Free metal ion depletion by "Good's" buffers. III. N-(2-acetamido)iminodiacetic acid, 2:1 complexes with zinc(II), cobalt(II), nickel(II), and copper(II); amide deprotonation by Zn(II), Co(II), and Cu(II).
Potentiometric, visible, infrared, electron spin, and nuclear magnetic resonance studies of the complexation of N-(2-acetamido)iminodiacetic acid (H2ADA) by Ca(II), Mg(II), Mn(II), Zn(II), Co(II), Ni(II), and Cu(II) are reported. Ca(II) and Mg(II) were found not to form 2:1 ADA2- to M(II) complexes, while Mn(II), Cu(II), Ni(II), Zn(II), and Co(II) did form 2:1 metal chelates at or below physiological pH values. Co(II) and Zn(II), but not Cu(II), were found to induce stepwise deprotonation of the amide groups to form [M(H-1ADA)4-(2)]. Formation (affinity) constants for the various metal complexes are reported, and the probable structures of the various metal chelates in solution are discussed on the basis of various spectral data.
D002021:Buffers; D002413:Cations, Divalent; D055598:Chemical Phenomena; D002621:Chemistry; D003035:Cobalt; D003300:Copper; D007098:Imino Acids; D008670:Metals; D009532:Nickel; D011522:Protons; D015032:Zinc
D002021:Buffers; D002413:Cations, Divalent; D007098:Imino Acids; D008670:Metals; D011522:Protons; D003035:Cobalt; C020184:N-(2-acetamido)iminodiacetic acid; D003300:Copper; D009532:Nickel; D015032:Zinc