0.0304 (3)	−0.0002 (2)	0.0160 (3)	−0.0008 (2)
Si3	0.0246 (3)	0.0289 (3)	0.0285 (3)	0.0010 (2)	0.0164 (3)	0.0030 (2)
O1	0.0350 (9)	0.0413 (9)	0.0550 (10)	0.0110 (7)	0.0313 (8)	0.0087 (8)
O2	0.0242 (7)	0.0371 (8)	0.0343 (8)	−0.0014 (6)	0.0173 (7)	0.0041 (6)
C1	0.0628 (19)	0.079 (2)	0.0629 (18)	−0.0296 (16)	0.0394 (16)	−0.0404 (16)
C2	0.0432 (15)	0.0511 (15)	0.0713 (18)	0.0055 (12)	0.0319 (14)	0.0267 (14)
C11	0.0257 (11)	0.0358 (12)	0.0343 (12)	0.0034 (9)	0.0180 (10)	0.0046 (10)
C12	0.0535 (16)	0.0560 (16)	0.0376 (14)	0.0231 (13)	0.0250 (13)	0.0072 (12)
C13	0.0598 (17)	0.085 (2)	0.0354 (14)	0.0295 (16)	0.0265 (14)	0.0149 (14)
C14	0.0419 (15)	0.0668 (18)	0.0458 (15)	0.0181 (13)	0.0230 (13)	0.0257 (14)
C15	0.0448 (15)	0.0354 (13)	0.0597 (17)	0.0078 (11)	0.0292 (13)	0.0123 (12)
C16	0.0392 (13)	0.0338 (12)	0.0420 (13)	0.0008 (10)	0.0226 (12)	0.0003 (10)
C21	0.0272 (11)	0.0319 (11)	0.0328 (11)	0.0019 (9)	0.0195 (10)	−0.0046 (9)
C22	0.0332 (13)	0.0500 (14)	0.0414 (13)	−0.0027 (11)	0.0207 (11)	−0.0026 (11)
C23	0.0334 (14)	0.0749 (19)	0.0478 (15)	−0.0135 (13)	0.0185 (12)	−0.0074 (14)
C24	0.0442 (15)	0.0517 (16)	0.0655 (18)	−0.0194 (12)	0.0359 (14)	−0.0187 (14)
C25	0.0526 (16)	0.0369 (13)	0.0627 (17)	−0.0031 (11)	0.0414 (15)	−0.0001 (12)
C26	0.0343 (13)	0.0391 (13)	0.0435 (13)	0.0012 (10)	0.0242 (11)	−0.0003 (11)
C31	0.0274 (11)	0.0312 (11)	0.0313 (11)	0.0002 (9)	0.0155 (10)	0.0057 (9)
C32	0.0349 (13)	0.0561 (15)	0.0380 (13)	−0.0060 (11)	0.0204 (11)	−0.0082 (11)
C33	0.0549 (17)	0.0650 (17)	0.0428 (15)	−0.0074 (14)	0.0290 (14)	−0.0136 (13)
C34	0.0557 (17)	0.0514 (15)	0.0332 (13)	−0.0101 (13)	0.0168 (13)	−0.0058 (11)
C35	0.0327 (13)	0.0479 (15)	0.0407 (14)	−0.0055 (11)	0.0071 (12)	0.0068 (12)
C36	0.0318 (12)	0.0343 (12)	0.0394 (13)	0.0008 (10)	0.0158 (11)	0.0078 (10)
C41	0.0299 (11)	0.0283 (11)	0.0305 (11)	−0.0008 (9)	0.0170 (10)	0.0022 (9)
C42	0.0426 (14)	0.0453 (14)	0.0400 (13)	−0.0002 (11)	0.0275 (12)	0.0041 (11)
C43	0.0617 (17)	0.0526 (16)	0.0385 (14)	−0.0070 (13)	0.0319 (14)	0.0052 (12)
C44	0.0589 (17)	0.0365 (13)	0.0317 (13)	−0.0070 (12)	0.0167 (13)	0.0062 (10)
C45	0.0392 (13)	0.0303 (12)	0.0365 (13)	0.0042 (10)	0.0101 (11)	0.0018 (10)
C46	0.0378 (13)	0.0328 (12)	0.0321 (12)	0.0007 (10)	0.0180 (11)	0.0001 (10)
C51	0.0289 (11)	0.0294 (11)	0.0301 (11)	0.0010 (9)	0.0200 (10)	0.0058 (9)
C52	0.0315 (11)	0.0267 (10)	0.0335 (11)	0.0000 (9)	0.0202 (10)	0.0021 (9)
