The prototropic tautomerism and substituent effect through strong electron-withdrawing group in (E)-5-(diethylamino)-2-[(3-nitrophenylimino)methyl]phenol

Crystal structure, spectral characterization, molecular modeling studies and structural effects of the proton transfer process for (E)-5-methoxy-2-[(3,4-dimethylphenylimino) methyl]phenol

“…The absorption of ring protons is in the range of 6-8 ppm, which corresponds to an aromatic character. These results are in a good agreement with the literature and also show that the title compound adopts an OH form in solution [40,51]. …”

“…The lengths of the N1=C8 double, C1=C8 single and C2-O1 single bonds indicate that the compound adopts an OH tautomeric form rather than the NH form in the solid state. The good agreement can be seen between these bond lengths and counterparts in similar OH form compounds in the literature [40,41]. The harmonic oscillator model of aromaticity, the HOMA index, is also a sign of the aromaticity of a ring, which is why we calculated the HOMA indices for both rings using the following equation [42,43]:…”

The crystal structure of (E)-4-(3-ethoxy-2-hydroxybenzylideneamino)benzoic acid, C16H15NO4

“…The title compound adopts enol-imine tautomeric form and has E configuration around the C=N double bond. The bond lengths and angles are in the expected ranges and comparable with those of similar compounds in literature [10,11]. The compound displays a strong intramolecular hydrogen bond including the atoms O1 and N1 (O· · · N = 2.588(2) Å) as a common feature of o-hydroxysalicylidene systems.…”

Novel symmetric diimine-Schiff bases and asymmetric triimine-Schiff bases as chemosensors for the detection of various metal ions

“…Although salicylaldimine Schiff bases form mainly phenol-imine structure [43], naphthaldimine Schiff bases exhibit either keto-amine structure or mixture of two tautomers [44].…”