Redetermination of 3-methyl­isoquinoline at 150 K

Bond, A.D.

doi:10.1107/S1600536810039838

organic compounds

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Volume 66| Part 11| November 2010| Page o2768

https://doi.org/10.1107/S1600536810039838

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Redetermination of 3-methylisoquinoline at 150 K

Andrew D. Bond ^a ^*

^aUniversity of Southern Denmark, Department of Physics and Chemistry, Campusvej 55, 5230 Odense, Denmark
^*Correspondence e-mail: adb@chem.sdu.dk

(Received 30 September 2010; accepted 5 October 2010; online 9 October 2010)

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 ). 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). For the structure of the parent compound isoquinoline, see: Hensen et al. (1999 ). The C—N bond length in the structure of Ribar et al. (1974) 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 )]. The corresponding C—N bond length in this redetermination lies exactly at the mean of the CSD sample.

Experimental

Crystal data

C₁₀H₉N
M_r = 143.18
Monoclinic, P 2₁ /c
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 ) 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[F² > 2σ(F²)] = 0.042
wR(F²) = 0.119
S = 1.06
1844 reflections
101 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5A⋯N2ⁱ	0.95	2.88	3.6891 (14)	144
C6—H6A⋯N2ⁱⁱ	0.95	2.64	3.5813 (15)	170
Symmetry codes: (i) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT (Bruker, 2003 ); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810039838/hb5670sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810039838/hb5670Isup2.hkl

checkCIF report

Comment top

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.

Related literature top

For the structure at room temperature, see: Ribar et al. (1974). For the structure of the parent compound isoquinoline, see: Hensen et al. (1999). The C—N bond length in this structure 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)].

Experimental top

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

Structure description top

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

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

3-methylisoquinoline top

Crystal data top

C₁₀H₉N	F(000) = 304
M_r = 143.18	D_x = 1.253 Mg m⁻³
Monoclinic, P2₁/c	Melting point = 336–338 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 6.1991 (4) Å	Cell parameters from 1780 reflections
b = 7.4176 (6) Å	θ = 2.5–25.4°
c = 16.5421 (12) Å	µ = 0.07 mm⁻¹
β = 93.438 (2)°	T = 150 K
V = 759.28 (10) Å³	Block, colourless
Z = 4	0.25 × 0.15 × 0.12 mm

Data collection top

Bruker–Nonius X8 APEXII CCD diffractometer	1844 independent reflections
Radiation source: fine-focus sealed tube	1171 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
thin–slice ω and φ scans	θ_max = 28.4°, θ_min = 3.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −7→8
T_min = 0.826, T_max = 0.991	k = −9→9
9801 measured reflections	l = −21→20

Refinement top

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.119	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0637P)²] where P = (F_o² + 2F_c²)/3
1844 reflections	(Δ/σ)_max < 0.001
101 parameters	Δρ_max = 0.24 e Å⁻³
0 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₀H₉N	V = 759.28 (10) Å³
M_r = 143.18	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 6.1991 (4) Å	µ = 0.07 mm⁻¹
b = 7.4176 (6) Å	T = 150 K
c = 16.5421 (12) Å	0.25 × 0.15 × 0.12 mm
β = 93.438 (2)°

Data collection top

Bruker–Nonius X8 APEXII CCD diffractometer	1844 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	1171 reflections with I > 2σ(I)
T_min = 0.826, T_max = 0.991	R_int = 0.034
9801 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	0 restraints
wR(F²) = 0.119	H-atom parameters constrained
S = 1.06	Δρ_max = 0.24 e Å⁻³
1844 reflections	Δρ_min = −0.20 e Å⁻³
101 parameters

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

	x	y	z	U_iso*/U_eq
C1	0.11212 (16)	0.91552 (15)	0.31390 (6)	0.0232 (3)
H1A	−0.0145	0.9742	0.3301	0.028*
N2	0.26422 (14)	0.87917 (12)	0.37033 (5)	0.0247 (3)
C3	0.44782 (16)	0.79419 (15)	0.34720 (7)	0.0234 (3)
C4	0.47647 (16)	0.75059 (15)	0.26814 (7)	0.0232 (3)
H4A	0.6070	0.6944	0.2544	0.028*
C5	0.32884 (18)	0.74255 (15)	0.12395 (7)	0.0257 (3)
H5A	0.4564	0.6873	0.1066	0.031*
C6	0.16084 (19)	0.77766 (16)	0.06908 (7)	0.0294 (3)
H6A	0.1709	0.7434	0.0141	0.035*
C7	−0.02738 (18)	0.86413 (16)	0.09309 (7)	0.0289 (3)
H7A	−0.1420	0.8894	0.0540	0.035*
C8	−0.04638 (16)	0.91186 (15)	0.17202 (7)	0.0247 (3)
H8A	−0.1734	0.9708	0.1877	0.030*
C9	0.12341 (16)	0.87349 (14)	0.23056 (6)	0.0205 (3)
C10	0.31404 (16)	0.78813 (14)	0.20670 (7)	0.0209 (3)
C11	0.61079 (18)	0.74985 (17)	0.41473 (7)	0.0317 (3)
H11A	0.6495	0.8598	0.4451	0.048*
H11B	0.7403	0.6991	0.3923	0.048*
H11C	0.5493	0.6617	0.4510	0.048*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0222 (6)	0.0219 (7)	0.0259 (6)	0.0014 (5)	0.0044 (5)	0.0006 (5)
N2	0.0262 (5)	0.0249 (6)	0.0232 (5)	0.0014 (4)	0.0022 (4)	0.0010 (4)
C3	0.0235 (6)	0.0196 (7)	0.0271 (7)	−0.0011 (4)	0.0003 (5)	0.0040 (5)
C4	0.0198 (5)	0.0212 (6)	0.0289 (7)	0.0011 (4)	0.0050 (5)	0.0025 (5)
C5	0.0300 (6)	0.0221 (6)	0.0258 (7)	0.0000 (5)	0.0089 (5)	−0.0002 (5)
C6	0.0402 (7)	0.0277 (7)	0.0206 (6)	−0.0059 (5)	0.0043 (5)	0.0007 (5)
C7	0.0287 (6)	0.0299 (7)	0.0274 (7)	−0.0049 (5)	−0.0050 (5)	0.0048 (5)
C8	0.0216 (6)	0.0233 (7)	0.0290 (7)	−0.0006 (4)	0.0001 (5)	0.0028 (5)
C9	0.0211 (5)	0.0172 (6)	0.0233 (6)	−0.0019 (4)	0.0028 (4)	0.0021 (5)
C10	0.0223 (6)	0.0173 (6)	0.0235 (6)	−0.0028 (4)	0.0042 (4)	0.0016 (5)
C11	0.0303 (6)	0.0335 (8)	0.0307 (7)	0.0015 (5)	−0.0040 (5)	0.0053 (6)

