Photo-induced coloration of 2-hydroxychalcone in the clay interlayer

Abstract

2-hydroxychalcones are known to be converted to the colored flavylium form under UV irradiation. In this study, the photochemical conversion of two 2-hydroxychalcone derivatives (4'-dimethylamino-2-hydroxychalcone and 4'-methoxy-2-hydroxychalcone) has been carried out in the solid matrix by the intercalation into the layer of the clay, montmorillonite. The 2-hydroxychalcone has been adsorbed on the clay by modifying the clay interlayer with a cationic surfactant, dodecyltrimethylammonium chloride. The addition of an acidic compound (benzenesulfonic acid) has induced the successful coloring reaction of the 2-hydroxychalcone derivatives by the conversion to the flavylium under UV irradiation between the clay interlayer. A delayed coloration has been observed on the short time irradiation of 4'-methoxy-2-hydroxychalcone included in the clay layer.

Effect of Methyl, Hydroxyl, and Chloro Substituents in Position 3 of 3′,4′,7‐Trihydroxyflavylium: Stability, Kinetics, and Thermodynamics

“…Some details of anthocyanin chemistry could be fully understood only after achievements obtained by the study of synthetic flavylium analogues . On the other hand, flavylium derivatives can perform as photochromic systems, both in solution and in more organized matrices, as well as models for the development of optical memories …”

“…[1][2][3][4] Some details of anthocyanin chemistry could be fully understood only after achievements obtained by the study of synthetic flavylium analogues. [5,6] On the otherh and, flavyliumd erivatives can perform as photochromic systems, [1,7,8] both in solutiona nd in more organizedm atrices, [9][10][11][12][13] as well as models for the developmento fo pticalm emories. [1,14] One interestingc haracteristic of flavylium derivatives is the existence of ac ommon sequence of chemicalr eactions, as shown in Scheme1 for malvidin-3-O-glucoside (oenin).…”

“…Ta utomerization is generally faster than hydration, except for very acidic pH values, as observed in reversepHj umps or even in direct pH jumps. In the former case, two kineticp rocesses are observed given by Equations (12) and (13): [20]…”

Anthocyanidin Dye and Al/Fe-Containing Mesoporous Silica Composites and their Color Properties

“…It is reported that various dyes could be stabilized by their adsorption into the interlayer of clays 7,8,12,13) or pores of MPS 3,9,10) . However, AD dyes tend to decompose more easily than AN dyes as the sugar chain from anthocyanin has been removed by hydrolysis in the former.…”

Nanocomposites Based on Thermoplastic Polymers and Functional Nanofiller for Sensor Applications

“…A similar behavior has been shown by the 2-hydroxychalcones dye (HC), which is converted to the colored flavylium form (FV) under UV irradiation [31]. The immobilization of HC dyes within clay lamellae affects the photochromic response depending on the polarity of the interlayer space as well as the acidity by considering that the FV form prefers the polar environment.…”