Tautomerism of metal complexes with quinalizarin

Fain, V. Ya.; Зайцев, Б. Е.; Ryabov, M. A.

doi:10.1134/s1070328407080131

Cited by 12 publications

(21 citation statements)

References 10 publications

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“…The structure of the metal-dye complexes, either 1,2-hydroxyanthraquinone (alizarin) or 1,2,4-hydroxyanthraquinone (1,2,4-HAQ), and the nature of their possible chemical interactions are still under debate 102 . However, the formation of di-nuclear chelated complexes shows energetic disadvantages deriving from two adjacent and negatively charged oxygen atoms 48 , and shall be only considered for other anthraquinoid resonant structures 48,103,104 . Thus, we have chosen to study only mono-nuclear bidentate forms, which prevail with respect to the monodentate ones for similar systems 49,105 .…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…SHINERS, in some cases, necessitate specific spectral libraries for fingerprint-style identification, making necessary more research before it can be applied to cultural heritage F I G U R E 6 Proposed structures for the interaction of alizarin with SiO 2 surface in this study, via hydroxy and carbonyl groups: carbonyls in (a) positions 9,10 and (b) 2,9 and 1,2, respectively. The general structures representations are based on those from literature [42] F I G U R E 7 (a) The average shell-isolated nanoparticleenhanced Raman spectroscopy (SHINERS) spectra (632.8 nm) from alizarin obtained with Ag@SiO 2 at pHs 3.9, 6.0, 7.7, and 9.3. (b) The average SHINERS spectra (632.8 nm) from pyridine obtained with Ag@SiO 2 at pHs 3.9, 6.0, 7.7, and 9.3 and the average Ag-surface-enhanced Raman spectroscopy (SERS) spectrum (632.8 nm) of pyridine at pH 7.2 objects.…”

Section: Discussionmentioning

confidence: 99%

SHINERS in cultural heritage: Can SHINERS spectra always be compared with normal Raman spectra? A study of alizarin and its adsorption in the silicon dioxide shell

Puglieri

Madden

Andrade

2021

J Raman Spectroscopy

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Raman microspectroscopy is a powerful analytical technique in cultural heritage. However, results are often compromised by luminescence interference and poor sensitivity. Surface-enhanced Raman spectroscopy (SERS) is an alternative that can enhance the Raman signal and quench luminescence, but the interaction of an analyte and metal substrate produces altered Raman spectra. Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) is a promising modification of SERS that encases the metal nanoparticles in ultrathin inert shells. As a consequence, it is reported that SHINERS spectra can be directly compared with normal Raman spectra, but this is not always the case, as discussed in this work. SHINERS, SERS, and normal Raman spectra were obtained from alizarin. The resulting spectra showed that the SHINERS data are comparable with the normal Raman spectrum of alizarin adsorbed in silica, not that of isolated alizarin. The structure of alizarin adsorbed in silica is discussed. Luminescence quenching observed in the SHINERS spectra can be attributed both to LSPR of the metallic nanoparticle cores and to alizarin-silica shell chemisorption. Both silica-encapsulated silver and gold nanoparticles were considered, and it is shown that SHINERS spectra are dependent on the interaction of alizarin with silica, rather than the specific metal core within, in contrast to our observations of Ag and Au SERS nanoparticles. The metal agnostic quality of SHINERS is a potential advantage for the collection and comparison of reference data. Additionally, SHINERS systems result in quite stable spectra in pHs ranging from, at least, 6.0 to 9.3. Future research directions for SHINERS in cultural heritage are also discussed.

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“…In the presence of an adsorbent, ARS can be bonded in the chelate (with a shift of the main peak) or salt (without a shift of the main peak) form [28]. These investigations were supported theoretically by calculations showing the tautomeric anthraquinoid structures [29,30].…”

Section: Sample\ Assignment [23] B-sheetmentioning

confidence: 92%

Oxidation activity of horseradish peroxidase hosted in molecular sieves: spectroscopic investigations show hindering of the enzyme activity

Frunză

Gheorghe

Ganea

et al. 2011

Reac Kinet Mech Cat

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Horseradish peroxidase immobilization inside molecular sieves with pores hexagonally structured as such or functionalized with copper ions is presented in comparison with the bidimensional immobilization onto aerosil A380 particles. Immobilization was performed under mild conditions that do not lead to enzyme denaturation. Guest-host interactions were pursued spectrophotometrically and by thermal analysis measurements. FTIR spectroscopy showed no major secondary structural change for the entrapped enzyme despite some influence of the support functionalization that can be supposed. The activity of the immobilized enzyme was tested in the oxidation of Alizarin Red S (ARS) with hydrogen peroxide. It was found that the dye oxidation is catalyzed by the enzyme in homogeneous reaction but the rate becomes much slower in heterogeneous catalytic processes with prepared catalysts. It seems that horseradish peroxidase immobilization in simple porous silica or alumino-silica post synthesis blocks the enzyme activity. In addition, copper ions make a stable complex with ARS hindering its oxidation as well.

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Tautomerism of metal complexes with quinalizarin

Cited by 12 publications

References 10 publications

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

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

SHINERS in cultural heritage: Can SHINERS spectra always be compared with normal Raman spectra? A study of alizarin and its adsorption in the silicon dioxide shell

Oxidation activity of horseradish peroxidase hosted in molecular sieves: spectroscopic investigations show hindering of the enzyme activity

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