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The title compound, 3-[4-(di­methyl­amino)­phenyl]-1-(2-hydroxy­phenyl)­prop-2-en-1-one, C17H17NO2, is a chalcone derivative substituted by 2'-hydroxyl and 4''-di­methyl­amino groups. The crystal structure indicates that the aniline and hydroxy­phenyl groups are nearly coplanar, with a dihedral angle of 10.32 (16)° between their phenyl rings. The molecular planarity of this substituted chalcone is strongly affected by the 2'-hydroxyl group.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102010247/ob1067sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270102010247/ob1067Isup2.hkl
Contains datablock I

CCDC reference: 193412

Comment top

In the past decade, synthetic chemosensors have been the focus of fields related to molecular opto-electronics. As a typical intramolecular charge-transfer (ICT) compound, 4''-dimethylaminochalcone (DMAC) has been reported to be a potential chemosensor due to its intense emission (DiCasare & Lakowicz, 2000). In particular, when it is substituted by different groups and/or is in different micro-surroundings, the fluorescent properties of the molecule can be severely altered, due to the different ICT nature of the excited states. To understand this structure-property relationship, some interesting work has been carried out. Murafuji et al. (1999) have reported two crystal structures of similar compounds with different groups at the 2'-position, namely 2'-diethylboryl-4''-dimethylaminochalcone and DMAC. In the former structure, the dihedral angle between the phenyl rings is 3.28 (9)°, but in the latter, which has no substituted group, the dihedral angle is 18.5 (2)°. The difference comes from an extra intramolecular B—O coordination bond. In this paper, we report the structure of the title compound, (I), which is 2'-hydroxyl-DMAC. \sch

The molecule of (I), along with the atom-numbering scheme, is illustrated in Fig. 1. This molecule can be classified into the D-π-A (electron donor-π-bridge-electron acceptor) model. The dimethylamino, the benzoyl and the styrene act as the electron donor, the electron acceptor and the π bridge, respectively. As expected, the backbone of the compound is nearly planar (Fig. 2). The dihedral angle between the phenyl plane of the aniline and that of the benzoyl is only 10.32 (16)°. There is some noticeable conjugation in the C10—C9C8—C7 bridge between the two phenyl rings, as seen in the increased length of the C8C9 double bond [1.344 (4) Å] and the decreased length of the C7—C8 [1.447 (4) Å] and C9—C10 [1.431 (4) Å] single bonds (Table 1).

Comparing our results with those of Murafuji et al. (1999), it can be seen that the planarity of the substituted chalcone molecule is strongly affected by the substituted group on the 2'-position. The hydroxyl group is connected to the carbonyl by an O1—H···O2 hydrogen bond (Table 2). This H···O intramolecular interaction is obviously weaker than the O B coordination bond reported by Murafuji et al. (1999).

It is interesting to compare the origination of the dihedral angles of DMAC [18.5 (2)°] and of (I) [10.32 (16)°]. In DMAC (with the same atom-numbering scheme as in Fig. 1), the C5—C4—C7—C8 [20.3 (5)°] and C3—C4—C7—O [19.0 (5)°] torsion angles are remarkable, and make the twist between the carbonyl plane (C8—C7—O2) and the phenyl plane (C1—C6) the main contribution to the non-planarity of DMAC. In (I), however, the carbonyl plane (C8—C7—O2) and the phenyl plane (C1—C6) are nearly coplanar. Obviously, the torsion to make the carbonyl plane parallel to the phenol plane is the O1—H···O2 intramolecular interaction. This seems to mean that the bonding between the substituted group at the 2'-postion and the O atom of the carbonyl is helpful for enhancing the planarity of the whole molecule. The stronger the bonding, the better the planarity. From this point of view, we can understand why the planarity of 2'-hydroxyl-DMAC, (I), is better than DMAC but poorer than 2'-diethylboryl-DMAC. The dihedral angle between the two phenyl rings in (I) comes from a gradual small skewing of the carbon chain between the two phenyl rings, and the C7—C8C9—C10 torsion angle of 3.9 (3)° is the largest one in this skewing series (Table 1).