C53	0.0306 (12)	0.0334 (12)	0.0414 (13)	0.0056 (10)	0.0215 (11)	0.0102 (10)
C54	0.0423 (14)	0.0325 (12)	0.0492 (14)	0.0084 (10)	0.0338 (12)	0.0073 (11)
C55	0.0501 (15)	0.0352 (12)	0.0440 (14)	−0.0004 (11)	0.0325 (13)	−0.0052 (10)
C56	0.0339 (12)	0.0397 (13)	0.0356 (12)	0.0009 (10)	0.0203 (11)	−0.0011 (10)
C61	0.0239 (10)	0.0313 (11)	0.0312 (11)	0.0003 (9)	0.0191 (9)	0.0016 (9)
C62	0.0326 (12)	0.0338 (12)	0.0372 (12)	−0.0009 (10)	0.0175 (11)	0.0063 (10)
C63	0.0414 (14)	0.0285 (12)	0.0549 (16)	−0.0023 (10)	0.0252 (13)	−0.0024 (11)
C64	0.0390 (14)	0.0470 (14)	0.0447 (14)	−0.0049 (11)	0.0243 (12)	−0.0167 (12)
C65	0.0455 (14)	0.0496 (15)	0.0335 (12)	0.0041 (11)	0.0253 (12)	−0.0002 (11)
C66	0.0450 (14)	0.0320 (12)	0.0368 (12)	0.0029 (10)	0.0282 (11)	0.0025 (10)
Si4	0.0250 (3)	0.0255 (3)	0.0237 (3)	0.0007 (2)	0.0145 (2)	0.0006 (2)
Si5	0.0279 (4)	0.0211 (4)	0.0237 (4)	0.0000	0.0160 (4)	0.0000
O3	0.0270 (7)	0.0286 (7)	0.0284 (7)	−0.0010 (6)	0.0163 (6)	0.0022 (6)
C3	0.0442 (14)	0.0425 (13)	0.0435 (13)	0.0102 (11)	0.0283 (12)	0.0182 (11)
C71	0.0281 (11)	0.0271 (10)	0.0257 (10)	0.0016 (9)	0.0153 (9)	0.0020 (9)
C72	0.0333 (12)	0.0270 (11)	0.0341 (12)	−0.0033 (9)	0.0205 (10)	−0.0048 (9)
C73	0.0436 (14)	0.0300 (11)	0.0409 (13)	−0.0007 (10)	0.0297 (12)	−0.0043 (10)
C74	0.0411 (14)	0.0471 (14)	0.0308 (12)	−0.0044 (11)	0.0206 (11)	−0.0106 (10)
C75	0.0361 (14)	0.092 (2)	0.0420 (14)	−0.0168 (14)	0.0208 (12)	−0.0293 (14)
C76	0.0326 (13)	0.0806 (18)	0.0402 (14)	−0.0102 (12)	0.0237 (12)	−0.0195 (13)
C81	0.0250 (11)	0.0266 (10)	0.0277 (10)	−0.0025 (8)	0.0137 (9)	−0.0025 (9)
C82	0.0344 (13)	0.0410 (13)	0.0373 (13)	0.0058 (10)	0.0191 (11)	0.0079 (10)
C83	0.0392 (14)	0.0413 (14)	0.0535 (15)	0.0136 (11)	0.0186 (13)	0.0117 (12)
C84	0.0345 (13)	0.0397 (14)	0.0621 (17)	0.0078 (11)	0.0231 (13)	−0.0093 (13)
C85	0.0412 (14)	0.0483 (14)	0.0540 (15)	0.0016 (12)	0.0320 (13)	−0.0087 (12)
C86	0.0344 (12)	0.0363 (12)	0.0358 (12)	0.0011 (10)	0.0211 (11)	−0.0010 (10)
C91	0.0240 (10)	0.0252 (10)	0.0295 (11)	0.0009 (8)	0.0181 (9)	0.0015 (8)
C92	0.0407 (13)	0.0287 (11)	0.0366 (12)	−0.0049 (10)	0.0239 (11)	−0.0038 (10)
C93	0.0535 (15)	0.0261 (12)	0.0580 (16)	−0.0024 (10)	0.0370 (14)	0.0043 (11)
C94	0.0437 (14)	0.0359 (12)	0.0455 (14)	0.0112 (10)	0.0327 (12)	0.0155 (11)
C95	0.0419 (13)	0.0403 (13)	0.0297 (11)	0.0056 (10)	0.0207 (11)	0.0054 (10)
C96	0.0390 (12)	0.0256 (11)	0.0323 (11)	0.0007 (9)	0.0211 (10)	0.0021 (9)

