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- Ghasemi, Shima, 1993, et al.
(författare)
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Pyrene Functionalized Norbornadiene-Quadricyclane Fluorescent Photoswitches: Characterization of their Spectral Properties and Application in Imaging of Amyloid Beta Plaques
- 2024
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Ingår i: Chemistry - A European Journal. - 1521-3765 .- 0947-6539. ; 30:34
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the synthesis and characterization of two fluorescent norbornadiene (NBD) photoswitches, each incorporating two conjugated pyrene units. Expanding on the limited repertoire of reported photoswitchable fluorescent NBDs, we explore their properties with a focus on applications in bioimaging of amyloid beta (Aβ) plaques. While the fluorescence emission of the NBD decreases upon photoisomerization, aligning with what has been previously reported, for the first time we observed luminescence after irradiation of the quadricyclane (QC) isomer. We deduce how the observed emission is induced by photoisomerization to the excited state of the parent isomer (NBD) which is then the emitting species. Thorough characterizations including NMR, UV-Vis, fluorescence, X-ray structural analysis and density functional theory (DFT) calculations provide a comprehensive understanding of these systems. Notably, one NBD-QC system exhibits exceptional durability. Additionally, these molecules serve as effective fluorescent stains targeting Aβ plaques in situ, with observed NBD/QC switching within the plaques. Molecular docking simulations explore NBD interactions with amyloid, unveiling novel binding modes. These insights mark a crucial advancement in the comprehension and design of future photochromic NBDs for bioimaging applications and beyond, emphasizing their potential in studying and addressing protein aggregates.
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| 2. |
- Shamsabadi, Monika, 1997
(författare)
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Synthesis and Characterisation of Phase Change Materials for Molecular Solar Thermal Systems
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Demand for energy has steadily increased over the last decade and several technologies have been developed to combat the resulting global impact. Solar power systems are an attractive option for a cleaner and more sustainable source of energy owing to the magnitude of energy the sun provides as well as its availability and consistency. However, modern versions of these technologies still face challenges in effectively storing energy, particularly concerning storage capacity, lifespan, and disposal of the devices. The Molecular Solar Thermal Systems (MOST) are a class of organic materials which can undergo a reversible photochemical reaction allowing for storage of solar energy as chemical energy which ultimately can be released as heat. One such system is based on the norbornadiene (NBD) derivatives that can isomerise to form the metastable quadricyclane (QC). The QC to NBD conversion can be initiated with the use of a catalyst, light, or heat to release thermal energy. However, the best performing NBDs struggle to be integrated into devices due to properties such as poor solubility and short storage life. Phase change materials (PCMs) can also store energy via a phase transition from solid-to-liquid from latent heat, although the energy density stored is limited. Thus, a material that combines the function of MOST and PCM was synthesised to tackle the drawbacks of the single function materials. In this thesis, a series of NBDs engineered with varying substituents in order to explore improvements to solubility of the systems. These compounds were synthesised via Diels-Alder reactions in a comparative study of thermal and microwave-assisted synthesis. Furthermore, evaluation of different purification methods (distillation, HPLC, flash chromatography) of the products were explored to determine which method yields pure products for photocharacterisation, solubility, and stability studies. It was revealed that the chosen substituents had a positive effect on the solubility of the molecules, though did not improve on the degradation observed in similar derivatives. Another class of MOST compounds were studied to improve the phase change transition properties for future MOST-PCM applications. By varying the alkyl chain length on an azobenzene moiety, the effects on the phase-transition temperatures and energy storage were evaluated. This led to the observation that the azobenzene with six carbons in the alkoxy chain are the best performing material for MOST-PCM applications with the highest energy storage density, achieving the target suggested for solar thermal storage systems.
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| 3. |
- Wang, Zhihang, 1989, et al.
(författare)
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Chasing the rainbow: Exploiting photosensitizers to drive photoisomerization reactions
- 2023
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Ingår i: Responsive Materials. - 2834-8966 .- 2834-8966. ; 1:2
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Forskningsöversikt (refereegranskat)abstract
- Photoswitchable molecules have garnered considerable attention for their versatility and diverse applications, spanning from solar energy harvesting and storage to drug delivery and molecular motors. The chemical conversions that make photoswitches a desirable system are driven by specific wavelengths of light, which often demand intricate molecular modifications. An alternative approach to achieve the photoisomerization reaction is through energy transfer with photosensitizers. Photosensitizers play a pivotal role in various light-induced processes and have demonstrated successful applications in photodynamic therapy, dye-sensitized solar cells, and activating photochemical reactions. Therefore, combining photoswitching systems with sensitizers presents an attractive alternative for advancing light-responsive material design and enabling innovative light-controlled technologies. This review summarizes the energy transfer mechanisms and strategies involved in sensitized molecular photoswitchable systems, emphasizing the performance of various combined systems, and potential applications. Furthermore, recent advances and emerging trends in this field are also discussed, offering insights into prospective future directions for the development of light-responsive materials.
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