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Acta Crystallogr Sect E Struct Rep Online. 2008 November 1; 64(Pt 11): o2128.
Published online 2008 October 18. doi:  10.1107/S1600536808033412
PMCID: PMC2959628

Bis(1-methyl-1-phenyl­ethyl) peroxide

Abstract

In the crystal structure, the title compound (also called dicumyl peroxide), C18H22O2, lies on a center of symmetry. The COOC plane including the di­oxy group makes a dihedral angle of 79.10 (5)° with the phenyl ring. An inter­molecular C—H(...)π inter­action is observed between the phenyl groups.

Related literature

For general background, see: Ferrero (2006 [triangle]); Konar et al. (1993 [triangle]); Ramar & Alagar (2004 [triangle]); Wang et al. (1998 [triangle]).

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Object name is e-64-o2128-scheme1.jpg

Experimental

Crystal data

  • C18H22O2
  • M r = 270.36
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-64-o2128-efi1.jpg
  • a = 10.040 (2) Å
  • b = 7.4774 (15) Å
  • c = 21.016 (4) Å
  • V = 1577.7 (5) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 293 (2) K
  • 0.25 × 0.20 × 0.15 mm

Data collection

  • Rigaku R-AXIS RAPID IP area-detector diffractometer
  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995 [triangle]) T min = 0.982, T max = 0.989
  • 11957 measured reflections
  • 1464 independent reflections
  • 1232 reflections with I > 2σ(I)
  • R int = 0.077

Refinement

  • R[F 2 > 2σ(F 2)] = 0.043
  • wR(F 2) = 0.110
  • S = 1.05
  • 1464 reflections
  • 92 parameters
  • H-atom parameters constrained
  • Δρmax = 0.26 e Å−3
  • Δρmin = −0.18 e Å−3

Data collection: RAPID-AUTO (Rigaku/MSC, 2004 [triangle]); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808033412/is2340sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033412/is2340Isup2.hkl

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

Acknowledgments

The authors gratefully acknowledge financial support from the SRCICT of Tianjin University and the material DCP afforded by Gaoqiao Petrochemical Corporation.

supplementary crystallographic information

Comment

The title compound, (I), a simple organic peroxide, has gradually become almost the most important additive in operations affected by molecular transport, such as grafting (Konar et al., 1993; Ramar & Alagar, 2004) and cross-linking (Wang et al., 1998; Ferrero, 2006), which are based on the formation of oxyradicals due to the thermal decomposition of the peroxides. It's widely used in the art as vulcanizing agents for resins and elastomers, as cross-linking agents for polyolefins.

The centrosymmetric molecular structure of (I) is shown in Fig. 1. In the molecule, two phenyl rings are, of course, parallel to each other due to the symmetry element. The peroxy unit has an O—O bond length of 1.6853 (16) Å, and the four atoms, C7, O1, O1A and C7A are coplanar with a C7—O1—O1A bond angle of 106.02 (9)°. There is no hydrogen bond in the packing structure, and cohesion of the crystal can be attributed to van der Waals interactions.

Experimental

At room temperature, the title compound (1 g) provided by Gaoqiao petrochemical corporation was dissolved in 20 mL ethanol (99.7%). The solvent was vaporized slowly by use of a film covering the container (beaker). Then the solution was placed in darkness until crystals appeared. The product was taken out from the solvent by tweezers, and dried in the air at room temperature.

Refinement

H atoms are placed in calculated positions and constrained to ride on their parent atoms, with C–H = 0.93–0.96 Å, and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C).

Figures

Fig. 1.
The molecular structure of the title compound, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
The packing diagram of (I), viewed down the b axis. H atoms have been omitted.

Crystal data

C18H22O2Dx = 1.138 Mg m3
Mr = 270.36Melting point: 315.15 K
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 8972 reflections
a = 10.040 (2) Åθ = 3.5–27.6°
b = 7.4774 (15) ŵ = 0.07 mm1
c = 21.016 (4) ÅT = 293 K
V = 1577.7 (5) Å3Plate, colorless
Z = 40.25 × 0.20 × 0.15 mm
F(000) = 584

Data collection

Rigaku R-AXIS RAPID IP area-detector diffractometer1464 independent reflections
Radiation source: rotating anode1232 reflections with I > 2σ(I)
graphiteRint = 0.077
oscillation scansθmax = 25.5°, θmin = 3.5°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)h = −12→10
Tmin = 0.982, Tmax = 0.989k = −9→9
11957 measured reflectionsl = −25→25

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.043H-atom parameters constrained
wR(F2) = 0.110w = 1/[σ2(Fo2) + (0.0556P)2 + 0.2734P] where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max = 0.010
1464 reflectionsΔρmax = 0.26 e Å3
92 parametersΔρmin = −0.17 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.027 (7)