Geometric parameters (Å, º) top

Si1—O1	1.619 (2)	C14—H14	0.950
Si1—C11	1.861 (2)	C15—H15	0.950
Si1—C21	1.869 (3)	C16—H16	0.950
Si1—C31	1.862 (2)	C22—H22	0.950
Si2—O1	1.611 (2)	C23—H23	0.950
Si2—O2	1.6209 (17)	C24—H24	0.950
Si2—C1	1.834 (3)	C25—H25	0.950
Si2—C2	1.831 (3)	C26—H26	0.950
Si3—O2	1.6312 (17)	C32—H32	0.950
Si3—C41	1.870 (2)	C33—H33	0.950
Si3—C51	1.871 (3)	C34—H34	0.950
Si3—C61	1.859 (2)	C35—H35	0.950
Si4—C71	1.869 (2)	C36—H36	0.950
Si4—C81	1.871 (2)	C42—H42	0.950
Si4—O3	1.6268 (17)	C43—H43	0.950
Si4—C91	1.8680 (19)	C44—H44	0.950
Si5—O3ⁱ	1.6303 (16)	C45—H45	0.950
Si5—C3ⁱ	1.834 (2)	C46—H46	0.950
Si5—O3	1.6303 (16)	C52—H52	0.950
Si5—C3	1.834 (2)	C53—H53	0.950
C11—C12	1.400 (3)	C54—H54	0.950
C11—C16	1.392 (3)	C55—H55	0.950
C12—C13	1.380 (3)	C56—H56	0.950
C13—C14	1.378 (4)	C62—H62	0.950
C14—C15	1.373 (4)	C63—H63	0.950
C15—C16	1.385 (3)	C64—H64	0.950
C21—C26	1.394 (3)	C65—H65	0.950
C21—C22	1.394 (4)	C66—H66	0.950
C22—C23	1.382 (4)	C71—C72	1.391 (4)
C23—C24	1.375 (4)	C71—C76	1.393 (4)
C24—C25	1.381 (4)	C72—C73	1.383 (3)
C25—C26	1.388 (4)	C73—C74	1.378 (4)
C31—C36	1.394 (4)	C74—C75	1.370 (5)
C31—C32	1.399 (4)	C75—C76	1.384 (4)
C32—C33	1.384 (3)	C81—C82	1.397 (3)
C33—C34	1.375 (5)	C81—C86	1.390 (4)
C34—C35	1.378 (5)	C82—C83	1.385 (4)
C35—C36	1.385 (3)	C83—C84	1.372 (4)
C41—C46	1.397 (4)	C84—C85	1.374 (3)
C41—C42	1.396 (4)	C85—C86	1.387 (4)
C42—C43	1.380 (3)	C91—C92	1.394 (3)
C43—C44	1.375 (4)	C91—C96	1.401 (3)
C44—C45	1.380 (4)	C92—C93	1.385 (3)
C45—C46	1.389 (3)	C93—C94	1.371 (3)
C51—C52	1.392 (3)	C94—C95	1.377 (3)
C51—C56	1.400 (3)	C95—C96	1.385 (3)
C52—C53	1.393 (4)	C3—H3A	0.980
C53—C54	1.377 (3)	C3—H3B	0.980
C54—C55	1.382 (4)	C3—H3C	0.980
C55—C56	1.390 (4)	C72—H72	0.950
C61—C62	1.397 (3)	C73—H73	0.950
C61—C66	1.400 (3)	C74—H74	0.950
C62—C63	1.388 (3)	C75—H75	0.950
C63—C64	1.374 (3)	C76—H76	0.950
C64—C65	1.381 (3)	C82—H82	0.950
C65—C66	1.378 (3)	C83—H83	0.950
C1—H1A	0.980	C84—H84	0.950
C1—H1B	0.980	C85—H85	0.950
C1—H1C	0.980	C86—H86	0.950
C2—H2A	0.980	C92—H92	0.950
C2—H2B	0.980	C93—H93	0.950
C2—H2C	0.980	C94—H94	0.950
C12—H12	0.950	C95—H95	0.950
C13—H13	0.950	C96—H96	0.950

