Ultrasonic synthesis of Oct. trans-Br2Cu(N ∩ N)2 Jahn-Teller distortion complex: XRD-properties, solvatochromism, thermal, kinetic and DNA-binding evaluations

Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp²–sp² single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and ¹H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

Synthesis and amide imidic prototropic tautomerization in thiophene-2-carbohydrazide: XRD, DFT/HSA-computation, DNA-docking, TG and isoconversional kinetics via FWO and KAS models

Thiophene-2-carbohydrazide as a novel small-molecule amide tautomer has been synthesized with an acceptable yield under microwave radiation (MW) conditions. The amide imidic thiophene-2-carbohydrazide prototropic tautomerization via single proton intramigration was computed using the DFT B3LYP/6-311G(d,p) level of theory. The endo-isomer amide structure of thiophene-2-carbohydrazide was proved by XRD and is considered to be the kinetically favored isomer. The DFT-structure parameters were compared to their corresponding XRD-experimental parameters. Several H-bond interactions were detected in the crystal lattice experimentally using the XRD-packing model then correlated to MEP and HSA calculations. The manual and calculated electronic parameters such as, frontier molecular orbital energies, excitation energy, absorption, dipole moment, DOS, GRD quantum parameters and TD-SCF/B3LYP were DFT computed. The thiophene-2-carbohydrazide isomers together with their prototropic (E)/(Z)-thiophene-2-carbohydrazonic acid tautomers were docked against 1BNA DNA. FWO and KAS isoconversional kinetic methods were applied, and the thermal behavior and estimated E_a–α relations were determined.

Thiophene-2-carbohydrazide as a novel small-molecule amide tautomer has been synthesized with an acceptable yield under microwave radiation (MW) conditions.