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In the title compound, C18H18O4, the mol­ecule is slightly twisted with a dihedral angle of 17.49 (5)° between the two benzene rings. All of the meth­oxy substituents lie almost in the planes of the benzene rings to which they are attached. The crystal structure is stabilized by inter­molecular C—H...O, C—H...π and π–π inter­actions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807018697/sj2294sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807018697/sj2294Isup2.hkl
Contains datablock I

CCDC reference: 647597

Key indicators

  • Single-crystal X-ray study
  • T = 100 K
  • Mean [sigma](C-C) = 0.001 Å
  • R factor = 0.049
  • wR factor = 0.157
  • Data-to-parameter ratio = 31.7

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT153_ALERT_1_C The su's on the Cell Axes are Equal (x 100000) . 20 Ang. PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000) 100 Deg. PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 = 3
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 2 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 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

We report here the molecular and supramolecular structure of the title compound, (I) (Figure 1).

The bond lengths and angles in (I) have normal values (Allen et al., 1987) and are comparable with those in a related structure (Ng et al., 2006). The molecule is slightly twisted about the C6—C7 bond with the dihedral angle between the two benzene rings (C1—C6 and C10—C15) being 17.49 (5)°. The methoxy groups attached at C3, C4 and C13 lie almost in the planes of the benzene rings to which they are attached (C1—C6 and C10—C15) [C17—O3—C4—C5 = 5.31 (13), C16—O2—C3—C2 = -3.87 (13) and C18—O4—C13—C12 = -0.56 (13)°].

The O1 atom is involved in both intramolecular and intermolecular interactions. An intramolecular C9—H9A···O1 interaction (Table 1 and Figure 1) generates an S(5) ring motif (Bernstein et al., 1995). In the crystal structure, the molecules are linked by intermolecular C11—H11A···O1i hydrogen bonds into cyclic centrosymmetric R22(14) dimers (Bernstein et al., 1995). The dimers are then interlinked by intermolecular C18—H18B···O1ii interactions. The crystal structure is further stablized by intermolecular π···π interactions involving the C1—C6 benzene ring (Centroid Cg1) with a Cg1···Cg1iv distance of 3.5267 (6)Å [symmetry code: (iv) 1 - x, 1 - y, -z]. In addition, the crystal packing is also stabilized by weak intermolecular C—H···π interactions involving C10—C15 (Centroid Cg2) (Table 1).

Related literature top

For related literature on hydrogen-bonding motifs, see Bernstein et al. (1995) and on values of bond lengths and angles, see Allen et al. (1987). For a related structure, see Ng et al. (2006).

Experimental top

4-Methoxybenzaldehyde (0.01 mol) and 3,4-dimethoxyacetophenone (0.01 mol) were stirred in 60 ml of methanol at room temperature. 10 ml of 10% aqueous NaOH solution was added and the mixture was stirred for 4 h. The precipitate was filtered, washed with water, dried and the crude product recrystallized from acetone. Crystals suitable for X-ray analysis were grown by slow evaporation of an acetone solution at room temperature.

Refinement top

H atoms were placed in calculated positions, with C—H distances in the range 0.93–0.96 Å. The Uiso values were constrained to be 1.5Ueq of the carrier atom for methyl H atoms and 1.2Ueq for the remaining H atoms.

Structure description top

We report here the molecular and supramolecular structure of the title compound, (I) (Figure 1).

The bond lengths and angles in (I) have normal values (Allen et al., 1987) and are comparable with those in a related structure (Ng et al., 2006). The molecule is slightly twisted about the C6—C7 bond with the dihedral angle between the two benzene rings (C1—C6 and C10—C15) being 17.49 (5)°. The methoxy groups attached at C3, C4 and C13 lie almost in the planes of the benzene rings to which they are attached (C1—C6 and C10—C15) [C17—O3—C4—C5 = 5.31 (13), C16—O2—C3—C2 = -3.87 (13) and C18—O4—C13—C12 = -0.56 (13)°].

