| 1. |
- Bouit, Pierre-Antoine, et al.
(författare)
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Dendron-decorated cyanine dyes for optical limiting applications in the range of telecommunication wavelengths
- 2009
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 964-968
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Tidskriftsartikel (refereegranskat)abstract
- Cyanine dyes decorated with 2,2-bis(methylol) propionic acid (bis-MPA) based dendrons up to third generation were synthesized. Dendrons were attached to the chromophore using a "click chemistry'' reaction. Photophysical characterizations of these dyes show intense absorption and emission in the near-infrared (NIR), while nonlinear transmission experiments of the dendron-decorated chromophores indicate that properties in the IR of the parent dyes are conserved. This synthetic approach is a crucial preliminary step towards the preparation of solid functional materials for optical limiting (OL) applications in the IR.
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| 2. |
- Chateau, Denis, et al.
(författare)
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Silica hybrid sol-gel materials with unusually high concentration of Pt-organic molecular guests : Studies of luminescence and nonlinear absorption of light
- 2012
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Ingår i: ACS Applied Materials and Interfaces. - Washington : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 4:5, s. 2369-2377
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Tidskriftsartikel (refereegranskat)abstract
- The development of new photonic materials is a key step towards improvement of existing optical devices and for the preparation of a new generation of systems. Therefore synthesis of photonic hybrid materials with a thorough understanding and control of the microstructure-to-properties relationships is crucial. In this perspective, a new preparation method based on fast gelation reactions using simple dispersion of dyes without strong covalent bonding between dye and matrix has been developed. This new sol-gel method is demonstrated through synthesis of monolithic siloxane-based hybrid materials highly doped by various platinum(II) acetylide derivatives. Concentrations of the chromophores as high as 400 mM were obtained and resulted in unprecedented optical power limiting (OPL) performance at 532 nm of the surface-polished solids. Static and time-resolved photoluminescence of the prepared hybrid materials were consistent with both OPL data and previous studies of similar Pt(II) compounds in solution. The impacts of the microstructure and the chemical composition of the matrix on the spectroscopic properties, are discussed.
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| 3. |
- Deiana, Marco, et al.
(författare)
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Light-induced in situ chemical activation of a fluorescent probe for monitoring intracellular G-quadruplex structures
- 2021
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 13:32, s. 13795-13808
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Tidskriftsartikel (refereegranskat)abstract
- Light-activated functional materials capable of remote control over duplex and G-quadruplex (G4) nucleic acids formation at the cellular level are still very rare. Herein, we report on the photoinduced macrocyclisation of a helicenoid quinoline derivative of binaphthol that selectively provides easy access to an unprecedented class of extended heteroaromatic structures with remarkable photophysical and DNA/RNA binding properties. Thus, while the native bisquinoline precursor shows no DNA binding activity, the new in situ photochemically generated probe features high association constants to DNA and RNA G4s. The latter inhibits DNA synthesis by selectively stabilizing G4 structures associated with oncogenic promoters and telomere repeat units. Finally, the light sensitive compound is capable of in cellulo photoconversion, localizes primarily in the G4-rich sites of cancer cells, competes with a well-known G4 binder and shows a clear nuclear co-localization with the quadruplex specific antibody BG4. This work provides a benchmark for the future design and development of a brand-new generation of light-activated target-selective G4-binders.
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| 4. |
- Lerouge, Frederic, et al.
(författare)
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In vivo targeting and multimodal imaging of cerebral amyloid-beta aggregates using hybrid GdF3 nanoparticles
- 2022
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Ingår i: Nanomedicine. - : FUTURE MEDICINE LTD. - 1743-5889 .- 1748-6963. ; 17:29, s. 2173-2187
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To propose a new multimodal imaging agent targeting amyloid-beta (A beta) plaques in Alzheimers disease. Materials & methods: A new generation of hybrid contrast agents, based on gadolinium fluoride nanoparticles grafted with a pentameric luminescent-conjugated polythiophene, was designed, extensively characterized and evaluated in animal models of Alzheimers disease through MRI, two-photon microscopy and synchrotron x-ray phase-contrast imaging. Results & conclusion: Two different grafting densities of luminescent-conjugated polythiophene were achieved while preserving colloidal stability and fluorescent properties, and without affecting biodistribution. In vivo brain uptake was dependent on the blood-brain barrier status. Nevertheless, multimodal imaging showed successful A beta targeting in both transgenic mice and A beta fibril-injected rats.
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| 5. |
- Lunden, Hampus, et al.
(författare)
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An optical power limiting and ultrafast photophysics investigation of a series of multi-branched heavy atom substituted fluorene molecules
- 2019
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Ingår i: Inorganics. - : MDPI AG. - 2304-6740. ; 7:10
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Tidskriftsartikel (refereegranskat)abstract
- A common molecular design paradigm for optical power limiting (OPL) applications is to introduce heavy atoms that promote intersystem crossing and triplet excited states. In order to investigate this effect, three multi-branched fluorene molecules were prepared where the central moiety was either an organic benzene unit, para-dibromobenzene, or a platinum(II)-alkynyl unit. All three molecules showed good nanosecond OPL performance in solution. However, only the dibromobenzene and Pt-alkynyl compounds showed strong microsecond triplet excited state absorption (ESA). To investigate the photophysical cause of the OPL, especially for the fully organic molecule, photokinetic measurements including ultrafast pump-probe spectroscopy were performed. At nanosecond timescales, the ESA of the organic molecule was larger than the two with intersystem crossing (ISC) promoters, explaining its good OPL performance. This points to a design strategy where the singlet-state ESA is balanced with the ISC rate to increase OPL performance at the beginning of a nanosecond pulse.