As shown in Fig. 2, the molecular planes of all the molecules are either perpendicular or parallel to each other in the crystal. Each pair of two nearest molecules is coupled in the head-to-tail manner. Thus, the main intermolecular interaction can be supposed to be dipole-dipole interactions. From a check of the intermolecular atomic distances, there are no other obvious short intermolecular contacts in the crystal.

Concering the structure-property relationship, we have measured the fluorescent properties of both DMAC and 2'-hydroxyl-DMAC, (I), using an Edinburgh FLS920 spectrometer. Both compounds have the same peak position in their emission spectra, but the fluorescent intensity and quantum yield of the former is about 100 times higher than that of the latter in four kinds of solvent with different polarity, from toluene to MeCN. We think that the O1—H···O2 hydrogen bond has both a positive and a negative influence on the emission properties. The planarity and invariability of a π-conjugated organic molecule are important for fluorescence. The intramolecular hydrogen bond in (I) is helpful for enhancing the molecular planarity, but is not useful for enhancing the molecular invariablity (this hydrogen bond may induce some structural variability by potentially inducing more resonance structures). The combined effect is the enhanced non-radiative energy transfer of (I) and therefore the enhanced fluorescence quenching.

Experimental top

Under the protection of an N2 atmosphere, a mixture of 2'-hydroxyacetophenone (2.72 g) and boron trifluoride etherate (2.6 ml, 48% BF3) was heated to reflux for 1 h. 4-Dimethylaminobenzaldehyde (3.0 g) in acetic anhydride (10 ml) was then added dropwise. The temperature was kept at 363 K for a further 2 h. The mixture was then added dropwise to water and extracted with CH2Cl2. The organic layer was separated out and further purified by column chromatography using petroleum ether-chloroform (1:1) as eluent. After removal of the solvent under reduced pressure, dark-red microcrystals of (I) were obtained (ield 78%, 4.15 g; m.p. 449–450 K). A sample of (I) for structure determination was obtained by recrystallization from acetonitrile.

Refinement top

After checking their presence in the difference map, all H atoms were geometrically fixed and allowed to ride on their attached atoms, with C—H = 0.93–0.96 Å and O—H = 0.82 Å, and Uiso(H) = 1.2Ueq(C) or 1.5Ueq(O). Please check added text.

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: PLATON (Spek, 2001).

Figures top
[Figure 1] Fig. 1. A view of the molecule of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. A packing diagram for (I).
3-[4-(dimethylamino)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one top
Crystal data top
C17H17NO2Dx = 1.266 Mg m3
Mr = 267.32Melting point: 176 K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 12.1194 (14) ÅCell parameters from 40 reflections
b = 10.2869 (8) Åθ = 5.1–12.8°
c = 12.5048 (16) ŵ = 0.08 mm1
β = 115.864 (8)°T = 293 K
V = 1402.8 (3) Å3Prism, red
Z = 40.36 × 0.30 × 0.20 mm
F(000) = 568
Data collection top
Bruker P4
diffractometer
1353 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.028
Graphite monochromatorθmax = 26.0°, θmin = 2.7°
ω scansh = 141
Absorption correction: ψ scan
(XSCANS; Siemens, 1996)
k = 112
Tmin = 0.807, Tmax = 0.984l = 1415
3510 measured reflections3 standard reflections every 97 reflections
2745 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.065H-atom parameters constrained
wR(F2) = 0.216 w = 1/[σ2(Fo2) + (0.1111P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max < 0.001
2745 reflectionsΔρmax = 0.32 e Å3
182 parametersΔρmin = 0.22 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.012 (4)
Crystal data top
C17H17NO2V = 1402.8 (3) Å3
Mr = 267.32Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.1194 (14) ŵ = 0.08 mm1
b = 10.2869 (8) ÅT = 293 K
c = 12.5048 (16) Å0.36 × 0.30 × 0.20 mm
β = 115.864 (8)°
Data collection top
Bruker P4
diffractometer
1353 reflections with I > 2σ(I)
Absorption correction: ψ scan
(XSCANS; Siemens, 1996)
Rint = 0.028
Tmin = 0.807, Tmax = 0.9843 standard reflections every 97 reflections
3510 measured reflections intensity decay: none
2745 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0650 restraints
wR(F2) = 0.216H-atom parameters constrained
S = 1.01Δρmax = 0.32 e Å3
2745 reflectionsΔρmin = 0.22 e Å3
182 parameters
Special details top

