The 15N and 13C NMR study of Schiff bases of amino acids and their lithium salts in solid state and DMSO solution

NMR Studies of Optically Active Schiff Bases

“…For lithium salts in DMSO solution 3 J(NH,H), coupling constants varied from 10.6 to 13.0 Hz. 54 Similar values (12-13.1 Hz) were found for tetrabutylammonium salts in CDCl 3 . 33 The dC-2 values depended on the solvent, temperature, type of salt and type of NMR measurements (solution or CP MAS) and varied from 178.9 to 182.5 ppm.…”

“…33 The dC-2 values depended on the solvent, temperature, type of salt and type of NMR measurements (solution or CP MAS) and varied from 178.9 to 182.5 ppm. 33,54,55 The highest values were found for lithium salts in D 2 O. 55 The NMR measurements for the Schiff bases being derivatives of (R)-1-(9-anthryl)-ethylamine and 2-(2 0 -pyridyl or quinolyl)acetophenone [23] have revealed the presence of the rigid conformation of the enamine form.…”

“…The high negative values of 15 N CP MAS chemical shifts were in the range from $À203 to $À231 ppm. 54 The differences in chemical shifts were related to the type of amino acid moiety.…”

Synthesis and characterization of four new manganese(III) complexes and amino acid (L-aspartic acid, L-asparagine, L-glutamic acid, L-glutamine) Schiff bases

“…This kind of work shows us that amino acid residue groups play a very important role in the active centers of enzymes coordinated to essential metals [5,6]. Therefore to synthesise amino acid Schiff bases and their metal complexes it is important to obtain more information about their reaction mechanisms [7][8][9][10]. On the other hand, much work is required for the syntheses of new manganese complexes with different ligands as mimic models and whether they have any function or not for oxygen evolution as in the photosystem(II) enzyme [11][12][13][14].…”

An unexpected oxovanadium(IV) complex with in situ generated lactone ligand: Synthesis, crystal structure and DNA-binding property

“…To continue our research in this project, we designed a new aminophenol-based multifunctional Schiff base ligand K 2 HL 1 (K 2 HL 1 = potassium 2-(((2-hydroxynaphthalen-1-yl)methylene)amino)pentanedioate) to construct potential oxovanadium-based material and drug. In this communication, we report the synthesis and structurally characterization of an unexpected novel oxovanadium complex, [VO(L)(Phen)] (H 2 L = 2-((2-hydroxynaphthalen-1 -yl)-methyleneamino)-5-oxotetrahydrofuran-2-carboxylic acid, Phen = 1, 10-phenanthroline) (1), in which the L 2− is an in situ generated lactone Schiff base ligand from the precursor of K 2 HL 1 (Scheme 1) [31,32]. The DNA-binding properties of 1 with calf thymus DNA (CT-DNA) have also been investigated by fluorescence and circular dichroism (CD) spectra.…”