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Acta Crystallogr Sect E Struct Rep Online. 2010 November 1; 66(Pt 11): o2768.
Published online 2010 October 9. doi:  10.1107/S1600536810039838
PMCID: PMC3009354

Redetermination of 3-methyl­isoquinoline at 150 K

Abstract

The structure of the title compound, C19H9O, has been redetermined at 150 K. The redetermination is of significantly higher precision than a previous room-temperature structure [Ribar et al. (1974 [triangle]). Cryst. Struct. Commun. 3, 323–325]. The C—N bond lengths for this redetermination are much closer to those observed in comparable structures, and the orientation of the methyl group with respect to the isoquinoline plane is clarified. Inter­molecular weak C—H(...)N contacts are present in the crystal.

Related literature

For the structure at room temperature, see: Ribar et al. (1974 [triangle]). For the structure of the parent compound isoquinoline, see: Hensen et al. (1999 [triangle]). The C—N bond length in the structure of Ribar et al. (1974 [triangle]) clearly lies outside of the main distribution for 19 relevant structural fragments in the Cambridge Structural Database, being the second shortest bond in the sample [one shorter bond exists for refcode SAKCIQ, but this structure has R1 = 14.2% (Trumpp-Kallmeyer et al., 1998 [triangle])]. The corresponding C—N bond length in this redetermination lies exactly at the mean of the CSD sample.

An external file that holds a picture, illustration, etc.
Object name is e-66-o2768-scheme1.jpg

Experimental

Crystal data

  • C10H9N
  • M r = 143.18
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2768-efi1.jpg
  • a = 6.1991 (4) Å
  • b = 7.4176 (6) Å
  • c = 16.5421 (12) Å
  • β = 93.438 (2)°
  • V = 759.28 (10) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 150 K
  • 0.25 × 0.15 × 0.12 mm

Data collection

  • Bruker–Nonius X8 APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003 [triangle]) T min = 0.826, T max = 0.991
  • 9801 measured reflections
  • 1844 independent reflections
  • 1171 reflections with I > 2σ(I)
  • R int = 0.034

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.119
  • S = 1.06
  • 1844 reflections
  • 101 parameters
  • H-atom parameters constrained
  • Δρmax = 0.24 e Å−3
  • Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2004 [triangle]); cell refinement: SAINT (Bruker, 2003 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; 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/S1600536810039838/hb5670sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810039838/hb5670Isup2.hkl

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

Acknowledgments

The Danish Natural Sciences Research Council and the Carlsberg Foundation are acknowledged for provision of the X-ray equipment.

supplementary crystallographic information

Comment

The structure of 3-iso-methylquinoline at room temperature has been reported by Ribar et al. (1974). This redetermination at 150 K provides significantly improved precision, and more regular positions for the H atoms.

Considering the Cl1—N2 bond length: the CCDC Mogul package identifies 19 relevant structural fragments in the CSD, with a mean bond length of 1.314 (10) Å. The structure of Ribar et al. [C—N = 1.300 (5) Å] lies clearly outside of the main distribution, being the second shortest bond in the sample (one shorter bond of 1.292 Å exists for refcode SAKCIQ, but this structure has R1 = 14.2% (Trumpp-Kallmeyer et al., 1998). By contrast, the C1—N2 bond length of 1.3144 (13) Å in this redetermination corresponds exactly with the mean value. Alternation is also more clearly seen for the bond lengths C5—C6, C6—C7 and C7—C8 (1.3649 (16), 1.4093 (16) and 1.3646 (15) Å, respectively), compared to the previous structure.

Concerning the H atoms, the orientation of the methyl group in particular is clarified: in the structure of Ribar et al., the H—C(methyl)—H angles are irregular (range 94.8–112.8 °) and the orientation of the group is such that one C—H bond is twisted from the isoquinoline plane with a C—C—C(methyl)—H torsion angle ca 22 °. In the redetermination, the refined orientation of the methyl group places one C—H bond much more clearly in the isoquinoline plane (torsion angle 5.8 (1) °). This also has an influence on the geometry observed for the intermolecular contact between the methyl group and a neighbouring isoquinoline molecule. In the redetermination, atom H11B lies over the centroid of the C5—C10 ring with H11B···Cg = 2.95 Å and C11—H11B···Cg = 131.9 Å.

