Phthalazin-1(2H)-one

Abstract

The molecule of the title compound, C8H6N2O, is almost planar, with a dihedral angle of 0.52 (7)degrees between the two rings. In the crystal structure, intermolecular N-H center dot center dot center dot O, C-H center dot center dot center dot N and C-H center dot center dot center dot O hydrogen bonds and pi-pi interactions link the molecules into a three-dimensional network. The pi-pi interaction occurs between the pyridazinone and benzene rings of the molecules at (x; y; z) and (x-1; y; z); the centroid-centroid distance is 3.588 (1) angstrom and the plane-plane separation is 3.434 angstrom.