Synthesis, single crystal structure, DNA binding and antioxidant properties of 5-(4-(dimethylamino)phenyl)-3-(thiophen-2-yl)-pyrazoline-1-carbothioamide

Compound 3c (5-(4-(dimethylamino)phenyl)-3-(thiophen-2-yl)-pyrazoline-1-carbothioamide) was synthesized and characterized experimentally using UV-Vis, FT-IR, ESI-MS and NMR (H-1 and C-13) analysis. The compound shows strong antioxidant activity with IC50 value of 0.632 +/- 0.002 mu g/mL. The compound crystallizes as a monoclinic system, P2(1)/c centro-symmetric space group, Z = 8 and size of the corresponding unit cell: a = 11.7134(10) angstrom, b = 17.3334(15) angstrom, c= 16.9831(14) angstrom, a= 90 degrees, beta= 108.038(2)degrees, gamma= 90 degrees. DNA binding measurements (UV-vis., fluorescence, cyclic voltammetry and competitive assay using ethidium bromide) of compounds showed intercalative mode of interaction. The binding constant (K b), Gibbs free energy (Delta G) of compound 3c were found to be 1.3x10(5) M-1 and -67.17 KJmol(-1), respectively. The calculated K-sv values at two different temperatures (298 and 303 K) are 3.02x10(3) and 2.16x10(3) M-1 respectively. To optimize molecular structure and compute wavenumbers of normal vibrational modes, B3LYP method and 6-311 ++ G (d, p) basis set were used. Hirshfeld surface analysis provides a thorough illustration of the intermolecular interactions on crystal surface, and fingerprint plots were discovered. Experimental bond lengths and bond angles corroborated well with the computational parameters. The GIAO approach was used to estimate H-1-NMR and C-13-NMR chemical shifts, and compared to experimental spectra. Electronic properties such as UV-Vis (in gas phase, ethanol and DMSO) were analyzed using TD-DFT method and the PCM solvent model, and results were compared to experimental UV-Vis spectra. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Compound 3c was synthesized and characterized, showing strong antioxidant activity and intercalative mode of interaction with DNA. The study provided a comprehensive analysis of its molecular structure and properties using experimental and computational methods.