Synthesis, crystal structure and computational analysis of 2,7-bis(4-chlorophenyl)-3,3-dimethyl-1,4-diazepan-5-one

In the title compound, C19H20Cl2N2O, the seven-membered 1,4-diazepane ring adopts a chair conformation while the 4-chlorophenyl substituents adopt equatorial orientations. The chlorophenyl ring at position 7 is disordered over two positions [site occupancies 0.480 (16):0.520 (16)]. The dihedral angle between the two benzene rings is 63.0 (4)degrees. The methyl groups at position 3 have an axial and an equatorial orientation. The compound exists as a dimer exhibiting intermolecular N-H center dot center dot center dot O hydrogen bonding with R-2(2)(8) graph-set motifs. The crystal structure is further stabilized by C-H center dot center dot center dot O hydrogen bonds together with two C-Cl center dot center dot center dot pi (ring) interactions. The geometry was optimized by DFT using the B3LYP/6-31 G(d,p) level basis set. In addition, the HOMO and LUMO energies, chemical reactivity parameters and molecular electrostatic potential were calculated at the same level of theory. Hirshfeld surface analysis indicated that the most important contributions to the crystal packing are from H center dot center dot center dot H (45.6%), Cl center dot center dot center dot H/H center dot center dot center dot Cl (23.8%), H center dot center dot center dot C/C center dot center dot center dot H (12.6%), H center dot center dot center dot O/O center dot center dot center dot H (8.7%) and C center dot center dot center dot Cl/Cl center dot center dot center dot C (7.1%) interactions. Analysis of the interaction energies showed that the dispersion energy is greater than the electrostatic energy. A crystal void volume of 237.16 angstrom(3) is observed. A molecular docking study with the human oestrogen receptor 3ERT protein revealed good docking with a score of -8.9 kcal mol(-1).