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
N10.2075 (2)0.6199 (3)0.4665 (2)0.0567 (7)
O10.3576 (2)0.5929 (3)0.00121 (19)0.0751 (8)
H1A0.29450.56090.00380.113*
O20.1947 (2)0.5444 (2)0.0653 (2)0.0677 (7)
C10.5819 (3)0.7999 (4)0.2190 (3)0.0723 (11)
H1B0.65600.83920.23280.087*
C20.5228 (3)0.7224 (4)0.1199 (3)0.0734 (11)
H2A0.55770.70870.06780.088*
C30.4124 (3)0.6656 (3)0.0983 (3)0.0545 (8)
C40.3601 (3)0.6813 (3)0.1785 (3)0.0488 (8)
C50.4224 (3)0.7604 (3)0.2779 (3)0.0565 (9)
H5A0.38950.77350.33180.068*
C60.5316 (3)0.8192 (3)0.2972 (3)0.0658 (10)
H6A0.57140.87200.36340.079*
C70.2436 (3)0.6162 (3)0.1549 (3)0.0497 (8)
C80.1863 (3)0.6338 (3)0.2340 (3)0.0536 (8)
H8A0.22230.69050.29790.064*
C90.0830 (3)0.5714 (3)0.2188 (3)0.0534 (8)
H9A0.05330.51170.15680.064*
C100.0125 (3)0.5845 (3)0.2849 (2)0.0483 (8)
C110.0923 (3)0.5084 (3)0.2558 (3)0.0557 (9)
H11A0.11310.44770.19500.067*
C120.1659 (3)0.5196 (3)0.3133 (3)0.0555 (8)
H12A0.23510.46740.29040.067*
C130.1376 (3)0.6091 (3)0.4066 (3)0.0485 (8)
C140.0320 (3)0.6872 (3)0.4354 (3)0.0543 (8)
H14A0.01090.74880.49550.065*
C150.0390 (3)0.6738 (3)0.3766 (3)0.0541 (8)
H15A0.10790.72630.39850.065*
C160.1776 (3)0.7133 (4)0.5620 (3)0.0662 (10)
H16A0.10950.76550.56800.099*
H16B0.15620.66800.63550.099*
H16C0.24720.76820.54570.099*
C170.3088 (3)0.5328 (3)0.4438 (3)0.0671 (10)
H17A0.31920.47590.37920.101*
H17B0.38240.58240.42330.101*
H17C0.29210.48220.51370.101*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0543 (16)0.0586 (17)0.0610 (15)0.0085 (14)0.0285 (13)0.0083 (14)
O10.0769 (16)0.095 (2)0.0603 (13)0.0124 (15)0.0364 (12)0.0133 (14)
O20.0671 (15)0.0751 (17)0.0643 (14)0.0122 (13)0.0317 (12)0.0124 (13)
C10.063 (2)0.085 (3)0.073 (2)0.011 (2)0.0330 (19)0.000 (2)
C20.064 (2)0.097 (3)0.067 (2)0.005 (2)0.0359 (19)0.002 (2)
C30.061 (2)0.057 (2)0.0480 (17)0.0012 (17)0.0255 (16)0.0008 (15)
C40.0513 (17)0.0452 (18)0.0480 (16)0.0074 (14)0.0200 (14)0.0063 (14)
C50.0579 (19)0.059 (2)0.0495 (16)0.0059 (17)0.0205 (15)0.0009 (16)
C60.063 (2)0.061 (2)0.067 (2)0.0075 (18)0.0221 (18)0.0055 (17)
C70.0511 (18)0.0488 (18)0.0467 (16)0.0056 (15)0.0189 (14)0.0024 (14)
C80.0567 (19)0.0519 (19)0.0540 (18)0.0035 (16)0.0259 (16)0.0020 (15)
C90.061 (2)0.0452 (18)0.0536 (17)0.0028 (16)0.0251 (16)0.0015 (15)
C100.0509 (17)0.0464 (18)0.0472 (16)0.0009 (15)0.0210 (14)0.0022 (14)
C110.059 (2)0.052 (2)0.0550 (18)0.0043 (16)0.0234 (16)0.0075 (15)
C120.0515 (18)0.052 (2)0.0625 (19)0.0103 (16)0.0239 (16)0.0085 (16)
C130.0454 (17)0.0463 (17)0.0512 (16)0.0019 (14)0.0187 (14)0.0042 (15)
C140.0570 (18)0.0484 (19)0.0556 (18)0.0090 (16)0.0228 (16)0.0093 (15)
