Photochromism of the spiropyran radical cation to the corresponding merocyanine form is investigated by a combination of electrochemical oxidation, UV/vis absorption spectroscopy, spectroelectrochemistry and first-principles calculations (TD-DFT, CAS-SCF and CAS-PT2). First, we demonstrate that the ring-opening of mono-spiropyrans occurs upon one-electron oxidation and that it can be driven pho...

Hexagonal columnar liquid-crystalline phases are induced for a new fan-shaped spiropyran compound as the result of an acidichromism effect of spiro-merocyanine isomerisation through protonation upon incorporation of 4-methylbenzenesulfonic acid.

The purpose of this study was to evaluate the photosensitizing dye merocyanine 540 (MC540) as a means for extracorporeal purging of Plasmodium falciparum-infected erythrocytes from human blood. Parasitized red blood cells bound more dye than nonparasitized cells, and exposure to MC540 and light under conditions that are relatively well tolerated by normal erythrocytes and normal pluripotent hem...

This paper describes a simple platform that employs spiropyran-functionalized semiconducting polymer dots as a fluorescent probe for photoactivated ratiometric and sensitive Cu(2+) detection, in which the sensing mechanism is based on photogenerated merocyanine that can selectively bind Cu(2+) to induce Förster resonance energy transfer.

Design of optical molecular probes for selective detection of aromatic thiols has attracted much attention. Although several types of probes have been proposed, all of them exhibit colorimetric or fluorometric response via irreversible reaction with aromatic thiols and cannot be reused. Here we report that a spiropyran dye is the first example of a reusable chemosensor for aromatic thiols. A co...

In lymphocytes, the cytoskeletal protein spectrin exhibits two organizational states. Because the plasma membrane lipids of lymphocytes also display two organizational states, it was asked whether there is a relation between the organization of spectrin and of membrane lipids. When mouse thymocytes were stained with merocyanine 540 (MC540), a fluorescent lipophilic probe that binds preferential...

Merocyanine 540 (MC540) is a fluorescent probe that binds preferentially to membranes with loosely packed lipids. When combined with flow cytometry, it provides a novel methodology for rapidly and quantitatively assessing lipid organization in individual leukocytes. Analysis of cells stained simultaneously with MC540 and 1-[4-trimethylammoniumphenyl]-6-phenyl-1,3,5-hexatriene, to normalize for ...

Merocyanine dyes have proven valuable for live cell fluorescence imaging applications, but many structures have been limited by rapid photobleaching. We show that photostability is substantially enhanced for merocyanines having a cyano group at a specific position in the central polymethine chain. Evidence is presented that this is due to reduction in reactivity of the dyes with singlet oxygen....

We have designed and prepared a new dual stimuli-responsive guest molecule containing a spiropyran fragment and a pyridinium moiety. Acid addition or UV-light irradiation induces guest transformation to a merocyanine isomer, promoting the threading motion through a 24-crown-8 macrocycle and the formation of a [2]pseudorotaxane complex.