LAUSR

Abstract The nitrilotripropionic acid (H3ntp) is a flexible polycarboxylate ligand that has been used in the preparation of polynuclear compounds with several metal cations. In this work, we present the in solution study of the interaction of ntp with a wide range of metal ions (M): Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Fe(III). The species [Mntp]−, [M(Hntp)], and [M3(Hntp)2]2+ were detected for most metal ions. In the case of Cu(II), the potentiometric model was also supported through additional thermodynamic characterization by spectroscopy. We also performed computational calculations at the UB3LYP/LANL2DZ SMD level of theory that allowed us to predict the electronic spectra of the proposed species. The computational model showed a satisfactory performance, as demonstrated by the calculated electronic spectra fit to the experimental data. A possible assembly mechanism for the reported capsule-shaped complex [Cu3(Hntp)2]2+ is proposed.