N-Benzoyl-morpholine-4-carbothioamides: Crystal structures, Hirshfeld surface analysis, and Density functional theory calculations

The current research describes facile synthesis, single crystal X-ray structures, Hirshfeld surface (HS) analysis, and density functional theory (DFT) calculations of two N-benzoyl-morpholine-4-carbothioamides (NDMC and NMMC). Consequently, the synthesized compounds, C12H12Cl2N2O2S (NDMC) and C13H12N2O2S (NMMC) crystallized in triclinic and monoclinic crystal systems each having respective space groups of P -1 and P 21, with corresponding a = 7.8045 (3) Å, b = 12.8458 (6) Å, c = 13.4946 (7) Å, α = 97.313 (4)°, β = 94.358 (4)°, γ = 93.348 (3)°, Z = 4 and V = 1334.84 (11) Å3 for compound (NDMC). Similarly, for compound (NMMC), a = 7.3322 (2) Å, b = 5.3045 (1) Å, c = 16.3367 (5) Å, β = 94.285 (3)°, Z = 2 and V = 633.62 (3) Å3. Subsequently, the asymmetric unit of compound (NDMC) contains two molecules, while compound (NMMC) has single molecule. Strong intermolecular N—H···O, and weaker C—H···Cl and C—H···S hydrogen bonds link the molecules of (NDMC) into dimers, enclosing R22(7) and R22(9) ring motifs. Intermolecular C—H···S, bifurcated N—H···O and C—H···O hydrogen bonds, as well as C—H···π interactions in (NMMC), attach molecules, enclosing R22(7) and R22(14) ring motifs. Furthermore, HS analysis explored, visualized, and quantified the significance of hydrogen bond contacts, and revealed active contributions for the packed crystals encompasses H…H 33.6% for (NDMC), and 46.6% for (NMMC), H…S/S…H 17.9% for (NDMC), and 17.0% for (NMMC), H…C/C…H 9.0% for (NDMC), and 19.7% for (NMMC), H…O/O…H 14.8% for (NDMC), and 14.3% for (NMMC), and H…Cl/Cl…H 17.8% for (NMMC). Hydrogen bonding and van der Waals contacts strongly influence crystal packings of the crystallized compounds. Similarly, evaluation of energy frameworks (electrostatic, dispersion and total energies) indicated stabilization is strongly dominated by dispersion energy contribution in (NMMC). Finally, optimum molecular structures of compounds (NDMC and NMMC), were related with the experimental ones employing DFT at B3LYP/6–311G**(d,p) level. The most stable optimized conformation was geometrically complementary with crystal structure. DFT computed frontier molecular energies and iso-densities predicted the compounds to exhibit better electron pair acceptance nature than electron pair donor.