Co-ordination tendency of [3k]aneN<sub>k</sub>polyazacycloalkanes. Thermodynamic study of solution equilibria

Bencini, Andrea; Bianchi, Antonio; Micheloni, Mauro; Paoletti, Piero; Garcı́a-España, Enrique; Niño, Miguel Ángel

doi:10.1039/dt9910001171

Cited by 44 publications

(32 citation statements)

References 30 publications

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“…By similar reasoning, and taking into account the experimental errors on the determined equilibrium constants, the number of uncoordinated primary nitrogens can be reasonably estimated as six in Cu 2 L2 4+ , five in Cu 3 L2 6+ , three in Cu 4 L2 8+ , and none in Cu 5 L2 10+ . The equilibrium constants for the successive binding of the first and the second Cu 2+ ions are very high (log K = 23.66 and 22.9, Table 1 ) and consistent with the stability of hexacoordinated Cu 2+ complexes of polyamines [ 13 , 14 ]. Accordingly, the first two Cu 2+ ions binding L2 should be coordinated by three primary and three secondary amine groups near the surface of the G-3 dendrimer.…”

Section: Resultssupporting

confidence: 62%

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Savastano¹,

Bazzicalupi²,

Giorgi³

et al. 2017

Molecules

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The G-3 poly(ethylene imine) ligand L2 shows a multifaceted coordination ability, being able to bind metal cations, anions and ion-pairs. The equilibrium constants for the formation of metal (Cu2+, Zn2+), anion (SO42−) and ion-pair (Cu2+/SO42−) complexes were determined in 0.1 M Me4NCl aqueous solution at 298.1 ± 0.1 K by means of potentiometric titrations. Thanks to its dendrimeric nature, L2 can form highly nucleated metal complexes, such as Cu5L210+ and Zn4L28+, in successive and well-defined complexation steps. Protonated forms of L2 give rise to relatively weak anion complexes with SO42−, but the addition of Cu2+ significantly enhances the binding ability of the ligand toward this anion below pH 9. In more alkaline solutions, an opposite trend is observed. The coordination properties of L2 are discussed with the support of modelling calculations. According to results, L2 is a promising molecule for the preparation of solid supported materials for the recovery of cations and anions from aqueous media and/or for applications in heterogeneous catalysis.

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Section: Resultssupporting

confidence: 62%

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Savastano¹,

Bazzicalupi²,

Giorgi³

et al. 2017

Molecules

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“…Crystal data. C1SH30N10012, A4 = 578.5, orthorhombic, space group Pbca, a = 15.980(1), b = 10.015(1), c' = 16.204(2) …”

mentioning

confidence: 99%

“…Thermodynamic and electronic spectral data for metal-ion complexation by L' at 25 "C in 0.100 mol dm-, KNO, Data for [CuL3I2+ from ref 35. at 25 "C and in 0.1 5 mol dm-, NaCIO,: log p1 = 24.4, -AH" = 100.0 kJ mol-', T A P = 39.1 kJ rnol ' and Pd-,, = 15 200 cm (85 dm3 mol-' cm-').…”

mentioning

confidence: 99%

Protonation and metal-ion complexation in aqueous solution by pyridine-containing hexaaza macrocycles

Dhont¹,

Herman²,

Fabretti³

et al. 1996

J. Chem. Soc., Dalton Trans.

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“…Because of their more preorganized cyclic structure and the higher number of amine groups available for metal coordination, the complexes of Mn II with cyclic ligands H 2 DO2A and H 2 Me 2 DO2A showed a higher stability than those with H 3 EDTA(OH) and H 4 EGTA [43]. The thermodynamic stability of the [MnDO2A] and [MnMe 2 DO2A] complexes is also higher than the Mn II complexes with macrocyclic polyamines containing 4, 5 or 6 secondary nitrogen donors [44]. A further difference between the complexes with cyclic and acyclic ligands resides in their hydrophobic characteristics.…”

Section: Mn II Complexes With Polyamine-polycarboxylate Ligandsmentioning

confidence: 86%

Developing ROS Scavenging Agents for Pharmacological Purposes: Recent Advances in Design of Manganese-Based Complexes with Anti-Inflammatory and Anti- Nociceptive Activity

Bani¹,

Bencini

2012

CMC

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Reactive oxygen and nitrogen species, which are normal products of cell metabolism, may play a dual beneficial/deleterious role, depending on local concentration and mode of generation. As such, they have been identified as key pathogenic factors for many inflammatory and degenerative disorders, carcinogenesis, nociception and ageing. In this perspective, low molecular weight transition metal complexes with organic ligands have been and are still viewed as promising pharmaceutical agents with antioxidant/free radical scavenging properties, owing to their ability to interact and/or react with reactive oxygen or nitrogen species and counterbalance excessive endogenous free radical generation in biological systems. Among these compounds, manganese(II/III) complexes have resulted effective as ROS scavengers both in vitro and in vivo. In particular, Mn(III) complexes with porphyrins and salen derivatives as well as Mn(II) complexes with macrocyclic pentaamines and polyamine-polycarboxylic acids have been recently analyzed as ROS scavengers for therapeutic purposes. In this article, we summarize the chemical and biological properties of manganese complexes with low molecular weight synthetic ligands as scavengers of pro-oxidant species, with particular attention to the mechanisms operating at the metal center in the scavenging process. A proper design of the organic scaffolds may yield manganese complexes capable to catalyze different scavenging reactions, including superoxide and/or hydrogen peroxide dismutation and peroxynitrite decomposition. These manganese complexes can be viewed either as a novel class of drugs helpful to reduce oxidative tissue injury or as useful tools to get further light on the role played by ROS in biological systems.

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Co-ordination tendency of [3k]aneN_kpolyazacycloalkanes. Thermodynamic study of solution equilibria

Abstract: Equilibria between polyazacycloalkanes of the series [3k]aneN, (k = 3-1 1 ) and the bivalent metal ions of Mn through Zn have been studied. The stability constants (log K) for the complexes of Mn2+,

Cited by 44 publications

References 30 publications

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Protonation and metal-ion complexation in aqueous solution by pyridine-containing hexaaza macrocycles

Developing ROS Scavenging Agents for Pharmacological Purposes: Recent Advances in Design of Manganese-Based Complexes with Anti-Inflammatory and Anti- Nociceptive Activity

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Co-ordination tendency of [3k]aneNkpolyazacycloalkanes. Thermodynamic study of solution equilibria

Abstract: Equilibria between polyazacycloalkanes of the series [3k]aneN, (k = 3-1 1 ) and the bivalent metal ions of Mn through Zn have been studied. The stability constants (log K) for the complexes of Mn2+,

Cited by 44 publications

References 30 publications

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution

Protonation and metal-ion complexation in aqueous solution by pyridine-containing hexaaza macrocycles

Developing ROS Scavenging Agents for Pharmacological Purposes: Recent Advances in Design of Manganese-Based Complexes with Anti-Inflammatory and Anti- Nociceptive Activity

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Co-ordination tendency of [3k]aneN_kpolyazacycloalkanes. Thermodynamic study of solution equilibria