Complexes of 6A-(2-Aminoethylamino)-6A-deoxy-b-cyclodextrin and 6A-[Bis(carboxylatomethyl)amino]-6A-deoxy-b-cyclodextrin with (R)- and (S)-Tryptophanate and (R)- and (S)-Phenylalaninate in Aqueous Solution. A pH Titrimetric and N.M.R. Spectroscopic Study

1999 ◽  
Vol 52 (12) ◽  
pp. 1143 ◽  
Author(s):  
Melissa Sandow ◽  
Bruce L. May ◽  
Philip Clements ◽  
Christopher J. Easton ◽  
Stephen F. Lincoln
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Spectroscopic Study ◽  
The Stability

The 1 : 1 host–guest complexes formed by 6A-(2-aminoethylamino)-6A-deoxy-β-cyclodextrin and (R)- and (S)-tryptophanate are characterized by log(K/dm3 mol–1) = 4.83±0.02 and 4.72±0.03, respectively, and for those formed with (R)- and (S)-phenylalaninate log(K/dm3 mol–1) = 3.82±0.05 and 4.12±0.02, respectively, in aqueous solution at 298.2 K and I = 0.10 mol dm–3 (NaClO4), where K is the stability constant. The corresponding values for the analogous complexes formed by 6A-[bis(carboxylatomethyl)amino]-6A-deoxy-β-cyclodextrin are 3.4±0.1, 3.3±0.1, 4.02±0.06 and 4.00±0.06, respectively. Host–guest complexes are also formed by the monoprotonated substituted β-cyclodextrins. 1H n.m.r. spectroscopy (ROESY) indicates that the guests are complexed with their indole and phenyl entities inside the annuli of the substituted β-cyclodextrin hosts.

Evaluation of the stability constant of Cl2˙–in neutral aqueous solution

1995 ◽  
Vol 91 (18) ◽  
pp. 3303-3305 ◽  
Author(s):  
David J. Adams ◽  
Susan Barlow ◽  
George V. Buxton ◽  
Treena M. Malone ◽  
G. Arthur Salmon
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Neutral Aqueous Solution ◽  
The Stability

scholarly journals Determination of the protonation state of [H3PW11O39]4− and the stability constant of [Ag(H2O)(H3PW11O39)]3− in aqueous solution

2016 ◽  
Vol 69 (17) ◽  
pp. 2525-2531 ◽  
Author(s):  
Jidan Wang ◽  
Jiansheng Li ◽  
Wansheng You ◽  
Chunxiang He ◽  
Zaiming Zhu
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Protonation State ◽  
The Stability

The coordination of β-amino ketoximes with divalent iron, cobalt, nickel and zinc

1978 ◽  
Vol 31 (11) ◽  
pp. 2409 ◽  
Author(s):  
HKJ Powell ◽  
JM Russell
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Stability Constant ◽  
Methyl Ether ◽  
Infrared Spectra ◽  
Iron Cobalt ◽  
Divalent Iron ◽  
Cobalt Nickel ◽  
Stability Order ◽  
The Stability

The iron(II), nickel(II) and zinc(II) complexes of the diamine dioxime ligand 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime (H2dddo) and the cobalt(II), nickel(II) and zinc(II) complexes of its O-methyl ether (Hddmo) have been studied potentiometrically at 25°C, I 0.10M NaCl. Stability constant data are compared with those obtained for the copper(II) and cobalt(II) complexes of H2dddo and the copper(II) complexes of Hddmo. H2dddo coordinates in the oxime-oximato form [M(Hdddo)]+ with iron(II), cobalt(II), nickel(II) and zinc(II) Hddmo forms complexes with the ligand coordinated in the oxime form [M(Hddmo)]2+ and the oximato form [M(ddmo)]+. The complexes [Zn(Hddmo)2]2+, [Zn(Hddmo)(ddmo)]+ and [Co(ddmo)(OH)] were also characterized in aqueous solution. The stability order FeII < CoII < NiII < CuII > ZnII was observed for the formation of 1 : 1 complexes with the ligands Hdddo- (log K = 8.8, 11.7, 15.2, 23.3, 12.0 for Fe to Zn respectively) and Hddmo (5.7, 6.6, 12.1, 5.3 for Co to Zn). The infrared spectra of the complexes [Ni(Hdddo)] ClO4,H2O and [Zn(Hdddo)] ClO4 are discussed in terms of oxime-oximato hydrogen bonding.

