α Methyl­styrene

Acta Cryst.(2002). E58, o331±o333 DOI: 10.1107/S1600536802003392 Bond and Davies C₉H₁₀

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organic papers

Acta Crystallographica Section E Structure Reports Online

ISSN 1600-5368

a

-Methylstyrene

Andrew D. Bond* and John E. Davies

Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, England

Correspondence e-mail: [email protected]

Key indicators

Single-crystal X-ray study T= 180 K

Mean(C±C) = 0.005 AÊ Rfactor = 0.085 wRfactor = 0.250

Data-to-parameter ratio = 10.8

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2002 International Union of Crystallography Printed in Great Britain ± all rights reserved

The crystal structure of -methylstyrene, C9H10, has been determined at 180 (2) K followingin situcrystal growth from the liquid. In space group P21/n, the structure consists of herring-bone-packed layers within which intermolecular CÐ H interactions are evident.

Comment

As part of a study devoted to improving techniques for determining the crystal structures of substances that are liquid at room temperature, we have recently reported the structure of styrene, C8H8(Bond & Davies, 2001; Yasudaet al., 2001). We report here the crystal structure of the-methyl deriva-tive, C9H10, determined at 180 (2) K followingin situ crystal growth from the liquid.

±Methylstyrene, (I), crystallizes in the monoclinic space groupP21/nwith one whole molecule in the asymmetric unit (Fig. 1). The propenyl substituent lies approximately coplanar with the phenyl ring [the angle between the least-squares planes through C1±C6 and C7±C9 is 1.8 (3)_{]. Molecules of (I)} form herring-bone-packed layers parallel to (001) (Fig. 2). These layers may be considered to stack in an ABAB

arrangement (Fig. 3). CÐH interactions are evident between molecules within layers [H5 cent(C7±C8)i_{= 3.06 AÊ,} C5ÐH5 cent(C7±C8)i_{= 153; H6 cent(C1±C6)}i_{= 3.06 AÊ,} C6ÐH6 cent(C1±C6)i _{= 137; H8B cent(C1±C6)}ii ₌ 3.03 AÊ, C8ÐH8B cent(C1±C6)ii_{= 138; symmetry codes: (i)}

ÿ1/2ÿx, 1/2+y, 1/2ÿz; (ii) 1/2ÿx,ÿ1/2+y, 1/2ÿz; cent denotes the centroid of the indicated ring]. A similar arrangement is observed in styrene itself, but in that case, the-hydrogen also acts as a CÐH donor; this interaction is clearly prohibited in (I).

Experimental

The sample (99%) was obtained from the Lancaster company and used without further puri®cation. The crystal was grown in a 0.3 mm glass capillary tube atca247.4 K (a temperature only slightly less than the melting point of the solid in the capillary) using a technique described earlier (Davies & Bond, 2001). Once grown, the crystal was

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cooled to 180 (2) K for data collection. The length of the cylindrical crystal was not estimated, but it exceeded the diameter of the colli-mator (0.35 mm).

Crystal data C9H10

Mr= 118.17

Monoclinic,P21=n

a= 5.795 (1) AÊ

b= 7.829 (1) AÊ

c= 15.820 (1) AÊ

= 93.23 (1)

V= 716.60 (16) AÊ3

Z= 4

Dx= 1.095 Mg mÿ3

MoKradiation Cell parameters from 2680

re¯ections

= 1.0±22.5

= 0.06 mmÿ1

T= 180 (2) K Cylinder, colourless 0.15 mm (radius) Data collection

Nonius KappaCCD diffractometer Thin-slice!and'scans Absorption correction: none 3208 measured re¯ections 895 independent re¯ections 676 re¯ections withI> 2(I)

Rint= 0.089

max= 22.3

h=ÿ5!6

k=ÿ7!8

l=ÿ15!16

Re®nement Re®nement onF2

R[F2_{> 2(F}2_{)] = 0.085}

wR(F2_{) = 0.250}

S= 1.15 895 re¯ections 83 parameters

H-atom parameters constrained

w= 1/[2_(F

o2) + (0.1448P)2

+ 0.2267P]

whereP= (Fo2+ 2Fc2)/3

(/)max< 0.001

max= 0.37 e AÊÿ3

min=ÿ0.27 e AÊÿ3

H atoms were placed geometrically and allowed to ride during subsequent re®nement withUiso(H) =xUeq(C) (x= 1.2 for alkene and

phenyl H, and 1.5 for methyl H). The methyl group was allowed to rotate about its local threefold axis. No signi®cant diffracted intensity was observed beyond 22.5_{in(equivalent to 0.93 AÊ resolution) and} the data were truncated at this point; the precision of the result is reduced accordingly.

