Comparative photodegradation study between spiro[indoline—oxazine] and spiro[indoline—pyran] derivatives in solution

Baillet, G.; Giusti, G.; Guglielmetti, R.

doi:10.1016/1010-6030(93)85036-8

Cited by 97 publications

(47 citation statements)

References 6 publications

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“…It can also be observed that with the repeated cycles of UV/visible light irradiation, a slight decrease in the fluorescence intensity in the "On" state (upon UV irradiation) occurs, indicating that some spiropyran moieties might undergo irreversible photodamage. [30][31][32] Moreover, other triblock copolymer micelle samples also exhibit similar spectral behavior as that of the sample VII (PEO 110 -b-PS 85 -b-PSPMA 3 ) in aqueous dispersion, except that at the same micelle concentration, the triblock copolymer micelle samples with longer PSPMA block (spiropyran-containing block) display higher fluorescence intensity at 645 nm upon UV irradiation.…”

Section: Spectral Properties Of Peo-b-ps-b-pspma Micelle Dispersions supporting

confidence: 52%

Construction of Energy Transfer Systems within Nanosized Polymer Micelles and their Fluorescence Modulation Properties

Chen

Zeng

2010

ChemPhysChem

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The nanoparticle-based fluorescence resonance energy transfer (FRET) systems have recently attracted considerable attention due to some of their advantages; however, these systems are structurally more complicated than that of small molecule systems, and the energy transfer behavior for particle systems has been seldom investigated. In this study, we synthesized a series of ABC triblock copolymers that contain hydrophilic poly(ethylene oxide) (PEO), hydrophobic poly(styrene) (PS) and photochromic poly(2-(3-(3',3'-dimethyl-6-nitrospiro(indoline-2',2-[2H-1]benzopyran)-1'-yl)propanoylo-xy)ethyl methacrylate) (PSPMA) blocks by using the sequential two-step atom transfer radical polymerization (ATRP). The amphiphilic micelles made from these copolymers can incorporate a hydrophobic fluorescent dye, the nitrobenzoxadiazolyl derivative (NBD), thus forming a water dispersible energy transfer system with the fluorescent dye NBD as the donor and spiropyran moieties as the potential acceptor. The spectral properties of NBD/triblock copolymers with varied PS block lengths and PSPMA block lengths have been investigated; the results indicate that the length of PS block in triblock copolymers can affect the energy transfer efficiency of the micelle-based fluorescence modulation system, the micelles with moderate PS block length are preferable for forming FRET system with higher energy transfer efficiency, and short PSPMA blocks (less than 5 repetition units) are enough for efficient energy transfer.

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Section: Spectral Properties Of Peo-b-ps-b-pspma Micelle Dispersions supporting

confidence: 52%

Construction of Energy Transfer Systems within Nanosized Polymer Micelles and their Fluorescence Modulation Properties

Chen

Zeng

2010

ChemPhysChem

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“…Another issue to be considered when dealing with spiropyran photochromic dyes is their photostability over time, due to a well documented photobleaching process 3,[31][32][33][34] that occurs when the molecule is exposed to UV-vis radiation for extended time periods. It is generally agreed that photodegradation is enhanced by the presence of free radical or singlet oxygen, by the formation of MC aggregates and by the light source used (especially in the UV region).…”

Section: Optical Properties Of Spiropyran Coated Microbeadsmentioning

confidence: 99%

Polystyrene bead-based system for optical sensing using spiropyran photoswitches

Scarmagnani¹,

Walsh²,

Slater³

et al. 2008

J. Mater. Chem.

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Spiropyran derivatives have been immobilised on the surface of polystyrene microbeads using different immobilisation strategies. These functionalised polymeric beads can be reversibly switched between the colourless inactive spiropyran (SP) and highly coloured (purple) active merocyanine (MC) forms using low power light sources, such as light emitting diodes (LEDs). A UV-LED (375 nm) is used for the SP to MC conversion, and a white LED (430-760 nm) for the reverse MC to SP conversion. The photochromic behaviour of the coated beads has been characterised using different LEDs and reflection spectroscopy, employing optic fibres and an in-house designed holder. Investigations into the metal-ion binding behaviour of the spiropyran modified microbeads have shown that Cu 2+ ions cause an appreciable colour and spectral change when brought into contact with the beads in the MC form, suggesting that a significant interaction is occurring. However, the Cu 2+ ions can be completely expelled by photonicconversion of the beads into the inactive SP form using a white LED. This sequence has been successfully repeated six times suggesting that it is possible to cycle through activation of the functionalised beads from a non-binding to a binding form (SP to MC) using a UV-LED, allow binding with Cu 2+ ions to occur, and subsequently, expel the bound ions and regenerate the passive SP surface using a white-LED. Other metals, such as calcium, do not cause any appreciable colour or spectral change over the same concentration range and in the presence of the same anion (final concentration 7.1 x 10 -4 M nitrate salt in ethanol). The system is therefore self-indicating in terms of whether the active MC or inactive SP forms are present, and whether Cu 2+ ions are bound to the MC form. In principle, therefore, these functionalised beads could form the basis of a photoswitchable stationary phase for metal ion binding and detection: irradiation of the stationary phase with UV-LEDs causes retention of guest species due to the presence of the MC form, while subsequent exposure to white LEDs causes release of guest species into the mobile phase.

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“…We have previously demonstrated that using LEDs instead of more powerful light sources substantially reduces the well-known photodegradation processes that occur when the switching equilibrium between the SP and the MC form is performed repeatedly over time (Baillet et al, 1993(Baillet et al, , 1994Matsushima et al, 2001;Li et al, 2004;Demadrille et al, 2004). Despite the fact that the power of LEDs is much lower than the more commonly employed arc lamp light sources (1 mW/cm 2 compared to 50-100 W), the switching efficiency is relatively unaffected and Notes: In the presence of certain metal ions, especially transition metals such as Cu 2+ and Co 2+ , the MC forms a complex where two phenolate groups bind the metal ion.…”

Section: Introductionmentioning

confidence: 99%

Photoreversible ion-binding using spiropyran modified silica microbeads

Scarmagnani

Slater

Benito‐Lopez

et al. 2010

IJNM

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Abstract:In this paper, we report the covalent immobilisation of spiropyran on silica microbeads of 5 μm diameter and subsequent evaluation of the photoswitchable behaviour and light-modulated ion-binding properties of the spiropyran modified silica microbeads towards a range of different metal ions. The beads can be effectively switched using light emitting diodes between a white spiropyran form (by irradiation with a white 430-760 nm light emitting diode) and a pink merocyanine form (upon irradiation with a UV light 375 nm emitting diodes) that undergoes, under exposure to certain metal ions (such as Cu 2+ and Zn 2+, final concentration of 7.7 × 10 -4 M in ethanol solution), a further reversible spectral and colour change due to the formation of merocyanine-metal ion complexes. Furthermore, the accumulated ions can subsequently released from the beads on demand using light emitting diodes to reform the inactive spiro form.

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Comparative photodegradation study between spiro[indoline—oxazine] and spiro[indoline—pyran] derivatives in solution

Cited by 97 publications

References 6 publications

Construction of Energy Transfer Systems within Nanosized Polymer Micelles and their Fluorescence Modulation Properties

Construction of Energy Transfer Systems within Nanosized Polymer Micelles and their Fluorescence Modulation Properties

Polystyrene bead-based system for optical sensing using spiropyran photoswitches

Photoreversible ion-binding using spiropyran modified silica microbeads

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