scholarly journals A study of the formation constants of ternary and quaternary complexes of some bivalent transition metals

2010 ◽  
Vol 75 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Sangita Sharma ◽  
Dipika Dalwadi ◽  
Madhurjya Neog
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Transition Metals ◽  
Metal Ions ◽  
Aqueous Medium ◽  
Coordination Number ◽  
Metal Ion ◽  
Formation Constants ◽  
Bivalent Transition Metals ◽  
The Stability

The formation of hetero-ligand 1:1:1, M(II)-Opda-Sal/Gly ternary and 1:1:1:1, M(II)-Opda-Sal-Gly quaternary complexes, where M(II) = Ni, Cu, Zn and Cd; Opda = o-phenylenediamine, Sal = salicylic acid, Gly = glycine, was studied pH-metrically in aqueous medium. The formation constants for the resulting ternary and quaternary complexes were evaluated at a constant ionic strength, ? = 0.20 mol dm-3 and temperature, 30?0.1 ?C. The order of the formation constants in terms of the metal ion for both type of complexes was found to be Cu(II) > Ni(II) > Zn(II) > Cd(II). This order was explained based on the increasing number of fused rings, the coordination number of the metal ions, the Irving - William order and the stability of various species. The expected species formed in solution were pruned with the Fortran IV program SPEPLOT and the stability of the ternary and quaternary complexes is explained.

scholarly journals Formation constants of lanthanide metal ion chelates with some substituted sulfonic acids

2010 ◽  
Vol 7 (1) ◽  
pp. 235-238
Author(s):  
R. S. Sonone ◽  
G. H. Murhekar
Keyword(s):  
Ionic Strength ◽  
Sulfonic Acid ◽  
Metal Ion ◽  
Formation Constants ◽  
Trifluoromethanesulfonic Acid ◽  
Water Mixture ◽  
Benzenesulfonic Acid ◽  
Sulfonic Acids ◽  
Lanthanide Metal ◽  
The Stability

The pKa and logK values of some substituted sulfonic acid in 70% (v/v) dioxane-water mixture have been determined using pH metric measurements. The stability constant of complexes of Gd (III), Tb (III) and Ho (III) with p-aminobenzenesulfonic (L1) and p-sulfophthalic acid (L2), 2-amino-5-chloro benzenesulfonic acid (L3) and trifluoromethanesulfonic acid (L4) have been determined at 0.1M ionic strength at 28±0.1 0C pH metrically. It is observed that both the metal ions formed 1:1 & 1:2 complexes with all the ligands.

scholarly journals Complexation equilibria of ambroxol hydrochloride in solution by potentiometric and conductometric methods

2018 ◽  
Vol 9 (1) ◽  
pp. 49-56
Author(s):  
Ahmed Hosny Naggar ◽  
Hammed Mohammed Al-Saidi ◽  
Othman Abd El-Moaty Farghaly ◽  
Taher Mohammed Hassan ◽  
Salma Zaidan Mohamed Bortata
Keyword(s):  
Ionic Strength ◽  
Metal Ions ◽  
Stability Constants ◽  
Formation Constants ◽  
Alkaline Media ◽  
Ligand Complex ◽  
Complex Species ◽  
The Stability ◽  
Ambroxol Hydrochloride ◽  
Metal Ligand

The formation constants of Li(I), Mg(II), Sr(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ba(II), Pb(II), Al(III), Cr(III), Fe(III) and Th(IV) ions with ambroxol hydrochloride (AMB) were calculated using the half-n value. In presence of 0.1 M NaNO3, metal ions such as Zn(II), Cd(II), Ni(II), Cr(III), Li(I), Mg(II) and Al(III) forms three types of metal-ligand complexes (1:1, 1:2 and/or 1:3), while Sr(II) and Co(II) tend to form two types of metal complexes 1:1 and 1:2 (M:L). For ligand protonation constants, two logarithmic association constant values were calculated by the half-n method and are 10.7 and 7.6, respectively. The effect of ionic strength on stability constant of AMP, with different metal ions viz. Fe(III), Th(IV), Al(III), Cr(III) and Cu(II) was studied. Based on relationship between the ionic strength studied values and the 1st stability constants (Log K1H), we can conclude that the stability constants of the formed metal-ligand complex (1:1) were decreased as the ionic strength increased. The stoichiometry of the formed complexes in solution were determined by conductometric method and it is found to be of 1:1, 1:2 and/or 1:3 (M:L) complex species is formed in alkaline media. Also, study the species distribution diagrams of AMP for the calculated mole fraction αML and αML2 were discussed.

scholarly journals Inhibition of enzymes by metal ion-chelating reagents. Theory and new graphical methods of study

1974 ◽  
Vol 137 (1) ◽  
pp. 55-60 ◽  
Author(s):  
William G. Bardsley ◽  
Robert E. Childs
Keyword(s):  
Stability Constant ◽  
Metal Ions ◽  
Metal Ion ◽  
Graphical Methods ◽  
Ligand Interaction ◽  
Mechanism Of Inhibition ◽  
The Stability ◽  
Chelating Reagents

1. The mechanism of inhibition of enzymes by metal ion-chelating reagents is discussed and equations derived. 2. Two distinct mechanisms are postulated and graphical methods are given for differentiating between them. 3. Where the metal ion is actually removed from the enzyme to form a co-ordination complex in solution, a procedure is described for obtaining the stability constant for metal–enzyme interaction, the number of metal ions involved and the stoicheiometry of metal ion–ligand interaction.

