Determination of composition and instability constants of maltol complexes with iron(iii) ions

Antipova, I. A.; Mukha, Svetlana A.; Медведева, С. А.

doi:10.1023/b:rucb.0000037841.67079.2b

Cited by 11 publications

(11 citation statements)

References 5 publications

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“…That confirmed the position coincidence of observed absorption maxima at 270 and 312 nm with those of initial maltol ( Figure 1a) and maltol in alkaline buffer ( Fig. 1 (с)) (where it is present mainly as anion), 23,24 respectively. Decrease in the excitation energy is caused by the shift of π-electrons across the conjugated chain (polarization) under maltol ionization with formation of the chelate.…”

Section: +supporting

confidence: 71%

“…It is known that the ion-coordinative chelatation of maltol is favored by its ionization at the О-Н bond to form one-charge maltolate-anion С 6 Н 5 О 3¯ (L). 23 Therefore, the reaction was carried out in the presence of alkali (2N NaOH), which leads to maltol ionization (рК а in water 8.6). At the same time the reaction equilibrium was shifted towards the formation of target chelate complex due to the neutralization of acid released during the reaction (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

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Stereoactive lone pair of electrons on bismuth(III): tris(3-hydroxy- 2-methyl-4H-pyran-4-onato)bismuth(III)

Сухов¹,

Mukha²,

Antipova³

et al. 2008

Arkivoc

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Section: +supporting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Stereoactive lone pair of electrons on bismuth(III): tris(3-hydroxy- 2-methyl-4H-pyran-4-onato)bismuth(III)

Сухов¹,

Mukha²,

Antipova³

et al. 2008

Arkivoc

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“…However, most of these absorption peaks are not noticed from the spectra of both tribofilms. More interestingly, new chemical species are identified from the tribofilms with absorption peaks at 826 and 805 cm –1 , as indicated by the arrows in Figure a,b, corresponding to metal chelate salts of methyl phenolic alcohol Fe(OOC 6 H 5 ) and Fe(OC 21 H 30 ). − This implies that tribochemical reactions between the polymer molecules and the steel occurred. As schematically depicted in Figure c, the molecular chains of phenolic resin are broken because of mechanical and thermal effects and thus phenolic hydroxyl free radicals and methyl phenol radicals are produced.…”

Section: Results and Discussionmentioning

confidence: 93%

Switching Brake Materials To Extremely Wear-Resistant Self-Lubrication Materials via Tuning Interface Nanostructures

Che

Zhang

et al. 2018

ACS Appl. Mater. Interfaces

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Tribological performance of motion components is one of the key aspects that must be considered in a wide range of applications such as vehicles, aircrafts, and manufacturing equipment. This work demonstrates that further addition of only low-loading hard nanoparticles into a formulated nonasbestos organic brake material directly switches its functionality to a self-lubrication material. More importantly, the newly developed nanocomposites exhibit an extremely low wear rate. Comprehensive investigations on the friction interface reveal that the great friction and wear reduction are due to the formation of a nanostructured lubricious tribofilm. Tribofilm formation is continuously fed by complex molecular species released from the bulk nanocomposites, for which nanoparticles digested within the tribofilm greatly enhance its robustness and lubricity. This work gains insight into the crucial role of the interface nanostructure and paves a route for developing extremely wear-resistant self-lubrication composites for numerous applications.

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“…Metal/maltol speciation data are available in literature for Al(III) and for Fe(III), which have a coordination chemistry similar to that of Ga(III). Both ions form the same 1:1, 1:2 and 1:3 metal/maltol complexes, having log β values of 7.70, 15.25 and 21.90 for Al(III) (Chiacchierini & Bartusek, ) and 12.43, 21.81 and 30.86 for Fe(III) (Antipova et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Reduction in absorption of gallium maltolate in adult horses following oral administration with food: chemistry and pharmacokinetics

Pollina¹,

Pepe

Dean

et al. 2013

Vet Pharm & Therapeutics

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Gallium (Ga) is under study for the treatment of osteolytic disorders in equines. Previous studies indicate that oral gallium maltolate (GaM) would provide a higher bioavailability than oral Ga salts. However, oral administration to adult horses of 2 mg/kg of GaM, in the form of a solution mixed with food, did not lead to detectable Ga levels in plasma. Therefore, a study was performed to model the chemical behaviour of GaM in the digestive tract. The equilibrium formation constants for Ga(III) and maltol were calculated by means of UV–visible measurements and validated by 1H-NMR measurements at selected pH values. Data indicate that the dissociation of GaM in aqueous solutions is very rapid, while the re-association is slower. Based on these results, poor Ga absorption seems to be due to the equilibrium dissociation of GaM in the stomach and to its slow formation rate in the intestine. The concomitant presence of high concentrations of phytates (strong charged metal chelating agents, which represent about 1% of dry matter in vegetables) might also explain the low absorption of GaM by the gastrointestinal tract. Methods of optimizing Ga absorption after oral administration of GaM require further investigation.

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Determination of composition and instability constants of maltol complexes with iron(iii) ions

Cited by 11 publications

References 5 publications

Stereoactive lone pair of electrons on bismuth(III): tris(3-hydroxy- 2-methyl-4H-pyran-4-onato)bismuth(III)

Stereoactive lone pair of electrons on bismuth(III): tris(3-hydroxy- 2-methyl-4H-pyran-4-onato)bismuth(III)

Switching Brake Materials To Extremely Wear-Resistant Self-Lubrication Materials via Tuning Interface Nanostructures

Reduction in absorption of gallium maltolate in adult horses following oral administration with food: chemistry and pharmacokinetics

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