O1—Si1—C11	107.44 (11)	C25—C24—H24	120.0
O1—Si1—C21	110.39 (10)	C23—C24—H24	120.0
O1—Si1—C31	108.99 (11)	C24—C25—H25	120.0
C11—Si1—C21	107.04 (11)	C26—C25—H25	120.0
C11—Si1—C31	112.46 (10)	C25—C26—H26	119.0
C21—Si1—C31	110.47 (11)	C21—C26—H26	119.0
O1—Si2—O2	107.83 (9)	C31—C32—H32	119.0
O1—Si2—C1	108.35 (12)	C33—C32—H32	119.0
O1—Si2—C2	109.76 (12)	C32—C33—H33	120.0
O2—Si2—C1	108.65 (13)	C34—C33—H33	120.0
O2—Si2—C2	109.02 (11)	C35—C34—H34	120.0
C1—Si2—C2	113.09 (13)	C33—C34—H34	120.0
O2—Si3—C41	110.98 (10)	C34—C35—H35	120.0
O2—Si3—C51	107.86 (9)	C36—C35—H35	120.0
O2—Si3—C61	105.79 (10)	C31—C36—H36	119.0
C41—Si3—C51	109.55 (10)	C35—C36—H36	119.0
C41—Si3—C61	111.24 (10)	C41—C42—H42	119.0
C51—Si3—C61	111.33 (11)	C43—C42—H42	119.0
C81—Si4—C91	109.85 (11)	C44—C43—H43	120.0
C71—Si4—C91	110.78 (8)	C42—C43—H43	120.0
C71—Si4—C81	108.80 (10)	C43—C44—H44	120.0
O3—Si4—C71	110.03 (10)	C45—C44—H44	120.0
O3—Si4—C81	109.90 (8)	C44—C45—H45	120.0
O3—Si4—C91	107.48 (9)	C46—C45—H45	120.0
O3—Si5—C3ⁱ	108.25 (10)	C41—C46—H46	119.0
O3ⁱ—Si5—C3	108.25 (10)	C45—C46—H46	119.0
C3—Si5—C3ⁱ	112.76 (11)	C51—C52—H52	119.0
O3—Si5—O3ⁱ	108.13 (8)	C53—C52—H52	119.0
O3—Si5—C3	109.67 (11)	C52—C53—H53	120.0
O3ⁱ—Si5—C3ⁱ	109.67 (11)	C54—C53—H53	120.0
Si1—O1—Si2	164.17 (13)	C53—C54—H54	120.0
Si2—O2—Si3	151.51 (10)	C55—C54—H54	120.0
Si4—O3—Si5	153.62 (10)	C54—C55—H55	120.0
C12—C11—C16	117.0 (2)	C56—C55—H55	120.0
Si1—C11—C12	118.88 (17)	C55—C56—H56	119.0
Si1—C11—C16	123.89 (16)	C51—C56—H56	119.0
C11—C12—C13	121.2 (2)	C63—C62—H62	119.0
C12—C13—C14	120.5 (2)	C61—C62—H62	119.0
C13—C14—C15	119.5 (2)	C64—C63—H63	120.0
C14—C15—C16	120.3 (2)	C62—C63—H63	120.0
C11—C16—C15	121.5 (2)	C63—C64—H64	120.0
C22—C21—C26	117.3 (2)	C65—C64—H64	120.0
Si1—C21—C26	121.49 (19)	C66—C65—H65	120.0
Si1—C21—C22	121.20 (17)	C64—C65—H65	120.0
C21—C22—C23	121.7 (2)	C65—C66—H66	119.0
C22—C23—C24	119.6 (3)	C61—C66—H66	119.0
C23—C24—C25	120.4 (3)	Si4—C71—C72	122.54 (17)
C24—C25—C26	119.6 (2)	Si4—C71—C76	120.9 (2)
C21—C26—C25	121.4 (2)	C72—C71—C76	116.5 (2)
Si1—C31—C36	121.56 (19)	C71—C72—C73	121.7 (2)
Si1—C31—C32	121.14 (19)	C72—C73—C74	120.4 (3)
C32—C31—C36	117.2 (2)	C73—C74—C75	119.2 (2)
