Redetermination of (E)-3-(anthracen-9-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one1

The redetermined structure of title chalcone derivative, C23H16O2, corrects errors in the title, scheme and synthesis in the previous report of the same structure [Jasinski et al. (2011 ▶). Acta Cryst. E67, o795]. There are two independent molecules in the asymmetric unit with slight differences in bond lengths and angles. The dihedral angle between the benzene ring and the anthracene ring system is 73.30 (4)° in one molecule and 73.18 (4)° in the other. Both molecules feature an intramolecular O—H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, molecules are arranged into sheets lying parallel to the ac plane and further stacked along the b axis by π–π interactions with centroid–centroid distances in the range 3.6421 (6)–3.7607 (6) Å. The crystal structure is further stabilized by C—H⋯π interactions. There are also C⋯O [3.2159 (15) Å] short contacts.

The redetermined structure of title chalcone derivative, C 23 H 16 O 2 , corrects errors in the title, scheme and synthesis in the previous report of the same structure [Jasinski et al. (2011). Acta Cryst. E67, o795]. There are two independent molecules in the asymmetric unit with slight differences in bond lengths and angles. The dihedral angle between the benzene ring and the anthracene ring system is 73.30 (4) in one molecule and 73.18 (4) in the other. Both molecules feature an intramolecular O-HÁ Á ÁO hydrogen bond, which generates an S(6) ring. In the crystal, molecules are arranged into sheets lying parallel to the ac plane and further stacked along the b axis byinteractions with centroid-centroid distances in the range 3.6421 (6)-3.7607 (6) Å . The crystal structure is further stabilized by C-HÁ Á Á interactions. There are also CÁ Á ÁO [3.2159 (15) Å ] short contacts.

Related literature
For the previous structure determination, see: Jasinski et al. (2011). For a related structure and background references, see: Joothamongkhon et al. (2010). For graph-set motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used in the data collection, see Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ).
Redetermination of (E)-3-(anthracen-9-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one S. Chantrapromma, T. Kobkeatthawin, K. Chanawanno, J. Joothamongkhon and H.-K. Fun Comment From our previous work, which revealed that a chalcone derivative containing the anthracene moiety displayed fluorescence (Joothamongkhon et al., 2010), the title compound (I) was synthesized by changing the substituent group on the phenyl ring for comparison of their properties. It was then discovered that a recent study of the same structure (Jasinski et al., 2011) contained errors in the title, scheme and synthesis. It was found that (I) exhibits fluorescence with the maximum emission at 438 nm when excited at 380 nm in chloroform solution. In addition our experiment shows that (I) also exhibits tyrosinase inhibitory activity with % inhibition of 12.882±8.511 at the concentration 0.125 mg ml -1 when L-tyrosine was used as substrate.
The asymmetric unit of (I) contains two molecules, A and B, with the same configuration but with slight differences in bond lengths and angles. The molecule of (I) (  (Table 1) generate S(6) ring motifs (Bernstein et al., 1995).
The bond distances are comparable with those in the related structure noted above (Joothamongkhon et al., 2010).

Experimental
The title compound was synthesized by the condensation of anthracene-9-carbaldehyde (2 mmol, 0.41 g) with 2-hydroxyacetophenone (2 mmol, 0.27 g) in ethanol (40 ml) in the presence of NaOH(aq) (10 ml, 40%). After stirring for 4 hr at room temperature, a yellow solid appeared and was then collected by filtration, washed with distilled water and dried in air. Yellow blocks of (I) were recrystalized from acetone by the slow evaporation of the solvent at room temperature after several days, Mp. 431-432 K.

Refinement
Hydroxy H atoms were located in a difference maps and refined isotropically. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with d(C-H) = 0.93 Å for aromatic and CH. and the U iso values were constrained to be 1.2U eq of the carrier atoms. The highest residual electron density peak is located at 0.71 Å from C1A and the deepest hole is located at 0.43 Å from H1OA.  (E)-3-(anthracen-9-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one