1264045-29-5

Upstream product

• 100-46-9 benzylamine 
• 1761-61-1 5-bromosalicyclaldehyde 
• 115540-65-3 6-bromobenzo[e][1,2,3]oxathiazine 2,2-dioxide 
• 672-13-9 2-hydroxy-5-methoxybenzaldehyde 

Downstream Products

• 1219710-76-5 [RuCl(CO)(PPh₃)2(2-(benzylimino methyl)-4-bromophenol)] 

Relevant academic research and scientific papers

NMR structural study of the prototropic equilibrium in solution of schiff bases as model compounds

An NMR titration method has been used to simultaneously measure the acid dissociation constant (pKa) and the intramolecular NHO prototropic constant δKNHO on a set of Schiff bases. The model compounds were synthesized from benzylamine and substituted ortho-hydroxyaldehydes, appropriately substituted with electron-donating and electron-withdrawing groups to modulate the acidity of the intramolecular NHO hydrogen bond. The structure in solution was established by 1H-, 13C- and 15N-NMR spectroscopy. The physicochemical parameters of the intramolecular NHO hydrogen bond (pKa, δKNHO and δδG°) were obtained from 1H-NMR titration data and pH measurements. The Henderson-Hasselbalch data analysis indicated that the systems are weakly acidic, and the predominant NHO equilibrium was established using Polster-Lachmann d-diagram analysis and Perrin model data linearization.

Hydrogen bonding in Schiff bases - NMR, structural and experimental charge density studies

A series of sixteen Schiff bases (derivatives of salicylaldehydes and aryl amines) was studied to reveal the influence of substituents and the length of the linker on the properties of the H-bonding formed. In theory, two groups of compounds, derivatives of 2-(2-hydroxybenzylidenoamine)phenol) and 2-hydroxy-N-(2-hydroxybenzylideno)benzylamine, can form different types of H-bonds using one or two hydroxyl groups present in the molecules. Two other groups of compounds, derivatives of 4-(2-hydroxybenzylidenoamine)phenol and N-(2-hydroxybenzyideno)benzylamine, can form only one type of H-bond. It was confirmed by 15N and 13C NMR experiments, that in all cases only traditional, H-bonded six-membered chelate rings were formed. The positions of the hydrogen atom in the rings depend on the substituent and phase. Generally, the OH H-bond form dominates in solution, with exception of the nitro derivatives, where the NH tautomer is present. In the solid state the tautomeric equilibrium is strongly shifted to the NH form. Only for the 5-Br derivative of one compound was the reverse relationship found. According to the results of experimental charge density investigations, two intramolecular H-bonds in the 5-methoxy derivative of 2-hydroxy-N-(2′-hydroxybenzylideno) benzylamine) differ significantly in terms of charge density properties. The intra- and intermolecular H-bonds formed by the deprotonated oxygen atom from 2-OH group are strong, with significant charge density concentration at the bond critical point and a straight, well-defined bond path, whereas the second intramolecular H-bond formed by the oxygen atom from the 2′-OH group is quite weak, with ca. five times smaller charge density concentration than in the previous case and a bent bond path. In terms of energy densities, the latter H-bond appears to be a non-bonding interaction, with total energy density being slightly positive. In terms of source contributions to the density at the H-bond critical point from the atoms involved, the intermolecular, linear H-bond is very strong and charge-assisted in the source function classification, the N(1)-H(1N)...O(1) H-bond is medium-strength, while the third H-bond is extremely weak.

Catalyst-free direct ring-opening of cyclic aldimines with aliphatic primary amines to construct o-hydroxy schiff bases

We firstly describe a catalyst-free direct ring-opening of cyclic aldimines with abundant aliphatic primary amines to construct o-hydroxy schiff bases under mild reaction conditions. The corresponding products were generated in good to excellent yields (80–99%). In addition, a gram-scale reaction and further application of the reaction strategy were performed.

Single-crystal UV-vis spectroscopic examination of a striking odd-even effect on structure and chromic behaviour of salicylidene alkylamines

We have found that a series of N-(5-bromosalicylidene) alkylamines exhibited distinct chromic behaviour depending on the parity of their alkyl chain length. A group with an even number of carbon atoms in the alkyl chain showed photochromism, while another group with odd number showed thermochromism.

Vanadyl binary schiff base complexes containing N2O2 coordination sphere: Synthesis, ab initio calculations and thermodynamic properties

Some vanadyl complexes were synthesized by treating a methanolic solution of the appropriate Schiff base ligand and one equivalent of VO(SO 4)2 to yield [(VOL2 1-14)](L= Salicylaldehyde's derivatives, Schemes 1,