Crystal Structures and Hirshfeld Surface Analyses of 4-benzyl-6-phenyl-4,5-di­hydro­pyridazin-3(2H)-One and Methyl 2-[5-(2,6-di­chloro­benz­yl)-6-oxo-3-phenyl-1,4,5,6-tetra­hydropyridazin-1-yl]Acetate

Abstract

The asymmetric units of the title compounds both contain one nonplanar molecule. In 4-benzyl-6-phenyl-4,5-dihydropyridazin-3(2H)-one, C<inf>17</inf>H<inf>14</inf>N<inf>2</inf>O, (I), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 46.69 (9)°; the phenyl ring of the benzyl group is nearly perpendicular to the plane of the pyridazine ring, the dihedral angle being 78.31 (10)°. In methyl 2-[5-(2,6-dichlorobenzyl)-6-oxo-3-phenyl-1,4,5,6-tetrahydropyridazin-1-yl]acetate, C<inf>20</inf>H<inf>16</inf>Cl<inf>2</inf>N<inf>2</inf>O<inf>3</inf>, (II), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 21.76 (18)°, whereas the phenyl ring of the dichlorobenzyl group is inclined to the pyridazine ring by 79.61 (19)°. In the crystal structure of (I), pairs of N-H..O hydrogen bonds link the molecules into inversion dimers with an R 2 2(8) ring motif. In the crystal structure of (II), C-H..O hydrogen bonds generate dimers with R 1 2(7), R 2 2(16) and R 2 2(18) ring motifs. The Hirshfeld surface analyses of compound (I) suggests that the most significant contributions to the crystal packing are by H..H (48.2%), C..H/H..C (29.9%) and O..H/H..O (8.9%) contacts. For compound (II), H..H (34.4%), C..H/H..C (21.3%) and O..H/H..O (16.5%) interactions are the most important contributions. © 2019 International Union of Crystallography. All rights reserved.