Recurrent π-π stacking motifs in three new 4,5-dihydropyrazolyl-thiazole-coumarin hybrids: X-ray characterization, Hirshfeld surface analysis and DFT calculations

The synthesis and X-ray characterization of three new 4,5-dihydropyrazolylthiazole-coumarin hybrids (1-3) are reported herein, namely 3-(2-(3,5-bis(4-chlorophenyl)-4,5-dihydropyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one (1), 3-(2-(5-(4-chlorophenyl)-4,5-dihydro-3-phenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one (2) and 3-(2-(3-(4-chlorophenyl)-4,5-dihydro-5-p-tolylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one (3). A detailed structural analysis of the noncovalent interactions and their evaluation using Hirshfeld surface analysis is also reported, evidencing the importance of C-HMIDLINE HORIZONTAL ELLIPSISO and pi-pi interactions. Finally, DFT calculations along with the molecular electrostatic potential (MEP) and NCIplot index analysis have been used to evaluate those interactions energetically and to investigate the relative importance of two different pi-stacking modes that are recurrent binding motifs in the solid state architecture of the three complexes.