2,3-Lutidine

The crystal structure of 2,3-lutidine (2,3-di­methyl­pyridine, C₇H₉N) has been determined at 150 (2) K, following in situ crystal growth from the liquid. Molecules are linked into polar chains via C—H...N interactions. The structure is best described as disordered in space group C2/c, with half a mol­ecule in the asymmetric unit.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.001 Å
• Disorder in main residue
• R factor = 0.050
• wR factor = 0.157
• Data-to-parameter ratio = 33.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (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 (Sheldrick, 1997).

2,3-dimethylpyridine

Crystal data

C7H9N	Dx = 1.125 Mg m^−3
Mr = 107.15	Melting point: 258 K
Monoclinic, C2/c	Mo Kα radiation, λ = 0.7107 Å
a = 11.4158 (7) Å	Cell parameters from 3561 reflections
b = 7.5787 (5) Å	θ = 1.0–35.0°
c = 7.4714 (4) Å	µ = 0.07 mm^−1
β = 101.900 (4)°	T = 150 K
V = 632.51 (7) Å^3	Cylinder, colourless
Z = 4	0.15 mm (radius)
F(000) = 232

Data collection

Nonius KappaCCD diffractometer	1035 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.023
Graphite monochromator	θmax = 35.3°, θmin = 4.5°
Thin–slice ω and φ scans	h = −18→18
2468 measured reflections	k = −12→11
1366 independent reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.157	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0759P)^2 + 0.1323P] where P = (Fo^2 + 2Fc^2)/3
1366 reflections	(Δ/σ)max = 0.003
41 parameters	Δρmax = 0.36 e Å^−3
0 restraints	Δρmin = −0.17 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
N1	0.38396 (7)	0.29005 (11)	0.15137 (11)	0.0379 (2)	0.50
C4	0.38396 (7)	0.29005 (11)	0.15137 (11)	0.0379 (2)	0.50
H4	0.3039	0.2892	0.0833	0.074 (3)*	0.50
C2	0.44100 (6)	0.44503 (9)	0.20050 (9)	0.02796 (19)
C6	0.44263 (10)	0.13626 (12)	0.20058 (14)	0.0492 (3)
H6	0.4034	0.0273	0.1658	0.078 (5)*
C7	0.37536 (9)	0.61430 (14)	0.14849 (13)	0.0464 (3)
H7C	0.2962	0.5888	0.0732	0.073 (2)*
H7B	0.4208	0.6877	0.0789	0.073 (2)*
H7A	0.3661	0.6772	0.2593	0.073 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0329 (4)	0.0438 (5)	0.0339 (4)	−0.0090 (3)	−0.0003 (3)	−0.0015 (3)
C4	0.0329 (4)	0.0438 (5)	0.0339 (4)	−0.0090 (3)	−0.0003 (3)	−0.0015 (3)
C2	0.0272 (3)	0.0317 (4)	0.0250 (3)	0.0037 (2)	0.0057 (2)	0.0028 (2)
C6	0.0660 (6)	0.0320 (4)	0.0466 (5)	−0.0152 (4)	0.0046 (4)	−0.0043 (3)
C7	0.0528 (5)	0.0462 (5)	0.0431 (5)	0.0236 (4)	0.0164 (4)	0.0108 (4)

Geometric parameters (Å, º)

N1—C2	1.3564 (11)	C6—H6	0.950
N1—C6	1.3567 (13)	C7—H7C	0.980
C2—C2^i	1.3966 (14)	C7—H7B	0.980
C2—C7	1.4961 (11)	C7—H7A	0.980
C6—C6^i	1.365 (2)
C2—N1—C6	119.21 (8)	C2—C7—H7C	109.5
N1—C2—C2^i	120.00 (4)	C2—C7—H7B	109.5
N1—C2—C7	119.04 (8)	H7C—C7—H7B	109.5
C2^i—C2—C7	120.95 (5)	C2—C7—H7A	109.5
N1—C6—C6^i	120.78 (5)	H7C—C7—H7A	109.5
N1—C6—H6	119.6	H7B—C7—H7A	109.5
C6^i—C6—H6	119.6
C6—N1—C2—C2^i	0.43 (14)	C2—N1—C6—C6^i	0.45 (19)
C6—N1—C2—C7	−179.05 (8)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···N1^ii	0.95	2.55	3.4622 (14)	162

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