ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Complex-compounds in solutions using paper electrophoresis. Chelation with alcoholic hydroxy groups. III

V. Jokl, J. Majer, and M. Mazáčová

Komenský University, Bratislava

Abstract: cf. CA 60, 12714f. The curves of the electrophoretic mobility of N,N-his(hydroxyethyl)glycine (I), N-hydroxyethyliminodiacetic acid (II), and unsubstituted glycine and iminodiacetic acid with a series of bi- and trivalent central ions are described. I and II are potentially 4-donor complex forming agents because the alc. hydroxyl can participate as donor group in the formation of chelates. In contrast to glycine, I does not form anionic complexes with bivalent central ions of the coordination no. 6. Although the basicity of the N atom in I and II is considerably decreased as compared with unsubstituted amino acids, the stability of the first degree complexes mostly is the same or greater. The difference between the stability of the first and second degree complexes is increased at I and II as compared with unsubstituted amino acids, because the bonding of the 2nd ligand can be achieved by breaking up of 1 chelate ring. The hydroxyethyl groups of I and II participate on chelation only where not all coordination positions of the central atom are taken by N and carboxyl O of ligands. It is that way with the first degree complexes of I and II (except Cu-II) and with the second degree of octahedral I complexes. Under these conditions there is no cleavage of proton at the coordination of alc. hydroxyl except with Fe+++ and apparently with Pb++ complexes.

Full paper in Portable Document Format: 188a584.pdf (in Czech)

Chemical Papers 18 (8) 584–596 (1964)