Structure, tautomerism, spectroscopic and DFT study of o-vanillin derived Schiff bases containing thiophene ring

Schiff Bases and Their Metallic Derivatives: Highly Versatile Molecules with Biological and Abiological Perspective

“…Generally, there is no difference between IR and Raman frequencies and between the spectra of pure liquids and solids and their solutions in common organic solvents CCl 4 or other not very associative solvents. Generally, water of crystallization appeared at 3300 cm −1 plus range [46].…”

“…Solvent affects are very complex phenomena, and the absorbance maxima altered inconsistently with respect to solvent and the position/type of the substituent(s) and geometrical features. In addition, other molecular properties like dipole moments, difference of electronegativity, partial charges, and chemical reactivity also significantly affected electronic spectra [46]. In the IR spectra, C=N is most commonly reported in the 1690-1640 cm −1 region as a strong and a sharp band at somewhat lower frequencies than the bands of C=O groups and close to C=C stretching frequencies.…”

Tautomeric Study of Schiff Bases Derived from o‐Dihydroxybenzaldehyde by UV‐Vis, IR, 1H NMR, 13C NMR Spectroscopy and Computational Modeling.

“…[7][8][9] For years the tautomeric equilibrium of Schiff bases has been studied by different spectroscopic techniques in solid and liquid states. [10][11][12][13] Tautomeric equilibrium constants and thermodynamic parameters have been determined using NMR and UV-Vis spectroscopies. [14][15] Ground state equilibrium and excited state deactivation have been studied by solvatochromic measurements and the proton transfer rate in crystalline phase was calculated by fluorescence spectroscopy.…”

“…[16][17] On the other hand, the prototropic tautomerism nature of Schiff bases has been studied through various computational methods in order to aid in the correlation of experimental information. [18][19][20] This has been done mainly with either one structure or with structures with different molecular skeletons. Here we take advantage of the accuracy and relative speed of standard DFT functionals to provide insight into the spectroscopic properties of different structural isomers.…”

Synthesis, characterization, DFT calculations and anticancer activity of a new oxidovanadium(iv) complex with a ligand derived from o-vanillin and thiophene

“…In the present work, the selected ligand HL (oVATPNH2 , see Figure 1) is an example of Schiff base derived from primary amines involving a heterocycle and has been obtained and fully characterized in our laboratory. 13 It is the condensation product of o-vanillin (2-hydroxy-3-methoxybenzaldehyde, hereafter oHVa) and 2-thiophenemethylamine (TPNH2).…”