Extraction of Heavy Metals from Aqueous Medium by Husk Biomass: Adsorption Isotherm, Kinetic and Thermodynamic study

2019 ◽  
Vol 233 (2) ◽  
pp. 201-223 ◽  
Author(s):  
Khalida Naseem ◽  
Rahila Huma ◽  
Aiman Shahbaz ◽  
Jawaria Jamal ◽  
Muhammad Zia Ur Rehman ◽  
...  
Keyword(s):  
Metal Ions ◽  
Aqueous Medium ◽  
Contact Time ◽  
Metal Ion ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Adsorption Sites ◽  
Order Kinetic Model

Abstract This study describes the adsorption of Cu (II), Co (II) and Ni (II) ions from wastewater on Vigna radiata husk biomass. The ability of adsorbent to capture the metal ions has been found to be in the order of Ni (II)>Co (II) and Cu (II) depending upon the size and nature of metal ions to be adsorbed. It has been observed that percentage removal of Cu (II), Co (II) and Ni (II) ions increases with increase of adsorbent dosage, contact time and pH of the medium but up to a certain extent. Maximum adsorption capacity (qmax) for Cu (II), Co (II) and Ni (II) ions has been found to be 11.05, 15.04 and 19.88 mg/g, respectively, under optimum conditions of adsorbent dosage, contact time and pH of the medium. Langmuir model best fits the adsorption process with R2 value approaches to unity for all metal ions as compared to other models because adsorption sites are seemed to be equivalent and only monolayer adsorption may occur as a result of binding of metal ion with a functional moiety of adsorbent. Pseudo second order kinetic model best interprets the adsorption process of Cu (II), Co (II) and Ni (II) ions. Thermodynamic parameters such as negative value of Gibbs energy (∆G°) gives information about feasibility and spontaneity of the process. Adsorption process was found to be endothermic for Cu (II) ions while exothermic for Co (II) and Ni (II) ions as signified by the value of enthalpy change (∆H°). Husk biomass was recycled three times for removal of Ni (II) from aqueous medium to investigate its recoverability and reusability. Moreover V. radiata husk biomass has a potential to extract Cu (II) and Ni (II) from electroplating wastewater to overcome the industrial waste water pollution.

scholarly journals Interaction of Ampicillin and Amoxicillin with Mn2+: A Speciation Study in Aqueous Solution

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3110
Author(s):  
Claudia Foti ◽  
Ottavia Giuffrè
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Metal Ion ◽  
Formation Constants ◽  
Enthalpy Change ◽  
Ligand Concentration ◽  
Empirical Parameter ◽  
Speciation Study ◽  
Potentiometric Measurements ◽  
The Stability

A potentiometric and UV spectrophotometric investigation on Mn2+-ampicillin and Mn2+-amoxicillin systems in NaCl aqueous solution is reported. The potentiometric measurements were carried out under different conditions of temperature (15 ≤ t/°C ≤ 37). The obtained speciation pattern includes two species for both the investigated systems. More in detail, for system containing ampicillin MLH and ML species, for that containing amoxicillin, MLH2 and MLH ones. The spectrophotometric findings have fully confirmed the results obtained by potentiometry for both the systems, in terms of speciation models as well as the stability constants of the formed species. Enthalpy change values were calculated via the dependence of formation constants of the species on temperature. The sequestering ability of ampicillin and amoxicillin towards Mn2+ was also evaluated under different conditions of pH and temperature via pL0.5 empirical parameter (i.e., cologarithm of the ligand concentration required to sequester 50% of the metal ion present in traces).

Interligand interaction in ternary complexes of Zn(II) and Cd(II) with dipeptides and aminoacids

1994 ◽  
Vol 72 (4) ◽  
pp. 1107-1110 ◽  
Author(s):  
Alexander Varghese Vaidyan ◽  
Pabitra K. Bhattacharya
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Computer System ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Binary And Ternary Complexes ◽  
The Stability ◽  
Interligand Interaction

The stability constants of binary and ternary complexes [MA], [Ma2], and [MAL] (where M = Zn(II) or Cd(II); A = glycylglycine, glycyl L-alanine, glycyl L-leucine; L = α-alanine phenylalanine, tyrosine, tryptophan, or L-histidine) in aqueous medium have been determined potentometrically at 25 °C and an ionic strength of 0.2 M NaClO4 (0.2 mol dm−3) using a computer system. It is observed that Δ log K of MAL complexes has low negative or positive values. Probable reasons have been discussed.

scholarly journals Design and Development of Complexation of Ce+3 Metal Ions with Synthesized INZ Incorporated Bio-active Schiff Bases

