1-[5-(Anthracen-9-yl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]ethanone

In the title compound, C25H20N2O, the pyrazoline ring is nearly planar [maximum atomic deviation = 0.0254 (17) Å]; but the anthracene ring system is distorted from a coplanar structure [maximum atomic deviation = 0.181 (3) Å], the dihedral angle between the outer benzene rings being 10.68 (13)°. The pyrazoline ring is almost perpendicular to the mean plane of the anthracene ring system [dihedral angle = 76.94 (8)°], but nearly coplanar with the phenyl ring [dihedral angle = 1.63 (7)°]. π–π stacking is observed between parallel benzene rings of adjacent anthracene units, the face-to-face distance being 3.27 (3) Å. Weak intramolecular C—H⋯N hydrogen bonding also occurs.

In the title compound, C 25 H 20 N 2 O, the pyrazoline ring is nearly planar [maximum atomic deviation = 0.0254 (17) Å ]; but the anthracene ring system is distorted from a coplanar structure [maximum atomic deviation = 0.181 (3) Å ], the dihedral angle between the outer benzene rings being 10.68 (13) . The pyrazoline ring is almost perpendicular to the mean plane of the anthracene ring system [dihedral angle = 76.94 (8) ], but nearly coplanar with the phenyl ring [dihedral angle = 1.63 (7) ].stacking is observed between parallel benzene rings of adjacent anthracene units, the faceto-face distance being 3.27 (3) Å . Weak intramolecular C-HÁ Á ÁN hydrogen bonding also occurs.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU5095). analgesic [Parmar et al., 1974, Soni et al.,1978. Furthermore, some of them have widely been used as fluorescence probes in some elaborated chemosensors [Christoph et al., 2003], as hole-transport materials in the electrophotography and electroluminescence [Wei et al., 2007], due to the favorable photophysical properties. Here we report the structure of the title compound, a new derivative of pyrazoline.
In the pyrazoline ring, all the atoms are coplanar with a maximum deviation of 0.0254 (17) [Krishna et al., 1999]. The mean plane of pyrazoline ring makes dihedral angles of 1.63 (17)°a nd 76.94 (8)° with phenyl and anthryl ring, respectively. There are present only weak intermolecular interactions in the structure: C-H···π-electron and π-electron ring -π-electron ring interactions. The latter one is between the two parallel anthryl rings with the distance of 3.232Å. The anthryl ring shows a slightly distortion with C2 deviating by 1.811 (24)Å from planarity. The distance between the methine H15a and the anthryl H11a atoms is short, it is strange that the deviation of anthryl c11 from planarity is minimum in all the anthryl carbon atoms. It maybe result from the /p-stacking between the two parallel anthryl rings.
Experimental 3-(9-Anthryl)-1-phenylprop-2-en-1-one (3 mmol) and hydrazine hydrate (50%, 6 mmol) were dissolved in 10 ml of glacial acetic acid. The mixture was stirred for 8 h at 391 K. The resultant solution was poured into a beaker containing crushed ice and the solid separated was collected by filtration. The product was recrystallized from ethanol-ethyl acetate (1:1 v/v) mixed solution, light yellow single-crystals of the title compound were obtained.

Refinement
H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93-0.97 Å, U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for the others.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds supplementary materials sup-3 in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.