Data collection:COLLECT(Nonius, 1998); cell re®nement:HKL SCALEPACK(Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure:SIR-92 (Altomareet al., 1994); program(s) used to re®ne structure:SHELXL97 (Sheldrick, 1997); molecular graphics:XP(Sheldrick, 1993) andCAMERON(Watkinet al., 1996); software used to prepare material for publication: SHELXL97.

We thank the EPSRC for ®nancial assistance towards the purchase of the Nonius CCD diffractometer.

Figure 2

Projection on to (001) of a single layer of (I), showing the herring-bone packing arrangement (CAMERON; Watkinet al., 1996).

Figure 1

The molecular unit in (I), showing displacement ellipsoids at the 50% probability level for non-H atoms (XP; Sheldrick, 1993).

Figure 3

References

Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994).J. Appl. Cryst.27, 435.

Bond, A. D. & Davies, J. E. (2001).Acta Cryst.E57, o1191±o1193. Davies, J. E. & Bond, A. D. (2001).Acta Cryst.E57, o947±o949. Nonius (1998).COLLECT. Nonius BV, Delft, The Netherlands.

Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276,

Macromolecular Crystallography, Part A, edited by C. W. Carter and R. M. Sweet, pp. 307±326. London: Academic Press.

Sheldrick, G. M. (1993).XP. University of GoÈttingen, Germany. Sheldrick, G. M. (1997).SHELXL97. University of GoÈttingen, Germany. Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996).CAMERON. Chemical

Crystallography Laboratory, University of Oxford, England.

Yasuda, N. Uekusa, H. & Ohashi, Y. (2001).Acta Cryst.E57, o1189±o1190.

Acta Cryst.(2002). E58, o331±o333 Bond and Davies C₉H₁₀

o333

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Acta Cryst. (2002). E58, o331–o333 [doi:10.1107/S1600536802003392]

α

-Methylstyrene

Andrew D. Bond and John E. Davies

S1. Comment

As part of a study devoted to improving techniques for determining the crystal structures of substances that are liquid at

room temperature, we have recently reported the structure of styrene, C8H8 (Bond & Davies, 2001; Yasuda et al., 2001).

We report here the crystal structure of the α-methyl derivative, C9H10, determined at 180 (2) K following in situ crystal

growth from the liquid.

α-Methylstyrene, (I), crystallizes in the monoclinic space group P21/n with one whole molecule in the asymmetric unit

(Fig. 1). The propenyl substituent lies approximately coplanar with the phenyl ring [the angle between the least-squares

planes through C1–C6 and C7–C9 is 1.8 (3)°]. Molecules of (I) form herring-bone packed layers parallel to (001) (Fig.

2). These layers may be considered to stack in an ABAB arrangement (Fig. 3). C—H···π interactions are evident between

molecules within layers [H5···cent(C7–C8)i _{= 3.06 Å, C5—H5···cent(C7–C8)}i _{= 153°; H6···cent(C1–C6)}i _{= 3.06 Å, C6—}

H6···cent(C1–C6)i _{= 137°; H8B···cent(C1–C6)}ii _{= 3.03 Å, C8—H8B···cent(C1–C6)}ii _{= 138°; symmetry codes: (i) -0.5 - x,}

0.5 + y, 0.5 - z; (ii) 0.5 - x, -0.5 + y, 0.5 - z; cent denotes the centroid of the indicated ring]. A similar arrangement is

observed in styrene itself, but in that case, the α-hydrogen also acts as a C—H···π donor; this interaction is clearly

prohibited in (I).

