The acid-base properties and zinc(II) complexes of glycylhistamine, sarcosylhistamine, carcinine and carnosine have been studied by potentiometric, 13C and 14N NMR methods. Macroscopic species for the three states of protonation (LH22+, LH+, L) and the corresponding microspecies involving three protonation sites (terminal amino, N-1 and -3 imidazole nitrogens) are quantitatively estimated for the metal-free ligands. Zinc(II) complexation is shown to reverse the tautomeric preference between 1- and 3-H tautomeric forms of the imidazole ring (in LH+ and L), as compared to the free ligands where the 1-H tautomer is predominant.
|Number of pages||8|
|Journal||Journal of the Chemical Society. Perkin Transactions 2|
|Publication status||Published - 1994|
ASJC Scopus subject areas