C150.0525 (18)0.0503 (19)0.0585 (18)0.0070 (15)0.0232 (16)0.0006 (15)
C160.070 (2)0.068 (2)0.069 (2)0.001 (2)0.0388 (18)0.0115 (19)
C170.061 (2)0.068 (2)0.080 (2)0.0092 (19)0.0379 (19)0.0048 (19)
Geometric parameters (Å, º) top
N1—C131.359 (4)C8—H8A0.9300
N1—C171.444 (4)C9—C101.431 (4)
N1—C161.449 (4)C9—H9A0.9300
O1—C31.352 (4)C10—C151.393 (4)
O1—H1A0.8200C10—C111.398 (4)
O2—C71.254 (4)C11—C121.373 (4)
C1—C61.374 (5)C11—H11A0.9300
C1—C21.382 (5)C12—C131.406 (4)
C1—H1B0.9300C12—H12A0.9300
C2—C31.374 (5)C13—C141.418 (4)
C2—H2A0.9300C14—C151.361 (4)
C3—C41.410 (4)C14—H14A0.9300
C4—C51.399 (4)C15—H15A0.9300
C4—C71.472 (4)C16—H16A0.9600
C5—C61.378 (5)C16—H16B0.9600
C5—H5A0.9300C16—H16C0.9600
C6—H6A0.9300C17—H17A0.9600
C7—C81.447 (4)C17—H17B0.9600
C8—C91.344 (4)C17—H17C0.9600
C13—N1—C17121.4 (3)C15—C10—C11116.1 (3)
C13—N1—C16121.1 (3)C15—C10—C9123.8 (3)
C17—N1—C16117.4 (3)C11—C10—C9120.1 (3)
C3—O1—H1A109.5C12—C11—C10122.7 (3)
C6—C1—C2120.2 (3)C12—C11—H11A118.6
C6—C1—H1B119.9C10—C11—H11A118.6
C2—C1—H1B119.9C11—C12—C13120.7 (3)
C3—C2—C1120.1 (3)C11—C12—H12A119.6
C3—C2—H2A120.0C13—C12—H12A119.6
C1—C2—H2A120.0N1—C13—C12121.8 (3)
O1—C3—C2117.5 (3)N1—C13—C14121.6 (3)
O1—C3—C4121.7 (3)C12—C13—C14116.6 (3)
C2—C3—C4120.9 (3)C15—C14—C13121.3 (3)
C5—C4—C3117.5 (3)C15—C14—H14A119.4
C5—C4—C7122.8 (3)C13—C14—H14A119.4
C3—C4—C7119.7 (3)C14—C15—C10122.6 (3)
C6—C5—C4121.1 (3)C14—C15—H15A118.7
C6—C5—H5A119.5C10—C15—H15A118.7
C4—C5—H5A119.5N1—C16—H16A109.5
C1—C6—C5120.2 (3)N1—C16—H16B109.5
C1—C6—H6A119.9H16A—C16—H16B109.5
C5—C6—H6A119.9N1—C16—H16C109.5
O2—C7—C8120.3 (3)H16A—C16—H16C109.5
O2—C7—C4119.0 (3)H16B—C16—H16C109.5
C8—C7—C4120.7 (3)N1—C17—H17A109.5
C9—C8—C7122.6 (3)N1—C17—H17B109.5
C9—C8—H8A118.7H17A—C17—H17B109.5
C7—C8—H8A118.7N1—C17—H17C109.5
C8—C9—C10128.8 (3)H17A—C17—H17C109.5
C8—C9—H9A115.6H17B—C17—H17C109.5
C10—C9—H9A115.6
C6—C1—C2—C30.9 (6)C7—C8—C9—C10176.1 (3)
C1—C2—C3—O1178.7 (3)C8—C9—C10—C153.5 (5)
C1—C2—C3—C42.4 (6)C8—C9—C10—C11179.0 (3)
O1—C3—C4—C5178.8 (3)C15—C10—C11—C120.1 (5)
C2—C3—C4—C52.3 (5)C9—C10—C11—C12177.8 (3)
O1—C3—C4—C70.7 (5)C10—C11—C12—C130.6 (5)
C2—C3—C4—C7178.2 (3)C17—N1—C13—C125.0 (5)
C3—C4—C5—C60.9 (5)C16—N1—C13—C12179.6 (3)
C7—C4—C5—C6179.7 (3)C17—N1—C13—C14174.7 (3)
C2—C1—C6—C50.6 (6)C16—N1—C13—C140.7 (5)
C4—C5—C6—C10.5 (5)C11—C12—C13—N1178.5 (3)
C5—C4—C7—O2178.4 (3)C11—C12—C13—C141.1 (4)
C3—C4—C7—O22.1 (4)N1—C13—C14—C15178.5 (3)
C5—C4—C7—C81.3 (4)C12—C13—C14—C151.1 (4)
C3—C4—C7—C8178.2 (3)C13—C14—C15—C100.5 (5)
O2—C7—C8—C92.9 (5)C11—C10—C15—C140.1 (4)
C4—C7—C8—C9176.8 (3)C9—C10—C15—C14177.7 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O20.821.772.504 (3)147

