Single and double crown macrocyclic derivatives of cyclotriphosphazene as receptors of silver(i) ions

RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38435-38442 ◽  
Author(s):  
Natalia Gutowska ◽  
Piotr Seliger ◽  
Grzegorz Andrijewski ◽  
Mariola Siwy ◽  
Magdalena Małecka ◽  
...  
Keyword(s):  
Stability Constants ◽  
Lariat Ethers ◽  
Double Crown ◽  
Methanol Solutions ◽  
The Stability ◽  
Derivatives Of

Two new single and double P-pivot lariat ethers have been synthesized and the stability constants of their complexes with silver(i) ions were determined in acetonitrile and methanol solutions.

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.

The Relative Stability of Internal Metal Complexes. II. Metal Derivatives of 8-Hydroxyquinoline 5-Sulphonic Acid and a Series of Monocarboxylic Mono-α-amino Acids including Histidine

1949 ◽  
Vol 2 (4) ◽  
pp. 579 ◽  
Author(s):  
LE Maley ◽  
DP Mellor
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Complexes ◽  
Stability Constants ◽  
Sulphonic Acid ◽  
Mathematical Treatment ◽  
Metal Derivatives ◽  
A Chain ◽  
The Stability ◽  
Derivatives Of

Stability constants of ct series of metal complexes derived from the series of α-amino acids, glycine, alanine, leucine, valine, histidine, and 8-hydroxyquinoline 5-sulphonic acid have been determined by an electrometric method. The metals fall in the same order, as regards stability of their complexes, as was found for the chelating molecules studied in Part I of this series. As the length of the a chain of the amino acid increases, there is a small decrease in the stability of the amino acid complexes of any one metal. The cobalt II complex of histidine is much more stable than cobalt II complexes derived from any of the other α-amino acids. It is suggested that this explains why histidine is able to nullify the inhibiting action of cobalt on the growth and respiration of various aerobic and anaerobic organisms. Though there is no great difference in the stability of corresponding metal complexes derived from 8-hydroxyquinoline and 8-hydroxyquinoline 5-sulphonic acid (when allowance is made for different solvents used in making the measurements), there is a marked difference in the bacteriostatic action of these two chelating molecules. A reason for this difference is suggested. The stability constants of any chelating reaction involving the liberation of any number of hydrogen ions can be evaluated by using the generalized mathematical treatment which has been set out in this series of papers.

scholarly journals Complexation of molybdenum(VI) with methyliminodiacetic acid in different water + methanol solutions

2016 ◽  
Vol 81 (5) ◽  
pp. 541-551
Author(s):  
Saleh Zeighaminezhad ◽  
Kavosh Majlesi
Keyword(s):  
Sodium Chloride ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Specific Interactions ◽  
Microsoft Excel ◽  
Methanol Solutions ◽  
The Stability ◽  
Methyliminodiacetic Acid

The complexation of molybdenum(VI) with methyliminodiacetic acid (MIDA) at pH = 6.00, T = 298 K , I = 0.1 mol.dm-3 of sodium chloride and different water + methanol solutions (0-45% v/v) was studied by using potentiometric and UV spectrophotometric measurements. The stability constants values were calculated and their trends have been interpreted by using the Kamlet-Abboud-Taft (KAT) model in order to investigate the role of different specific and non-specific interactions in the aqueous solutions of methanol. Hyperquad 2013 and Microsoft Excel 2010 softwares have been used for the calculations.

Thio derivatives of β-diketones and their metal chelates. V. Acid dissociation constants of some Monothio-β-diektones and stability constants of anickel(II) and a copper(II) chelate

1966 ◽  
Vol 19 (11) ◽  
pp. 2035 ◽  
Author(s):  
SHH Chaston ◽  
SE Livingstone
Keyword(s):  
Stability Constants ◽  
Mole Fraction ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Acid Dissociation ◽  
Acid Dissociation Constants ◽  
Water Solutions ◽  
Acetyl Acetone ◽  
The Stability ◽  
Derivatives Of

The acid dissociation constants (PKD) of the monothio derivatives of acetyl-acetone, dibenzoylmethane, and 3,3,3-trifluoro-1-(2- thenoyl)acetone, viz. 4-mercap-topent-3-en-2-one (I), 3-mercapto-1,3- diphenylprop-2-en-1-one (II), and 1,1,1-trifluoro-4-mercapto-4-(2- thienyl)but-3-en-2-one (III), were determined in dioxan/water solutions with varying mole fraction (n2) of dioxan. Over a range of n2 from 0.18 to 0.44 the values of pKD were found to vary linearly with n2 as given by the equations: (I) pKD = 5.7+12.0n2; (II) pKD = 7.0+10.9n2; (III) pKD = 3.55 + 9.2n2. The thio derivatives (I), (II), and (III) have pKD values 2.0-2.7 log units lower than their oxygen analogues. The logarithm of the stability constants (log β2) for the nickel(II) and copper(II) complexes of (II) were found to be 21.7 and 22.2, respectively. For both complexes K2 > K1. Comparison with the stability constants of the dibenzoylmethane complexes shows that for nickel(II) the complex of the monothio-β-diketone is more stable than that of the β-diketone while the converse is true for copper(II).

Binding of calcium and lead ions to carboxystarch prepared by action of nitrogen dioxide on native starch and its 2,3-dialdehyde derivatives

1986 ◽  
Vol 51 (6) ◽  
pp. 1340-1351 ◽  
Author(s):  
Rudolf Kohn ◽  
Karol Tihlárik
Keyword(s):  
Nitrogen Dioxide ◽  
Alkaline Medium ◽  
Binding Capacity ◽  
Lead Ions ◽  
Carbonyl Groups ◽  
Weakly Alkaline ◽  
Exchange Cations ◽  
Counter Ions ◽  
The Stability ◽  
Derivatives Of

The binding of calcium and lead ions to carboxy derivatives of starch prepared by allowing nitrogen dioxide to act on native maize starch (procedure A) and on starch 2,3-dialdehyde derivatives of degrees of oxidation DO(d.a.) ≥ 0.94 (procedure B) was studied. The carboxy group content of the samples in the H+ form was 4.6 - 12.1 mmol g-1. The effect of alkaline medium on the stability of the carboxy derivatives and on their ability to bind and exchange cations was examined. The Ca2+ → 2K+ exchange was evaluated in terms of the decrease in the electrostatic free enthalpy Δ(Gel/N)KCa, determined by alkalimetric potentiometric titrations, and the binding of Pb2+ ions was evaluated in terms of the activity of the Pb2+ counter-ions determined in suspensions of Pb salts of the carboxy derivatives by means of an ion specific electrode. The IR and CD spectra revealed that the carboxystarch preparations obtained by procedure A contained, in addition to free carboxy groups, a considerable amount of carbonyl groups. During the conversion of the latter groups to the former, even in a weakly alkaline medium, the carboxy derivatives undergo an appreciable degradation and lose, to a great extent, their ability to bind and exchange cations. Procedure B, on the other hand, leads to highly selective starch and amylose carboxy derivatives, exhibiting a small amount of carbonyl groups and featuring a relative stability towards alkaline medium; their binding capacity is as high as 12 milliequivalents of cations per g of sample.

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.

scholarly journals Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Laura Brelle ◽  
Estelle Renard ◽  
Valerie Langlois
Keyword(s):  
Gallic Acid ◽  
Tannic Acid ◽  
Water Soluble ◽  
Gel Formation ◽  
Ene Reaction ◽  
Inorganic Cations ◽  
Medium Chain Length ◽  
Physically Crosslinked ◽  
The Stability ◽  
Derivatives Of

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

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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