The O1 atom is involved in both intramolecular and intermolecular interactions. An intramolecular C9—H9A···O1 interaction (Table 1 and Figure 1) generates an S(5) ring motif (Bernstein et al., 1995). In the crystal structure, the molecules are linked by intermolecular C11—H11A···O1i hydrogen bonds into cyclic centrosymmetric R22(14) dimers (Bernstein et al., 1995). The dimers are then interlinked by intermolecular C18—H18B···O1ii interactions. The crystal structure is further stablized by intermolecular π···π interactions involving the C1—C6 benzene ring (Centroid Cg1) with a Cg1···Cg1iv distance of 3.5267 (6)Å [symmetry code: (iv) 1 - x, 1 - y, -z]. In addition, the crystal packing is also stabilized by weak intermolecular C—H···π interactions involving C10—C15 (Centroid Cg2) (Table 1).

For related literature on hydrogen-bonding motifs, see Bernstein et al. (1995) and on values of bond lengths and angles, see Allen et al. (1987). For a related structure, see Ng et al. (2006).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atomic numbering. The dashed line indicates an intramolecular hydrogen bond.
[Figure 2] Fig. 2. The crystal packing of (I), viewed down the b axis. Intermolecular C—H···O hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted.
1-(3,4-Dimethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one top
Crystal data top
C18H18O4Z = 2
Mr = 298.32F(000) = 316
Triclinic, P1Dx = 1.338 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.6745 (2) ÅCell parameters from 4878 reflections
b = 8.8452 (2) Åθ = 2.0–35.0°
c = 11.3132 (2) ŵ = 0.09 mm1
α = 108.314 (1)°T = 100 K
β = 102.391 (1)°Block, yellow
γ = 107.237 (1)°0.59 × 0.51 × 0.25 mm
V = 740.35 (3) Å3
Data collection top
Bruker SMART APEX2 CCD area-detector
diffractometer
6413 independent reflections
Radiation source: fine-focus sealed tube5074 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
Detector resolution: 8.33 pixels mm-1θmax = 35.0°, θmin = 2.0°
ω scansh = 1313
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
k = 1414
Tmin = 0.883, Tmax = 0.977l = 1818
19236 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.050Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.157H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0906P)2 + 0.0805P]
where P = (Fo2 + 2Fc2)/3
6413 reflections(Δ/σ)max < 0.001
202 parametersΔρmax = 0.34 e Å3
0 restraintsΔρmin = 0.40 e Å3
Crystal data top
C18H18O4γ = 107.237 (1)°
Mr = 298.32V = 740.35 (3) Å3
Triclinic, P1Z = 2
a = 8.6745 (2) ÅMo Kα radiation
b = 8.8452 (2) ŵ = 0.09 mm1
c = 11.3132 (2) ÅT = 100 K
α = 108.314 (1)°0.59 × 0.51 × 0.25 mm
β = 102.391 (1)°
Data collection top
Bruker SMART APEX2 CCD area-detector
diffractometer
6413 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
5074 reflections with I > 2σ(I)
Tmin = 0.883, Tmax = 0.977Rint = 0.035
19236 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.157H-atom parameters constrained
S = 1.07Δρmax = 0.34 e Å3
6413 reflectionsΔρmin = 0.40 e Å3
202 parameters
Special details top

