1,1,4,4-Tetra-tert-butyl-1,4-dichloro-2,2,3,3-tetra-phenyl-tetra-silane.

The title compound, C(40)H(56)Cl(2)Si(4), was synthesized by the coupling of 1,1-di-tert-butyl-1,2-dichloro-2,2-diphenyl-disilane with lithium. The asymmetric unit contains one half-mol-ecule, which is completed by an inversion centre. In the mol-ecule, the tetra-silane skeleton adopts a perfect anti conformation and the Si-Si bonds [2.4355 (5) and 2.4328 (7) Å] are longer than the standard Si-Si bond length (2.34 Å). The Si-Si-Si angle [116.09 (2)°] is larger than the tetra-hedral bond angle (109.5°). These long bond lengths and the wide angle are favorable for reducing the steric hindrance among the tert-butyl and the phenyl groups. The dihedral angle between the phenyl rings in the asymmetric unit is 37.36 (8)°.

Related literature

For details of Wurtz-type reactions for formation of silicon–silicon bonds, see: Burkhard (1949 ▶); Gilman & Tomasi (1963 ▶); Stolberg (1963 ▶); Laguerre et al. (1978 ▶); Herman et al. (1985 ▶); Watanabe et al. (1988 ▶). For related structures of oligosilanes with anti conformations, see: Baumeister et al. (1997 ▶); Michl & West (2000 ▶); Tsuji et al. (2004 ▶); Fukazawa et al. (2006 ▶); Haga et al. (2008 ▶).

Experimental

Crystal data

C40H56Cl2Si4

M = 720.11

Monoclinic,

a = 9.6981 (8) Å

b = 15.3893 (11) Å

c = 13.8546 (11) Å

β = 105.7717 (7)°

V = 1989.9 (3) Å3

Z = 2

Mo Kα radiation

μ = 0.31 mm−1

T = 153 K

0.30 × 0.10 × 0.10 mm

Data collection

Rigaku RAXIS-IV imaging plate diffractometer

Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T min = 0.913, T max = 0.970

12290 measured reflections

4895 independent reflections

4826 reflections with I > 2σ(I)

R int = 0.020

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.094

S = 1.10

4895 reflections

214 parameters

H-atom parameters constrained

Δρmax = 0.32 e Å−3

Δρmin = −0.32 e Å−3

Data collection: CrystalClear (Rigaku, 2003 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008 ▶) and Yadokari-XG 2009 (Kabuto et al., 2009 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812000669/is5036sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812000669/is5036Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812000669/is5036Isup3.cml

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

C40H56Cl2Si4	F(000) = 772
Mr = 720.11	Dx = 1.202 Mg m−3
Monoclinic, P21/n	Melting point = 517–520 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 9.6981 (8) Å	Cell parameters from 9597 reflections
b = 15.3893 (11) Å	θ = 1.3–28.3°
c = 13.8546 (11) Å	µ = 0.31 mm−1
β = 105.7717 (7)°	T = 153 K
V = 1989.9 (3) Å3	Prism, colourless
Z = 2	0.30 × 0.10 × 0.10 mm

Rigaku RAXIS-IV imaging plate diffractometer	4895 independent reflections
Radiation source: rotating anode	4826 reflections with I > 2σ(I)
graphite	Rint = 0.020
Detector resolution: 10.00 pixels mm-1	θmax = 28.3°, θmin = 2.0°
ω scans	h = −12→12
Absorption correction: multi-scan (REQAB; Jacobson, 1998)	k = −20→20
Tmin = 0.913, Tmax = 0.970	l = −18→18
12290 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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.094	H-atom parameters constrained
S = 1.10	w = 1/[σ2(Fo2) + (0.0373P)2 + 1.7041P] where P = (Fo2 + 2Fc2)/3
4895 reflections	(Δ/σ)max < 0.001
214 parameters	Δρmax = 0.32 e Å−3
0 restraints	Δρmin = −0.32 e Å−3

Experimental. IR (KBr): 3080, 3050, 2980, 2950, 2940, 2890, 2850, 1470, 1430, 1390, 1370, 1360, 1180, 1090, 1010, 810, 730, 700 cm–1. MS (EI, 70 eV): m/z 541 (M+–177, 100), 359 (24), 324 (69), 267 (31), 259 (42), 197 (50), 183 (26), 135 (46).

