1-Benzoyl-3-(pyridin-2-yl)-1H-pyrazole

In the title compound, C15H11N3O, the dihedral angle betwen the heterocyclic rings is 9.23 (5)° and the dihedral angle between the benzoyl and pyrazole rings is 58.64 (5)°. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R 2 2(10) loops. The dimers stack into a column running parallel to the b-axis direction.

In the title compound, C 15 H 11 N 3 O, the dihedral angle betwen the heterocyclic rings is 9.23 (5) and the dihedral angle between the benzoyl and pyrazole rings is 58.64 (5) . In the crystal, inversion dimers linked by pairs of C-HÁ Á ÁO hydrogen bonds generate R 2 2 (10) loops. The dimers stack into a column running parallel to the b-axis direction.

Comment
The starting material, 3-(2-pyridyl)pyrazole, is a bidentate ligand which is commonly used in coordination chemistry (Jones et al. 1997& Adams et al. 2006. The title compound is made up of a 3-(2-pyridyl)pyrazole and benzoyl fragments. This new compound has a potential to be applied as a tridentate ligand (ONN) involving the O atom on the carbonyl group and the N atom on the pyrazole and pyridine rings.
A C-H···O intermolecular hydrogen bond links adjacent molecules into centrosymmetric dimers forming a one dimensional column parallel to the b-axis.
Experimental 3-(2-pyridyl)pyrazole (0.728 g, 5.0 mmol) was deprotonated by reacting with NaH (60% in mineral oil) in 30 ml of dry THF under N 2 at room temperature for 2 h. Then, benzoyl chloride (0.702 g, 5.0 mmol) was added slowly to the mixture and the temperature was brought to reflux and left stirring for 4 hrs. The solvent was removed and the residue was re-dissolved in a minimum volume of DCM, washed 3 times with 30 ml of distilled water. The organic fraction was collected and dried with MgSO 4 , filtered and the solvent was removed in vacuo. Slow evaporation of acetone/DCM solution of the residue afforded colourless blocks of (I). Yield 78%.

Refinement
All H atoms were positioned geometrically with C-H bond lengths in the range of 0.93 -0.97 Å and refined in the riding model approximation with U iso (H)=1.2U eq (C).   as those based on F, and R-factors based on ALL data will be even larger.