4-Bromo-8-methoxy­quinoline

Abstract

The non-H atoms of the title mol­ecule, C₁₀H₈BrNO, are essentially coplanar. In the crystal structure, mol­ecules are linked by weak inter­molecular C—H⋯π(arene) inter­actions, forming one-dimensional chains along the a axis.

Related literature

For related literature, see: Michael (2008 ▶); Kulkarni et al. (2006 ▶); Irving & Pinnington (1957 ▶).

Experimental

Crystal data

• C₁₀H₈BrNO

• M _r = 238.08

• Orthorhombic,

• a = 5.1615 (1) Å

• b = 12.1337 (6) Å

• c = 14.2436 (7) Å

• V = 892.05 (6) ų

• Z = 4

• Mo Kα radiation

• μ = 4.56 mm⁻¹

• T = 150 (1) K

• 0.30 × 0.12 × 0.11 mm

Data collection

• Nonius KappaCCD diffractometer

• Absorption correction: multi-scan (SORTAV; Blessing 1995 ▶) T _min = 0.545, T _max = 0.607

• 6134 measured reflections

• 2026 independent reflections

• 1872 reflections with I > 2σ(I)

• R _int = 0.035

Refinement

• R[F ² > 2σ(F ²)] = 0.028

• wR(F ²) = 0.059

• S = 1.01

• 2026 reflections

• 120 parameters

• H-atom parameters constrained

• Δρ_max = 0.38 e Å⁻³

• Δρ_min = −0.40 e Å⁻³

• Absolute structure: Flack (1983 ▶), 815 Friedel pairs

• Flack parameter: −0.017 (11)

Data collection: COLLECT (Nonius, 2002 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: SHELXTL (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶) and SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10A⋯Cgi	0.98	2.66	3.531 (3)	148

Symmetry code: (i) . Cg is the centroid of the C4–C9 ring.

supplementary crystallographic information

Comment

Quinoline derivatatives are established chelating agents and also have applications as precursors for pesticides and pharmaceuticals (Michael, 2008). Our laboratories are pursuing the development of radiohalogenated 8-hydroxyquinoline derivatives for positron emission tomography (PET) and single photon emission computed tomography (SPECT), specifically to image extracellular glial deposition of amyloid plaque protein in Alzheimer's disease and matrix metalloproteinases in tumours (Kulkarni et al., 2006). 4-Bromo-8-methoxyquinoline, first reported by Irving & Pinnington (1957) may be used as a precursor for radiohalogenation reactions to prepare labelled 8-hydroxyquinoline-based PET or SPECT radiopharmaceuticals. To our surprise, neutral compounds bearing a 4-halogen substituted, 8-phenoxyquinoline core have not yet been studied by single-crystal X-ray crystallography. In the present study we report the crystal structure of the title compound at 150 K.

The non-hydrogen atoms of title molecule (Fig. 1), C₁₀H₈BrNO, are essentially co-planar (r.m.s. deviation of all non-H atoms = 0.0242 Å). In the crystal structure, molecules are linked by weak intermolecuar C—H···π(arene) interactions to form one-dimensional chains along the a axis (Fig. 2). There are no other hydrogen bonds or π···π stacking interactions.

Experimental

X-ray quality crystals were obtained by evaporation of a solution of the title compound (ECA International Corporation, Palatine, Illinois, USA) in chloroform.

Refinement

H atoms were placed in calculated positions with C—H = 0.95Å (aryl) and 0.98Å (methyl) and were included in the refinement in the riding-model approximation with U_iso(H) = 1.2U_eq(C) or U_iso(H) = 1.5U_eq(C) for methyl H atoms.

Figures

Fig. 1.

Molecular structure showing 30% probability displacement ellipsoids (arbitrary spheres for H atoms).

Fig. 2.

Part of the crystal structure showing weak C—H···π(arene) interactions as dashed lines.

Crystal data

C10H8BrNO	F000 = 472
Mr = 238.08	Dx = 1.773 Mg m−3
Orthorhombic, P212121	Mo Kα radiation λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 6134 reflections
a = 5.1615 (1) Å	θ = 2.9–27.5º
b = 12.1337 (6) Å	µ = 4.56 mm−1
c = 14.2436 (7) Å	T = 150 (1) K
V = 892.05 (6) Å3	Needle, colourless
Z = 4	0.30 × 0.12 × 0.11 mm

Data collection

Nonius KappaCCD diffractometer	2026 independent reflections
Radiation source: fine-focus sealed tube	1872 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.036
Detector resolution: 9 pixels mm-1	θmax = 27.5º
T = 150(2) K	θmin = 2.9º
φ scans and ω scans with κ offsets	h = −5→6
Absorption correction: multi-scan(SORTAV; Blessing 1995)	k = −14→15
Tmin = 0.545, Tmax = 0.607	l = −18→18
6134 measured reflections

Refinement

Refinement on F2	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0306P)2 + 0.0333P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.028	(Δ/σ)max = 0.001
wR(F2) = 0.059	Δρmax = 0.38 e Å−3
S = 1.01	Δρmin = −0.40 e Å−3
2026 reflections	Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
120 parameters	Extinction coefficient: 0.0062 (8)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 815 Friedel pairs
Secondary atom site location: difference Fourier map	Flack parameter: −0.017 (11)
Hydrogen site location: inferred from neighbouring sites

