2-(2-Chloro­phen­yl)-7-methyl-4H-chromen-4-one

The title compound, C₁₆H₁₁ClO₂, is a synthetic flavonoid. The fused-ring system is almost planar, with a mean deviation from the least-squares plane of 0.0204 (2) Å. The dihedral angle between the chromene group and the chloro­phenyl ring is 50.9 (6)°, due to unfavourable steric inter­actions with the Cl atom. Aromatic π–π stacking inter­actions between the fused benzene (π-rich) and pyran (π-deficient) rings are observed, with a centroid–centroid distance of 3.578 Å.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.045
• wR factor = 0.128
• Data-to-parameter ratio = 12.9

checkCIF/PLATON results

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Alert level C
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
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S1. Comment

The title compound composed of a benzopyran ring system including ring A(C4—C9) and C(O1/C1—C4/C9), a phenyl ring B(C10—C15), a methyl group attached to ring A and a nitro group attached to ring B. The bond lengths and angles show normal values. The chromen including rings A and C is almost planar with mean deviation from their least square plane being 0.0204 (2) Å. A dihedral angle being 50.9 (6)° existed between the chromen part and ring B for the spatial conflict of the Cl atom.

It seems like that the π–π stacking interaction is a normal interaction found in flavonoid (Jiang et al., 2002; Etti, et al., 2005; Fun, et al., 2005; Stomberg, et al., 2002). Fig. 2 shows the intermolecular stacking via π–π stacking. In each molecule, ring A (π-rich) and C(π-deficient) was partial overlapped with ring C (π-deficient) and A (π-rich) from the other molecule at (2 - x, 1 - y, 2 - z), respectively, with intercentroid distances both of 3.578 Å (CgA and CgC represents the centroids of rings B and C) indicating that a strong π-π stacking interaction exists in the title compound.

Related literature

The π–π stacking interaction observed in the title compound is a normal interaction found in flavonoids (see Jiang et al., 2002; Etti et al., 2005; Fun et al., 2005; Stomberg et al., 2002).

S2. Experimental

A mixture of 1-(2-hydroxy-5-methylphenyl)ethanone (3.0 g, 20 mmol) and ovendried potassium carbonate (11.8 g, 90 mmol) in dry acetone was stirred with refluxing for 10 min. o-Chlorobenzoyl chloride (3.5 g, 20 mmol) was added to the reaction mixture, and the mixture was stired for 8 h. The percipate was acidified to pH 7.0~8.0 with 10% HOAc, and the solid was filtered to give 1-(2-hydroxy-5-methylphenyl)-3-(2-chlorophenyl)propane-1, 3-dione (A) 4.7 g, yield 82.3%. A (4.7 g) was mixed with HOAc (30 ml)-NaOAc (6 g) solution, and the mixture was stirred under refluxing for 6 h. The mixture was least to room temperature and water was added. The solid was filtered and washed with warm water, 5% NaHCO₃ solution and water, respectively, giving the title compound 3.8 g, yield 86.1%. ESI-MS: [M+H]⁺= 271. Prismatic crystals suitable for X-ray studies were grown from CH₂Cl₂ by slow evaporation at room temperature.

S3. Refinement

The methyl H atoms were constrained to an ideal geometry with C—H = 0.96 Å and U_iso(H) = 1.5U_eq(C), but were allowed to rotate freely about the C—C bonds. All remaining H atoms were placed in geometrically idealized positions (C—H = 0.93–0.97 Å) and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SMART (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000) and WinGX (Farrugia, 1999).

Figures

	Fig. 1. A view of the asymmetric unit of the title compound, showing the atom labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. H-atoms are shown as spheres of arbitrary radii.
	Fig. 2. Part of the crystal structure of (I), showing the π-π stacking. Atoms marked with a (i) are at the symmetry positions (2 - x, 1 - y, 2 - z). CgA and CgC are the centroids of rings A and C.

2-(2-Chlorophenyl)-7-methyl-4H-chromen-4-one

Crystal data

C16H11ClO2	F(000) = 560
Mr = 270.70	Dx = 1.418 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1659 reflections
a = 7.8394 (10) Å	θ = 2.7–23.0°
b = 22.936 (3) Å	µ = 0.30 mm^−1
c = 7.8790 (9) Å	T = 298 K
β = 116.462 (2)°	Prism, colourless
V = 1268.2 (3) Å^3	0.49 × 0.45 × 0.28 mm
Z = 4

Data collection

Bruker SMART-1000 CCD area-detector diffractometer	2231 independent reflections
Radiation source: fine-focus sealed tube	1362 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
π and ω scans	θmax = 25.0°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −9→9
Tmin = 0.869, Tmax = 0.922	k = −27→18
6274 measured reflections	l = −9→9