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| 6. |
- Rouillon, Jean, 1993, et al.
(författare)
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Assembly of Aggregation-Induced Emission Active Bola-Amphiphilic Macromolecules into Luminescent Nanoparticles Optimized for Two-Photon Microscopy In Vivo
- 2022
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 23:6, s. 2485-2495
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Tidskriftsartikel (refereegranskat)abstract
- The (Z) and (E)-isomers of an extended tetraphenylethylene-based chromophore with optimized two-photon-induced luminescence properties are separated and functionalized with water-solubilizing pendant polymer groups, promoting their self-assembly in physiological media in the form of small, colloidal stable organic nanoparticles. The two resulting fluorescent suspensions are then evaluated as potential two-photon luminescent contrast agents for intravital epifluorescence and two-photon fluorescence microscopy. Comparisons with previously reported works involving similar fluorophores devoid of polymer side chains illustrate the benefits of later functionalization regarding the control of the self-assembly of the nano-objects and ultimately their biocompatibility toward the imaged organism.
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| 7. |
- Sen, Pinar, et al.
(författare)
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Fluorescence and FTIR Spectra Analysis of Trans-A(2)B(2)-Substituted Di- and Tetra-Phenyl Porphyrins
- 2010
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Ingår i: Materials. - Basel, Switzerland : MDPI AG. - 1996-1944. ; 3:8, s. 4446-4475
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Tidskriftsartikel (refereegranskat)abstract
- A series of asymmetrically substituted free-base di- and tetra-phenylporphyrins and the associated Zn-phenylporphyrins were synthesized and studied by X-ray diffraction, NMR, infrared, electronic absorption spectra, as well as fluorescence emission spectroscopy, along with theoretical simulations of the electronic and vibration structures. The synthesis selectively afforded trans-A(2)B(2) porphyrins, without scrambling observed, where the AA and BB were taken as donor-and acceptor-substituted phenyl groups. The combined results point to similar properties to symmetrically substituted porphyrins reported in the literature. The differences in FTIR and fluorescence were analyzed by means of detailed density functional theory (DFT) calculations. The X-ray diffraction analysis for single crystals of zinc-containing porphyrins revealed small deviations from planarity for the porphyrin core in perfect agreement with the DFT optimized structures. All calculated vibrational modes (2162 modes for all six compounds studied) were found and fully characterized and assigned to the observed FTIR spectra. The most intense IR bands are discussed in connection with the generic similarity and differences of calculated normal modes. Absorption spectra of all compounds in the UV and visible regions show the typical ethio type feature of meso-tetraarylporphyrins with a very intense Soret band and weak Q bands of decreasing intensity. In diphenyl derivatives, the presence of only two phenyl rings causes a pronounced hypsochromic shift of all bands in the absorption spectra. Time-dependent DFT calculations revealed some peculiarities in the electronic excited states structure and connected them with vibronic bands in the absorption and fluorescence spectra from associated vibrational sublevels.
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| 8. |
- Şen, Pınar, et al.
(författare)
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Fluorescence and FTIR Spectra Analysis of Trans-A2B2-Substituted Di- and Tetra-Phenyl Porphyrins
- 2010
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; :8, s. 4446-4475
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Tidskriftsartikel (refereegranskat)abstract
- A series of asymmetrically substituted free-base di- and tetra-phenylporphyrins and the associated Zn-phenylporphyrins were synthesized and studied by X-ray diffraction, NMR, infrared, electronic absorption spectra, as well as fluorescence emission spectroscopy, along with theoretical simulations of the electronic and vibration structures. The synthesis selectively afforded trans-A2B2 porphyrins, without scrambling observed, where the AA and BB were taken as donor- and acceptor-substituted phenyl groups. The combined results point to similar properties to symmetrically substituted porphyrins reported in the literature. The differences in FTIR and fluorescence were analyzed by means of detailed density functional theory (DFT) calculations. The X-ray diffraction analysis for single crystals of zinc-containing porphyrins revealed small deviations from planarity for the porphyrin core in perfect agreement with the DFT optimized structures. All calculated vibrational modes (2162 modes for all six compounds studied) were found and fully characterized and assigned to the observed FTIR spectra. The most intense IR bands are discussed in connection with the generic similarity and differences of calculated normal modes. Absorption spectra of all compounds in the UV and visible regions show the typical ethio type feature of meso-tetraarylporphyrins with a very intense Soret band and weak Q bands of decreasing intensity. In diphenyl derivatives, the presence of only two phenyl rings causes a pronounced hypsochromic shift of all bands in the absorption spectra. Time-dependent DFT calculations revealed some peculiarities in the electronic excited states structure and connected them with vibronic bands in the absorption and fluorescence spectra from associated vibrational sublevels.
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