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
Br1	1.02034 (5)	0.36147 (2)	0.509948 (18)	0.02940 (11)
O1	0.1007 (3)	0.62674 (16)	0.72708 (14)	0.0259 (4)
N1	0.4260 (4)	0.64140 (17)	0.58326 (14)	0.0233 (4)
C1	0.5884 (5)	0.6481 (2)	0.51287 (18)	0.0278 (6)
H1A	0.5819	0.7126	0.4752	0.033*
C2	0.7717 (5)	0.5671 (2)	0.48878 (19)	0.0268 (6)
H2A	0.8842	0.5768	0.4366	0.032*
C3	0.7833 (5)	0.4746 (2)	0.54217 (19)	0.0239 (6)
C4	0.6190 (5)	0.4611 (2)	0.62176 (17)	0.0188 (5)
C5	0.6239 (5)	0.3694 (2)	0.68244 (18)	0.0232 (6)
H5A	0.7429	0.3109	0.6718	0.028*
C6	0.4556 (5)	0.3650 (2)	0.75705 (17)	0.0243 (6)
H6A	0.4624	0.3038	0.7986	0.029*
C7	0.2739 (5)	0.4487 (2)	0.77325 (18)	0.0235 (6)
H7A	0.1558	0.4424	0.8241	0.028*
C8	0.2656 (5)	0.5400 (2)	0.71586 (17)	0.0195 (5)
C9	0.4408 (5)	0.54916 (19)	0.63810 (16)	0.0199 (5)
C10	−0.0731 (5)	0.6201 (2)	0.80535 (18)	0.0271 (7)
H10C	−0.1784	0.6872	0.8083	0.041*
H10D	0.0269	0.6126	0.8635	0.041*
H10A	−0.1865	0.5559	0.7978	0.041*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.02472 (15)	0.03108 (16)	0.03239 (16)	0.00303 (10)	0.00306 (11)	−0.00756 (11)
O1	0.0264 (10)	0.0255 (11)	0.0259 (10)	0.0030 (8)	0.0047 (7)	0.0004 (8)
N1	0.0281 (10)	0.0212 (11)	0.0206 (11)	−0.0009 (9)	−0.0021 (8)	0.0001 (10)
C1	0.0339 (13)	0.0259 (14)	0.0237 (14)	−0.0019 (10)	0.0030 (10)	0.0087 (14)
C2	0.0265 (12)	0.0299 (14)	0.0240 (14)	−0.0065 (10)	0.0049 (12)	0.0001 (13)
C3	0.0215 (13)	0.0257 (14)	0.0246 (15)	−0.0015 (10)	−0.0025 (10)	−0.0078 (12)
C4	0.0210 (13)	0.0184 (13)	0.0169 (13)	−0.0037 (9)	−0.0018 (9)	−0.0016 (11)
C5	0.0224 (12)	0.0215 (14)	0.0257 (14)	0.0016 (11)	−0.0064 (10)	−0.0019 (12)
C6	0.0328 (15)	0.0176 (13)	0.0225 (13)	−0.0037 (13)	−0.0074 (11)	0.0035 (11)
C7	0.0257 (14)	0.0258 (15)	0.0191 (14)	−0.0088 (11)	0.0018 (11)	−0.0010 (11)
C8	0.0208 (13)	0.0185 (13)	0.0193 (13)	−0.0003 (10)	−0.0021 (10)	−0.0014 (11)
C9	0.0207 (12)	0.0204 (13)	0.0186 (12)	−0.0042 (10)	−0.0046 (10)	0.0010 (10)
C10	0.0240 (14)	0.0314 (17)	0.0258 (15)	0.0015 (12)	0.0047 (11)	−0.0028 (12)

Geometric parameters (Å, °)

Br1—C3	1.895 (2)	C4—C9	1.429 (3)
O1—C8	1.362 (3)	C5—C6	1.374 (4)
O1—C10	1.433 (3)	C5—H5A	0.9500
N1—C1	1.309 (3)	C6—C7	1.402 (4)
N1—C9	1.367 (3)	C6—H6A	0.9500
C1—C2	1.407 (4)	C7—C8	1.378 (4)
C1—H1A	0.9500	C7—H7A	0.9500
C2—C3	1.357 (3)	C8—C9	1.434 (3)
C2—H2A	0.9500	C10—H10C	0.9800
C3—C4	1.425 (3)	C10—H10D	0.9800
C4—C5	1.409 (4)	C10—H10A	0.9800
C8—O1—C10	116.0 (2)	C5—C6—H6A	119.3
C1—N1—C9	116.9 (2)	C7—C6—H6A	119.3
N1—C1—C2	125.0 (2)	C8—C7—C6	120.4 (2)
N1—C1—H1A	117.5	C8—C7—H7A	119.8
C2—C1—H1A	117.5	C6—C7—H7A	119.8
C3—C2—C1	118.1 (2)	O1—C8—C7	124.8 (2)
C3—C2—H2A	121.0	O1—C8—C9	115.1 (2)
C1—C2—H2A	121.0	C7—C8—C9	120.0 (2)
C2—C3—C4	121.0 (2)	N1—C9—C4	123.7 (2)
C2—C3—Br1	119.4 (2)	N1—C9—C8	118.0 (2)
C4—C3—Br1	119.58 (19)	C4—C9—C8	118.3 (2)
C5—C4—C3	124.6 (2)	O1—C10—H10C	109.5
C5—C4—C9	120.1 (2)	O1—C10—H10D	109.5
C3—C4—C9	115.3 (2)	H10C—C10—H10D	109.5
C6—C5—C4	119.6 (3)	O1—C10—H10A	109.5
C6—C5—H5A	120.2	H10C—C10—H10A	109.5
C4—C5—H5A	120.2	H10D—C10—H10A	109.5
C5—C6—C7	121.5 (2)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···Cgi	0.98	2.66	3.531 (3)	148

Symmetry codes: (i) x−1, y, z.