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.
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)

xyzUiso*/Ueq
O10.46269 (8)0.07789 (11)0.51277 (4)0.0309 (3)
C10.44577 (13)−0.10967 (18)0.62787 (6)0.0373 (4)
H1A0.3746−0.11150.59960.045*
C20.44768 (16)−0.2285 (2)0.67854 (6)0.0462 (4)
H2A0.3785−0.30990.68360.055*
C30.55144 (16)−0.2265 (2)0.72135 (6)0.0482 (4)
H3A0.5527−0.30600.75540.058*
C40.65322 (16)−0.1055 (2)0.71319 (6)0.0453 (4)
H4A0.7231−0.10250.74220.054*
C50.65252 (13)0.01215 (17)0.66204 (6)0.0353 (3)
H5A0.72270.09200.65680.042*
C60.54838 (12)0.01186 (16)0.61873 (5)0.0285 (3)
C70.54171 (12)0.14706 (16)0.56434 (6)0.0302 (3)
C80.67730 (14)0.20577 (19)0.54013 (6)0.0419 (4)
H8A0.72740.10270.52710.063*
H8B0.72420.26700.57340.063*
H8C0.66600.28470.50450.063*
C90.45933 (16)0.30860 (19)0.58538 (6)0.0457 (4)
H9A0.37400.26890.60040.068*
H9B0.44720.38800.55000.068*
H9C0.50510.37030.61900.068*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0353 (5)0.0293 (5)0.0282 (5)0.0064 (4)−0.0042 (4)−0.0065 (3)
C10.0372 (7)0.0434 (8)0.0312 (7)−0.0045 (6)0.0036 (6)0.0002 (6)
C20.0558 (9)0.0452 (9)0.0377 (8)−0.0046 (7)0.0142 (7)0.0028 (6)
C30.0711 (11)0.0426 (9)0.0309 (7)0.0163 (7)0.0120 (7)0.0058 (6)
C40.0556 (9)0.0506 (9)0.0297 (7)0.0182 (7)−0.0080 (7)−0.0051 (6)
C50.0383 (7)0.0358 (7)0.0319 (7)0.0045 (6)−0.0042 (6)−0.0074 (5)
C60.0330 (7)0.0288 (7)0.0235 (6)0.0042 (5)0.0017 (5)−0.0057 (5)
C70.0377 (7)0.0271 (6)0.0258 (6)−0.0014 (5)−0.0039 (5)−0.0034 (5)
C80.0495 (8)0.0387 (8)0.0376 (7)−0.0153 (6)−0.0015 (7)0.0017 (6)
C90.0654 (10)0.0339 (8)0.0377 (8)0.0124 (7)−0.0072 (7)−0.0068 (6)

Geometric parameters (Å, °)

O1—C71.4392 (15)C5—C61.3862 (17)
O1—O1i1.4853 (16)C5—H5A0.9300
C1—C61.3871 (18)C6—C71.5273 (17)
C1—C21.387 (2)C7—C81.5181 (18)
C1—H1A0.9300C7—C91.5292 (18)
C2—C31.377 (2)C8—H8A0.9600
C2—H2A0.9300C8—H8B0.9600
C3—C41.375 (2)C8—H8C0.9600
C3—H3A0.9300C9—H9A0.9600
C4—C51.3893 (19)C9—H9B0.9600
C4—H4A0.9300C9—H9C0.9600
C7—O1—O1i106.02 (9)O1—C7—C8110.23 (10)
C6—C1—C2121.05 (13)O1—C7—C6110.47 (10)
C6—C1—H1A119.5C8—C7—C6113.76 (10)
C2—C1—H1A119.5O1—C7—C9101.74 (10)
C3—C2—C1120.35 (14)C8—C7—C9110.70 (11)
C3—C2—H2A119.8C6—C7—C9109.28 (10)
C1—C2—H2A119.8C7—C8—H8A109.5
C4—C3—C2119.21 (14)C7—C8—H8B109.5
C4—C3—H3A120.4H8A—C8—H8B109.5
C2—C3—H3A120.4C7—C8—H8C109.5
C3—C4—C5120.61 (13)H8A—C8—H8C109.5
C3—C4—H4A119.7H8B—C8—H8C109.5
C5—C4—H4A119.7C7—C9—H9A109.5
C6—C5—C4120.72 (13)C7—C9—H9B109.5
C6—C5—H5A119.6H9A—C9—H9B109.5
C4—C5—H5A119.6C7—C9—H9C109.5
C5—C6—C1118.05 (12)H9A—C9—H9C109.5
C5—C6—C7121.56 (11)H9B—C9—H9C109.5
C1—C6—C7120.31 (11)
C6—C1—C2—C30.7 (2)O1i—O1—C7—C6−65.93 (12)
C1—C2—C3—C4−0.1 (2)O1i—O1—C7—C9178.12 (10)
C2—C3—C4—C5−0.7 (2)C5—C6—C7—O1155.72 (11)
C3—C4—C5—C60.95 (19)C1—C6—C7—O1−27.54 (15)
C4—C5—C6—C1−0.32 (18)C5—C6—C7—C831.13 (16)
C4—C5—C6—C7176.48 (11)C1—C6—C7—C8−152.13 (12)
C2—C1—C6—C5−0.51 (19)C5—C6—C7—C9−93.14 (14)
C2—C1—C6—C7−177.36 (12)C1—C6—C7—C983.59 (14)
O1i—O1—C7—C860.64 (13)

Symmetry codes: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C3—H3A···Cgii0.932.933.7874 (17)154

Symmetry codes: (ii) −x+1, y−1/2, −z+3/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IS2340).

References

  • Ferrero, F. (2006). J. Therm. Anal. Calorim.83, 373–378.
  • Higashi, T. (1995). ABSCOR Rigaku Corporation, Tokyo, Japan.
  • Konar, J., Sen, A. K. & Bhowmick, A. K. (1993). J. Appl. Polym. Sci.48, 1579–1585.
  • Ramar, P. & Alagar, M. (2004). Polym. Adv. Technol.15, 377–381.
  • Rigaku/MSC (2004). RAPID-AUTO and CrystalStructure Rigaku/MSC, The Woodlands, Texas, USA.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Wang, Z., Chan, C.-M., Zhu, S.-H. & Shen, J.-R. (1998). Polymer, 39, 6801–6806.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography