Complex formation equilibria of polyamine ligands with copper(II) and zinc(II)

Bifunctional 3-Hydroxy-4-Pyridinones as Potential Selective Iron(III) Chelators: Solution Studies and Comparison with Other Metals of Biological and Environmental Relevance

“…The different length of the alkyl moiety is also another factor influencing the stability of the species; in fact, from the comparison between the data obtained for Cu( L2 ) 0 (aq) and Cu( L3 ) 0 (aq) species, which only differ in the ligand structures by an additional -CH 2 group present in the H 2 ( L3 ) alkyl chain ( Figure 1 ), a decrease of the formation constants with alkyl moiety length decreasing can be observed ( Table 1 ). Furthermore, from the comparison among the Cu( L1 ) 0 (aq) and Cu( L5 ) + stability constants it can be observed that the ligand featured by the only amino group (H( L5 )) in the alkyl chain forms Cu 2+ complexes with higher stability than the carboxylic-3-hydroxy-4-pyridinone (H 2 ( L1 )), a trend which is in accordance with data reported in the literature [ 24 , 25 , 26 ] on the interactions of alkylamines and carboxylic acids towards Cu 2+ , also following the Pearson’s principle of “ hard and soft acids and bases” theory (HSAB) for ligand-metal preferences [ 27 , 28 , 29 ].…”

“…As already observed for the stability constants, the sequestering ability is also influenced by the presence in the ligands structure of the -CO 2 H, -NH 2 , -CHNH 2 CO 2 H [ 24 ] and, possibly, the amidic moiety in the alkyl chain. In addition, the p L 0.5 value obtained for the amino-3-hydroxy-4-pyridinone (H( L5 )) is slightly higher than the one calculated for H 2 ( L1 ) (terminal -CO 2 H group), highlighting a better Cu 2+ sequestration by the ligand featured by the terminal -NH 2 group (H( L5 )) with respect to the carboxylic one [ 24 , 25 , 26 ].…”

Decarboxylative Phosphine Synthesis: Insights into the Catalytic, Autocatalytic, and Inhibitory Roles of Additives and Intermediates

“…However, excessively fast reduction may lead to rapid unproductive depletion of ester 3 . PMDTA has been used as a ligand for the stabilization of lower-order zinc complexes, being more effective than mono- and diamines . Thus, one of the roles that PMDTA can play in the decarboxylative phosphine synthesis is dampening the reduction of NHPI esters 6 without completely shutting it down by partially sequestering the Lewis acidic Zn 2+ on the metal surface and bringing the reduction rate into alignment with the downstream steps en route to the phosphine product.…”

A Family of Kojic Acid Derivatives Aimed to Remediation of Pb2+ and Cd2+

“…1) towards Pb 2+ and Cd 2+ , using potentiometry and spectrophotometry supported by 1 H and 13 C NMR spectroscopy and DFT calculations. The proposed molecules join the chelating properties of the hydroxypyrone molecules (vicinal carbonyl and O − groups) and those of polyamines (ethylenediamine (en), 1,3-diaminopropane (dpa), 1,4-diaminobutane (dba) and 2,2′,2″-triaminotriethyllamine (tren)) (Nurchi et al, 2019a). These ligands show an extremely high similarity with some of the aminopolycarboxylic acids previously evaluated (Nurchi et al, 2020), as can be argued from the comparison of the structures reported in Fig.…”