Experimental. The data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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
xyzUiso*/Ueq
O10.60249 (9)0.91155 (10)0.34039 (7)0.02048 (14)
O20.68372 (9)0.50985 (10)0.19431 (7)0.02111 (14)
O30.86081 (9)0.58127 (10)0.04335 (7)0.02213 (15)
O40.18166 (9)1.28476 (10)0.31923 (7)0.02137 (15)
C10.47983 (11)0.77178 (12)0.01605 (9)0.01705 (16)
H1A0.39560.81500.03220.020*
C20.51867 (11)0.67691 (12)0.12132 (9)0.01841 (16)
H2A0.46070.65800.20730.022*
C30.64301 (11)0.61069 (11)0.09870 (9)0.01643 (15)
C40.73710 (11)0.64655 (12)0.03273 (9)0.01661 (15)
C50.69780 (11)0.74036 (12)0.13624 (9)0.01642 (15)
H5A0.75870.76330.22260.020*
C60.56670 (10)0.80193 (11)0.11301 (8)0.01507 (15)
C70.52360 (11)0.89143 (11)0.22823 (8)0.01578 (15)
C80.38377 (11)0.95373 (12)0.20778 (9)0.01766 (16)
H8A0.33530.95340.12590.021*
C90.32676 (11)1.01090 (12)0.30768 (9)0.01699 (15)
H9A0.37951.00730.38690.020*
C100.19162 (10)1.07816 (11)0.30654 (8)0.01582 (15)
C110.14495 (11)1.12011 (12)0.41977 (9)0.01748 (16)
H11A0.19911.10270.49170.021*
C120.01963 (11)1.18722 (12)0.42755 (9)0.01821 (16)
H12A0.01041.21320.50340.022*
C130.06058 (11)1.21513 (12)0.32035 (8)0.01630 (15)
C140.01674 (11)1.17283 (12)0.20553 (9)0.01796 (16)
H14A0.07071.19100.13390.022*
C150.10662 (11)1.10416 (12)0.19840 (9)0.01709 (15)
H15A0.13381.07480.12130.021*
C160.58389 (14)0.46028 (14)0.32809 (9)0.02451 (19)
H16A0.60870.37180.38560.037*
H16B0.61150.55900.35020.037*
H16D0.46420.41660.33860.037*
C170.94934 (12)0.59903 (13)0.17186 (10)0.02154 (18)
H17A1.03560.55220.16700.032*
H17D0.86940.53750.20420.032*
H17B1.00270.71930.23090.032*
C180.22757 (12)1.32908 (13)0.43559 (9)0.02108 (17)
H18D0.31101.37910.42430.032*
H18A0.12741.41120.51020.032*
H18B0.27521.22680.45040.032*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0224 (3)0.0271 (3)0.0163 (3)0.0155 (3)0.0059 (2)0.0091 (3)
O20.0253 (3)0.0256 (3)0.0189 (3)0.0158 (3)0.0120 (2)0.0086 (3)
O30.0213 (3)0.0314 (4)0.0223 (3)0.0196 (3)0.0094 (2)0.0117 (3)
O40.0239 (3)0.0321 (4)0.0195 (3)0.0212 (3)0.0110 (2)0.0124 (3)
C10.0180 (3)0.0192 (4)0.0180 (3)0.0113 (3)0.0065 (3)0.0087 (3)
C20.0213 (4)0.0216 (4)0.0168 (3)0.0127 (3)0.0071 (3)0.0089 (3)
C30.0186 (3)0.0181 (4)0.0174 (3)0.0100 (3)0.0093 (3)0.0083 (3)
C40.0155 (3)0.0191 (4)0.0201 (4)0.0102 (3)0.0079 (3)0.0095 (3)
C50.0156 (3)0.0193 (4)0.0177 (3)0.0104 (3)0.0059 (3)0.0082 (3)
C60.0156 (3)0.0163 (3)0.0164 (3)0.0088 (3)0.0065 (3)0.0073 (3)
