-
Angewandte Chemie (International Ed. in... Jun 2024In this work, six benzothioxanthene-based oxime esters were employed as photoinitiators for photopolymerization with visible light (LED) and sunlight. Their abilities to...
High Photoinitiating Efficiency of Benzothioxanthene-based Oxime Esters in Photopolymerization via Photocleavage and/or Single Electron Transfer under Visible Light and Sunlight.
In this work, six benzothioxanthene-based oxime esters were employed as photoinitiators for photopolymerization with visible light (LED) and sunlight. Their abilities to behave as Type I photoinitiators by mean of a photocleavage mechanism of oxime esters but also in multicomponent photoinitiating system with an iodonium salt (through an electron transfer mechanism) were both explored with the different structures. Due to their broad absorption spectra tailing up 600 nm, photoinitiating properties of the benzothioxanthene-based oxime esters were systematically tested under excitation with low-intensity LED light at wavelengths of 405 nm and 450 nm. Additionally, to the polymerization tests done under artificial light, different benzothioxanthene-based oxime esters were also investigated as solar photoinitiators and displayed a high reactivity in France (Western Europe) even in winter conditions. For the best candidates i.e. the most reactive structures, direct laser write experiments were carried out, evidencing the interest of these structures.
PubMed: 38877857
DOI: 10.1002/anie.202405337 -
Advanced Science (Weinheim,... Jun 2024White light-emitting diodes (WLEDs) with high color-rendering index (CRI, >90) are important for backlight displays and solid-state lighting applications. Although the...
White light-emitting diodes (WLEDs) with high color-rendering index (CRI, >90) are important for backlight displays and solid-state lighting applications. Although the well-developed colloidal quantum dots (QDs) based on heavy metals such as cadmium and lead are promising candidates for WLEDs, the low CRI still remains a significant limitation. In addition, the severe toxicity of heavy metals greatly limits their widespread use. Herein, the study demonstrates low-cost and environmentally friendly carbon quantum dots (CQDs)-based WLEDs that exhibit a high CRI of 94.33, surpassing that of conventional cadmium/lead-containing QD-based WLEDs. This achievement is attained through the employment of a binary host-induced exciplex strategy. The high hole/electron mobility and suitable energy levels of the donor and acceptor give rise to a broadband orange-yellow emission stemming from the exciplex. As the host, the binary exciplex is capable of contributing blue and orange-yellow emission components while efficiently mitigating the aggregation-induced quenching of CQDs. Meanwhile, CQDs effectively address the deep-red emission gap, enabling the realization of CQDs-based WLEDs with high CRI. These WLEDs also exhibit a remarkably low turn-on voltage of 2.8 V, a maximum luminance exceeding 2000 cd m , a correlated color temperature of 4976 K, and Commission Internationale de l'Eclairage coordinates of (0.34, 0.32).
PubMed: 38872266
DOI: 10.1002/advs.202404485 -
Nature Communications Jun 2024Direct solar-to-hydrogen conversion from pure water using all-organic heterogeneous catalysts remains elusive. The challenges are twofold: (i) full-band low-frequent...
Direct solar-to-hydrogen conversion from pure water using all-organic heterogeneous catalysts remains elusive. The challenges are twofold: (i) full-band low-frequent photons in the solar spectrum cannot be harnessed into a unified S excited state for water-splitting based on the common Kasha-allowed S → S excitation; (ii) the H → H evolution suffers the high overpotential on pristine organic surfaces. Here, we report an organic molecular crystal nanobelt through the self-assembly of spin-one open-shell perylene diimide diradical anions (:PDI) and their tautomeric spin-zero closed-shell quinoid isomers (PDI). The self-assembled :PDI/PDI crystal nanobelt alters the spin-dependent excitation evolution, leading to spin-allowed SS → (TT) → T + T singlet fission under visible-light (420 nm~700 nm) and a spin-forbidden S → T transition under near-infrared (700 nm~1100 nm) within spin-hybrid chromophores. With a triplet-triplet annihilation upconversion, a newly formed S excited state on the diradical-quinoid hybrid induces the H reduction through a favorable hydrophilic diradical-mediated electron transfer, which enables simultaneous H and O production from pure water with an average apparent quantum yield over 1.5% under the visible to near-infrared solar spectrum.
PubMed: 38871750
DOI: 10.1038/s41467-024-49511-7 -
Angewandte Chemie (International Ed. in... Jun 2024We herein report a fundamental mechanistic investigation into photochemical metal-nitrenoid generation and inner-sphere transposition reactivity using organometallic...