2021 ◽  
Vol 11 (4) ◽  
pp. 3989-4006
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Schiff Bases ◽  
Elemental Analysis ◽  
Metal Ion ◽  
Organic Ligands ◽  
Schiff Base Complexes ◽  
Spectral Techniques ◽  
The Stability ◽  
Antibacterial And Antifungal

In the present research, a series of Ce+3 metal ions complexation with INZ incorporating Schiff bases have been reported. INZ incorporated Schiff Bases (3a-e) were developed by condensing INZ with substituted aromatic aldehyde and confirmed with various spectral Techniques such as Elemental analysis, UV, IR, 1H-NMR, 13H NMR. All the synthesized organic ligands were evaluated against antibacterial and antifungal stains and found moderate to significant results. The Ce+3 metal ion solution mixed with newly prepared bio-active INZ Schiff bases (3a-e) to afford the [Ce-INZ Schiff Base] complexes (4a-e). The stability constants of prepared complexes were evaluated and found in order as a (3e) > (3d) > (3a) > (3b) > (3c).

scholarly journals A Reaction of 4, 5-Diphenylimidazole Nitration in the Presence of Some 3d-Metals Nitrates

2012 ◽  
Vol 7 (2) ◽  
pp. 124-129
Author(s):  
I. Voda ◽  
V. Druta ◽  
C. Indricean ◽  
I. Ciumacov ◽  
C. Turta
Keyword(s):  
Nitrogen Atom ◽  
Oxygen Atom ◽  
Metal Ions ◽  
Coordination Number ◽  
Metal Ion ◽  
Distorted Octahedral Environment ◽  
3D Metals ◽  
Octahedral Environment ◽  
Distorted Octahedral

By interaction of cobalt(II), nickel(II), or zinc(II) nitrate with 4,5- diphenylimidazole in methanol in solvotermal conditions the new derivative of imidazole (4,5-diphenyl-2-nitroimidazole) and three new coordinative compounds [M(4,5-Ph2ImNO2)2(CH3OH)2] have been synthesized and investigated. Metal ions have a distorted octahedral environment with N2O4. Coordination number of metal is six. Ligand is coordinated to metal ion by one oxygen atom of nitrogroup and one nitrogen atom of imidazole.

Structural variations of trinitrato(terpyridine)lanthanoid complexes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahsa Armaghan ◽  
Khodabakhsh Darzinezhad ◽  
Mostafa M. Amini ◽  
Christoph Janiak
Keyword(s):  
Metal Ions ◽  
Coordination Number ◽  
Structural Characterization ◽  
Metal Ion ◽  
Hirshfeld Surface ◽  
Structural Variations ◽  
Coordination Polyhedra ◽  
Percentage Contribution ◽  
Terpyridine Ligands

Abstract The structural characterization of the newly synthesized trinitrato(terpyridine)lanthanoid complexes [Nd(NO3)3(pytpy)(H2O)] (1), [Eu(NO3)3(pytpy)(EtOH)]·EtOH (2·EtOH) and [Tb(NO3)3(ptpy)(EtOH)] (3), with the modified terpyridine ligands pytpy = 4′-(pyridin-3-yl)-2,2′:6′,2″-terpyridine and ptpy = 4′-phenyl-2,2′:6′,2″-terpyridine, show all a coordination number of 10 at the metal ion with three bidentate nitrato ligands and an additional solvent ligand. The coordination polyhedra around the metal ions are highly irregular. Hirshfeld surface analyses of the intermolecular interactions show (C/O–)H⋯O bonding having the largest percentage contribution in all three structures, while there are remarkably few π-π interactions despite the numerous aryl rings.

Complexation of Europium(III) with Carbonate Ions in Groundwater

1988 ◽  
Vol 127 ◽  
Author(s):  
A. Chatt ◽  
R. R. Rao
Keyword(s):  
Ionic Strength ◽  
Metal Ion ◽  
Ion Pairing ◽  
Formation Constants ◽  
Trioctylphosphine Oxide ◽  
Synergic Effect ◽  
Extraction Behavior ◽  
Carbonate Ions ◽  
Synergic Extraction ◽  
Carbonate Complexation

ABSTRACTThe equilibrium extraction behavior of Eu(III) studied in chloroform solutions containing l-nitroso-2-naphthol (HA), either alone or combined with 2, 2'-dipyridyl, 1, 10-phenanthroline (phen), or trioctylphosphine oxide (TOPO) shows that the metal ion is extracted as either EuA, EuA3.2, 2'-dipyridyl, EuA3·phen, or EuA3·2TOPO, respectively. The synergic effect of phen or TOPO on the extraction of Eu(III) with l-nitroso-2-naphthol is more pronounced over that of 2, 2'-dipyridyl. The carbonate complexation of Eu(III) has been studied in 1.0 M ionic strength solutions at pH 8.0–9.0 and 25 °C using the synergic extraction system of 1-nitrşso-2-naphthol and pheo. The following complexes have been identified: EuCO34, Eu(CO3)2-, Eu(CO3)33-, and Eu(CO3)45- the results suggest that the first two species predominate at carbonate concentrations and pH similar to those found in most groundwaters. The formation constants of these species have been calculated at zero ionic strength using both SIT and ion pairing models.

Sign in / Sign up

Export Citation Format

Share Document