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.128	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0477P)^2 + 0.646P] where P = (Fo^2 + 2Fc^2)/3
2231 reflections	(Δ/σ)max < 0.001
173 parameters	Δρmax = 0.20 e Å^−3
0 restraints	Δρmin = −0.22 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
Cl1	0.97339 (14)	0.22512 (4)	0.89359 (15)	0.0847 (4)
O1	0.8098 (3)	0.39353 (7)	0.9756 (3)	0.0480 (5)
O2	1.1790 (4)	0.42147 (11)	0.7482 (4)	0.0909 (8)
C1	0.9519 (4)	0.35489 (11)	1.0026 (4)	0.0460 (7)
C2	1.0726 (4)	0.36287 (13)	0.9272 (4)	0.0580 (8)
H2	1.1649	0.3346	0.9476	0.070*
C3	1.0661 (5)	0.41337 (14)	0.8157 (4)	0.0607 (9)
C4	0.9143 (4)	0.45480 (12)	0.7903 (4)	0.0489 (7)
C5	0.7900 (4)	0.44250 (11)	0.8673 (4)	0.0445 (7)
C6	0.6394 (4)	0.47863 (12)	0.8413 (4)	0.0498 (7)
H6	0.5569	0.4685	0.8923	0.060*
C7	0.6113 (4)	0.52959 (12)	0.7399 (4)	0.0547 (8)
C8	0.7362 (5)	0.54276 (14)	0.6632 (4)	0.0632 (9)
H8	0.7188	0.5770	0.5943	0.076*
C9	0.8835 (5)	0.50654 (14)	0.6869 (4)	0.0623 (9)
H9	0.9642	0.5164	0.6336	0.075*
C10	0.9574 (4)	0.30831 (12)	1.1331 (4)	0.0498 (7)
C11	0.9700 (4)	0.24929 (13)	1.1007 (5)	0.0593 (8)
C12	0.9784 (4)	0.20779 (15)	1.2319 (7)	0.0752 (11)
H12	0.9865	0.1684	1.2081	0.090*
C13	0.9748 (5)	0.22476 (18)	1.3959 (6)	0.0776 (11)
H13	0.9807	0.1968	1.4839	0.093*
C14	0.9626 (5)	0.28284 (17)	1.4327 (5)	0.0749 (10)
H14	0.9620	0.2941	1.5458	0.090*
C15	0.9513 (4)	0.32395 (15)	1.3025 (5)	0.0617 (8)
H15	0.9393	0.3630	1.3267	0.074*
C16	0.4510 (5)	0.56963 (14)	0.7152 (5)	0.0734 (10)
H16A	0.3497	0.5475	0.7208	0.110*
H16B	0.4049	0.5888	0.5944	0.110*
H16C	0.4957	0.5983	0.8144	0.110*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0859 (7)	0.0583 (5)	0.1092 (8)	0.0015 (4)	0.0427 (6)	−0.0188 (5)
O1	0.0508 (12)	0.0408 (11)	0.0590 (12)	0.0009 (9)	0.0304 (10)	0.0048 (9)
O2	0.109 (2)	0.0878 (18)	0.122 (2)	−0.0074 (14)	0.0931 (19)	−0.0010 (15)
C1	0.0444 (17)	0.0404 (15)	0.0534 (17)	−0.0043 (12)	0.0219 (15)	−0.0046 (13)
C2	0.0584 (19)	0.0502 (18)	0.079 (2)	−0.0035 (14)	0.0433 (19)	−0.0064 (16)
C3	0.074 (2)	0.0588 (19)	0.065 (2)	−0.0183 (17)	0.0460 (19)	−0.0149 (16)
C4	0.0592 (18)	0.0465 (17)	0.0469 (17)	−0.0145 (14)	0.0290 (15)	−0.0096 (14)
C5	0.0544 (18)	0.0373 (15)	0.0414 (16)	−0.0103 (13)	0.0210 (14)	−0.0032 (12)
C6	0.0577 (19)	0.0441 (17)	0.0513 (17)	−0.0028 (14)	0.0276 (15)	0.0010 (14)
C7	0.065 (2)	0.0419 (17)	0.0474 (17)	−0.0053 (14)	0.0160 (16)	−0.0036 (14)
C8	0.086 (3)	0.0483 (18)	0.0516 (19)	−0.0162 (18)	0.0271 (19)	0.0019 (15)
C9	0.084 (2)	0.058 (2)	0.0543 (19)	−0.0199 (18)	0.0392 (19)	−0.0043 (16)
C10	0.0362 (16)	0.0457 (17)	0.065 (2)	−0.0019 (12)	0.0204 (15)	0.0047 (15)
C11	0.0372 (17)	0.0475 (18)	0.084 (2)	0.0019 (13)	0.0190 (17)	0.0054 (17)
C12	0.045 (2)	0.053 (2)	0.113 (3)	0.0057 (15)	0.022 (2)	0.020 (2)
C13	0.051 (2)	0.079 (3)	0.097 (3)	0.0005 (18)	0.028 (2)	0.039 (2)
C14	0.061 (2)	0.089 (3)	0.078 (3)	−0.0028 (19)	0.034 (2)	0.023 (2)
C15	0.0525 (19)	0.062 (2)	0.074 (2)	0.0002 (15)	0.0304 (18)	0.0128 (18)
C16	0.080 (3)	0.054 (2)	0.070 (2)	0.0079 (17)	0.018 (2)	0.0111 (17)

Geometric parameters (Å, º)