S2. Experimental

The sample (99%) was obtained from the Lancaster company and used without further purification. The crystal was

grown in a 0.3 mm glass capillary tube at ca 247.4 K (a temperature only slightly less than the melting point of the solid

in the capillary) using a technique described earlier (Davies & Bond, 2001). Once grown, the crystal was cooled to

180 (2) K for data collection. The length of the cylindrical crystal was not estimated, but it exceeded the diameter of the

collimator (0.35 mm).

S3. Refinement

H atoms were placed geometrically and allowed to ride during subsequent refinement with Uiso(H) = xUeq(C) (x = 1.2 for

alkene and phenyl H, and 1.5 for methyl H). The methyl group was allowed to rotate about its local threefold axis. No

significant diffracted intensity was observed beyond 22.5° in θ (equivalent to 0.93 Å resolution) and the data were

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Figure 1

The molecular unit in (I), showing displacement ellipsoids at the 50% probability level for non-H atoms (XP; Sheldrick,

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Figure 2

Projection on to (001) of a single layer of (I), showing the herring-bone packing arrangement (CAMERON; Watkin et al.,

1996).

Figure 3

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isopropenylbenzene

Crystal data

C9H10

Mr = 118.17 Monoclinic, P21/n

a = 5.795 (1) Å

b = 7.829 (1) Å

c = 15.820 (1) Å

β = 93.23 (1)°

V = 716.60 (16) Å3

Z = 4

F(000) = 256

Dx = 1.095 Mg m−3

Melting point: 250 K

Mo Kα radiation, λ = 0.7107 Å Cell parameters from 2680 reflections

θ = 1.0–22.5°

µ = 0.06 mm−1

T = 180 K

Cylinder, colourless 0.15 mm (radius)

Data collection

Nonius KappaCCD diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

Thin–slice ω and φ scans 3208 measured reflections 895 independent reflections

676 reflections with I > 2σ(I)

Rint = 0.089

θmax = 22.3°, θmin = 3.7°

h = −5→6

k = −7→8

l = −15→16

Refinement

Refinement on F2

Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.085}

wR(F2_{) = 0.250}

S = 1.15 895 reflections 83 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained

w = 1/[σ2_(F

o2) + (0.1448P)2 + 0.2267P]

where P = (Fo2 + 2Fc2)/3

(Δ/σ)max < 0.001

Δρmax = 0.37 e Å−3

Δρmin = −0.27 e Å−3

Special details

Experimental. Crystal grown in situ at 247.4 K in 0.3 mm diameter glass capillary tube.

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 3.0239 (0.0069) x + 6.6056 (0.0061) y + 1.5219 (0.0192) z = 1.4245 (0.0060)

* 0.0002 (0.0019) C1 * -0.0008 (0.0020) C2 * -0.0005 (0.0022) C3 * 0.0024 (0.0022) C4 * -0.0030 (0.0021) C5 * 0.0018 (0.0020) C6

Rms deviation of fitted atoms = 0.0018

3.0744 (0.0127) x + 6.5936 (0.0096) y + 1.0447 (0.0850) z = 1.3655 (0.0095) Angle to previous plane (with approximate e.s.d.) = 1.78 (0.27)

* 0.0000 (0.0000) C7 * 0.0000 (0.0000) C8 * 0.0000 (0.0000) C9 Rms deviation of fitted atoms = 0.0000

Refinement. Refinement of F2 _{against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F}2_,

conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) 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

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

x y z Uiso*/Ueq

C1 0.0133 (5) 0.1575 (3) 0.22612 (18) 0.0411 (10)

C2 0.1594 (5) 0.0765 (4) 0.2865 (2) 0.0529 (11)

H2 0.2931 0.0192 0.2690 0.064*

C3 0.1140 (6) 0.0778 (4) 0.3716 (2) 0.0579 (11)

H3 0.2161 0.0216 0.4116 0.070*

C4 −0.0787 (6) 0.1603 (4) 0.3982 (2) 0.0593 (11)

H4 −0.1095 0.1618 0.4565 0.071*

C5 −0.2261 (6) 0.2404 (4) 0.3398 (2) 0.0563 (11)

H5 −0.3602 0.2967 0.3576 0.068*

C6 −0.1790 (6) 0.2391 (4) 0.2549 (2) 0.0535 (11)