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 > 2σ(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
Si1	0.31115 (4)	0.00675 (2)	0.27448 (3)	0.01114 (9)
Si2	0.52023 (4)	−0.00985 (2)	0.41781 (3)	0.00975 (9)
Cl1	0.23186 (4)	0.12785 (2)	0.30352 (3)	0.01879 (9)
C1	0.37002 (17)	0.02227 (11)	0.15322 (11)	0.0199 (3)
C2	0.4726 (2)	−0.05206 (14)	0.14543 (13)	0.0315 (4)
H1	0.4230	−0.1078	0.1431	0.047*
H2	0.5563	−0.0508	0.2040	0.047*
H3	0.5036	−0.0449	0.0843	0.047*
C3	0.24115 (19)	0.02135 (13)	0.05901 (12)	0.0274 (4)
H4	0.2749	0.0307	−0.0007	0.041*
H5	0.1742	0.0677	0.0640	0.041*
H6	0.1924	−0.0349	0.0539	0.041*
C4	0.4457 (2)	0.11019 (13)	0.15219 (13)	0.0296 (4)
H7	0.5316	0.1129	0.2091	0.044*
H8	0.3805	0.1575	0.1574	0.044*
H9	0.4731	0.1160	0.0894	0.044*
C5	0.14973 (15)	−0.07002 (9)	0.25896 (11)	0.0165 (3)
C6	0.16775 (19)	−0.15608 (11)	0.20623 (15)	0.0306 (4)
H10	0.2618	−0.1812	0.2386	0.046*
H11	0.1604	−0.1447	0.1354	0.046*
H12	0.0924	−0.1969	0.2113	0.046*
C7	0.13114 (18)	−0.09028 (13)	0.36307 (13)	0.0288 (4)
H13	0.0449	−0.1256	0.3559	0.043*
H14	0.1217	−0.0358	0.3974	0.043*
H15	0.2150	−0.1223	0.4024	0.043*
C8	0.00900 (16)	−0.02761 (11)	0.19730 (12)	0.0216 (3)
H16	−0.0712	−0.0673	0.1939	0.032*
H17	0.0158	−0.0153	0.1293	0.032*
H18	−0.0069	0.0267	0.2296	0.032*
C9	0.63923 (14)	0.08247 (9)	0.39841 (10)	0.0129 (3)
C10	0.60184 (15)	0.16802 (9)	0.41542 (11)	0.0154 (3)
H19	0.5174	0.1780	0.4360	0.018*
C11	0.68493 (17)	0.23859 (10)	0.40297 (13)	0.0224 (3)
H20	0.6580	0.2958	0.4161	0.027*
C12	0.80733 (18)	0.22523 (11)	0.37132 (14)	0.0283 (4)
H21	0.8644	0.2732	0.3625	0.034*
C13	0.84559 (18)	0.14169 (12)	0.35275 (14)	0.0269 (4)
H22	0.9293	0.1325	0.3310	0.032*
C14	0.76306 (16)	0.07092 (10)	0.36547 (11)	0.0183 (3)
H23	0.7907	0.0140	0.3517	0.022*
C15	0.61049 (15)	−0.11866 (9)	0.41486 (10)	0.0125 (3)
C16	0.75912 (16)	−0.13158 (10)	0.44964 (12)	0.0189 (3)
H24	0.8197	−0.0833	0.4739	0.023*
C17	0.81957 (17)	−0.21366 (11)	0.44931 (13)	0.0242 (3)
H25	0.9206	−0.2204	0.4717	0.029*
C18	0.73361 (19)	−0.28541 (11)	0.41658 (13)	0.0247 (3)
H26	0.7753	−0.3413	0.4168	0.030*
C19	0.58640 (19)	−0.27512 (11)	0.38349 (13)	0.0255 (3)
H27	0.5264	−0.3241	0.3617	0.031*
C20	0.52687 (16)	−0.19285 (10)	0.38224 (12)	0.0195 (3)
H28	0.4258	−0.1866	0.3584	0.023*

