Crystal structures and Hirshfeld surface analyses of 2-amino-4-(4-bromophenyl)-6-oxo-1-phenyl-1,4,5,6-tetrahydropyridine-3-carbonitrile hemi-hydrate and 1,6-diamino-2-oxo-4-phenyl-1,2-di-hydropyridine-3,5-dicarbonitrile

In 2-amino-4-(4-bromophenyl)-6-oxo-1-phenyl-1,4,5,6-tetrahydropyridine-3-carbonitrile hemihydrate, C18H14BrN3O center dot 0.5H(2)O, (I), pairs of molecules are linked by pairs of N-H center dot center dot center dot N hydrogen bonds, forming dimers with an R-2(2)(12) ring motif. The dimers are connected by N-H center dot center dot center dot Br and O-H center dot center dot center dot O hydrogen bonds, and C-Br center dot center dot center dot pi interactions, forming layers parallel to the (010) plane. 1,6-Diamino-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile, C13H9N5O, (II), crystallizes in the triclinic space group P (1) over bar with two independent molecules (IIA and IIB) in the asymmetric unit. In the crystal of (II), molecules IIA and IIB are linked by intermolecular N-H center dot center dot center dot N and N-H center dot center dot center dot O hydrogen bonds into layers parallel to (001). These layers are connected along the c-axis direction by weak C-H center dot center dot center dot N contacts. C-H center dot center dot center dot pi and C-N center dot center dot center dot pi interactions connect adjacent molecules, forming chains along the a-axis direction. In (I) and (II), the stability of the packing is ensured by van derWaals interactions between the layers. In (I), Hirshfeld surface analysis showed that the most important contributions to the crystal packing are from H center dot center dot center dot H (37.9%), C center dot center dot center dot H/H center dot center dot center dot C (18.4%), Br center dot center dot center dot H/H center dot center dot center dot Br (13.3%), N center dot center dot center dot H/H center dot center dot center dot N (11.5%) and O center dot center dot center dot H/H center dot center dot center dot O (10.0%) interactions, while in (II), H center dot center dot center dot H interactions are the most significant contributors to the crystal packing (27.6% for molecule IIA and 23.1% for molecule IIB).