scholarly journals  Complex Formation of Alkyl-N-iminodiacetic Acids and Hard Metal Ions in Aqueous Solution and Solid State

2020 ◽  
Vol 49 (9-10) ◽  
pp. 1250-1266
Author(s):  
Cecilia Lindblad ◽  
Anders Cassel ◽  
Ingmar Persson
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Bond Distance ◽  
Degree Of Hydrolysis ◽  
Acid Base ◽  
Strong Base ◽  
Slow Kinetics ◽  
The Mean ◽  
Low Solubility ◽  
Base Properties

Abstract The calcium(II), iron(III) and chromium(III) alkyl-N-iminodiacetate systems have been studied in aqueous solution with respect to stability, acid–base properties and structure. The calcium(II) ion forms only one weak complex with methyl-N-iminodiacetic acid in water, K1 = 12.9 (2) mol–1⋅dm3, while iron(III) and chromium(III) form very stable complexes with alkyl-N-iminodiacetic acids. The calcium(II)–methyl-N-iminodiacetate complex is octahedral in the solid state with most probably water in the remaining positions giving a mean Ca–O bond distance of ca. 2.36 Å. The iron(III) alkyl-N-iminodiacetate complexes have low solubility due to a strong tendency to form polymeric structures. Depending on pH in the solution at their preparation, the degree of hydrolysis in the resulting compound(s) may differ. In the solid state, the polymeric iron(III) alkyl-N-iminodiacetate compounds seem to have the mean composition Fe2O(Cx-IDA)5; the mean Fe–O bond distances to the oxo group and the alkyl-N-iminodiacetate ligands are 1.92 and 2.02 Å, respectively. In these complexes the nitrogen atoms are bound at much longer bond distances, 0.1–0.2 Å, than the carboxylate oxygens. This distribution with short strong Fe–O bonds and much longer and weaker Fe–N bonds is also found in most other structurally characterized iron(III) carboxylated amine/polyamine complexes. The chromium(III) alkyl-N-iminodiacetate complexes are octahedral in both solution and solid state, and the low solubility of the solid compounds indicates a polymeric structure with the ligands bridging chromium(III) ions. Also, chromium(III) binds oxygen atoms in carboxylated amines at significantly shorter distance than the nitrogen stoms. The chromium(III) alkyl-N-iminodiacetate complexes display such slow kinetics at titration with strong base that the back-titration with strong acid shows completely different acid–base properties, thus the acid–base reactions are irreversible.

Toward novel sulphur-containing derivatives of tetraazacyclododecane: synthesis, acid–base properties, spectroscopic characterization, DFT calculations, and cadmium(ii) complex formation in aqueous solution

2020 ◽  
Vol 44 (20) ◽  
pp. 8337-8350 ◽  
Author(s):  
Marianna Tosato ◽  
Marco Verona ◽  
Riccardo Doro ◽  
Marco Dalla Tiezza ◽  
Laura Orian ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Dft Calculations ◽  
Spectroscopic Characterization ◽  
Acid Base ◽  
Derivatives Of ◽  
Base Properties

New sulphur derivatives of cyclen, with potential complementary properties with respect to known compounds, have been synthesized and studied.

scholarly journals Complex Formation Between Zinc(II) and Alkyl-N-iminodiacetic Acids in Aqueous Solution and Solid State

2020 ◽  
Vol 49 (9-10) ◽  
pp. 1279-1289
Author(s):  
Leif Häggman ◽  
Cecilia Lindblad ◽  
Anders Cassel ◽  
Ingmar Persson
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Bond Distance ◽  
Solution Chemistry ◽  
Detailed Knowledge ◽  
Metal Compounds ◽  
Slow Kinetics ◽  
Distorted Octahedral ◽  
Varying Length ◽  
Fundamental Systems

Abstract Removal of metal compounds from wastewater using processes where metals can be removed and valuable chemicals recycled is of significant industrial importance. Chelating surfactants are an interesting group of chemicals to be used in such applications. Carboxylated polyamines are a promising group to be used in such processes. To apply carboxylated polyamines as chelating surfactants, detailed knowledge of the solution chemistry, including complex formation, kinetics and structures of pure fundamental systems, is required. In this study zinc(II) alkyl-N-iminodiacetate systems with varying length of the alkyl chain have been studied. Acidic and stability constants have been studied by potentiometry, and the structures of both solids and aqueous solutions have been determined by EXAFS. Zinc(II) forms two strong complexes with alkyl-N-iminodiacetates in aqueous solution. In an attempt to determine the acidic constants of these complexes, the deprotonation of the nitrogen atom in the complex bound ligands, it was observed that this reaction is very slow and no accurate values could be obtained. The bis(alkyl-N-iminodiacetato)zincate(II) complexes take, however, up two protons in the pH region 3–7, which means that this complex is approximately singly protonated in the pH region 3–7 and doubly protonated at pH < 3. The bis(n-hexyl-N-iminodiacetato)zincate(II) complex at pH = 13 has a distorted octahedral configuration with four short strong Zn–O bonds at 2.08(1) Å, while the Zn–N bonds are weaker at much longer distance, 2.28(2) Å. Similar configurations are also found in most reported structures of zinc(II) complexes with carboxylated amines/polyamines. The singly protonated complex seems to be five-coordinate, with four Zn–O bond distances at ca. 2.03 Å, and a single Zn–N bond distance in the range 2.15–2.25 Å. The relationship between the structure of the protonated bis(n-hexyl-N-iminodiacetato)zincate(II) complex and the slow kinetics in the region pH = 3–7 are discussed.