H6 −0.2817 0.2960 0.2153 0.064*

C7 0.0638 (6) 0.1560 (4) 0.1350 (2) 0.0518 (11)

C8 0.2540 (6) 0.0716 (5) 0.1078 (2) 0.0685 (12)

H8A 0.2814 0.0681 0.0492 0.082*

H8B 0.3581 0.0167 0.1477 0.082*

C9 −0.0938 (7) 0.2390 (5) 0.0749 (2) 0.0731 (13)

H9A −0.0436 0.2199 0.0175 0.110*

H9B −0.0961 0.3618 0.0867 0.110*

H9C −0.2492 0.1918 0.0795 0.110*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

C1 0.0422 (19) 0.0306 (16) 0.050 (2) −0.0042 (12) −0.0015 (14) −0.0005 (12)

C2 0.048 (2) 0.0472 (18) 0.063 (2) 0.0071 (14) −0.0020 (16) −0.0025 (14)

C3 0.066 (2) 0.055 (2) 0.051 (2) 0.0043 (16) −0.0110 (17) 0.0051 (15)

C4 0.075 (3) 0.053 (2) 0.050 (2) −0.0062 (17) 0.0070 (17) −0.0032 (15)

C5 0.050 (2) 0.057 (2) 0.062 (2) 0.0041 (15) 0.0075 (17) −0.0044 (15)

C6 0.051 (2) 0.0481 (19) 0.060 (2) 0.0013 (14) −0.0086 (17) 0.0020 (14)

C7 0.060 (2) 0.0428 (18) 0.052 (2) −0.0090 (14) −0.0020 (16) −0.0013 (13)

C8 0.077 (3) 0.070 (2) 0.061 (2) 0.0117 (19) 0.0174 (19) 0.0002 (17)

C9 0.073 (3) 0.093 (3) 0.053 (3) 0.001 (2) −0.0033 (19) 0.0014 (18)

Geometric parameters (Å, º)

C1—C6 1.384 (4) C5—H5 0.950

C1—C2 1.393 (4) C6—H6 0.950

C1—C7 1.487 (4) C7—C8 1.375 (5)

C2—C3 1.386 (5) C7—C9 1.436 (5)

C2—H2 0.950 C8—H8A 0.950

C3—C4 1.376 (5) C8—H8B 0.950

C3—H3 0.950 C9—H9A 0.980

C4—C5 1.374 (5) C9—H9B 0.980

C4—H4 0.950 C9—H9C 0.980

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C6—C1—C2 117.0 (3) C1—C6—C5 121.9 (3)

C6—C1—C7 121.9 (3) C1—C6—H6 119.0

C2—C1—C7 121.1 (3) C5—C6—H6 119.0

C3—C2—C1 121.4 (3) C8—C7—C9 120.1 (3)

C3—C2—H2 119.3 C8—C7—C1 120.8 (3)

C1—C2—H2 119.3 C9—C7—C1 119.1 (3)

C4—C3—C2 120.1 (3) C7—C8—H8A 120.0

C4—C3—H3 119.9 C7—C8—H8B 120.0

C2—C3—H3 119.9 H8A—C8—H8B 120.0

C5—C4—C3 119.5 (3) C7—C9—H9A 109.5

C5—C4—H4 120.2 C7—C9—H9B 109.5

C3—C4—H4 120.2 H9A—C9—H9B 109.5

C4—C5—C6 120.0 (3) C7—C9—H9C 109.5

C4—C5—H5 120.0 H9A—C9—H9C 109.5

C6—C5—H5 120.0 H9B—C9—H9C 109.5

C6—C1—C2—C3 0.0 (4) C7—C1—C6—C5 179.9 (3)

C7—C1—C2—C3 179.8 (3) C4—C5—C6—C1 0.6 (5)

C1—C2—C3—C4 −0.1 (5) C6—C1—C7—C8 −178.9 (3)

C2—C3—C4—C5 0.4 (5) C2—C1—C7—C8 1.3 (4)

C3—C4—C5—C6 −0.6 (5) C6—C1—C7—C9 −1.2 (4)