3-Methyl-5,6-diphenyl-1H-pyrazolo[1,2-a]cinnolin-1-one

Abstract

The asymmetric unit of the title compound, C24H18N2O, comprises two crystallographically independent molecules (A and B), with slightly different conformations. In each molecule, there is an intramolecular C—H...O hydrogen bond forming an S(6) ring motif. The pyridazine rings of the pyrazolo[1,2-a]cinnoline units have screw-boat conformations. Their mean planes are inclined to the phenyl rings by 83.81 (8) and 74.19 (8)° in molecule A, and 89.72 (8) and 71.07 (8)° in molecule B. In the crystal, the A and B molecules are linked by a pair of C—H...O hydrogen bonds, forming an A–B dimer with an R22(14) ring motif. These dimers are linked by further C—H...O hydrogen bonds, forming ribbons propagating along the b-axis direction. The ribbons are linked by a number of C—H...π interactions, forming a three-dimensional structure.

Keywords

• crystal structure
• cinnoline
• pyrazole
• pyridazine
• hydrogen bonding
• C—H...π interactions