(1E,4E)-1,5-Bis[4-(di­ethyl­amino)­phen­yl]penta-1,4-dien-3-one

Pumsak Ruanwas; Suchada Chantrapromma; Hazem A Ghabbour; Hoong-Kun Fun

doi:10.1107/S1600536814008356

. 2014 Apr 26;70(Pt 5):o589–o590. doi: 10.1107/S1600536814008356

(1E,4E)-1,5-Bis[4-(diethylamino)phenyl]penta-1,4-dien-3-one

Pumsak Ruanwas ^a, Suchada Chantrapromma ^b,^*,^‡, Hazem A Ghabbour ^c, Hoong-Kun Fun ^c,^d,^§

PMCID: PMC4011286 PMID: 24860388

Abstract

There are two crystallograpically independent molecules in the asymmetric unit of the title bischalcone derivative, C₂₅H₃₂N₂O. Both molecules are twisted with a dihedral angle between the two substituted benzene rings of 11.19 (16)° in one molecule and 14.40 (15)° in the other. The central penta-1,4-dien-3-one fragments make dihedral angles of 8.49 (17) and 4.26 (17)° with the two adjacent benzene rings in one molecule, whereas the corresponding values are 8.42 (16) and 6.18 (16)° in the other. In the crystal, molecules are arranged into chains along the c-axis direction. Adjacent chains are inter-linked by weak intermolecular C—H⋯O interactions. The crystal is further stabilized by C—H⋯π interactions.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For related structures, see: Fun et al. (2010 ▶); Harrison et al. (2006 ▶); Ruanwas et al. (2011 ▶). For background to and applications of bischalcones, see: Barnabas et al. (1992 ▶); Makarov et al. (2012 ▶); Shibata et al. (2009 ▶); Wanare et al. (2010 ▶); Weber et al. (2005 ▶); Zhao et al. (2010 ▶) graphic file with name e-70-0o589-scheme1.jpg

Experimental

Crystal data

C₂₅H₃₂N₂O
M _r = 376.53
Monoclinic,
a = 10.4290 (4) Å
b = 40.4773 (16) Å
c = 10.8087 (5) Å
β = 100.2621 (13)°
V = 4489.8 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 296 K
0.42 × 0.38 × 0.34 mm

Data collection

Bruker APEXII D8 Venture diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.972, T _max = 0.977
79317 measured reflections
10289 independent reflections
5710 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.083
wR(F ²) = 0.270
S = 1.03
10289 reflections
501 parameters
H-atom parameters constrained
Δρ_max = 0.73 e Å⁻³
Δρ_min = −0.50 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL, PLATON (Spek, 2009 ▶), Mercury (Macrae et al., 2006 ▶) and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536814008356/sj5396sup1.cif

e-70-0o589-sup1.cif^{(48.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814008356/sj5396Isup2.hkl

e-70-0o589-Isup2.hkl^{(503.2KB, hkl)}

Click here for additional data file.^{(8.3KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814008356/sj5396Isup3.cml

CCDC reference: 997066

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

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

Cg3 and Cg4 are the centroids of the C1B–C6B and C12B–C17B rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8B—H8BA⋯O1B ⁱ	0.93	2.59	3.479 (4)	160
C16A—H16A⋯Cg3ⁱⁱ	0.93	2.91	3.758 (4)	152
C21A—H21A⋯Cg4ⁱⁱⁱ	0.96	2.79	3.541 (5)	136

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

PR thanks the Thailand Research Fund through the Royal Golden Jubilee PhD Program (grant No. PHD/0314/2552) and the Center of Excellence for Innovation in Chemistry (PERCH–CIC), Office of the Higher Education, Ministry of Education, Thailand, for financial support. The authors extend their appreciation to The Deanship of Scientific Research at King Saud University for funding the work through research group project No. RGP-VPP-207.

supplementary crystallographic information

1. Comment

Mono-carbonyl analogues of curcumin are an important class of compounds due to their variety of properties. For example these compounds exhibit anti-inflammatory (Zhao et al., 2010), antimalarial (Wanare et al., 2010), antitumor (Shibata et al., 2009) and anti-oxidant properties (Weber et al., 2005). They also act as dye sensitizers (Barnabas et al., 1992) and fluorescence agents (Makarov et al., 2012). These analogues were designed to counteract some of the disadvantageous properties of curcumin such as its poor bioavailability and instability in neutral to basic conditions. We have previously reported the crystal structures of (1E,4E)-1,5-bis(2,4,5-trimethoxyphenyl)penta-1,4-dien-3-one (I) (Fun et al., 2010) and (1E,4E)-1,5-bis(2,4,6-trimethoxyphenyl)penta-1,4-dien-3-one (II) (Ruanwas et al., 2011). The title compound (III) is one of the mono-carbonyl analogues of curcumin designed and synthesized by our group to study anti-tyrosinase activity and its fluorescence properties. It was found that the title compound exhibits fluorescence properties with an orange fluorescence color which will be reported elsewhere with its closely related compounds, it also possesses anti-tyrosinase activity by the dopachrome method with an IC₅₀ value of 0.018 mg ml^-1. We reported herein the crystal structure of (III).

There are two crystallographically independent molecules A and B in the asymmetric unit of (III) (Fig. 1) with the same conformation but slight differences in bond angles. The molecular structure of (III), C₂₅H₃₂N₂O is unsymmetrical and twisted. The dihedral angle between the C1–C6 and C12–C17 benzene rings is 11.19 (16)° in molecule A (Fig. 2a) whereas it is 14.40 (15)° in molecule B. The central penta-1,4-dien-3-one unit (C7–C11/O1) is planar with r.m.s. deviations 0.0463 (3) and 0.0357 (3) Å for molecules A and B, respectively. The mean plane through this central unit makes dihedral angles of 8.49 (17) and 4.26 (17)° with the two adjacent C1–C6 and C12–C17 benzene rings, respectively in molecule A whereas the corresponding values are 8.42 (16) and 6.18 (16)° in molecule B. The two ethyl groups of each diethylamino substituent in both molecules A and B deviate from the molecular plane and point to opposite sides of the molecule to reduce the steric hindrance between them with the torsion angles C3–N1–C18–C19 = 104.1 (5)°, C3–N1–C20–C21 = 79.5 (5)°, C15–N2–C22–C23 = 106.8 (6)° and C15–N2–C24–C25 = 75.1 (6)° in molecule A. The corresponding values are 96.1 (4), 79.9 (4), 90.3 (4) and 97.6 (5)° in molecule B. The bond distances are in normal ranges (Allen et al., 1987) and are comparable with those found in related structures (Fun et al., 2010; Harrison et al., 2006 and Ruanwas et al., 2011).

In the crystal packing (Fig. 2), the molecules are arranged into chains along the c axis and the adjacent chains are further linked by weak C—H···O interactions (Table 1). The crystal is further stabilized by weak intermolecular C—H···π interactions (Table 1). Interestingly there are only one C—H···O and two C—H···π interactions stabilising the structure of (III). This contrasts sharply with the packing for (I) and (II) where significantly more weak C—H···O and C—H···π interactions were observed (Fun et al., 2010 and Ruanwas et al., 2011).

2. Experimental

The title compound was synthesized by mixing 4-diethylaminobenzaldehyde (0.90 g, 6 mmol) and acetone (0.25 ml, 3 mmol) in ethanol (30 ml). 30% NaOH aqueous solution (5 ml) was then added and the mixture was stirred at room temperature for 2 h, The resulting orange solid obtained was collected by filtration, washed with distilled water and dried. Orange block-shaped single crystals of the title compound were grown in ethanol by slow evaporation, Mp. 440–441 K.