Spectrophotometric Study of the Formation of Iron(III) Complexes with Some Salicylic Acid Derivatives

1995 ◽  
Vol 60 (3) ◽  
pp. 464-472 ◽  
Author(s):  
Terézia M. Surányi ◽  
Evgenija A. Djurendić ◽  
Gyöngyi Gy. Vastag
Keyword(s):  
Salicylic Acid ◽  
Stability Constants ◽  
Aqueous Ethanol ◽  
Side Reaction ◽  
Spectrophotometric Study ◽  
Stoichiometric Ratio ◽  
Ligand Ratio ◽  
Salicylic Acid Derivatives ◽  
The Stability

The stoichiometric ratio and stability constants of iron(III) complexes with 1,n-di-O-salicyloylalkane-1,n-diols (n = 2 - 8) and N,N'-disalicyloyl-1,n-alkanediamines (n= 2 - 4) were determined spectrophotometrically. In 61.10% aqueous ethanol, the iron-to-ligand ratio is 1 : 1 (FeL+). The stability constants of the complexes were measured at 298 K and μ = 0.5 mol dm-3 (LiCl). Since the determination was performed in a glycinate buffer, the constants were corrected for the side reaction of iron(III) with glycine.

Synthesis of some salicylic acid derivatives and studies of their interaction with uranyl ion

1991 ◽  
Vol 56 (7) ◽  
pp. 1446-1453 ◽  
Author(s):  
Evgenija A. Djurendić ◽  
Terézia M. Surányi ◽  
Dušan A. Miljković
Keyword(s):  
Salicylic Acid ◽  
Stability Constants ◽  
Aqueous Ethanol ◽  
Continuous Variation ◽  
Acidity Constants ◽  
Stability Constants Of Complexes ◽  
Salicylic Acid Derivatives ◽  
Method Of Continuous Variation ◽  
The Stability ◽  
Derivatives Of

Some unsubstituted and substituted bis-derivatives of salicylic acid have been synthesized and their acidity constants determined spectrophotometrically in 61.10% aqueous ethanol. The stability constants of complexes these compounds from with UO22+-ion were determined spectrophotometrically using the method of continuous variation under following conditions: pH 3.58 and 3.98, 61.10% aqueous ethanol, μ = 0.5 (LiCl), 25 ± 1 °C.

scholarly journals 1H NMR and spectrophotometric study of alkaline metal ion complexes with N-dansyl aza-18-crown-6

2006 ◽  
Vol 4 (1) ◽  
pp. 13-28 ◽  
Author(s):  
Tadeusz Ossowski ◽  
Hanna Sulowska ◽  
Tomasz Karbowiak ◽  
Dorota Zarzeczanska ◽  
Błażej Gierczyk ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Stability Constants ◽  
Metal Ion ◽  
Spectrophotometric Study ◽  
Alkaline Metal ◽  
Empirical Methods ◽  
Absorption And Fluorescence Spectroscopy ◽  
The Stability ◽  
Semi Empirical ◽  
Formation Of Complexes

AbstractFormation of complexes of A18C6-Dns and metal cations (Ca2+, Sr2+, Ba2+ and Mg2+) in acetonitrile has been studied by NMR, absorption and fluorescence spectroscopy and PM5 semi-empirical methods. A18C6-Dns forms stable complexes with Ca2+, Sr2+ and Ba2+ cations. The stability constants of various complexes are determined by different methods and their structures are visualised by the PM5 semi-empirical calculations.

A spectrophotometric study of the complex formation between cobalt(III) and trans-1,2-cyclohexanedinitrilotetraacetic acid (CyDTA)

1979 ◽  
Vol 57 (17) ◽  
pp. 2292-2296 ◽  
Author(s):  
Rita K. Hessley ◽  
Shoba Waykole ◽  
Robert L. Sublett
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Spectrophotometric Study ◽  
Higher Order ◽  
Order Complex ◽  
Spectrophotometric Methods ◽  
Investigation Result ◽  
Unique System ◽  
The Stability

An intriguing and unique system has been observed during the otherwise routine study of the cobalt(III) complex of trans-1,2-cyclohexanedinitrilotetraacetic acid (CyDTA). Using classical spectrophotometric methods to determine the stoichiometry and the stability of a complex, significant deviations from the predicted 1:1 complex were observed in a system buffered at pH = 4.6. It is postulated that in addition to the usual 1:1 complex, the propensity of the reactants to form complexes and the strong oxidizing conditions used in this investigation result in the formation of a second, higher order complex between Co(III) and CyDTA. When the concentration of CyDTA exceeds that of Co(III), the metal:ligand ratio for this complex is 1:2. A structure is proposed, and approximate stability constants of both complexes are discussed.

scholarly journals Copper(II) and lead(II) complexation by humic acid and humic-like ligands

2011 ◽  
Vol 76 (9) ◽  
pp. 1325-1336 ◽  
Author(s):  
Ivana Kostic ◽  
Tatjana Andjelkovic ◽  
Ruzica Nikolic ◽  
Aleksandar Bojic ◽  
Milovan Purenovic ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Humic Acid ◽  
Stability Constants ◽  
Comparative Investigation ◽  
Binding Ability ◽  
Exchange Method ◽  
Mononuclear Complexes ◽  
Ion Exchange Method ◽  
The Stability

The stability of metal-humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II) and Pb(II) with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25?C and at an ionic strength of 0.01 (NaCl) using the Schubert ion-exchange method and its modified form. The stability constants were calculated from the experimental data by the Schubert method for complexes with benzoic and humic acid. A modified Schubert method was used for the determination of the stability constants of the complexes with salicylic acid. It was found that Cu(II) and Pb(II) form mononuclear complexes with benzoic and humic acid while with salicylic acid both metals form polynuclear complexes. The results indicate that Pb(II) has a higher binding ability than Cu(II) to all the investigated ligands. The Cu(II)-salicylate and Pb(II)-salicylate complexes showed noticeable higher stability constants compared with their complexes with humic acid, while the stabilities of the complexes with benzoic acid differed less. Salicylic and benzoic acids as humic-like ligands can be used for setting the range of stability constants of humic complexes with Cu(II) and Pb(II).

Synthesis and Biological Evaluation of the Salicylamide and Salicylic Acid Derivatives as Anti-Estrogen Agents

2012 ◽  
Vol 8 (3) ◽  
pp. 481-490 ◽  
Author(s):  
Yasemin Dundar ◽  
Yasemin Ozatik ◽  
Orhan Ozatik ◽  
Volkan Ergin ◽  
Tijen Onkol ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Biological Evaluation ◽  
Salicylic Acid Derivatives ◽  
Synthesis And Biological Evaluation

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.

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