256. Zusammensetzung und Struktur von Komplexen des einwertigen Kupfers mit Imidazolderivaten

Kaden, Th.; Zuberbühler, Andreas D.

doi:10.1002/hlca.660490723

Cited by 17 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This behavior can be ascribed to the larger ϩI inductive effect of the longer propylenic chains, which increases the basicity of each amine group, as well as to the longer distance between amine nitrogens, which allows a better minimization of the electrostatic repulsion between protonated ammonium groups in the [H n L1] nϩ polycharged cations with respect to the [H n L2] nϩ ones. This effect has been also observed in aliphatic diamines, such as N,NЈ-dimethyl-1,2-diaminoethane (log K 1 = 10.05 and log K 2 = 7.12) 24 and N,NЈ-dimethyl-1,3-diaminopropane (log K 1 = 10.80 and log K 2 = 9.1), 25 which contain two secondary amine groups linked respectively by an ethylenic and a propylenic chain.…”

Section: Protonation Of L1mentioning

confidence: 70%

Phenanthroline-containing macrocycles as multifunctional receptors for nucleotide anions. A thermodynamic and NMR study †

Bazzicalupi

Beconcini

Bencini

et al. 1999

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

The synthesis of the phenanthroline-containing macrocycle 2,6,10,14-tetraaza [15](2,9)cyclo(1,10)phenanthrolinophane (L1) is reported. L1 contains a tetraamine chain connecting the 2,9-positions of a phenanthroline unit. Protonation of L1 has been studied by means of potentiometric and 1 H and 13 C NMR techniques, allowing the determination of the basicity constants and of the stepwise protonation sites. The protonation features of L1 are compared with those of macrocycle 2,5,8,11-tetraaza[12](2,9)cyclophenanthrolinophane (L2), in which the amine groups are linked by ethylenic chains. Considering the [H 4 L1] 4ϩ and the [H 4 L2] 4ϩ species, the acidic protons are located on the aliphatic nitrogens, while phenanthroline is not involved in protonation. Binding of diphosphate, triphosphate, ATP and ADP has been studied by means of potentiometry and 1 H and 31 P NMR. Both L1 and L2 behave as multifunctional receptors for the nucleotide anions at neutral or slight acidic pHs, giving 1 : 1 complexes. Charge-charge and hydrogen bonding interactions take place between the polyphosphate chain of nucleotides and the polyammonium groups of L1 and L2, while the adenine moiety gives charge-dipole interactions with the ammonium groups and π-stacking with the phenanthroline unit of the receptors. The high upfield displacements in the 1 H NMR spectra exhibited by the adenine protons upon complexation by L1 suggest a partial inclusion of nucleotides inside the macrocyclic cavity.

show abstract

Section: Protonation Of L1mentioning

confidence: 70%

Phenanthroline-containing macrocycles as multifunctional receptors for nucleotide anions. A thermodynamic and NMR study †

Bazzicalupi

Beconcini

Bencini

et al. 1999

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

show abstract

“…Correspondingly, heterocyclic nitrogen moieties in HA may provide an environment for strong Cu + binding. Additionally, formation of strong Cu + -chelates similar to histamine and formation of mixed N/S coordination may represent quantitatively relevant pathways for Cu + binding to HA. In the first part of this study, mixed 3- to 4-fold coordination of Cu + was found to be important at low loadings and especially under oxic conditions, where Cu + was stabilized in 3- to 4-fold coordination by HA.…”

Section: Resultsmentioning

confidence: 99%

Copper Redox Transformation and Complexation by Reduced and Oxidized Soil Humic Acid. 2. Potentiometric Titrations and Dialysis Cell Experiments

Maurer

Christl

Fulda

et al. 2013

Environ. Sci. Technol.

View full text Add to dashboard Cite

Cation binding and electron transfer reactions of humic substances determine copper speciation in redox-dynamic systems, but quantitative studies for Cu+ binding to humic substances are lacking. We investigated reduction of Cu2+ and binding of Cu+ at pH 7.0 in a dialysis cell experiment using reduced and reoxidized soil humic acid (HA) as reductant and sorbent at copper loadings of 9.5-600 mmol kg(-1). The data were used to quantitatively explain the interaction between cation binding and electron transfer processes that determine copper speciation in the presence of HA under anoxic and oxic conditions. Addition of Cu2+ to reduced HA resulted in almost complete reduction to Cu(I) within 1 h. Reduction was also significant under oxic conditions. The slow decrease of the Cu(I) fraction was attributed to formation of Cu(0) based on thermodynamic consideration. Cu+ binding to HA was found to be strong compared to other chalcophile cations like Ag+ or Cd2+. Our results indicate that Cu+ and Cu2+ isotherms exhibit a redox potential-dependent intersection point. According to the differences in Cu+ and Cu2+ binding, the presence of HA was found to extend the stability field of Cu(II) to moderately reducing conditions and to reduce the stability field of Cu(0) due to the formation of Cu(I) complexes.

show abstract

“…The recurrent theme in Zuberbuhler 's academic career, copper and its coordination chemistry, became manifest even in the first of his publications in HCA, which appeared in 1966 [47]. This, and very many of his later papers were co-authored by Knden, particularly those in the series 'Kupferkomplexe von Bisamiden'.…”

Section: A 1956 Publication [39] Introducedmentioning

confidence: 93%

Helvetica Chimica Acta and Coordination Chemistry

Venanzi¹

1992

Helvetica Chimica Acta

View full text Add to dashboard Cite

256. Zusammensetzung und Struktur von Komplexen des einwertigen Kupfers mit Imidazolderivaten

Cited by 17 publications

References 7 publications

Phenanthroline-containing macrocycles as multifunctional receptors for nucleotide anions. A thermodynamic and NMR study †

Phenanthroline-containing macrocycles as multifunctional receptors for nucleotide anions. A thermodynamic and NMR study †

Copper Redox Transformation and Complexation by Reduced and Oxidized Soil Humic Acid. 2. Potentiometric Titrations and Dialysis Cell Experiments

Helvetica Chimica Acta and Coordination Chemistry

Contact Info

Product

Resources

About