	U11	U22	U33	U12	U13	U23
Si1	0.00980 (17)	0.01148 (18)	0.01079 (17)	0.00034 (13)	0.00048 (13)	−0.00035 (13)
Si2	0.00847 (17)	0.00997 (17)	0.01055 (17)	0.00025 (12)	0.00215 (13)	−0.00022 (12)
Cl1	0.01666 (17)	0.01261 (16)	0.02527 (19)	0.00270 (12)	0.00259 (13)	−0.00031 (12)
C1	0.0185 (7)	0.0299 (8)	0.0111 (6)	0.0007 (6)	0.0036 (5)	0.0007 (6)
C2	0.0296 (9)	0.0477 (11)	0.0194 (8)	0.0128 (8)	0.0104 (7)	−0.0017 (7)
C3	0.0251 (8)	0.0420 (10)	0.0124 (7)	−0.0017 (7)	0.0005 (6)	0.0021 (7)
C4	0.0291 (9)	0.0424 (10)	0.0174 (7)	−0.0104 (8)	0.0064 (6)	0.0062 (7)
C5	0.0122 (6)	0.0142 (6)	0.0187 (7)	−0.0024 (5)	−0.0033 (5)	0.0010 (5)
C6	0.0233 (8)	0.0164 (7)	0.0421 (10)	−0.0018 (6)	−0.0079 (7)	−0.0074 (7)
C7	0.0211 (8)	0.0375 (10)	0.0238 (8)	−0.0132 (7)	−0.0011 (6)	0.0097 (7)
C8	0.0134 (7)	0.0223 (7)	0.0246 (8)	−0.0004 (6)	−0.0024 (6)	0.0012 (6)
C9	0.0115 (6)	0.0152 (6)	0.0111 (6)	−0.0019 (5)	0.0015 (5)	0.0014 (5)
C10	0.0136 (6)	0.0152 (6)	0.0158 (6)	0.0001 (5)	0.0015 (5)	0.0011 (5)
C11	0.0200 (7)	0.0154 (7)	0.0276 (8)	−0.0031 (6)	−0.0007 (6)	0.0031 (6)
C12	0.0208 (8)	0.0245 (8)	0.0385 (10)	−0.0106 (6)	0.0064 (7)	0.0077 (7)
C13	0.0175 (7)	0.0319 (9)	0.0344 (9)	−0.0043 (7)	0.0123 (7)	0.0045 (7)
C14	0.0159 (6)	0.0198 (7)	0.0210 (7)	−0.0004 (5)	0.0081 (5)	0.0007 (5)
C15	0.0131 (6)	0.0131 (6)	0.0116 (6)	0.0027 (5)	0.0037 (5)	0.0003 (5)
C16	0.0146 (7)	0.0167 (7)	0.0242 (7)	0.0011 (5)	0.0033 (5)	0.0001 (6)
C17	0.0153 (7)	0.0240 (8)	0.0328 (9)	0.0089 (6)	0.0057 (6)	0.0044 (6)
C18	0.0277 (8)	0.0176 (7)	0.0298 (8)	0.0100 (6)	0.0095 (7)	−0.0009 (6)
C19	0.0255 (8)	0.0161 (7)	0.0318 (9)	−0.0001 (6)	0.0027 (7)	−0.0076 (6)
C20	0.0150 (6)	0.0172 (7)	0.0235 (7)	0.0018 (5)	0.0001 (5)	−0.0041 (6)