scholarly journals Modeling and Thermodynamic Values of Complex Equilibrium of Cobalt(II) with Diethylenetriaminepentaacetic Acid in Aqueous Solution

2021 ◽  
Author(s):  
Ghusoon Faidhi Hameed ◽  
Fawzi Yahya Waddai ◽  
Nahla Shakir Salman
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Complex Formation ◽  
Stability Constant ◽  
Wide Spectrum ◽  
Equilibrium Constants ◽  
Diethylenetriaminepentaacetic Acid ◽  
The Stability ◽  
Hoff Equation ◽  
Potentiometric Data

The paper reports the study of the complex formation of cobalt (II) with diethylenetriaminepentaacetic acid (DTPA, H5L) based on spectrophotometric (SF) and potentiometric data (pH). Complexes of different compositions were found, and equilibrium constants, as well as the stability constants of these complexes, were determined. Accumulation of complexes in proportion is calculated based on the acidity of the medium. The experimental data have been carried out by using mathematical models to assess the solution's possible existence with a wide spectrum of complex particles and to point out those which are quite sufficient to copy the experimental data. In addition, thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for the studying complexes were calculated according to the values of stability constant (KST) at 25 °C obtained from the temperature dependence of stability constant by using van’t Hoff equation.

Metallo-β-cyclodextrins of 6A-(2-(2-(2-Aminoethylamino)-ethylamino)ethylamino)-6A-deoxy-β-cyclodextrin and 6A-Deoxy-6A-(1,4,7,10-tetraazacyclododecan-1-yl)-β-cyclodextrin: Their Formation and Complexation of (R)- and (S)-Tryptophan and Tryptophanate in Aqueous Solution

2000 ◽  
Vol 53 (5) ◽  
pp. 375 ◽  
Author(s):  
Suzanna D. Kean ◽  
Christopher J. Easton ◽  
Stephen F. Lincoln
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Binary Complexes ◽  
The Stability

The binary metallo-β-cyclodextrins formed by 6A-(2-(2-(2-aminoethylamino)ethylamino)ethylamino)-6A-deoxy-β-cyclodextrin, [M(βCDtrien)]2+, where M2+ = Ni2+, Cu2+ and Zn2+, are characterized by log(K/dm3 mol-1) = 11.500.02, 10.700.07 and 9.400.01, respectively, in aqueous solution at 298.2 K and I = 0.1 mol dm-3 (NaClO4), where K is the stability constant. For those formed by 6A-deoxy-6A-(1,4,7,10-tetraazacyclododecan-1-yl)-β-cyclodextrin, [M(βCDcyclen)]2+, where M2+ = Cu2+ and Zn2+, log(K/dm3 mol-1) = 13.610.02 and 11.620.04, respectively. The ternary metallo-β-cyclodextrins formed by [M(βCDtrien)]2+ and (R)- and (S)-tryptophanate, [M(βCDtrien)((R)-Trp)]+ and [M(βCDtrien)((S)-Trp)]+ are characterized by log(K/dm3 mol-1) = 6.900.04 and 6.790.04, 8.20.3 and 7.90.2, and 6.640.08 and 7.010.07, respectively, where M2+ = Ni2+, Cu2+ and Zn2+. For the ternary metallo-β-cyclodextrins formed by [M(βCDcyclen)]2+ and (R)- and (S)-tryptophanate, [M(βCDcyclen)((R)-Trp)]+ and [M(βCDcyclen)((S)-Trp)]+, log(K/dm3 mol-1) = 6.840.06 and 6.850.06, and 4.950.05 and 4.940.04, respectively, where M2+ = Cu2+ and Zn2+. Other binary and ternary metallo-β-cyclo-dextrins are also formed. Binary complexes formed by the substituted β-cyclodextrins are exemplified by βCDcyclen.(R)-Trp- and βCDcyclen.(S)-Trp- for which log(Kd/m3 mol-1) = 3.690.04 and 3.950.03, respectively. These data are discussed together with those from the literature characterizing other metallo-β-cyclodextrin and substituted β-cyclodextrin systems.

