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Showing 1 to 20 of 20 for “"merocyanine"”.
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Spectroscopic studies of hydrophobic association of merocyanine dyes in cationic and anionic micelles
<p>Merocyanine dyes exhibit interesting changes in absorption spectra with changes in solvent polarity. For example solutions of 1-methyl-4- (oxocyclohexadienylidene) ethylidene -1,4-dihydropyridine (MOED) are yellow, red, violet, or blue, in water, ethanol, acetone or pyridine …
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Amino acid interactions of spiropyran
… between the spiropyran molecule in its merocyanine zwitterionic merocyanine 'open' form and amino acids. The principal amino acids chosen for investigation were β-Alanine, L-Phenylalanine and 8-Aminocaprylic acid. Both single phase and two-phase switching experiments were undertaken to …
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Photochemical Applications to the Study of Complexity Phospholipid Bilayer Environments
… were investigated using novel spiropyran/merocyanine molecular probes. The femtosecond to second dynamics of this system's photochemistry enabled bilayer viscosity and free volume to be studied over a broad time scale. Spiropyrans/merocyanines with different polarity were synthesized by …
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Visible light-induced pH control and its applications
… substitution patterns influence the acidity of merocyanine photoacids in the dark as well as under light irradiation. The parameters which are crucial for increasing light-induced pH changes are defined and applied to synthesized merocyanine photoacids. The light-induced pH changes starting from …
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Mechanisms by Which Apoptotic Membranes Become Susceptible to Secretory Phospholipase A2
… the sPLA2 active site. First, intercalation of merocyanine 540 into the membrane was improved, suggesting increased lipid spacing. Second, laurdan detected increased solvation of the lower head group region of the membrane. Third, the rate at which fluorescent lipids could be removed from the …
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Investigation of spiropyrans and merocyanines in mixed thin films with long chain alkyl silanes: Towards a command surface for liquid crystal realignment
… The rate of the thermal reaction from the open (merocyanine) to the closed form of the spiropyran was measured, and shows no dependence on the length of the spiropyran molecule, though the rate is much closer to that found for spiropyran molecules doped into polymers than in solution. Sessile …
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Control of mechanochromic reactions in a polymer matrix
… rate constants and activation energies for SP–merocyanine (MC) transition is characterized in bulk polymers. Under different values of a macroscopic tensile stress, the change in fluorescence intensity is measured, indicating the evolution of merocyanine. Assuming first-order reaction kinetics, …
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Fracture-induced mechanophore activation and solvent healing in poly(methyl methacrylate)
… colorless SP is converted to the highly colored merocyanine (MC) form. One requirement for SP activation in bulk polymers is large scale plastic deformation. In order to induce this plastic deformation during fracture testing of SP-linked brittle polymers such as poly(methyl methacrylate) (PMMA), …
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Preparation and characterization of photo-, thermo-, and solvatochromic materials containing benzospiropyran
… immobilised spiropyran on a solid support to merocyanine for repeat detection of metal ions. These results demonstrate a polymer-modified surface that can adapt its hctionality through reversible molecular rearrangements triggered by external stimuli (photons). The photo- thermo and …
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Development of new adaptive materials based on spiropyran molecular photoswitches
… highly coloured, polar, conjugated, zwitterionic merocyanine form (MC), i.e. SP → MC (UV light), MC → SP (green, white light). Furthermore, the MC form possesses a phenolate group that can reversibly bind metal ions and this ion binding is also photo-reversible, as when the MC-ion complex reverts …
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Using Fluorescent Probes to Study the Location and Interaction of Disaccharides within Lipid Bilayers
… incorporated into a cell membrane. The second, merocyanine 540, is a negatively charged cyanine dye located slightly above the glycerol backbone of the phospholipids and is sensitive to any structural variations within the membrane. The data obtained with each respective probe indicates that the …
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modeling and application of nonlinear metasurface
… and induces isomerization of spiropyrans to merocyanines. Due to the large Purcell enhancement introduced by the film-coupled nanocubes, fluorescence lifetime measurements on the merocyanine form reveal large enhancements on spontaneous emission rate, as well as high quantum efficiency. We …
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Towards reversible mechanochemically triggered strengthening, toughening and assembly of soft materials
… from a ring-closed state to a ring-open state, merocyanine (MC), in response to a variety of stimuli, including UV light, heat, and mechanical force. Herein, a strategy is proposed to reversibly crosslink polymer chains using SP’s well documented ability to bind to metal cations in its MC state. …
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Force-induced mechanochemical reactions in polymeric systems
… converts to a colored and fluorescent merocyanine (MC) form upon the application of heat, UV light, or mechanical force, when linked into a polymer backbone. The SP to MC (activation) reaction is also reversible, and can be driven back to the colorless SP form by visible light. The SP …
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Spiropyrans as color-generating mechanophores
… force. This ring-opening yields a colored merocyanine which would allow the location and progress of the mechanically-induced reactions to be followed. A modular synthesis was developed which allowed for easy access to a wide variety of mechanophore and control spiropyrans. Since …
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Physicochemical Study of Nano-structuring Within Ionic Liquids Using Photoswitchable Spirocyclic Compounds
… relaxation of the compounds from their open merocyanine (MC) form to their closed (SP) form and the equilibrium effects upon the MC-SP inter-conversion and the dependence of cation and anion choice while optimising the choice of probe molecule by establishing whether spiropyran (BSP) or …
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Mechanical and optical characterization of force induced chemical reactions in solid state linear polymers
… The mechanophore, spiropyran (SP), reacts to a merocyanine (MC) form under tensile force when linked into a polymer backbone. This reaction is reversible and can be driven toward either SP or MC photochemically. Reaction of SP to MC (activation) is accompanied by the emergence of a strong color …
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Multiscale characterization of mechanochemical reactions in mechanophore-crosslinked polymers under shear loading
… The opening of spiropyran (SP) into merocyanine (MC) is driven by mechanical force, UV light, or heat, and is reversible. The focus of this dissertation is to evaluate the transformation of SP to MC under shear loading conditions in bulk polymers and at the interface between a glass …
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Controlling and Exploiting Spiropyran-based Mechanochromism
… of the reaction that converts spiropyran into merocyanine, we</p><p>are able to teach and connect a number of standard general chemistry course topics</p><p>while also introducing students to polymer concepts. By framing a number of different</p><p>concepts including molecular orbital theory, …
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Sensing in biological systems
… spiropyran (SP) and highly fluorescent merocyanine (MC) isomers occurs on irradiation with UV light or in the presence of the target metal ion, while visible light reverses the isomerisation (see Figure 1). This thesis describes the functionalisation of the spiropyran molecule in order …