The stabilities of some metal complexes of 8-hydroxyquinoline and related substances

Irving, H. M. N. H.; Rossotti, Hazel

doi:10.1039/jr9540002910

Cited by 121 publications

(34 citation statements)

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“…The ionization constants of the investigated Schiff bases and the stability constants of their metal chelates with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Th(IV), and UO2(II) ions were determined potentiometrically using the technique of Sarin and Munshi [16]. The ionization constants of the ligands are calculated using the equation used by Irving and Rossotti [17]. While metal-ligand stability constants were calculated using methods applied for computing successive stability constants [18].…”

Section: Potentiometric Measurementsmentioning

confidence: 99%

Spectroscopic and biological activity studies on tridentate Schiff base ligands and their transition metal complexes

et al. 2011

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Section: Potentiometric Measurementsmentioning

confidence: 99%

Spectroscopic and biological activity studies on tridentate Schiff base ligands and their transition metal complexes

et al. 2011

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“…The pH metric study were carried out in 0.1M NaClO 4 at constant temperature. The proton ligand formation was calculated by Irving Rossotti method [22,23] . The accurate pK values of complexes were calculated by half integral method and concordance with pointwise calculation method.…”

Section: Materials and Methodmentioning

confidence: 99%

Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

Naik

Poharkar

2016

ILCPA

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Abstract. The stability constant on complexation of rare earth metal ions Eu(III), Gd (III), Nd(III) and Tb(III) with substituted thiazole in 70% Dioxane (Dx)-water mixture have been determined by a pH and spectrophotometric method at 298.15K and ionic strength 0.1mol.dm -3 (sodium perchlorate).At constant temperature, the stability constant of the formed complexes decreases in the order Tb (III), Gd(III), Eu (III), Nd (III). The dissociation process is non-spontaneous, endothermic and entrophically unfavorable while formation of metal complexes has been found to be spontaneous, endothermic and entrophically favorable.

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“…32) To determine the stoichiometries of possible complexes, the degree of formation of Al(III) chelates n ᎐ was calculated from the formation curves employing the method of Irving and Rossotti. [35][36][37][38] The species distribution diagrams 39) …”

Section: Methodsmentioning

confidence: 99%

Potentiometric and Spectroscopic Studies on Aluminium(III) Complexes of Some Catechol Derivatives

Türkel

Berker

Özer

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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The aqua Al(III) ion is the "hardest" of the trivalent ions commonly found in the environment and in biological systems. Its effective ionic radius is 54 Å, which is smaller than other commonly encountered trivalent metal ions. Therefore the aqua Al(III) ion has the highest charge/size ratio and high affinity for hard anions. As a result, it has a strong tendency to hydrolyze in aqueous solution and its coordination equilibria contain rather complicated hydroxo complexes. 1 2,5) investigated the relations between the basicities of these oxygen donors and the stabilities of their Al(III) complexes. They concluded that the logarithm of protonation constants of monodentate donors and pK sum of bi-or terdentate donors provide a quantative measure for the hardness of each donor. The order of decreasing basicities along with the summation of their approximate logarithms of protonation constants are proposed to be: (catecholate ca. 22)Ͼ(aliphatic monohydroxy acid anion ca. 18) Ͼ(aromatic hydroxy acid anion ca. 16)Ͼ(alkoxide ca. 14)Ͼ(phenoxide ca. 10)Ͼ(carboxylate ca. 4). Therefore the complexes of Al(III) ion that are sufficiently stable to hydrolytic reactions and consequent precipitation in aqueous solution should contain ligands with the highest pK sum.The complexes of catechol derivatives with Al(III) ion including metal ions such as Fe(II), Fe(III), Mg(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cd(II), UO 2 (II), and VO(II) were studied by various researchers. 1,2,5-26) They determined that two or three moles of catechol derivatives are coordinated with one mole of these metal ions in their complexes. In particular, the constants of formation equilibria of Al(III) complexes of catechol derivatives have been the subject of a number of investigations. 1) Some of the hydroxy aromatic ligands are interesting three-protic ligands (H 3 L), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), 3,4-dihydroxyhydrocinnamic acid (3,4-DHHCA), and 3,4-dihydroxyphenylacetic acid (3,4-DHPA) are typical examples and they have affinities for metal ions to form stable complexes. 19,20,21,26) Some of their complexes do not hydrolyze and precipitate in aqueous solution, since 3,4-DHBA, 3,4-DHHCA, and 3,4-DHPA have one carboxylate binding site besides the catecholate sites that are in chelatable positions. 2,3-DHBA contains three potential binding sites on three adjacent ring carbons. It is a good model of the competitive salicylate (COO Ϫ , O Ϫ ) and catecholate type (O Ϫ , O Ϫ ) chelation in the same molecule. 5) Kennedy and Powell 7) investigated Al(III): catechol and 3,4-DHBA complexes using potentiometry in aqueous solution in Iϭ0.1 mol · l Ϫ KCl ionic medium at 25°C. They reported the stability constants for the mononuclear diphenolate complexes of Al(III) with catechol such as AlL, AlL 2 , and AlL 3 . They also indicated that monoand bis-complexes of catechol become hydrolyzed and then AlL(OH) Ϫ , and AlL 2 (OH) 4Ϫ hydroxo complexes formed. In the case of 3,4-DHBA, the existence of Al(HL)...

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The stabilities of some metal complexes of 8-hydroxyquinoline and related substances

Cited by 121 publications

References 0 publications

Spectroscopic and biological activity studies on tridentate Schiff base ligands and their transition metal complexes

Spectroscopic and biological activity studies on tridentate Schiff base ligands and their transition metal complexes

Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

Potentiometric and Spectroscopic Studies on Aluminium(III) Complexes of Some Catechol Derivatives

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