Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801020426/cf6133sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801020426/cf6133Isup2.hkl |
CCDC reference: 180526
The sample (99%) was obtained from the Aldrich Company and used without further purification. The crystal was grown in a 0.3 mm glass capillary tube at ca 256 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 150 (2) K for data collection. Although the diffraction pattern clearly contained contributions from more than one crystal (reflected to some extent in the relatively high Rint of 0.165), the pattern associated with the major crystal component was indexed successfully; only reflections associated with this component were included in the integration. The length of the cylindrical crystal was not estimated, but it exceeded the diameter of the collimator (0.35 mm).
The H atoms of the methyl group were placed geometrically, assigned one common isotropic displacement parameter and allowed to rotate about their local threefold axis. Other H atoms were refined independently with individual isotropic displacement parameters.
Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1993) and CAMERON (Watkin et al., 1996); software used to prepare material for publication: SHELXL97.
C7H9N | Dx = 1.113 Mg m−3 |
Mr = 107.15 | Melting point: 264 K |
Monoclinic, I2/a | Mo Kα radiation, λ = 0.7107 Å |
a = 9.7236 (9) Å | Cell parameters from 1914 reflections |
b = 6.2851 (8) Å | θ = 1.0–30.0° |
c = 10.517 (2) Å | µ = 0.07 mm−1 |
β = 95.691 (5)° | T = 150 K |
V = 639.57 (16) Å3 | Cylinder, colourless |
Z = 4 | 0.15 mm (radius) |
F(000) = 232 |
Nonius KappaCCD diffractometer | 620 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.165 |
Graphite monochromator | θmax = 30.0°, θmin = 3.8° |
Thin–slice ω and ϕ scans | h = −10→13 |
2651 measured reflections | k = −8→8 |
912 independent reflections | l = −10→14 |
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)] = 0.069 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.214 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.1018P)2 + 0.203P] where P = (Fo2 + 2Fc2)/3 |
912 reflections | (Δ/σ)max < 0.001 |
46 parameters | Δρmax = 0.21 e Å−3 |
0 restraints | Δρmin = −0.22 e Å−3 |
C7H9N | V = 639.57 (16) Å3 |
Mr = 107.15 | Z = 4 |
Monoclinic, I2/a | Mo Kα radiation |
a = 9.7236 (9) Å | µ = 0.07 mm−1 |
b = 6.2851 (8) Å | T = 150 K |
c = 10.517 (2) Å | 0.15 mm (radius) |
β = 95.691 (5)° |
Nonius KappaCCD diffractometer | 620 reflections with I > 2σ(I) |
2651 measured reflections | Rint = 0.165 |
912 independent reflections |
R[F2 > 2σ(F2)] = 0.069 | 0 restraints |
wR(F2) = 0.214 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.21 e Å−3 |
912 reflections | Δρmin = −0.22 e Å−3 |
46 parameters |
Experimental. The crystal was grown in situ in a 0.3 mm Lindemann tube at ca 256 K. |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.7500 | 0.1620 (3) | 1.0000 | 0.0464 (6) | |
C2 | 0.81964 (16) | 0.2733 (3) | 0.91918 (16) | 0.0404 (5) | |
H2 | 0.871 (3) | 0.193 (4) | 0.861 (2) | 0.072 (7)* | |
C3 | 0.82374 (14) | 0.4940 (2) | 0.91442 (13) | 0.0311 (5) | |
C4 | 0.7500 | 0.6042 (3) | 1.0000 | 0.0291 (5) | |
H4 | 0.7500 | 0.763 (5) | 1.0000 | 0.046 (7)* | |
C7 | 0.90627 (17) | 0.6065 (3) | 0.82106 (17) | 0.0429 (5) | |
H7A | 0.8930 | 0.7605 | 0.8280 | 0.095 (5)* | |
H7B | 0.8751 | 0.5599 | 0.7340 | 0.095 (5)* | |
H7C | 1.0045 | 0.5723 | 0.8404 | 0.095 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0640 (13) | 0.0267 (9) | 0.0507 (12) | 0.000 | 0.0167 (10) | 0.000 |
