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The title compound, C28H52Si4, crystallizes in the uncommon space group I4122 with 222 symmetry. Despite the reduction of the rings, several features of [2.2]paracyclo­phane strain are still apparent.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805018350/bt6680sup1.cif
Contains datablocks 3, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805018350/bt66803sup2.hkl
Contains datablock 3

CCDC reference: 277208

Key indicators

  • Single-crystal X-ray study
  • T = 143 K
  • Mean [sigma](Wave) = 0.000 Å
  • R factor = 0.040
  • wR factor = 0.114
  • Data-to-parameter ratio = 14.6

checkCIF/PLATON results

No syntax errors found



Alert level G REFLT03_ALERT_4_G WARNING: Large fraction of Friedel related reflns may be needed to determine absolute structure From the CIF: _diffrn_reflns_theta_max 27.54 From the CIF: _reflns_number_total 1068 Count of symmetry unique reflns 1071 Completeness (_total/calc) 99.72% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 Are heavy atom types Z>Si present yes
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 0 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 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 1 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: DIF4 (Stoe & Cie, 1992); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1992); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.

syn-exo-4,7,12,15-Tetrakis(trimethylsilyl)-4,7,12,15- tetrahydro[2.2]paracyclophane top
Crystal data top
C28H52Si4Dx = 1.058 Mg m3
Mr = 501.06Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4122Cell parameters from 66 reflections
a = 13.906 (4) Åθ = 10–11.5°
c = 16.263 (5) ŵ = 0.20 mm1
V = 3144.9 (16) Å3T = 143 K
Z = 4Block, colourless
F(000) = 11040.6 × 0.6 × 0.5 mm
Data collection top
Stoe Stadi-4
diffractometer
Rint = 0.031
Radiation source: fine-focus sealed tubeθmax = 27.5°, θmin = 3.3°
Graphite monochromatorh = 018
ω/θ scansk = 180
3911 measured reflectionsl = 2121
1068 independent reflections3 standard reflections every 60 min
936 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.114H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0668P)2 + 1.0612P]
where P = (Fo2 + 2Fc2)/3
1068 reflections(Δ/σ)max < 0.001
73 parametersΔρmax = 0.23 e Å3
35 restraintsΔρmin = 0.14 e Å3
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
xyzUiso*/Ueq
Si0.16886 (6)0.52245 (6)0.53829 (4)0.0428 (2)
C10.1250 (2)0.3449 (2)0.70525 (16)0.0435 (6)
H1A0.18360.33510.67170.052*
H1B0.08980.28310.70760.052*
C20.0621 (2)0.41960 (18)0.66414 (14)0.0364 (5)
C30.10507 (19)0.51574 (19)0.64261 (15)0.0370 (6)
H30.15670.52670.68440.044*
C40.0319 (2)0.40572 (18)0.65767 (16)0.0380 (6)
H40.05510.34170.66290.046*
C50.2973 (3)0.4950 (5)0.5501 (3)0.115 (2)
H5A0.32620.54000.58940.138*
H5B0.32950.50120.49680.138*
H5C0.30480.42910.57050.138*
C60.1600 (3)0.6470 (3)0.4989 (3)0.0730 (11)
H6A0.09210.66440.49220.088*
H6B0.19270.65140.44560.088*
H6C0.19040.69120.53800.088*
C70.1202 (4)0.4364 (4)0.4627 (3)0.0997 (19)
H7A0.14690.45060.40820.120*
H7B0.05000.44210.46080.120*
H7C0.13790.37090.47880.120*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Si0.0458 (4)0.0489 (5)0.0337 (4)0.0016 (4)0.0072 (3)0.0027 (3)
C10.0513 (15)0.0448 (15)0.0345 (13)0.0109 (13)0.0014 (12)0.0046 (11)
C20.0473 (13)0.0366 (13)0.0254 (11)0.0023 (11)0.0002 (11)0.0042 (10)
C30.0404 (13)0.0397 (14)0.0310 (12)0.0012 (11)0.0016 (10)0.0029 (11)
C40.0506 (15)0.0329 (11)0.0305 (12)0.0067 (11)0.0062 (11)0.0011 (10)
C50.071 (2)0.206 (6)0.067 (3)0.061 (3)0.019 (2)0.025 (3)
C60.088 (3)0.0553 (19)0.075 (2)0.0141 (17)0.029 (2)0.0099 (17)
C70.143 (4)0.094 (3)0.062 (2)0.061 (3)0.046 (3)0.038 (2)
Geometric parameters (Å, º) top
Si—C51.837 (4)C3—H31.0000
Si—C71.844 (4)C4—H40.9500
Si—C61.851 (4)C5—H5A0.9800
Si—C31.917 (3)C5—H5B0.9800
C1—C21.513 (4)C5—H5C0.9800
C1—C1i1.571 (5)C6—H6A0.9800
C1—H1A0.9900C6—H6B0.9800
C1—H1B0.9900C6—H6C0.9800
C2—C41.326 (4)C7—H7A0.9800
C2—C31.506 (4)C7—H7B0.9800
C3—C4ii1.512 (4)C7—H7C0.9800
C5—Si—C7106.9 (3)C2—C4—C3ii124.8 (2)
C5—Si—C6107.2 (3)C2—C4—H4117.6
C7—Si—C6110.6 (2)C3ii—C4—H4117.6
C5—Si—C3110.31 (17)Si—C5—H5A109.5
C7—Si—C3112.89 (15)Si—C5—H5B109.5
C6—Si—C3108.73 (16)H5A—C5—H5B109.5
C2—C1—C1i112.36 (15)Si—C5—H5C109.5
C2—C1—H1A109.1H5A—C5—H5C109.5
C1i—C1—H1A109.1H5B—C5—H5C109.5
C2—C1—H1B109.1Si—C6—H6A109.5
C1i—C1—H1B109.1Si—C6—H6B109.5
H1A—C1—H1B107.9H6A—C6—H6B109.5
C4—C2—C3120.2 (2)Si—C6—H6C109.5
C4—C2—C1120.3 (3)H6A—C6—H6C109.5
C3—C2—C1118.8 (2)H6B—C6—H6C109.5
C2—C3—C4ii109.7 (2)Si—C7—H7A109.5
C2—C3—Si115.65 (17)Si—C7—H7B109.5
C4ii—C3—Si114.79 (18)H7A—C7—H7B109.5
C2—C3—H3105.2Si—C7—H7C109.5
C4ii—C3—H3105.2H7A—C7—H7C109.5
Si—C3—H3105.2H7B—C7—H7C109.5
C1i—C1—C2—C4103.2 (4)C6—Si—C3—C2150.9 (2)
C1i—C1—C2—C367.5 (4)C5—Si—C3—C4ii138.9 (3)
C4—C2—C3—C4ii28.7 (3)C7—Si—C3—C4ii101.5 (3)
C1—C2—C3—C4ii142.0 (2)C6—Si—C3—C4ii21.6 (3)
C4—C2—C3—Si103.0 (3)C3—C2—C4—C3ii10.2 (4)
C1—C2—C3—Si86.2 (2)C1—C2—C4—C3ii160.4 (2)
C5—Si—C3—C291.8 (3)C2—C3—C4ii—C2ii18.9 (3)
C7—Si—C3—C227.8 (3)
Symmetry codes: (i) y+1/2, x+1/2, z+3/2; (ii) x, y+1, z.
 

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