Crystal structure refinement of Maya Blue pigment prepared with deuterated indigo, using neutron powder diffraction

Giustetto, Roberto; Levy, Davide; Chiari, Giacomo

doi:10.1127/0935-1221/2006/0018-0629

Cited by 40 publications

(41 citation statements)

References 28 publications

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“…Schematic illustration of preparation of the PAL/MV@SiO 2 ''Maya Violet'' pigment and the corresponding digital images. of organic dye or pigment is less than 3.0% in most cases [5,7,12,31,32]. In contrast, the MV content in the as-prepared PAL/MV pigment can be as high as 10%, substantially higher than all of the state-of-the-art Maya Blue pigments [21] and nearly equal to the Maya Blue-like pigments prepared by Fan et al [24] and Zhang et al [25].…”

Section: Preparation Of Pal/mv Pigmentsmentioning

confidence: 79%

“…The interaction between PAL and indigo is the origin of the high stability of Maya Blue, but the real nature of the interaction remains controversial. The most widely acknowledged interactions encompass hydrogen bonding between (i) carbonyl and amine groups of indigo and peripheral silanol groups of PAL [11]; (ii) carbonyl and amine groups of indigo and structural silanol groups of PAL [12,13]; and (iii) carbonyl group and coordinated water as well as the interaction between indigo molecule and the Mg 2+ and Al 3+ ions inside the octahedral PAL [13][14][15]. However, the definite position of indigo molecules in PAL is still in dispute.…”

Section: Introductionmentioning

confidence: 97%

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Facile preparation of stable palygorskite/methyl violet@SiO2 “Maya Violet” pigment

Zhang

Wang

2015

Journal of Colloid and Interface Science

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Section: Preparation Of Pal/mv Pigmentsmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 97%

Facile preparation of stable palygorskite/methyl violet@SiO2 “Maya Violet” pigment

Zhang

Wang

2015

Journal of Colloid and Interface Science

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“…[33] These indigo/palygorskite mixtures are known to generate very stable and beautiful blue pigments. [28,33,34] We note that the cross-sectional area in the internal channels of attapulgites is smaller than that of sepiolite.…”

Section: Introductionmentioning

confidence: 98%

The Incorporation of Indigo Molecules in Sepiolite Tunnels

Ovarlez¹,

Giulieri²,

Chaze³

et al. 2009

Chemistry A European J

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Evidence for access of molecules the size of acetone or pyridine to the intracrystalline tunnels of nanofibre clay (sepiolite) has indicated formation of a new type of organic-inorganic nanocomposites. However, the introduction of larger molecules has been a recurring problem. It is now agreed that for indigo, the molecules are located on the external surface and at the ends of the fibres, thus blocking access to internal tunnels. We claim, however, that it is possible for indigo molecules to access the internal channels of sepiolite. FTIR and XRD analyses have provided evidence for folding of the sepiolite structure preheated at high temperature (above 350 degrees C). By comparison, we have shown that for indigo/sepiolite mixtures treated in the same conditions, no change in the crystalline structure of the sepiolite is observed, and that blue samples, related to Maya blue, with indigo molecules incorporated deeply enough into sepiolite to prevent folding of the tunnels, can be obtained. NMR, FTIR and thermal analysis confirm the interaction of indigo with the water coordinated to magnesium(II) and located inside the internal and external channels of sepiolite. Two other hypotheses are excluded; we show both that zeolitic water is not blocked in the tunnels by indigo, and that if thermal decomposition products of indigo can be formed, they are in a minority.

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“…Scientists still do not fully agree in the mechanism of this organo-clay interaction [3]. It has been proposed that a partial or perhaps total evacuation of the zeolitic H 2 O is essential to allow the indigo to either penetrate in the tunnels or to sit and block the entrance of the tunnels [4]. In this work we apply neutron scattering to monitor the dehydration of palygorskite during the formation of MB.…”

Section: Introductionmentioning

confidence: 99%