Experimental

The colourless block of (I) used for structure determination was taken directly from the sample as supplied by Aldrich Chemical Company.

Refinement

H atoms bound to C(sp2) were positioned geometrically with C—H = 0.95 Å and refined as riding with Uiso(H) = 1.2 Ueq(C). The H atoms of the methyl group were positioned with C—H = 0.98 Å and refined as riding with Uiso(H) = 1.5 Ueq(C), and with rotation about the local 3-fold axis.

Figures

Fig. 1.
Molecular structure showing displacement ellipsoids at 50% probability for non-H atoms.
Fig. 2.
Unit-cell contents.

Crystal data

C10H9NF(000) = 304
Mr = 143.18Dx = 1.253 Mg m3
Monoclinic, P21/cMelting point = 336–338 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 6.1991 (4) ÅCell parameters from 1780 reflections
b = 7.4176 (6) Åθ = 2.5–25.4°
c = 16.5421 (12) ŵ = 0.07 mm1
β = 93.438 (2)°T = 150 K
V = 759.28 (10) Å3Block, colourless
Z = 40.25 × 0.15 × 0.12 mm

Data collection

Bruker–Nonius X8 APEXII CCD diffractometer1844 independent reflections
Radiation source: fine-focus sealed tube1171 reflections with I > 2σ(I)
graphiteRint = 0.034
thin–slice ω and [var phi] scansθmax = 28.4°, θmin = 3.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)h = −7→8
Tmin = 0.826, Tmax = 0.991k = −9→9
9801 measured reflectionsl = −21→20

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.119H-atom parameters constrained
S = 1.06w = 1/[σ2(Fo2) + (0.0637P)2] where P = (Fo2 + 2Fc2)/3
1844 reflections(Δ/σ)max < 0.001
101 parametersΔρmax = 0.24 e Å3
0 restraintsΔρmin = −0.20 e Å3

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
C10.11212 (16)0.91552 (15)0.31390 (6)0.0232 (3)
H1A−0.01450.97420.33010.028*
N20.26422 (14)0.87917 (12)0.37033 (5)0.0247 (3)
C30.44782 (16)0.79419 (15)0.34720 (7)0.0234 (3)
C40.47647 (16)0.75059 (15)0.26814 (7)0.0232 (3)
H4A0.60700.69440.25440.028*
C50.32884 (18)0.74255 (15)0.12395 (7)0.0257 (3)
H5A0.45640.68730.10660.031*
C60.16084 (19)0.77766 (16)0.06908 (7)0.0294 (3)
H6A0.17090.74340.01410.035*
C7−0.02738 (18)0.86413 (16)0.09309 (7)0.0289 (3)
H7A−0.14200.88940.05400.035*
C8−0.04638 (16)0.91186 (15)0.17202 (7)0.0247 (3)
H8A−0.17340.97080.18770.030*
C90.12341 (16)0.87349 (14)0.23056 (6)0.0205 (3)
C100.31404 (16)0.78813 (14)0.20670 (7)0.0209 (3)
C110.61079 (18)0.74985 (17)0.41473 (7)0.0317 (3)
H11A0.64950.85980.44510.048*
H11B0.74030.69910.39230.048*
H11C0.54930.66170.45100.048*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0222 (6)0.0219 (7)0.0259 (6)0.0014 (5)0.0044 (5)0.0006 (5)
N20.0262 (5)0.0249 (6)0.0232 (5)0.0014 (4)0.0022 (4)0.0010 (4)
C30.0235 (6)0.0196 (7)0.0271 (7)−0.0011 (4)0.0003 (5)0.0040 (5)
C40.0198 (5)0.0212 (6)0.0289 (7)0.0011 (4)0.0050 (5)0.0025 (5)
C50.0300 (6)0.0221 (6)0.0258 (7)0.0000 (5)0.0089 (5)−0.0002 (5)
C60.0402 (7)0.0277 (7)0.0206 (6)−0.0059 (5)0.0043 (5)0.0007 (5)
C70.0287 (6)0.0299 (7)0.0274 (7)−0.0049 (5)−0.0050 (5)0.0048 (5)
C80.0216 (6)0.0233 (7)0.0290 (7)−0.0006 (4)0.0001 (5)0.0028 (5)
C90.0211 (5)0.0172 (6)0.0233 (6)−0.0019 (4)0.0028 (4)0.0021 (5)
C100.0223 (6)0.0173 (6)0.0235 (6)−0.0028 (4)0.0042 (4)0.0016 (5)
C110.0303 (6)0.0335 (8)0.0307 (7)0.0015 (5)−0.0040 (5)0.0053 (6)