A 139La NMR study of the interactions between the La(III) cation and D-ribose in aqueous solution

1994 ◽  
Vol 72 (7) ◽  
pp. 1753-1757 ◽  
Author(s):  
Zhigang Chen ◽  
Nicole Morel-Desrosiers ◽  
Jean-Pierre Morel ◽  
Christian Detellier
Keyword(s):  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Stability Constant ◽  
Chemical Shifts ◽  
Similar Treatment ◽  
Calorimetric Measurements ◽  
Nmr Study ◽  
The Stability ◽  
Good Agreement

The interactions of the La(III) cation with D-ribose and with D-arabinose in aqueous solution were investigated by 139La NMR spectroscopy. In the case of D-ribose, the formation of a La(III)-sugar complex was indicated by variations of the 139La chemical shift and linewidth with an increase of the sugar concentration in solution. In contrast, the complexation of La(III) by arabinose is very weak and almost undetectable by 139La NMR. On the basis of a 1:1 stoichiometry, the stability constant for the complex of La(III) with D-ribose was calculated from the observed 139La chemical shift values. A similar treatment was done for the viscosity corrected 139La linewidths using arabinose as an uninteractive reference. The stability constants, K, obtained independently from 139La chemical shifts and linewidths are in good agreement, 2.8 ± 0.5 and 2.2 ± 0.6 M−1 respectively at 299.0 ± 0.5 K. The thermodynamic parameters for the complexation of La(III) by D-ribose could also be obtained: ΔH0 = −12 ± 2 kJ mol−1, and ΔS0 = −31 ± 5 J K−1 mol−1. These values are in very good agreement with those obtained by calorimetric measurements.

Metallocyclodextrins of 6A-(2-Aminoethylamino)-6A-deoxy-ß-cyclodextrin: Their Formation and Complexation of (R)- and (S)-Tryptophanate in Aqueous Solution

1999 ◽  
Vol 52 (12) ◽  
pp. 1151 ◽  
Author(s):  
Melissa Sandow ◽  
Christopher J. Easton ◽  
Stephen F. Lincoln
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
The Stability

The binary metallocyclodextrins formed by 6A-(2-aminoethylamino)-6A-deoxy-β-cyclodextrin ([M(βCDen)]2+ where M2+ = Co2+ , Ni2+ , Cu2+ and Zn2+) are characterized by log(K/dm3 mol–1) = 12.000.05, 7.810.01, 8.370.03 and 8.520.07, respectively, in aqueous solution at 298.2 K and I = 0.10 mol dm–3 (NaClO4), where K is the stability constant. The ternary metallocyclodextrins formed by [M(βCDen)]2+ and (R)- and (S)-tryptophanate, [M(βCDen)(R)-Trp]+ and [M(βCDen)(S)-Trp]+ , are characterized by log(K/dm3 mol–1) = 8.710.06 and 8.540.07, 5.380.06 and 5.410.04, 8.200.04 and 7.860.02, and 5.790.01 and 5.790.05, respectively, when M2+ = Co2+ , Ni2+ , Cu2+ and Zn2+. These data are discussed together with those characterizing the less stable metallocyclodextrins formed by 6A-(3-aminopropylamino)-6A-deoxy-β-cyclodextrin.

REMOVAL OF HEAVY METAL Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II) IONS FROM AQUEOUS SOLUTION BY MENTHA PIPERITA EXTRACT

2020 ◽  
pp. 15-20
Author(s):  
Ersin Yucel ◽  
Mine Yucel
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
High Efficiency ◽  
Correlation Coefficients ◽  
Langmuir Model ◽  
Mentha Piperita ◽  
Freundlich Model ◽  
Biosorption Capacity ◽  
Peppermint Extract ◽  
The Stability

In this study, the usage of the peppermint (Mentha piperita) for extracting the metal ions [Mg (II), Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II)] that exist at water was investigated. In order to analyze the stability properties, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used at removing the metal ions and the highest correlation coefficients (R2) were obtained at Langmuir isotherm. Therefore, it is seen that the Langmuir model is more proper than the Freundlich model. However, it was found that the correlation coefficients of removing Ni and Cd is higher at Freundlich model than Langmuir and low at Dubinin-Radushkevich isotherm. It is established that the biosorption amount increase depends on the increase of biosorbent and it can be achieved high efficiency (95%) even with small amount (0.6 mg, peppermint extract) at lead ions. It is also determined that the peppermint extracted that is used at this study shows high biosorption capacity for metal ions and can be used for immobilization of metals from polluted areas.

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