Benzothiazolyl substituted spiropyrans with ion-driven photochromic transformation

Photoresponsive reversible self-assembly of rod-coil amphiphiles containing spiropyran groups

“…52 Colorimetry is a commonly used method in which the intensity of the characteristic absorption peaks of samples can be analyzed, which can be visually observed by changes in the solution color. [53][54][55][56] The sensing capability of these spiropyrans is typically based on the enhancement of the fluorescence intensity in the 550-650 nm range, which occurs upon the binding of metal ions. 57,58 Some spiropyran sensors can only be used in organic solvents such as acetone, 59,60 ethanol, 61 or acetonitrile, 62 while other sensors reportedly function in mixtures of water and organic solvents, such as N,N-dimethylformamide (DMF)/water 9 : 1, 63 acetonitrile/water 1 : 1, 64 or ethanol/water 1 : 1.…”

Conformation- and Coordination Mode-Dependent Stimuli-Responsive Salicylaldehyde Hydrazone Zn(II) Complexes

“…Among them, mechanochromic and photochromic materials which can quickly change their chemical or physical properties have attracted much attention due to their simple operation and convenient visual monitoring. 7−16 To date, typical photochromic materials reported are based on viologen, 13,14 azobenzene, 20,21 spiropyran, 22 diarylethenes, 23,24 and Schiff base. 25−27 As a kind of electron-deficient compounds, viologen compounds containing pyridine or bipyridyl salts are easy to undergo electron transfer and produce free radicals when combined with other electron donors under irradiation and thermal excitation.…”

“…To date, typical photochromic materials reported are based on viologen, , azobenzene, , spiropyran, diarylethenes, , and Schiff base. − As a kind of electron-deficient compounds, viologen compounds containing pyridine or bipyridyl salts are easy to undergo electron transfer and produce free radicals when combined with other electron donors under irradiation and thermal excitation. − Salicylaldehyde Schiff base can also exhibit excellent thermochromic and photochromic properties with the advantages of facile synthesis, good reversibility, and fatigue resistance, which is mostly used as molecular switches. The reported mechanism mainly depends on the presence of intramolecular hydrogen bonds to generate reversible tautomerism between enol and keto forms. − Although most of the developed organic materials have certain advantages, there are still problems of poor thermal stability and low oxidation resistance.…”

Photoacidity of Indolinospirobenzopyrans in Water

“…The former is colourless, since the two halves of the molecule are located orthogonally to each other via the spiro carbon and therefore are not conjugated, whereas the latter is coloured because the indoline and the chromene parts are coplanar and conjugated through the central ethylene bridge [13] . Interconversion between these two forms can occur with a variety of external stimuli [14] such as light (photochromism), temperature (thermochromism [15] ), solvent polarity (solvatochromism [16] ), acids (acidochromism [17] ), metal ions (ionochromomism [18] ), redox potential (electrochromism [19] ), and even mechanical stress (mechanochromism [20] ). The photochromism can be of two types (Figure 1a).…”