C2 | 0.0488 (9) | 0.0338 (9) | 0.0404 (9) | 0.0055 (6) | 0.0138 (7) | −0.0046 (6) |
C3 | 0.0307 (7) | 0.0321 (8) | 0.0308 (7) | 0.0008 (5) | 0.0046 (5) | 0.0021 (5) |
C4 | 0.0301 (10) | 0.0251 (10) | 0.0320 (10) | 0.000 | 0.0033 (8) | 0.000 |
C7 | 0.0398 (9) | 0.0501 (10) | 0.0406 (9) | −0.0013 (6) | 0.0129 (7) | 0.0086 (7) |
N1—C2i | 1.3357 (19) | C4—C3i | 1.3900 (17) |
N1—C2 | 1.3357 (19) | C4—H4 | 1.00 (3) |
C2—C3 | 1.389 (2) | C7—H7A | 0.980 |
C2—H2 | 0.97 (3) | C7—H7B | 0.980 |
C3—C4 | 1.3900 (17) | C7—H7C | 0.980 |
C3—C7 | 1.5047 (19) | ||
C2i—N1—C2 | 116.88 (19) | C3—C4—H4 | 119.90 (9) |
N1—C2—C3 | 124.33 (14) | C3i—C4—H4 | 119.90 (9) |
N1—C2—H2 | 117.3 (15) | C3—C7—H7A | 109.5 |
C3—C2—H2 | 118.4 (15) | C3—C7—H7B | 109.5 |
C2—C3—C4 | 117.13 (13) | H7A—C7—H7B | 109.5 |
C2—C3—C7 | 120.79 (13) | C3—C7—H7C | 109.5 |
C4—C3—C7 | 122.07 (14) | H7A—C7—H7C | 109.5 |
C3—C4—C3i | 120.21 (18) | H7B—C7—H7C | 109.5 |
C2i—N1—C2—C3 | 0.00 (11) | C2—C3—C4—C3i | 0.00 (9) |
N1—C2—C3—C4 | 0.0 (2) | C7—C3—C4—C3i | −179.32 (14) |
N1—C2—C3—C7 | 179.33 (13) |
Symmetry code: (i) −x+3/2, y, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···N1ii | 1.00 (3) | 2.51 (3) | 3.506 (3) | 180 |
Symmetry code: (ii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C7H9N |
Mr | 107.15 |
Crystal system, space group | Monoclinic, I2/a |
Temperature (K) | 150 |
a, b, c (Å) | 9.7236 (9), 6.2851 (8), 10.517 (2) |
β (°) | 95.691 (5) |
V (Å3) | 639.57 (16) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.15 (radius) |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2651, 912, 620 |
Rint | 0.165 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.069, 0.214, 1.05 |
No. of reflections | 912 |
No. of parameters | 46 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.21, −0.22 |
Computer programs: COLLECT (Nonius, 1998), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL SCALEPACK and DENZO (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 1997), XP (Sheldrick, 1993) and CAMERON (Watkin et al., 1996), SHELXL97.
As part of a study devoted to improving the techniques for determining the crystal structures of substances that are liquids at room temperature, we have reported previously the crystal structure of 2,6-lutidine (2,6-dimethylpyridine) (Bond et al., 2001). We report here the crystal structure of the isomeric molecule, 3,5-lutidine, (I), determined at 150 (2) K following in situ crystal growth from the liquid.
In space group I2/a, the asymmetric unit comprises half a molecule, each molecule possessing a crystallographic diad axis passing through N1 and C4 (Fig. 1). Molecules are linked via linear C—H···N interactions [C4–H4···N1i = 2.51 (3) Å and C4–H4···N1i = 180°; symmetry code: (i) x, 1 + y, z] into extended polar chains, similar to those observed in the crystal structure of 2,6-lutidine. All chains propagate parallel to [010], forming polar sheets (Fig. 2) parallel to (101). Chains in adjacent sheets are arranged in an anti-parallel manner (Fig. 3) so that the crystal is not macroscopically polar. This is in contrast to the structure of 2,6-lutidine in which a change in the position of the methyl substituents produces a macroscopically polar structure in space group Fdd2, where all sheets are arranged in a parallel fashion. This observation may be of interest to researchers seeking organic molecular materials for non-linear optic (NLO) applications.