Si1—C5	1.9261 (15)	C7—H15	0.9800
Si1—C1	1.9306 (15)	C8—H16	0.9800
Si1—Cl1	2.0963 (5)	C8—H17	0.9800
Si1—Si2	2.4355 (5)	C8—H18	0.9800
Si2—C15	1.8951 (14)	C9—C10	1.402 (2)
Si2—C9	1.8950 (14)	C9—C14	1.4072 (19)
Si2—Si2i	2.4328 (7)	C10—C11	1.391 (2)
C1—C3	1.542 (2)	C10—H19	0.9500
C1—C2	1.538 (2)	C11—C12	1.388 (2)
C1—C4	1.541 (2)	C11—H20	0.9500
C2—H1	0.9800	C12—C13	1.381 (3)
C2—H2	0.9800	C12—H21	0.9500
C2—H3	0.9800	C13—C14	1.391 (2)
C3—H4	0.9800	C13—H22	0.9500
C3—H5	0.9800	C14—H23	0.9500
C3—H6	0.9800	C15—C20	1.402 (2)
C4—H7	0.9800	C15—C16	1.4043 (19)
C4—H8	0.9800	C16—C17	1.393 (2)
C4—H9	0.9800	C16—H24	0.9500
C5—C7	1.533 (2)	C17—C18	1.384 (2)
C5—C6	1.545 (2)	C17—H25	0.9500
C5—C8	1.544 (2)	C18—C19	1.385 (2)
C6—H10	0.9800	C18—H26	0.9500
C6—H11	0.9800	C19—C20	1.390 (2)
C6—H12	0.9800	C19—H27	0.9500
C7—H13	0.9800	C20—H28	0.9500
C7—H14	0.9800
C5—Si1—C1	113.73 (7)	C5—C7—H13	109.5
C5—Si1—Cl1	103.73 (5)	C5—C7—H14	109.5
C1—Si1—Cl1	105.53 (5)	H13—C7—H14	109.5
C5—Si1—Si2	119.87 (5)	C5—C7—H15	109.5
C1—Si1—Si2	110.17 (5)	H13—C7—H15	109.5
Cl1—Si1—Si2	101.79 (2)	H14—C7—H15	109.5
C15—Si2—C9	110.90 (6)	C5—C8—H16	109.5
C15—Si2—Si2i	108.86 (5)	C5—C8—H17	109.5
C9—Si2—Si2i	107.38 (5)	H16—C8—H17	109.5
C15—Si2—Si1	111.23 (5)	C5—C8—H18	109.5
C9—Si2—Si1	102.12 (4)	H16—C8—H18	109.5
Si2i—Si2—Si1	116.09 (2)	H17—C8—H18	109.5
C3—C1—C2	108.93 (14)	C10—C9—C14	117.10 (13)
C3—C1—C4	106.18 (14)	C10—C9—Si2	119.00 (10)
C2—C1—C4	109.48 (14)	C14—C9—Si2	123.89 (11)
C3—C1—Si1	111.84 (11)	C11—C10—C9	121.82 (14)
C2—C1—Si1	108.59 (11)	C11—C10—H19	119.1
C4—C1—Si1	111.77 (11)	C9—C10—H19	119.1
C1—C2—H1	109.5	C12—C11—C10	119.85 (15)
C1—C2—H2	109.5	C12—C11—H20	120.1
H1—C2—H2	109.5	C10—C11—H20	120.1
C1—C2—H3	109.5	C13—C12—C11	119.52 (15)
H1—C2—H3	109.5	C13—C12—H21	120.2
H2—C2—H3	109.5	C11—C12—H21	120.2
C1—C3—H4	109.5	C12—C13—C14	120.81 (15)
C1—C3—H5	109.5	C12—C13—H22	119.6
H4—C3—H5	109.5	C14—C13—H22	119.6
C1—C3—H6	109.5	C13—C14—C9	120.89 (15)
H4—C3—H6	109.5	C13—C14—H23	119.6
H5—C3—H6	109.5	C9—C14—H23	119.6
C1—C4—H7	109.5	C20—C15—C16	116.43 (13)
C1—C4—H8	109.5	C20—C15—Si2	119.76 (10)
