Stabilities of Scandium(III)- and Yttrium(III)-Tiron Chelates and their hydrolytic behavior

Abstract

The interactions of Sc 3+ and Y 3+ ions with disodium 1,2-dihydroxybenzene-3,5-disulfonate (Na 2 H 2 L, where H 2 L 2-= Tiron) were investigated in aqueous solution by means of potentiometric and spectroscopic methods. The coordination of Tiron to Sc 3+ and Y 3+ takes place through two phenolic oxygen atoms of catecholate ion in different stoichiometries. Thus, the binding of Tiron to Sc 3+ occurs either in 1 : 1 or 1 : 2 molar ratios; they have resulted by the formation of [ ScL ] -and [ScL 2 ] 5-type complexes, respectively. On the other hand, Y 3+ ion behaves like Th 4+ and Ln 3+ ions toward Tiron. It forms [YL] -type complex in 1 : 1 molar ratio; but in 1 : 2 or in higher molar ratios, only unique [ Y 2 L 3 ] 6-type complex formation takes place. The formation constants of [ ScL ] -, [ ScL 2 ] 5-, [ YL ] -, and [ Y 2 L 3 ] 6-complexes were determined by analysis of the potentiometric data in ionic medium of 0.1 M KNO 3 or NaClO 4 at 25° C. The hydrolytic reactions of Sc(III) and Y(III) complexes with Tiron were determined from potentiometric data and the formation constants of [ ScL ( OH )] 2-and [ YL ( OH )] 2-were also calculated.g°

Study on the Interaction of Yttrium(III) with Adrenaline, Noradrenaline, and Dopamine

“…In our previous studies, it was reported that the Y(III) ion forms stable complexes with a ligand where oxygen is the donor. In one of the said studies, interaction of disodium 1,2-dihydroxybenzene-3,5-disulfonate (Tiron), a catechole derivate, with the Y(III) ion was examined in I = 0.1 M NaClO 4 at 298.15 K. The number of protons decomposed in a 1:1 molar Y(III)−Tiron solution was found to be two per metal ion, and the stability constant of the ML complex was found to be log β 1 = 14.11 . As the constant was always found to be 3 for higher molar ratios, the stability constant was found to be log β 2 = 43.97 considering the presence of the M 2 L 3 dinuclear complex in the medium.…”

“…In one of the said studies, interaction of disodium 1,2-dihydroxybenzene-3,5-disulfonate (Tiron), a catechole derivate, with the Y(III) ion was examined in I ) 0.1 M NaClO 4 at 298.15 K. The number of protons decomposed in a 1:1 molar Y(III)-Tiron solution was found to be two per metal ion, and the stability constant of the ML complex was found to be log β 1 ) 14.11. 2 As the constant was always found to be 3 for higher molar ratios, the stability constant was found to be log β 2 ) 43.97 considering the presence of the M 2 L 3 dinuclear complex in the medium. It was reported that in the Y(III)-Tiron system Tiron bound to Y(III) by both phenolic hydroxyls and that a five-membered chelate ring was formed.…”

“…The structural formulas are shown in Figure 1. These ligands are written as H 2 LH + , where phenolic protons are written on the left side of L. The catecholamine complexes of many transition metals have been reported in the literature, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] but information about the interactions of lanthanide(III) and catecholamines is restricted. Wu et al 21 investigated complexes of lanthanum(III) with adrenaline by a potentiometric method and a quantum chemical ab initio method under physiological conditions (335 K and an ionic strength of 0.15 mol‚dm -3 NaCl), to clarify neuroendocrine effects and the underlying mechanism of lanthanides.…”

“…Its ionic radius is 1.04 Å for coordination number 6, and its chemical properties are very similar to the later lanthanides ((1.00 to 1.17) Å) . Recently, some authors have studied the equilibria of catecholate complexes of many transition metals and lanthanides. − In our previous papers, the interactions of Y(III) 2,3 and La(III) 4 with catecholates were reported, i.e., 1,2-dihydroxybenzene-3,5-disulfonate (TIRON) and 4-nitrocatechol. We proposed that in the Y(III)−catecholate and La(III)−catecholate complexes two phenolic hydroxyl groups serve as binding sites for Y(III), but two phenolic hydroxyl groups are deprotonated.…”

Structure and Photoluminescence Tuning Features of Mn2+- and Ln3+-Activated Zn-Based Heterometal–Organic Frameworks (MOFs) with a Single 5-Methylisophthalic Acid Ligand

“…Occasionally, parts of them are synthesized by single organic ligands containing both N- and O-donor atoms, such as imidazole–dicarboxylic acid or pyridine–dicarboxylic acid . Furthermore, in order to meet the high-coordination-number requirement of lanthanide ions and construct novel structural topologies, a lot of mixed organic ligands with N- or O-donor atoms can also be employed in construction of Zn–Ln MOFs …”