C70.0160 (3)0.0172 (4)0.0172 (3)0.0095 (3)0.0062 (3)0.0076 (3)
C80.0174 (3)0.0213 (4)0.0177 (3)0.0116 (3)0.0061 (3)0.0083 (3)
C90.0162 (3)0.0195 (4)0.0184 (3)0.0101 (3)0.0062 (3)0.0084 (3)
C100.0149 (3)0.0181 (4)0.0166 (3)0.0090 (3)0.0058 (3)0.0071 (3)
C110.0188 (3)0.0216 (4)0.0159 (3)0.0119 (3)0.0064 (3)0.0084 (3)
C120.0198 (3)0.0239 (4)0.0160 (3)0.0136 (3)0.0080 (3)0.0085 (3)
C130.0163 (3)0.0192 (4)0.0171 (3)0.0110 (3)0.0070 (3)0.0073 (3)
C140.0187 (3)0.0237 (4)0.0165 (3)0.0128 (3)0.0073 (3)0.0093 (3)
C150.0177 (3)0.0215 (4)0.0164 (3)0.0115 (3)0.0079 (3)0.0081 (3)
C160.0313 (5)0.0269 (5)0.0176 (4)0.0143 (4)0.0105 (3)0.0076 (3)
C170.0193 (4)0.0255 (4)0.0237 (4)0.0140 (3)0.0064 (3)0.0104 (4)
C180.0220 (4)0.0261 (4)0.0193 (4)0.0154 (3)0.0094 (3)0.0072 (3)
Geometric parameters (Å, º) top
O1—C71.2342 (10)C9—H9A0.9300
O2—C31.3544 (11)C10—C111.3983 (12)
O2—C161.4241 (12)C10—C151.4083 (11)
O3—C41.3620 (10)C11—C121.3902 (12)
O3—C171.4262 (12)C11—H11A0.9300
O4—C131.3657 (10)C12—C131.3942 (12)
O4—C181.4278 (11)C12—H12A0.9300
C1—C61.3910 (12)C13—C141.4010 (13)
C1—C21.3956 (13)C14—C151.3828 (12)
C1—H1A0.9300C14—H14A0.9300
C2—C31.3864 (12)C15—H15A0.9300
C2—H2A0.9300C16—H16A0.9600
C3—C41.4167 (12)C16—H16B0.9600
C4—C51.3800 (13)C16—H16D0.9600
C5—C61.4098 (11)C17—H17A0.9600
C5—H5A0.9300C17—H17D0.9600
C6—C71.4838 (12)C17—H17B0.9600
C7—C81.4779 (12)C18—H18D0.9600
C8—C91.3441 (13)C18—H18A0.9600
C8—H8A0.9300C18—H18B0.9600
C9—C101.4628 (12)
C3—O2—C16117.14 (7)C12—C11—C10121.69 (7)
C4—O3—C17117.36 (7)C12—C11—H11A119.2
C13—O4—C18116.83 (7)C10—C11—H11A119.2
C6—C1—C2120.19 (8)C11—C12—C13119.27 (8)
C6—C1—H1A119.9C11—C12—H12A120.4
C2—C1—H1A119.9C13—C12—H12A120.4
C3—C2—C1120.51 (8)O4—C13—C12123.92 (8)
C3—C2—H2A119.7O4—C13—C14116.08 (7)
C1—C2—H2A119.7C12—C13—C14120.00 (8)
O2—C3—C2124.98 (8)C15—C14—C13120.17 (8)
O2—C3—C4115.27 (7)C15—C14—H14A119.9
C2—C3—C4119.75 (8)C13—C14—H14A119.9
O3—C4—C5126.05 (8)C14—C15—C10120.73 (8)
O3—C4—C3114.64 (8)C14—C15—H15A119.6
C5—C4—C3119.30 (7)C10—C15—H15A119.6
C4—C5—C6120.97 (8)O2—C16—H16A109.5
C4—C5—H5A119.5O2—C16—H16B109.5
C6—C5—H5A119.5H16A—C16—H16B109.5
C1—C6—C5119.19 (8)O2—C16—H16D109.5
C1—C6—C7122.84 (7)H16A—C16—H16D109.5
C5—C6—C7117.94 (7)H16B—C16—H16D109.5
O1—C7—C8120.14 (8)O3—C17—H17A109.5
O1—C7—C6120.16 (7)O3—C17—H17D109.5
C8—C7—C6119.69 (7)H17A—C17—H17D109.5
C9—C8—C7119.90 (8)O3—C17—H17B109.5
C9—C8—H8A120.1H17A—C17—H17B109.5
C7—C8—H8A120.1H17D—C17—H17B109.5
