Synthesis, crystal structure, DFT calculations and Hirshfeld surface analysis of 3-butyl-2,6-bis(4- fluorophenyl)piperidin-4-one.

The title compound, C21H23F2NO, consists of two fluorophenyl groups and one butyl group equatorially oriented on a piperidine ring, which adopts a chair conformation. The dihedral angle between the mean planes of the phenyl rings is 72.1 (1)°. In the crystal, N--H…O and weak C--H…F interactions, which form R2 2 [14] motifs, link the molecules into infinite C(6) chains propagating along [001]. Aweak C--H…τ interaction is also observed. A Hirshfeld surface analysis of the crystal structure indicates that the most significant contributions to the crystal packing are from H…H (53.3%), H…C/C…H (19.1%), H…F/ F…H (15.7%) and H…O/O…H (7.7%) contacts. Density functional theory geometry-optimized calculations were compared to the experimentally determined structure in the solid state and used to determine the HOMO-LUMO energy gap and compare it to the UV-vis experimental spectrum. [ABSTRACT FROM AUTHOR]