Effect of various mixed aqueous solvents on the stability constants of Cu(II) chelates with piperidine-2-carboxylic acid

1985 ◽  
Vol 95 (5-6) ◽  
pp. 541-545
Author(s):  
Christine Rebello ◽  
G. Shashikala ◽  
M. G. Ram Reddy
Keyword(s):  
Carboxylic Acid ◽  
Stability Constants ◽  
Mixed Aqueous Solvents ◽  
The Stability

Interaction en milieu eau–dioxane des ions Cu2+, Ni2+ et Ag+ avec les acides furannecarboxylique-2 et tetrahydrofurannecarboxylique-2

1982 ◽  
Vol 60 (9) ◽  
pp. 1063-1066 ◽  
Author(s):  
Emmanuelle Michaud ◽  
Gilles Pivert ◽  
Gérard Duc ◽  
Michelle Petit-Ramel ◽  
Germaine Thomas-David
Keyword(s):  
Carboxylic Acid ◽  
Stability Constants ◽  
Protonation Constants ◽  
Acid System ◽  
Copper Nickel ◽  
Uv Visible ◽  
The Stability ◽  
Potentiometric Data

The protonation constants of furan-2 carboxylic (HFC) and tetrahydrofuran-2 carboxylic (THFC) acids and the stability constants of their copper, nickel and silver 1:1 complexes have been measured in water containing 50% dioxane (I = 0.1 (NaNO3); t = 25 °C). Treatment of the potentiometric data has been completed by uv–visible spectrophotometric measurements. The results are discussed and a chelate structure is displayed for the Cu – tetrahydrofuran-2 carboxylic acid system.

Stability constants and spectral studies of complexes of 2-hydroxy-5-methylazobenzene-2′-carboxylic acid with some divalent metal ions

1984 ◽  
Vol 62 (11) ◽  
pp. 2299-2301
Author(s):  
C. Mahalingam ◽  
J. K. Sthapak ◽  
D. D. Sharma ◽  
R. L. Tiwari ◽  
Smita Sthapak
Keyword(s):  
Carboxylic Acid ◽  
Metal Ions ◽  
Metal Complexes ◽  
Stability Constants ◽  
Divalent Metal ◽  
Reflectance Spectra ◽  
Spectral Studies ◽  
Divalent Metal Ions ◽  
The Stability

The stability constants of metal complexes of 2-hydroxy-5-methylazobenzene-2′-carboxylic acid have been determined spectrophotometrically. These follow the Irving–Williams sequence: log KOH(H) = 10.67, log K1(Co) = 9.02, log K1(Ni) = 9.68, log K1(Cu) = 13.37, log K1(Zn) = 7.58, and [Formula: see text]The chelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and [Formula: see text] with the dye have been prepared and characterized on the basis of their ir and reflectance spectra.

Metal Complexes of 6-Hydroxymethylpyridine-2-carboxylic Acid

1962 ◽  
Vol 15 (4) ◽  
pp. 786 ◽  
Author(s):  
RW Green ◽  
GKS Ooi
Keyword(s):  
Carboxylic Acid ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Stability Constants ◽  
Steric Hindrance ◽  
Transition Metal Ions ◽  
Complexing Agent ◽  
Ph Titration ◽  
The Stability

Spectrophotometric and pH-titration methods have been used to determine the stability constants at 25 �C of complexes between transition metal ions and the anion of 6-hydroxymethylpyridine-2-carboxylic acid. This anion is found to be a weaker base and a weaker complexing agent than the pyridine-2-carboxylate ion. There is some evidence for steric hindrance of tris complexes.

Extraction of strontium and barium salts by the nitrobenzene solution of dicarbolide in the presence of glymes

1985 ◽  
Vol 50 (3) ◽  
pp. 581-599 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Stability Constants ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Minor Role ◽  
Nitrobenzene Solution ◽  
Ligand Structure ◽  
Stability Constants Of Complexes ◽  
Separation Factors ◽  
The Stability ◽  
A Minor

Extraction of microamounts of Sr2+ and Ba2+ (henceforth M2+) from the aqueous solutions of perchloric acid (0.0125-1.02 mol/l) by means of the nitrobenzene solutions of dicarbolide (0.004-0.05 mol/l of H+{Co(C2B9H11)2}-) was studied in the presence of monoglyme (only Ba2+), diglyme, triglyme, and tetraglyme (CH3O-(CH2-CH2O)nCH3, where n = 1, 2, 3, 4). The distribution of glyme betweeen the aqueous and organic phases, the extraction of the protonized glyme molecule HL+ together with the extraction of M2+ ion and of the glyme complex with the M2+ ion, i.e., ML2+ (where L is the molecule of glyme), were found to be the dominating reactions in the systems under study. In the systems with tri- and tetraglymes the extraction of H+ and M2+ ions solvated with two glyme molecules, i.e., the formation of HL2+ and ML22+ species, can probably play a minor role. The values of the respective equilibrium constants, of the stability constants of complexes formed in the organic phase, and the theoretical separation factors αBa/Sr were determined. The effect of the ligand structure on the values of extraction and stability constants in the organic phase is discussed.

