Complexes binaires du nickel(II) et du zinc(II) avec la 1-canavanine et la 1-arginine, études potentiométriques et spectroscopiques

Abstract

The stability constants of binary complexes of 1-canavanine (Can) and 1-arginine (Arg) with Ni2+ and Zn2+ have been calculated at 25 °C and at ionic strength μ = 0.1 (NaNO3). This technique is completed with spectrophotometry and circular dichroïsm measurements in the ultraviolet and visible ranges. Thus we determined the molar absorbances and the molar circular dichroïsm of ligands and complexes with Ni2+ and Zn2+. Concerning the nickel(II), these measurements display three complexes, NiL, NiL2, and NiL3. 1-Canavanine, which generally has a tridentate ligand behaviour, becomes a bidentate ligand in the Ni(Can)3 complex. With regard to zinc(II), this study only displays the ZnL and ZnL2 species. Key words: 1-arginine, 1-canavanine, circular dichroïsm, nickel binary coordination, zinc binary coordination.