The Determination of the Stability Constants Binary Complexes of Alizarin with Ca(II) and Zn(II) by Potentiometrie and Spectrophotometric Methods

Bilgiç, D.; Bapli, Ihsan

doi:10.1515/revac.2007.26.2.99

Cited by 12 publications

(6 citation statements)

References 3 publications

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“…There are two potential sites in competition: 1,2-dihydroxyl (catechol) and 1-hydroxy-9-keto groups . Two contradictory hypothesis are proposed in the literature: (i) an Al 3+ can be chelated with the catechol group , or (ii) 1-hydroxy-9-keto group. ,, If Al 3+ was coordinated with 1-hydroxy-9-keto groups, C9 should obviously show a different chemical shift from C10. In fact, Al 3+ was coordinated with the catechol group.…”

Section: Resultsmentioning

confidence: 99%

“…If a monodentate fixation mode could be considered, bidentate complexes are usually the most stable ones, for such ligands. Two contradictory hypothesis are proposed in the literature, an Al 3+ fixation with the catechol group [55,56] and a metal chelation with the 1-hydroxy-9-keto group [4,28,31]. Both chemical shifts of C1 and C2 increased from 150.0 and 152.0 ppm to 163.6 ppm while the chemical shifts of C9 (188.8 ppm)…”

Section: Nmrmentioning

confidence: 97%

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New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

et al. 2020

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Alizarin (Az) lake is a typical example of lake pigments that is widely used in cultural heritages. Previous work focused on the complex formation in solution, theoretical models and crystallized stoichiometric complexes. The real nature of lake pigments, as well as the reason for its degradation, are still controversial. In this work, we prepared the Az lakes from the ancient recipe with non-stoichiometric complexes, i.e., R = 5-200 (R refers to molar ratio of Al 3+ /Az). The influences of the dye concentration, pH and basic reagents on the structures and chromatic properties of bulk Az lakes were studied by attenuated total reflection Fourier transform infrared spectrum (ATR-FTIR), nuclear magnetic resonance (NMR) and CIE 1976 color space.In order to investigate the surface interaction between Az and the alumina inorganic substrate, likely determining in the aging of pigments, Az was deposited on a thin Al 2 O x film prepared by physical vapor deposition method. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) was employed to characterize the chemical reactivity and degradation of Az-Al 2 O x film complex. Az derivatives interacted with Al 2 O x film like bulk lakes. Al 3+ were coordinated with 1,2-dihydroxyl (catechol) group, instead of 1-hydroxy-9-keto group. Exposure under UV light resulted in degradation of Az-Al 2 O x film complex by oxidizing catechol groups to carbonyl. This study presented a new insight into the structure and degradation of Az lake.

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Section: Resultsmentioning

confidence: 99%

Section: Nmrmentioning

confidence: 97%

New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

et al. 2020

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“…This behavior was ascribed to the formation of a complex between AO7 and chromium(VI). Since AR is known to chelate several metal ions, a similar mechanism could be envisaged. However, we will show in the following that the behavior observed in this case has a different origin.…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Reactivity of Strongly Coupled TiO₂ Ligands under Visible Irradiation: An Examination of an Alizarin Red@TiO₂ Nanoparticulate System

et al. 2008

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Similarly to alizarin molecules, 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonate (alizarin red, AR), chelates TiO 2 nanoparticles through the catechol moiety, and shifts the absorption threshold of the semiconductor to the visible region. The photoinduced reactivity of the coupled system AR@TiO 2 was investigated through quantum yields determinations in nonscattering sols of TiO 2 modified nanoparticles. In contrast with the behavior observed in TiO 2 microparticulated systems, the chemisorbed ligand has a high stability under aerated visible light irradiation. The quantum yield for alizarin red oxidation Φ -AR ) 4 × 10 -4 correlates with the negligible efficiency for oxygen reduction in the constrained environment of the smaller particles. Conversely, reduction of Cr(VI) to Cr(V) in the coupled AR@TiO 2 system, confirmed by electron paramagnetic resonance spectroscopy, utilizes a high fraction of the photogenerated electrons and induces the degradation of the complex. Quantum efficiencies for chromium(VI) disappearance, Φ -Cr(VI) , approaches 37% at [Cr(VI)] 0 ) 200 µM. The interactions between Cr(VI)/AR and Cr(VI)/TiO 2 are analyzed in detail. Spectroscopic evidence is presented for the first time that Cr(VI) forms a charge-transfer complex with TiO 2 nanoparticles that could be excited by visible light (λ e 440 nm). The environmental implications of the above findings are briefly discussed.

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“…It has been postulated 37,38 that alizarin complexes in solution are essentially mixtures of these two forms. Absorption and emission processes of free and complexed alizarin in the UV-Vis energy range have been studied both experimentally 4,[39][40][41][42] and computationally, [43][44][45] including environmental effects on the final optical properties. In fact, the strong dependence on environmental conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Environmental and complexation effects on the structures and spectroscopic signatures of organic pigments relevant to cultural heritage: the case of alizarin and alizarin–Mg(ii)/Al(iii) complexes

Carta

Biczysko

Bloino

et al. 2014

Phys. Chem. Chem. Phys.

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An integrated computational approach allowed an unbiased analysis of optical and structural properties of alizarin-based pigments, which can be directly compared with experimental results. Madder lake pigments have been modeled by Mg(II)- and Al(III)-coordinated alizarin taking into account solvation and metal-linkage effects, responsible for colour modifications. Moreover, different environmental conditions have been analyzed for free alizarin, showing in all cases semi-quantitative agreement with experimental spectroscopic data (UV-VIS). Our results point out the ability of in silico approaches to unravel the subtle interplay of stereo-electronic, dynamic, and environmental effects in tuning the physico-chemical properties of pigments relevant to cultural heritage.

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The Determination of the Stability Constants Binary Complexes of Alizarin with Ca(II) and Zn(II) by Potentiometrie and Spectrophotometric Methods

Cited by 12 publications

References 3 publications

New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

Photoinduced Reactivity of Strongly Coupled TiO₂ Ligands under Visible Irradiation: An Examination of an Alizarin Red@TiO₂ Nanoparticulate System

Environmental and complexation effects on the structures and spectroscopic signatures of organic pigments relevant to cultural heritage: the case of alizarin and alizarin–Mg(ii)/Al(iii) complexes

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The Determination of the Stability Constants Binary Complexes of Alizarin with Ca(II) and Zn(II) by Potentiometrie and Spectrophotometric Methods

Cited by 12 publications

References 3 publications

New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

New Insights into the Structure and Degradation of Alizarin Lake Pigments: Input of the Surface Study Approach

Photoinduced Reactivity of Strongly Coupled TiO2 Ligands under Visible Irradiation: An Examination of an Alizarin Red@TiO2 Nanoparticulate System

Environmental and complexation effects on the structures and spectroscopic signatures of organic pigments relevant to cultural heritage: the case of alizarin and alizarin–Mg(ii)/Al(iii) complexes

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Photoinduced Reactivity of Strongly Coupled TiO₂ Ligands under Visible Irradiation: An Examination of an Alizarin Red@TiO₂ Nanoparticulate System