C31—C32—C33	121.6 (3)	C74—C75—C76	120.2 (3)
C32—C33—C34	119.6 (3)	C71—C76—C75	122.0 (3)
C33—C34—C35	120.3 (2)	Si4—C81—C82	119.85 (19)
C34—C35—C36	120.0 (3)	Si4—C81—C86	123.24 (15)
C31—C36—C35	121.3 (3)	C82—C81—C86	116.9 (2)
Si3—C41—C46	120.80 (18)	C81—C82—C83	121.1 (2)
Si3—C41—C42	121.99 (19)	C82—C83—C84	120.8 (2)
C42—C41—C46	117.2 (2)	C83—C84—C85	119.4 (3)
C41—C42—C43	121.5 (3)	C84—C85—C86	120.1 (3)
C42—C43—C44	120.3 (3)	C81—C86—C85	121.8 (2)
C43—C44—C45	119.8 (2)	Si4—C91—C92	122.29 (15)
C44—C45—C46	119.9 (3)	Si4—C91—C96	120.71 (14)
C41—C46—C45	121.3 (2)	C92—C91—C96	116.99 (18)
Si3—C51—C52	123.20 (17)	C91—C92—C93	121.3 (2)
Si3—C51—C56	119.51 (19)	C92—C93—C94	120.8 (2)
C52—C51—C56	117.3 (2)	C93—C94—C95	119.2 (2)
C51—C52—C53	121.5 (2)	C94—C95—C96	120.5 (2)
C52—C53—C54	119.9 (2)	C91—C96—C95	121.2 (2)
C53—C54—C55	120.0 (3)	Si5—C3—H3A	109.0
C54—C55—C56	119.9 (2)	Si5—C3—H3B	110.0
C51—C56—C55	121.4 (2)	Si5—C3—H3C	109.0
Si3—C61—C66	119.74 (17)	H3A—C3—H3B	109.0
Si3—C61—C62	123.31 (15)	H3A—C3—H3C	110.0
C62—C61—C66	116.8 (2)	H3B—C3—H3C	110.0
C61—C62—C63	121.4 (2)	C71—C72—H72	119.0
C62—C63—C64	120.1 (2)	C73—C72—H72	119.0
C63—C64—C65	119.9 (2)	C72—C73—H73	120.0
C64—C65—C66	119.9 (2)	C74—C73—H73	120.0
C61—C66—C65	121.9 (2)	C73—C74—H74	120.0
Si2—C1—H1A	109.0	C75—C74—H74	120.0
Si2—C1—H1C	110.0	C74—C75—H75	120.0
H1A—C1—H1B	110.0	C76—C75—H75	120.0
Si2—C1—H1B	109.0	C71—C76—H76	119.0
H1B—C1—H1C	109.0	C75—C76—H76	119.0
H1A—C1—H1C	109.0	C81—C82—H82	120.0
Si2—C2—H2C	110.0	C83—C82—H82	119.0
Si2—C2—H2B	109.0	C82—C83—H83	120.0
Si2—C2—H2A	109.0	C84—C83—H83	120.0
H2B—C2—H2C	109.0	C83—C84—H84	120.0
H2A—C2—H2B	110.0	C85—C84—H84	120.0
H2A—C2—H2C	109.0	C84—C85—H85	120.0
C11—C12—H12	119.0	C86—C85—H85	120.0
C13—C12—H12	119.0	C81—C86—H86	119.0
C12—C13—H13	120.0	C85—C86—H86	119.0
C14—C13—H13	120.0	C91—C92—H92	119.0
C13—C14—H14	120.0	C93—C92—H92	119.0
C15—C14—H14	120.0	C92—C93—H93	120.0
C16—C15—H15	120.0	C94—C93—H93	120.0
C14—C15—H15	120.0	C93—C94—H94	120.0
C11—C16—H16	119.0	C95—C94—H94	120.0
C15—C16—H16	119.0	C94—C95—H95	120.0
C21—C22—H22	119.0	C96—C95—H95	120.0
C23—C22—H22	119.0	C91—C96—H96	119.0
C24—C23—H23	120.0	C95—C96—H96	119.0
C22—C23—H23	120.0

