Spiropyran dyes

Abstract

This article furnishes an introduction to one of the most well-known classes of photochromic colorant. While the properties of spiropyran dyes inspired pioneering efforts to exploit photochromism for industrial applications, their lack of robustness held them back from commercialization. Nevertheless, this type of dye remains at the heart of much of the work to develop light-responsive materials upon which many potential applications in different fields of scientific and technological endeavor depend. The article describes the photochromism, synthesis, and applications of spiropyran colorants with an emphasis on the structural subtype that has attracted the greatest scrutiny. It also acts as a springboard to sources of more detail on these aspects.

Multifunctional transition and temperature-responsive contact lenses

“…Based on the literature, 5 SP dyes exhibit much faster reverse photochromism rates than 6 SP dyes, yet this results in more significant photochromic intensities for 6 SP dyes. The nitro substitution leads to a much more prominent photochromism compared to that of other indolinobenzopyrans that do not comprise nitro groups, subsequently yielding photochromic intensities that are atleast an order of magnitude more than that of other derivatives 43 . Another difference between both dyes relates to the their solvatochromism, color change due to solvent (polarity) variation.…”

“…Similarly, the spiropyran used for both powders might also have different chemical structure. The two most common spiropyran dyes in literature are 5 SP , indolinospironaphthopyran, and 6 SP , indolinospirobenzopyran dye 6 possessing 6-nitro substitution 43 . The main difference in terms of chemical structure between both dyes is the replacement of the fused benzo ring in 5 SP with the 6-nitro group to yield 6 SP43 .…”

Stabilities of bis(thienyl)ethenes in polymethyl methacrylate (PMMA) coatings as absorbance modulation layers for nanoscale imaging

“…Thus, switchable molecules possessing the 5-(iminio)penta-1,3-dien-1-olate chromophor such 2-(indolium-2-yl)vinyl)phenolates 1 (open) undergo reversible ring-closure reactions to form 6-oxa-1-azaspiro[4.5]decadienes 1 (closed) (Scheme 1). 2 Cis – trans isomerism cause the photochromism of azobenzenes 2 , 3 and light-induced redox reactions form radical cations and radical anions of photochromic punicines 3 . 4…”

Photoacidity of Indolinospirobenzopyrans in Water

“…In this Review, we will focus only on the first scenario – i.e ., only on photoinduced proton transfer phenomena [36] in water. We suggest the readers interested in other physicochemical properties and applications to consult other more comprehensive reviews [3,31,37–41] …”

“…We suggest the readers interested in other physicochemical properties and applications to consult other more comprehensive reviews. [3,31,[37][38][39][40][41]…”