Synthesis and X‐ray Characterization of 4,5‐Dihydropyrazolyl‐Thiazoles Bearing a Coumarin Moiety: On the Importance of Antiparallel π‐Stacking
Murtaza Madni, Muhammad Naeem Ahmed, Ghazala Abbasi, Shahid Hameed, Mahmoud A. A. Ibrahim, Muhammad Nawaz Tahir, Muhammad Ashfaq, Diego M. Gil, Rosa M. Gomila, Antonio Frontera
Abstract
Abstract The synthetic protocol and solid state characterization of two new coumarin‐pyrazolylthiazole hybrids ( 1 ‐ 2 ) are detailed in this manuscript. Synthesized compounds were characterized applying nuclear magnetic resonance, Fourier‐transform infrared spectroscopy and single‐crystal X‐ray diffraction techniques. A detailed structural analysis of 3‐(2‐(5‐(4‐bromophenyl)‐3‐(4‐fluorophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one ( 1 ) and 3‐(2‐(3,5‐bis(4‐bromophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one ( 2 ) is reported along with a detailed description of the noncovalent interactions and their evaluation using Hirshfeld surface analysis, emphasizing the structure‐directing role of C−H⋅⋅⋅O, Br⋅⋅⋅π and π–π interactions. Finally, DFT energetics, molecular electrostatic potential (MEP), quantum theory of “atoms‐in‐molecules” (QTAIM) and noncovalent interaction plot (NCIplot) index computations have been used to further investigate the relative importance of two different π‐stacking complexes observed in the solid state of both compounds, which are recurrent binding motifs in their crystal packing.