6-Iodo-4-oxo-4H-chromene-3-carbaldehyde

Yoshinobu Ishikawa

doi:10.1107/S1600536814012471

. 2014 Jun 4;70(Pt 7):o744. doi: 10.1107/S1600536814012471

6-Iodo-4-oxo-4H-chromene-3-carbaldehyde

Yoshinobu Ishikawa ^a,^*

PMCID: PMC4120610 PMID: 25161541

Abstract

In the title compound, C₁₀H₅IO₃, an iodinated 3-formylchromone derivative, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0259 Å), with the largest deviation from the least-squares plane [0.056 (5) Å] being found for the formyl O atom. In the crystal, molecules are linked through I⋯O halogen bonds [I⋯O = 3.245 (4) Å, C—I⋯O = 165.95 (13) and C=O⋯I = 169.7 (4)°] along [101]. The supramolecular chains are assembled into layers via π–π stacking interactions along the b axis [shortest centroid–centroid distance between the pyran and benzene rings = 3.558 (3) Å].

Related literature

For related structures, see: Ishikawa (2014a ▶,b ▶,c ▶). For the synthesis of the precursor of the title compound, see: Bovonsombat et al. (2009 ▶). For halogen bonding, see: Auffinger et al. (2004 ▶); Metrangolo et al. (2005 ▶); Wilcken et al. (2013 ▶); Sirimulla et al. (2013 ▶). graphic file with name e-70-0o744-scheme1.jpg

Experimental

Crystal data

C₁₀H₅IO₃
M _r = 300.05
Triclinic,
a = 6.5741 (17) Å
b = 6.798 (3) Å
c = 10.437 (5) Å
α = 79.03 (3)°
β = 86.45 (3)°
γ = 76.00 (3)°
V = 444.3 (3) Å³
Z = 2
Mo Kα radiation
μ = 3.58 mm⁻¹
T = 100 K
0.25 × 0.25 × 0.08 mm

Data collection

Rigaku AFC-7R diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.432, T _max = 0.751
2519 measured reflections
2050 independent reflections
1989 reflections with F ² > 2σ(F ²)
R _int = 0.014
3 standard reflections every 150 reflections intensity decay: −1.8%

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.104
S = 1.11
2050 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 2.55 e Å⁻³
Δρ_min = −3.59 e Å⁻³

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999 ▶); cell refinement: WinAFC Diffractometer Control Software; data reduction: WinAFC Diffractometer Control Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalStructure (Rigaku, 2010 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablock(s) General, I. DOI: 10.1107/S1600536814012471/tk5319sup1.cif

e-70-0o744-sup1.cif^{(22.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814012471/tk5319Isup2.hkl

e-70-0o744-Isup2.hkl^{(100.8KB, hkl)}

Click here for additional data file.^{(3.3KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814012471/tk5319Isup3.cml

CCDC reference: 1005730

Additional supporting information: crystallographic information; 3D view; checkCIF report

Acknowledgments

The University of Shizuoka is acknowledged for instrumental support.

supplementary crystallographic information

S1. Structural commentary

Halogen bonds have been found to occur in organic, inorganic, and biological systems, and have recently attracted much attention in medicinal chemistry, chemical biology and supramolecular chemistry (Auffinger et al., 2004, Metrangolo et al., 2005, Wilcken et al., 2013, Sirimulla et al., 2013). We have recently reported the crystal structures of monohalogenated 3-formylchromone derivatives 6-fluoro-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014c, Fig.·3A), 6-chloro-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014a, Fig.·3B), and 6-bromo-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014b, Fig.·3C). It was found that halogen bond is formed between the formyl oxygen atom and the bromine atom in the bromo derivative, but is not formed in the others light-atom derivatives. As part of our interest in this type of chemical bonding, we herein report the crystal structure of a monoiodinated 3-formylchromone derivative 6-iodo-4-oxo-4H-chromene-3-carbaldehyde. The objective of this study is to reveal whether halogen bond(s) can be formed in the crystal structure of the title compound with the iodine atom in the 6-position.

The mean deviation of the least-squares plane for the non-hydrogen atoms is 0.0259 Å, and the largest deviation is 0.056 (5) Å for C10. These mean that these atoms are essentially coplanar (Fig. 1).

In the crystal, the molecules are stacked with the inversion-symmetry equivalents along the b axis [shortest centroid–centroid distance between the pyran and benzeneⁱ rings of the 4H-chromene units = 3.588 (3) Å, i: -x + 1, -y + 2, -z], as shown in Fig. 1.

Halogen bond is observed between the iodine atom and the formyl oxygen atom of the translation-symmetry equivalentⁱⁱ [I1···O3ⁱⁱ = 3.245 (4) Å, ii: x - 1, y, z + 1] along [101], as shown in Fig. 2. The angles of C–I···O and I···O=C are 165.95 (13) and 169.7 (4)°, respectively. Thus, it is found that halogen bond is formed for the iodine atom at 6-position, as shown in Fig.·3D. The space group and crystal packing mode of the title compound are the same with those of 6-chloro-4-oxo-4H-chromene-3-carbaldehyde and 6-bromo-4-oxo-4H-chromene-3-carbaldehyde. On the other hand, halogen bonding is observed for 6-bromo-4-oxo-4H-chromene-3-carbaldehyde (Fig.·3C) and the title compound (Fig.·3D), but is not observed for 6-chloro-4-oxo-4H-chromene-3-carbaldehyde (Fig.·3B). These should be accounted for by the larger size of the σ holes of the bromine and iodine atoms at 6-position (Wilcken et al., 2013).

S2. Synthesis and crystallization

2'-Hydroxy-5'-iodoacetophenone was prepared according to the literature method (Bovonsombat et al., 2009). To a solution of 2'-hydroxy-5'-iodoacetophenone (1.4 mmol) in N,N-dimethylformamide (5 ml) was added dropwise POCl₃ (3.4 mmol) for 3 min at 0 °C. After the mixture was stirred for 17 h at room temperature, water (30 ml) was added. The precipitates were collected, washed with water, and dried in vacuo (yield: 83%). ¹H NMR (400 MHz, DMSO-d₆): δ = 7.60 (d, 1H, J = 8.8 Hz), 8.18 (dd, 1H, J = 2.4 and 8.8 Hz), 8.37 (d, 1H, J = 2.4 Hz), 8.95 (s, 1H), 10.10 (s, 1H). DART-MS calcd for [C₁₀H₅I₁O₃ + H⁺]: 300.936, found 300.947. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a chloroform solution of the title compound held at room temperature.

S3. Refinement

The C(sp²)-bound hydrogen atoms were placed in geometrical positions [C–H = 0.95 Å, U_iso(H) = 1.2U_eq(C)], and refined using a riding model.