- Equilibrium and Structural Studies on Proton and Copper(II) Complexes of N-D-Gluconylglycine
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N-D-Gluconylglycine, a pseudopeptide derivative of glucono-1,5-lactone and glycine, was prepared and the equilibrium constants of its protonation and copper(II) co-ordination and the structures of the copper complexes formed were studied in aqueous solution by potentiometry, spectrophotometry, CD, EPR and (13)C NMR relaxation.The parent complexes formed in an acidic medium have low stabilities, characteristic of carboxylate co-ordination.In the range pH 5-9 the amide group and the 2-OH group of the ligand undergo deprotonation.In parallel with these processes, one ligand is replaced from the copper(II) coordination sphere.For the species MLH-2, 3O,1N co-ordination in the equatorial plane is proposed.The EPR measurements indicate that dimeric species are also formed.At pH > 9, further base-consuming processes start as an indication of the deprotonation of other alcoholic hydroxy groups of the sugar moiety or the formation of mixed hydroxo complexes.
- Gyurcsik, Bela,Gajda, Tamas,Nagy, Laszlo,Burger, Kalman
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- Synthesis, 13C-NMR characterization and crystal structure of some new N-D-gluconylamino acids
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Six N-D-gluconylamino acids were prepared through the reactions of D-glucono-δ-lactone with amino acids containing different side-chains. The compounds were characterized via high-resolution 13C-NMR spectrum in D2O, FTIR spectra and X-ray diffraction method. X-crystallographic results show that the N-D-gluconyl-β-alanine exists in an open-chain form in the solid state.
- Gyurcsik, Bela,Gajda, Tamas,Nagy, Laszlo,Parkanyi, Laszlo
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