C8—C9—C10127.71 (8)O4—C18—H18D109.5
C8—C9—H9A116.1O4—C18—H18A109.5
C10—C9—H9A116.1H18D—C18—H18A109.5
C11—C10—C15118.12 (7)O4—C18—H18B109.5
C11—C10—C9118.06 (7)H18D—C18—H18B109.5
C15—C10—C9123.82 (8)H18A—C18—H18B109.5
C6—C1—C2—C30.48 (14)C1—C6—C7—C80.50 (13)
C16—O2—C3—C23.87 (13)C5—C6—C7—C8178.33 (8)
C16—O2—C3—C4175.61 (8)O1—C7—C8—C99.03 (14)
C1—C2—C3—O2176.43 (8)C6—C7—C8—C9169.93 (8)
C1—C2—C3—C43.03 (13)C7—C8—C9—C10179.49 (8)
C17—O3—C4—C55.31 (13)C8—C9—C10—C11175.84 (9)
C17—O3—C4—C3174.36 (8)C8—C9—C10—C154.59 (15)
O2—C3—C4—O33.21 (11)C15—C10—C11—C120.60 (14)
C2—C3—C4—O3177.28 (8)C9—C10—C11—C12179.00 (8)
O2—C3—C4—C5176.47 (8)C10—C11—C12—C130.64 (14)
C2—C3—C4—C53.04 (13)C18—O4—C13—C120.56 (13)
O3—C4—C5—C6179.83 (8)C18—O4—C13—C14179.84 (8)
C3—C4—C5—C60.53 (13)C11—C12—C13—O4178.15 (8)
C2—C1—C6—C52.03 (13)C11—C12—C13—C141.10 (14)
C2—C1—C6—C7175.77 (8)O4—C13—C14—C15178.99 (8)
C4—C5—C6—C12.00 (13)C12—C13—C14—C150.31 (14)
C4—C5—C6—C7175.91 (8)C13—C14—C15—C100.96 (14)
C1—C6—C7—O1178.46 (8)C11—C10—C15—C141.40 (13)
C5—C6—C7—O10.63 (13)C9—C10—C15—C14178.17 (8)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O10.932.422.775 (1)102
C11—H11A···O1i0.932.343.245 (1)165
C18—H18B···O1ii0.962.443.250 (2)142
C5—H5A···Cg2iii0.933.303.604 (1)102
Symmetry codes: (i) x+1, y+2, z+1; (ii) x1, y, z; (iii) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC18H18O4
Mr298.32
Crystal system, space groupTriclinic, P1
Temperature (K)100
a, b, c (Å)8.6745 (2), 8.8452 (2), 11.3132 (2)
α, β, γ (°)108.314 (1), 102.391 (1), 107.237 (1)
V3)740.35 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.59 × 0.51 × 0.25
Data collection
DiffractometerBruker SMART APEX2 CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.883, 0.977
No. of measured, independent and
observed [I > 2σ(I)] reflections
19236, 6413, 5074
Rint0.035
(sin θ/λ)max1)0.807
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.157, 1.07
No. of reflections6413
No. of parameters202
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.34, 0.40

Computer programs: APEX2 (Bruker, 2005), APEX2, SAINT (Bruker, 2005), SHELXTL (Sheldrick, 1998), SHELXTL and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O10.932.422.775 (1)102
C11—H11A···O1i0.932.343.245 (1)165
C18—H18B···O1ii0.962.443.250 (2)142
C5—H5A···Cg2iii0.933.303.604 (1)102
Symmetry codes: (i) x+1, y+2, z+1; (ii) x1, y, z; (iii) x+1, y, z.
 

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