Cl1—C11	1.735 (4)	C8—C9	1.366 (4)
O1—C1	1.364 (3)	C8—H8	0.9300
O1—C5	1.377 (3)	C9—H9	0.9300
O2—C3	1.233 (3)	C10—C11	1.389 (4)
C1—C2	1.336 (4)	C10—C15	1.404 (4)
C1—C10	1.470 (4)	C11—C12	1.385 (5)
C2—C3	1.441 (4)	C12—C13	1.362 (5)
C2—H2	0.9300	C12—H12	0.9300
C3—C4	1.466 (4)	C13—C14	1.375 (5)
C4—C5	1.387 (4)	C13—H13	0.9300
C4—C9	1.398 (4)	C14—C15	1.366 (4)
C5—C6	1.381 (4)	C14—H14	0.9300
C6—C7	1.377 (4)	C15—H15	0.9300
C6—H6	0.9300	C16—H16A	0.9600
C7—C8	1.393 (4)	C16—H16B	0.9600
C7—C16	1.498 (4)	C16—H16C	0.9600
C1—O1—C5	119.1 (2)	C8—C9—H9	119.6
C2—C1—O1	122.2 (3)	C4—C9—H9	119.6
C2—C1—C10	127.2 (3)	C11—C10—C15	117.4 (3)
O1—C1—C10	110.4 (2)	C11—C10—C1	124.2 (3)
C1—C2—C3	122.8 (3)	C15—C10—C1	118.5 (3)
C1—C2—H2	118.6	C12—C11—C10	121.1 (3)
C3—C2—H2	118.6	C12—C11—Cl1	117.8 (3)
O2—C3—C2	123.2 (3)	C10—C11—Cl1	121.1 (3)
O2—C3—C4	122.6 (3)	C13—C12—C11	119.8 (3)
C2—C3—C4	114.2 (2)	C13—C12—H12	120.1
C5—C4—C9	117.1 (3)	C11—C12—H12	120.1
C5—C4—C3	119.6 (3)	C12—C13—C14	120.6 (3)
C9—C4—C3	123.3 (3)	C12—C13—H13	119.7
O1—C5—C6	115.8 (2)	C14—C13—H13	119.7
O1—C5—C4	122.0 (3)	C15—C14—C13	119.9 (4)
C6—C5—C4	122.3 (3)	C15—C14—H14	120.1
C7—C6—C5	120.0 (3)	C13—C14—H14	120.1
C7—C6—H6	120.0	C14—C15—C10	121.3 (3)
C5—C6—H6	120.0	C14—C15—H15	119.4
C6—C7—C8	118.3 (3)	C10—C15—H15	119.4
C6—C7—C16	120.3 (3)	C7—C16—H16A	109.5
C8—C7—C16	121.4 (3)	C7—C16—H16B	109.5
C9—C8—C7	121.6 (3)	H16A—C16—H16B	109.5
C9—C8—H8	119.2	C7—C16—H16C	109.5
C7—C8—H8	119.2	H16A—C16—H16C	109.5
C8—C9—C4	120.8 (3)	H16B—C16—H16C	109.5
C5—O1—C1—C2	−0.1 (4)	C6—C7—C8—C9	−0.1 (5)
C5—O1—C1—C10	175.8 (2)	C16—C7—C8—C9	179.5 (3)
O1—C1—C2—C3	1.6 (5)	C7—C8—C9—C4	−0.2 (5)
C10—C1—C2—C3	−173.5 (3)	C5—C4—C9—C8	−0.3 (4)
C1—C2—C3—O2	178.8 (3)	C3—C4—C9—C8	178.1 (3)
C1—C2—C3—C4	−0.7 (4)	C2—C1—C10—C11	−51.4 (4)
O2—C3—C4—C5	178.9 (3)	O1—C1—C10—C11	133.0 (3)
C2—C3—C4—C5	−1.6 (4)	C2—C1—C10—C15	128.0 (3)
O2—C3—C4—C9	0.5 (5)	O1—C1—C10—C15	−47.6 (3)
C2—C3—C4—C9	180.0 (3)	C15—C10—C11—C12	−0.7 (4)
C1—O1—C5—C6	178.0 (2)	C1—C10—C11—C12	178.7 (3)
C1—O1—C5—C4	−2.3 (4)	C15—C10—C11—Cl1	178.6 (2)
C9—C4—C5—O1	−178.3 (2)	C1—C10—C11—Cl1	−2.0 (4)
C3—C4—C5—O1	3.2 (4)	C10—C11—C12—C13	−0.2 (5)
C9—C4—C5—C6	1.3 (4)	Cl1—C11—C12—C13	−179.5 (3)
C3—C4—C5—C6	−177.2 (3)	C11—C12—C13—C14	0.1 (5)
O1—C5—C6—C7	178.0 (2)	C12—C13—C14—C15	0.9 (5)
C4—C5—C6—C7	−1.6 (4)	C13—C14—C15—C10	−1.8 (5)
C5—C6—C7—C8	1.0 (4)	C11—C10—C15—C14	1.7 (4)
C5—C6—C7—C16	−178.6 (3)	C1—C10—C15—C14	−177.7 (3)