FITTING AN UNUSUAL COMPLEXATION MODEL IN AQUEOUS ACID SOLUTIONS OF NICKEL(II) AND N,N,N',N',-TETRAKIS(CARBOXYMETHYL)-L-ORNITHINE
Titel:
FITTING AN UNUSUAL COMPLEXATION MODEL IN AQUEOUS ACID SOLUTIONS OF NICKEL(II) AND N,N,N',N',-TETRAKIS(CARBOXYMETHYL)-L-ORNITHINE
Auteur:
Tercero-moreno, J. M. Matilla, A. Moreno, C. F. Gonzalez, S. Niclos, J.
Verschenen in:
Journal of coordination chemistry
Paginering:
Jaargang 35 (1995) nr. 1-2 pagina's 73-83
Jaar:
1995-05-01
Inhoud:
Complex formation for nickel(II) with N,N,N',N',-tetrakis(carboxymethyl)-L-ornithine (H5TCO = H5L) in aqueous solution has been studied by potentiometric, conductometric and spectrophotometric methods. In addition to the complexes (MHL, ML or M2L2 and M2L) previously established for other closely related metal(II): H5L systems, the formation of Ni3L2 in acidic aqueous solution has been established. From 318 potentiometric data for 13 solutions with Ni(II):H5TCO = 0.5 to 4 and 2≤pH≤4.6 (I = 0.1M(KNO3) and T = 25°C) SUPERQUAD calculations yield the overall formation constants (βpqr = [MpHqLr]/[M]p[H]q[L]r) logβ111 = 20.82(1), logβ202 = 36.94(2), logβ302 = 40.36(5) and logβ201 = 19.42(12). Probable structures for these complexes are discussed.