Geometric parameters (Å, º) top

C1—N2	1.3144 (13)	C6—C7	1.4093 (16)
C1—C9	1.4194 (15)	C6—H6A	0.950
C1—H1A	0.950	C7—C8	1.3646 (15)
N2—C3	1.3753 (13)	C7—H7A	0.950
C3—C4	1.3690 (15)	C8—C9	1.4157 (14)
C3—C11	1.4971 (15)	C8—H8A	0.950
C4—C10	1.4148 (15)	C9—C10	1.4174 (15)
C4—H4A	0.950	C11—H11A	0.980
C5—C6	1.3649 (16)	C11—H11B	0.980
C5—C10	1.4184 (16)	C11—H11C	0.980
C5—H5A	0.950

N2—C1—C9	124.73 (10)	C8—C7—H7A	119.7
N2—C1—H1A	117.6	C6—C7—H7A	119.7
C9—C1—H1A	117.6	C7—C8—C9	119.93 (10)
C1—N2—C3	117.83 (9)	C7—C8—H8A	120.0
C4—C3—N2	122.08 (10)	C9—C8—H8A	120.0
C4—C3—C11	122.72 (10)	C8—C9—C10	119.83 (10)
N2—C3—C11	115.20 (10)	C8—C9—C1	122.84 (10)
C3—C4—C10	120.81 (10)	C10—C9—C1	117.33 (10)
C3—C4—H4A	119.6	C4—C10—C9	117.21 (10)
C10—C4—H4A	119.6	C4—C10—C5	124.19 (10)
C6—C5—C10	120.36 (10)	C9—C10—C5	118.59 (10)
C6—C5—H5A	119.8	C3—C11—H11A	109.5
C10—C5—H5A	119.8	C3—C11—H11B	109.5
C5—C6—C7	120.73 (11)	H11A—C11—H11B	109.5
C5—C6—H6A	119.6	C3—C11—H11C	109.5
C7—C6—H6A	119.6	H11A—C11—H11C	109.5
C8—C7—C6	120.54 (11)	H11B—C11—H11C	109.5

C9—C1—N2—C3	−0.04 (17)	N2—C1—C9—C8	178.66 (10)
C1—N2—C3—C4	1.19 (16)	N2—C1—C9—C10	−0.81 (17)
C1—N2—C3—C11	−177.61 (9)	C3—C4—C10—C9	0.55 (16)
N2—C3—C4—C10	−1.46 (17)	C3—C4—C10—C5	−178.11 (10)
C11—C3—C4—C10	177.24 (10)	C8—C9—C10—C4	−178.97 (9)
C10—C5—C6—C7	1.80 (17)	C1—C9—C10—C4	0.51 (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—C5	179.26 (9)
C7—C8—C9—C10	0.99 (16)	C6—C5—C10—C4	177.49 (10)
C7—C8—C9—C1	−178.46 (10)	C6—C5—C10—C9	−1.16 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5A···N2ⁱ	0.95	2.88	3.6891 (14)	144
C6—H6A···N2ⁱⁱ	0.95	2.64	3.5813 (15)	170

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

Experimental details

Crystal data
Chemical formula	C₁₀H₉N
M_r	143.18
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	150
a, b, c (Å)	6.1991 (4), 7.4176 (6), 16.5421 (12)
β (°)	93.438 (2)
V (Å³)	759.28 (10)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.25 × 0.15 × 0.12

Data collection
Diffractometer	Bruker–Nonius X8 APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.826, 0.991
No. of measured, independent and observed [I > 2σ(I)] reflections	9801, 1844, 1171
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.670

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.119, 1.06
No. of reflections	1844
No. of parameters	101
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.20

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2003), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5A···N2ⁱ	0.95	2.88	3.6891 (14)	144
C6—H6A···N2ⁱⁱ	0.95	2.64	3.5813 (15)	170

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

Acknowledgements

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

References

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