Geometric parameters (Å, °)

C1—N21.3144 (13)C6—C71.4093 (16)
C1—C91.4194 (15)C6—H6A0.950
C1—H1A0.950C7—C81.3646 (15)
N2—C31.3753 (13)C7—H7A0.950
C3—C41.3690 (15)C8—C91.4157 (14)
C3—C111.4971 (15)C8—H8A0.950
C4—C101.4148 (15)C9—C101.4174 (15)
C4—H4A0.950C11—H11A0.980
C5—C61.3649 (16)C11—H11B0.980
C5—C101.4184 (16)C11—H11C0.980
C5—H5A0.950
N2—C1—C9124.73 (10)C8—C7—H7A119.7
N2—C1—H1A117.6C6—C7—H7A119.7
C9—C1—H1A117.6C7—C8—C9119.93 (10)
C1—N2—C3117.83 (9)C7—C8—H8A120.0
C4—C3—N2122.08 (10)C9—C8—H8A120.0
C4—C3—C11122.72 (10)C8—C9—C10119.83 (10)
N2—C3—C11115.20 (10)C8—C9—C1122.84 (10)
C3—C4—C10120.81 (10)C10—C9—C1117.33 (10)
C3—C4—H4A119.6C4—C10—C9117.21 (10)
C10—C4—H4A119.6C4—C10—C5124.19 (10)
C6—C5—C10120.36 (10)C9—C10—C5118.59 (10)
C6—C5—H5A119.8C3—C11—H11A109.5
C10—C5—H5A119.8C3—C11—H11B109.5
C5—C6—C7120.73 (11)H11A—C11—H11B109.5
C5—C6—H6A119.6C3—C11—H11C109.5
C7—C6—H6A119.6H11A—C11—H11C109.5
C8—C7—C6120.54 (11)H11B—C11—H11C109.5
C9—C1—N2—C3−0.04 (17)N2—C1—C9—C8178.66 (10)
C1—N2—C3—C41.19 (16)N2—C1—C9—C10−0.81 (17)
C1—N2—C3—C11−177.61 (9)C3—C4—C10—C90.55 (16)
N2—C3—C4—C10−1.46 (17)C3—C4—C10—C5−178.11 (10)
C11—C3—C4—C10177.24 (10)C8—C9—C10—C4−178.97 (9)
C10—C5—C6—C71.80 (17)C1—C9—C10—C40.51 (15)
C5—C6—C7—C8−1.03 (18)C8—C9—C10—C5−0.23 (16)
C6—C7—C8—C9−0.38 (17)C1—C9—C10—C5179.26 (9)
C7—C8—C9—C100.99 (16)C6—C5—C10—C4177.49 (10)
C7—C8—C9—C1−178.46 (10)C6—C5—C10—C9−1.16 (16)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C5—H5A···N2i0.952.883.6891 (14)144
C6—H6A···N2ii0.952.643.5813 (15)170

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5670).

References

  • Bruker (2003). SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2004). APEX2 Bruker–Nonius BV, Delft, The Netherlands.
  • Hensen, K., Mayr-Stein, R. & Bolte, M. (1999). Acta Cryst. C55, 1565–1567.
  • Ribar, B., Divjakovic, V., Janic, I., Argay, G., Kalman, A. & Djuric, S. (1974). Cryst. Struct. Commun.3, 323–325.
  • Sheldrick, G. M. (2003). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Trumpp-Kallmeyer, S., Rubin, J. R., Humblet, C., Hamby, J. M. & Hollis Showalter, H. D. (1998). J. Med. Chem.41, 1752–1763. [PubMed]

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