Synthesis and supramolecular self-assembly of thioxothiazolidinone derivatives driven by H-bonding and diverse π–hole interactions: A combined experimental and theoretical analysis

Two new 3-aryl-5-(4-nitrobenzylidene)-2-thioxothiazolidin-4-one derivatives ( 1 & 2 ) were synthesized by the Knoevenagel condensation reaction of 3-(4-aryl)-2-thioxo-1,3-thiazolidin-4-ones with 4-nitrobenzaldehyde. Both products were isolated as orange crystalline solids in good yields and were fully characterized by analytical, spectroscopic and structural methods. The interesting supramolecular assemblies of the title compounds observed in the solid state were analyzed by Density Functional Theory (DFT) calculations (M06-2X/def2-TZVP), Molecular Electrostatic Potential (MEP) surfaces and characterized by means of the Bader's theory of “atoms-in-molecules” (AIM) and NCIplot. The computation of the energy features of the diverse noncovalent interactions including C H⋯π, π⋯π and lp⋯π-hole interactions revealed their conspicuous role in the stabilization of the three-dimensional supramolecular frameworks for both compounds in addition to the C H⋯O/S H-bonding interactions.