Crystal engineering with novel antipyrine derivatives: Insights from X-ray diffraction, Hirshfeld surface analysis, and DFT calculations on intermolecular interactions

• Published in: Journal of Molecular Structure
• Main Author: Rocha M.; Saeed A.; Gil D.M.; Echeverría G.A.; Piro O.E.; Khurshid A.; Arshad M.; Shah S.A.A.; Erben M.F.
• Format: Article
• Language: English
• Published: Elsevier B.V. 2025
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85200149601&doi=10.1016%2fj.molstruc.2024.139450&partnerID=40&md5=5ad0d2fc1bdcf6b426b8ad8a03055f12

In this study, we report the synthesis, structural characterization by X-ray diffraction, vibrational (Infrared and Raman) investigation, Hirshfeld surface analysis, and DFT calculations of three new antipyrine derivatives (1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) bearing amide groups (1–3). The compounds were synthesized in good yields and characterized spectroscopically. X-ray diffraction revealed that compound 1 crystallizes as a monohydrate in the monoclinic space group P21/c, while compound 3 also crystallizes as a monohydrate in the orthorhombic space group Pccn, exhibiting quasi-isomorphism with 1. Compound 2 crystallizes in the P21/c space group, forming H-bonded centrosymmetric dimers. The crystal packing is stabilized by N[sbnd]H···O and C[sbnd]H···O hydrogen bonds, along with C[sbnd]H···π interactions. FTIR and Raman spectroscopic analysis, supported by DFT calculations, identified key vibrational modes in the amide and pyrazole moieties. Hirshfeld surface analysis indicated that the molecular sheets are primarily formed by hydrogen bonds, with stabilization dominated by electrostatic energy contributions. DFT calculations (PBE0-D3/def2-TZVP) and QTAIM/NCIplot analyses revealed that the H-bonding interactions are energetically significant. © 2024 Elsevier B.V.