Acid-Base Properties of Peptide Peroxyl Radicals in Aqueous Solution

1989 ◽  
Vol 6 (2-3) ◽  
pp. 127-128 ◽  
Author(s):  
Oliver J. Mieden ◽  
Man Nien Schuchmann ◽  
Clemens Von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Peroxyl Radicals ◽  
Acid Base ◽  
Base Properties

Cooperative Effects in Aminothiols: Acid-Base Equilibria and the Molecular Structure of 2-(N, N-Dimethylaminomethyl)thiophenol

2008 ◽  
Vol 63 (10) ◽  
pp. 1199-1203
Author(s):  
Holger Fleischer ◽  
Dieter Schollmeyer
Keyword(s):  
Molecular Structure ◽  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Solid State ◽  
Ab Initio ◽  
Ab Initio Methods ◽  
Asymmetric Unit ◽  
Acid Base ◽  
Cooperative Effects ◽  
Independent Molecules

Abstract2-(N,N-Dimethylaminomethyl)thiophenol, (1, HL), is present as a non-zwitterionic aminothiol in the solid state, exhibiting an intramolecular S-H···N hydrogen bond. The S···N distances of the two independent molecules in the asymmetric unit are 2.929(10) and 3.050(10) Å. This structural feature is also present in an ab initio (MP2/6-31G*) optimized molecular structure. The investigation of the hydrogen bond by ab initio methods supports an n(N)-σ *(S-H) interaction as the reason for this bond type. On the basis of data from potentiometric acid-base titrations of a 0.01 M aqueous solution of [H2L]Cl with a 0.1 M aqueous solution of sodium hydroxide, values of 4.09±0.01 and 11.50±0.01 were obtained for pKa1 and pKa2 of [H2L]+. pKa1 is much smaller than pKa of thiophenol while pKa2 is bigger than pKa of benzyldimethylamine. The increased difference between pKa1 and pKa2 is attributed to the stabilization of HL by the intramolecular S-H···N hydrogen bond.

Synthesis of the tetranitro derivative of thiacalix[4]arene and its acid–base properties

2004 ◽  
Vol 82 (8) ◽  
pp. 1266-1270 ◽  
Author(s):  
Xiaojun Hu ◽  
Zhongliang Zhu ◽  
Tianxiang Shen ◽  
Xianfa Shi ◽  
Jie Ren ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Factor Analysis ◽  
Water Solution ◽  
Uv Spectroscopy ◽  
Nitro Derivative ◽  
Uv Absorption ◽  
Acid Base ◽  
Ph Distribution ◽  
Base Properties

The tetranitro derivative 3 of thiacalix[4]arene was synthesized and characterized. Its acid–base properties in water solution were studied by UV spectroscopy. The four pKa values of 3 were determined by target testing factor analysis (TTFA). The pure UV absorption curves and pH distribution curves of five forms of 3 presented in aqueous solution were also calculated by TTFA.Key words: thiacalixarene, nitro derivative, acid–base properties.

Acid-Base Properties of Adenosine 5′-O-Thiomonophosphate in Aqueous Solution

1997 ◽  
Vol 3 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Bin Song ◽  
Roland K. O. Sigel ◽  
Helmut Sigel
Keyword(s):  
Aqueous Solution ◽  
Acid Base ◽  
Base Properties

Synthesis, Acid-Base Properties, Kinetics and Mechanism of Cu2+ Incorporation into Water-Soluble Highly Substituted Porphyrins

2017 ◽  
Vol 21 (09) ◽  
pp. 611-621
Author(s):  
Hirofumi Konno ◽  
Jun Takeda
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Kinetics And Mechanism ◽  
Water Soluble ◽  
Acid Base ◽  
Base Equilibrium ◽  
Absorbance Change ◽  
Acid Base Equilibrium ◽  
Kinetics Of ◽  
Base Properties

The synthesis, acid-base properties, and kinetics of Cu[Formula: see text] incorporation into water-soluble highly substituted porphyrins were studied. The basicity increased and the stepwise acid-base equilibrium was clarified by increasing the number of phenyl groups at the [Formula: see text] position, and the basicity of a dodeca-substituted porphyrin increased with the ionic strength. The metalation reaction of the dodeca-substituted porphyrin with Cu[Formula: see text] in aqueous solution revealed a biphasic absorbance change at 453 nm. Plots of [Formula: see text] or[Formula: see text] vs. the Cu[Formula: see text] concentration and of log ([Formula: see text] or[Formula: see text]/[Formula: see text] 0) vs. the ionic strength show that [Formula: see text] is dependent on the Cu[Formula: see text] concentration and ionic strength, while [Formula: see text] is independent of these parameters. These results confirm the stepwise metalation mechanism and the existence of an intermediate in aqueous solution, which is indicated by the biphasic absorbance change at 453 nm.

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