Studies on the Coordination Reaction of VO2+ and Tannic Acid in the Tannin Extract Desulfurization

2012 ◽  
Vol 239-240 ◽  
pp. 1573-1576
Author(s):  
Zhu Qing Gao ◽  
Xiao Dong Cai ◽  
Kai Cheng Ling
Keyword(s):  
Stability Constants ◽  
Tannic Acid ◽  
Ph Value ◽  
Protonation Constants ◽  
Conditional Stability ◽  
Tannin Extract ◽  
Acid Effect ◽  
Different Temperatures ◽  
The Stability ◽  
Apparent Stability

At different temperatures, the protonation constants of tannic acid and the complex apparent stability constants between tannic acid and VO2+ were determined by using pH potentimetric method. The results showed that the protonation constants and the complex apparent stability constants slightly decreased with the raising temperature. In accordance with the pH value in the tannin extract technology, the conditional stability constants of the complex were calculated on the basis of the acid effect of tannic acid and the hydrolysis effect of VO2+. It was found that pH greatly affected the stability constants of the complex , so pH must be strictly controlled in the tannin extract technology.

scholarly journals Photoluminescent Coordination Polymers Based on Group 12 Metals and 1H-Indazole-6-Carboxylic Acid

Inorganics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 20
Author(s):  
Antonio A. García-Valdivia ◽  
Estitxu Echenique-Errandonea ◽  
Gloria B. Ramírez-Rodríguez ◽  
José M. Delgado-López ◽  
Belén Fernández ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Coordination Polymers ◽  
Density Functional ◽  
Free Ligand ◽  
Emission Spectra ◽  
Point Of View ◽  
Theoretical Point ◽  
Fourier Transformed Infrared Spectroscopy ◽  
3D Network ◽  
The Stability

Two new coordination polymers (CPs) based on Zn(II) and Cd(II) and 1H-indazole-6-carboxylic acid (H2L) of general formulae [Zn(L)(H2O)]n (1) and [Cd2(HL)4]n (2) have been synthesized and fully characterized by elemental analyses, Fourier transformed infrared spectroscopy and single crystal X-ray diffraction. The results indicate that compound 1 possesses double chains in its structure whereas 2 exhibits a 3D network. The intermolecular interactions, including hydrogen bonds, C–H···π and π···π stacking interactions, stabilize both crystal structures. Photoluminescence (PL) properties have shown that compounds 1 and 2 present similar emission spectra compared to the free-ligand. The emission spectra are also studied from the theoretical point of view by means of time-dependent density-functional theory (TD-DFT) calculations to confirm that ligand-centred π-π* electronic transitions govern emission of compound 1 and 2. Finally, the PL properties are also studied in aqueous solution to explore the stability and emission capacity of the compounds.

Complexation of Iron with the Orally Active Decorporation Drug L1 (3-Hydroxy-1,2-Dimethyl-4-Pyridinone)

1992 ◽  
Vol 38 (4) ◽  
pp. 562-565 ◽  
Author(s):  
M A Kline ◽  
C Orvig
Keyword(s):  
Blood Plasma ◽  
Potentiometric Titration ◽  
Stability Constants ◽  
Computer Model ◽  
Chelating Agent ◽  
Glass Electrode ◽  
Simple Computer ◽  
Active Iron ◽  
The Stability ◽  
Orally Active

Abstract The stability constants for the Fe(III) complexes of the orally active iron decorporation drug L1 (3-hydroxy-1,2-dimethyl-4-pyridinone) have been determined by potentiometric titration [glass electrode, 25.0 degrees C, mu = 0.15 mol/L (isotonic) NaCl]. A simple computer model of blood plasma (citrate 100 mumol/L, transferrin 37 mumol/L) has been used to compare the Fe(III) binding efficacies in blood of L1 and the clinically used intravenously administered chelating agent deferoxamine.

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