Experimental details

Crystal data
Chemical formulaC17H17NO2
Mr267.32
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)12.1194 (14), 10.2869 (8), 12.5048 (16)
β (°) 115.864 (8)
V3)1402.8 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.36 × 0.30 × 0.20
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionψ scan
(XSCANS; Siemens, 1996)
Tmin, Tmax0.807, 0.984
No. of measured, independent and
observed [I > 2σ(I)] reflections
3510, 2745, 1353
Rint0.028
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.065, 0.216, 1.01
No. of reflections2745
No. of parameters182
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.32, 0.22

Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL (Bruker, 1997), SHELXTL, PLATON (Spek, 2001).

Selected geometric parameters (Å, º) top
N1—C131.359 (4)C3—C41.410 (4)
N1—C171.444 (4)C4—C71.472 (4)
N1—C161.449 (4)C7—C81.447 (4)
O1—C31.352 (4)C8—C91.344 (4)
O1—H1A0.8200C9—C101.431 (4)
O2—C71.254 (4)
C13—N1—C17121.4 (3)O2—C7—C8120.3 (3)
C13—N1—C16121.1 (3)O2—C7—C4119.0 (3)
C17—N1—C16117.4 (3)C9—C8—C7122.6 (3)
O1—C3—C2117.5 (3)C8—C9—C10128.8 (3)
O1—C3—C4121.7 (3)C11—C10—C9120.1 (3)
C3—C4—C7119.7 (3)
O1—C3—C4—C70.7 (5)C7—C8—C9—C10176.1 (3)
C3—C4—C7—O22.1 (4)C8—C9—C10—C153.5 (5)
C3—C4—C7—C8178.2 (3)C8—C9—C10—C11179.0 (3)
C4—C7—C8—C9176.8 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···O20.821.772.504 (3)147
 

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