Crystal structure and Hirshfeld surface analysis of the hydrochloride salt of 8-{4-[(6-phenylpyridin-3-yl)methyl]piperazin-1-yl}-3,4-dihydroquinolin-2(1H)-one

The amine 8-{4-[(6-phenylpyridin-3-yl)methyl]piperazin-1-yl}-3,4-dihydroquinolin-2(1H)-one was crystallized as the hydrochloride salt, 4-(2-oxo-1,2,3,4-tetrahydroquinolin-8-yl)-1-[(6-phenylpyridin-3-yl)methyl]piperazin-1-ium chloride, C25H27N4 +·Cl- (I·HCl). The conformation of the organic cation is half-moon in shape enclosing the chloride anion. The piperidine ring of the 3,4-dihydroquinolin-2(1H)-one moiety has a screw-boat conformation, while the piperazine ring has a chair conformation. In the biaryl group, the pyridine ring is inclined to the phenyl ring by 40.17(7) and by 36.86(8)° to the aromatic ring of the quinoline moiety. In the crystal, the cations are linked by pairwise N - H⋯O hydrogen bonds, forming inversion dimers enclosing an R 2 2(8) ring motif. The Cl- anion is linked to the cation by an N - H⋯Cl hydrogen bond. These units are linked by a series of C - H⋯O, C - H⋯N and C - H⋯Cl hydrogen bonds, forming layers lying parallel to the ab plane.