Analysis of hydrogen bonding and weak interactions in the crystal structure of (E)-N-(4-ethylphenyl)-2-(4-hydroxybenzylidene)thiosemicarbazone: experimental and theoretical studies

Hydrogen-bonding interactions play an important role in the rational design of crystal systems with desirable architectures. The novel thiosemicarbazone derivative described herein, namely (E)-N-(4-ethylphenyl)-2-(4-hydroxybenzylidene)thiosemicarbazone, C₁₆H₁₇N₃OS, (I), was prepared and characterised by ¹H NMR, IR and single-crystal X-ray crystallography techniques. The compound is arranged in the lattice by O–H···S and N–H···S bonded polymeric ribbons that extend along the crystal b-axis, and the intermolecular N–H···S hydrogen bonds formed R2 2(8) ring motifs. More importantly, C–H···π interaction stabilises the supramolecular structure of (I). Hirshfeld surface and their associated two-dimensional fingerprint plot analyses are presented to illustrate the supramolecular connectivity in the solid state. The result shows that the short H···H contacts is dominated in the total Hirshfeld surface. As well as we report on n→π* interactions in thiosemicarbazone derivatives by using the reduced density gradient function and natural bond orbital analyses. Besides, molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analysis of the title compound are also investigated by theoretical calculations.