Symmetry code: (i) −x, y, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₃₈H₃₆O₂Si₃
M_r	608.94
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	47.7051 (5), 7.6270 (1), 33.1200 (5)
β (°)	124.1246 (6)
V (Å³)	9975.7 (2)
Z	12
Radiation type	Mo Kα
µ (mm⁻¹)	0.18
Crystal size (mm)	0.30 × 0.27 × 0.09

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	43681, 11325, 7490
R_int	0.066
(sin θ/λ)_max (Å⁻¹)	0.648

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.112, 1.02
No. of reflections	11325
No. of parameters	585
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.31

Computer programs: COLLECT (Hooft, 1998), DENZO (Otwinowski & Minor, 1997), DENZO, SHELXS86 (Sheldrick, 1985), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), PLATON.

Selected geometric parameters (Å, º) top

Si1—O1	1.619 (2)	Si3—O2	1.6312 (17)
Si2—O1	1.611 (2)	Si4—O3	1.6268 (17)
Si2—O2	1.6209 (17)	Si5—O3	1.6303 (16)
Si2—C1	1.834 (3)	Si5—C3	1.834 (2)
Si2—C2	1.831 (3)

O1—Si2—O2	107.83 (9)	C3—Si5—C3ⁱ	112.76 (11)
O1—Si2—C1	108.35 (12)	O3—Si5—O3ⁱ	108.13 (8)
O1—Si2—C2	109.76 (12)	O3—Si5—C3	109.67 (11)
O2—Si2—C1	108.65 (13)	O3ⁱ—Si5—C3ⁱ	109.67 (11)
O2—Si2—C2	109.02 (11)	Si1—O1—Si2	164.17 (13)
C1—Si2—C2	113.09 (13)	Si2—O2—Si3	151.51 (10)
O3—Si5—C3ⁱ	108.25 (10)	Si4—O3—Si5	153.62 (10)
O3ⁱ—Si5—C3	108.25 (10)

Symmetry code: (i) −x, y, −z+1/2.

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