H7—C4—H8	109.5	C16—C15—Si2	123.69 (11)
C1—C4—H9	109.5	C17—C16—C15	121.39 (14)
H7—C4—H9	109.5	C17—C16—H24	119.3
H8—C4—H9	109.5	C15—C16—H24	119.3
C7—C5—C6	109.13 (14)	C18—C17—C16	120.54 (14)
C7—C5—C8	107.10 (13)	C18—C17—H25	119.7
C6—C5—C8	107.30 (12)	C16—C17—H25	119.7
C7—C5—Si1	108.63 (10)	C19—C18—C17	119.50 (14)
C6—C5—Si1	112.68 (11)	C19—C18—H26	120.2
C8—C5—Si1	111.83 (10)	C17—C18—H26	120.2
C5—C6—H10	109.5	C18—C19—C20	119.71 (15)
C5—C6—H11	109.5	C18—C19—H27	120.1
H10—C6—H11	109.5	C20—C19—H27	120.1
C5—C6—H12	109.5	C19—C20—C15	122.41 (14)
H10—C6—H12	109.5	C19—C20—H28	118.8
H11—C6—H12	109.5	C15—C20—H28	118.8
C5—Si1—Si2—C15	63.66 (7)	Si2i—Si2—C9—C10	−50.23 (12)
C1—Si1—Si2—C15	−71.20 (7)	Si1—Si2—C9—C10	72.35 (11)
Cl1—Si1—Si2—C15	177.20 (5)	C15—Si2—C9—C14	12.38 (14)
C5—Si1—Si2—C9	−177.99 (7)	Si2i—Si2—C9—C14	131.21 (11)
C1—Si1—Si2—C9	47.15 (7)	Si1—Si2—C9—C14	−106.21 (12)
Cl1—Si1—Si2—C9	−64.44 (5)	C14—C9—C10—C11	−1.6 (2)
C5—Si1—Si2—Si2i	−61.54 (6)	Si2—C9—C10—C11	179.71 (12)
C1—Si1—Si2—Si2i	163.60 (6)	C9—C10—C11—C12	1.1 (2)
Cl1—Si1—Si2—Si2i	52.00 (3)	C10—C11—C12—C13	−0.2 (3)
C5—Si1—C1—C3	34.92 (14)	C11—C12—C13—C14	−0.1 (3)
Cl1—Si1—C1—C3	−78.12 (12)	C12—C13—C14—C9	−0.6 (3)
Si2—Si1—C1—C3	172.74 (11)	C10—C9—C14—C13	1.4 (2)
C5—Si1—C1—C2	−85.31 (13)	Si2—C9—C14—C13	179.96 (13)
Cl1—Si1—C1—C2	161.66 (11)	C9—Si2—C15—C20	−150.92 (11)
Si2—Si1—C1—C2	52.51 (12)	Si2i—Si2—C15—C20	91.15 (12)
C5—Si1—C1—C4	153.81 (11)	Si1—Si2—C15—C20	−38.00 (13)
Cl1—Si1—C1—C4	40.78 (12)	C9—Si2—C15—C16	33.11 (14)
Si2—Si1—C1—C4	−68.36 (12)	Si2i—Si2—C15—C16	−84.82 (12)
C1—Si1—C5—C7	169.63 (11)	Si1—Si2—C15—C16	146.04 (11)
Cl1—Si1—C5—C7	−76.26 (11)	C20—C15—C16—C17	1.4 (2)
Si2—Si1—C5—C7	36.25 (13)	Si2—C15—C16—C17	177.51 (12)
C1—Si1—C5—C6	48.58 (13)	C15—C16—C17—C18	−1.5 (3)
Cl1—Si1—C5—C6	162.69 (10)	C16—C17—C18—C19	0.3 (3)
Si2—Si1—C5—C6	−84.80 (12)	C17—C18—C19—C20	0.9 (3)
C1—Si1—C5—C8	−72.38 (12)	C18—C19—C20—C15	−0.9 (3)
Cl1—Si1—C5—C8	41.73 (11)	C16—C15—C20—C19	−0.2 (2)
Si2—Si1—C5—C8	154.24 (9)	Si2—C15—C20—C19	−176.46 (13)
C15—Si2—C9—C10	−169.06 (10)