We herein report a fundamental mechanistic investigation into photochemical metal-nitrenoid generation and inner-sphere transposition reactivity using organometallic photoprecursors. By designing Cp*Ir(hydroxamate)(Ar) complexes, we induced photo-initiated ligand activation, allowing us to explore the amidative σ(Ir-aryl) migration reactivity. A combination of experimental mechanistic studies, femtosecond transient absorption spectroscopy, and density functional theory (DFT) calculations revealed that the metal-to-ligand charge transfer enables the σ(N-O) cleavage, followed by Ir-acylnitrenoid generation. The final inner-sphere σ(Ir-aryl) group migration results in a net amidative group transposition.
PubMed: 38871650
DOI: 10.1002/anie.202408123 -
Nanomaterials (Basel, Switzerland) Jun 2024Diabetes is a common disease that seriously endangers human health. Continuous glucose monitoring (CGM) is important for the prevention and treatment of diabetes....
Diabetes is a common disease that seriously endangers human health. Continuous glucose monitoring (CGM) is important for the prevention and treatment of diabetes. Glucose-sensing photonic nanochains (PNCs) have the advantages of naked-eye colorimetric readouts, short response time and noninvasive detection of diabetes, showing immense potential in CGM systems. However, the developed PNCs cannot disperse in physiological environment at the pH of 7.4 because of their poor hydrophilicity. In this study, we report a new kind of PNCs that can continuously and reversibly detect the concentration of glucose (C) in physiological environment at the pH of 7.4. Polyacrylic acid (PAA) added to the preparation of PNCs forms hydrogen bonds with polyvinylpyrrolidone (PVP) in FeO@PVP colloidal nanoparticles and the hydrophilic monomer -2-hydroxyethyl acrylamide (HEAAm), which increases the content of PHEAAm in the polymer shell of prepared PNCs. Moreover, 4-(2-acrylamidoethylcarbamoyl)-3-fluorophenylboronic acid (AFPBA), with a relatively low pKa value, is used as the glucose-sensing monomer to further improve the hydrophilicity and glucose-sensing performances of PNCs. The obtained FeO@(PVP-PAA)@poly(AFPBA-co-HEAAm) PNCs disperse in artificial serum and change color from yellow-green to red when C increases from 3.9 mM to 11.4 mM, showing application potential for straightforward CGM.
PubMed: 38869588
DOI: 10.3390/nano14110964 -
The Journal of Physical Chemistry... Jun 2024Photoexcitation induces intricate changes in both the real and imaginary components of the complex refractive index of thin film materials, which is essential for...
Photoexcitation induces intricate changes in both the real and imaginary components of the complex refractive index of thin film materials, which is essential for interpreting transient spectral features. Here, we employ a Kramers-Kronig-based analytical approach to elucidate light-induced changes in the complex refractive index from transient transmission spectra of thin films. Using gold-perovskite films as model systems, we conduct experimental measurements of transient transmission spectra for both individual gold and perovskite films, as well as for the bilayer heterostructure. Our analysis reveals significant changes in the refractive index and absorption for these systems. Notably, we observe negligible photocarrier transfer between the gold and perovskite layers based on transient spectroscopic analysis. These findings have implications for the design and optimization of bilayer heterostructures in optoelectronic applications. This work highlights the importance of spectroscopic techniques in studying the photophysical properties of heterostructure films.
PubMed: 38869188
DOI: 10.1021/acs.jpclett.4c01249 -
Advanced Science (Weinheim,... Jun 2024Individual differences in size, experience, and task specialization in natural swarms often result in heterogeneity and hierarchy, facilitating efficient and coordinated...
Individual differences in size, experience, and task specialization in natural swarms often result in heterogeneity and hierarchy, facilitating efficient and coordinated task accomplishment. Drawing inspiration from this phenomenon, a general strategy is proposed for organizing magnetic micro/nanorobots (MNRs) with apparent differences in size, shape, and properties into cohesive microswarms with tunable heterogeneity, controlled spatial hierarchy, and collaborative tasking capability. In this strategy, disparate magnetic MNRs can be manipulated to show reversible transitions between synchronization and desynchronization by elaborately regulating parameter sets of the rotating magnetic field. Utilizing these transitions, alongside local robust hydrodynamic interactions, diverse heterospecific pairings of disparate magnetic MNRs can be organized into heterogeneous microswarms, and their spatial organization can be dynamically adjusted from egalitarian to leader-follower-like hierarchies on the fly, both in open space and complex microchannels. Furthermore, when specializing the disparate MNRs with distinct functions ("division of labor") such as sensing and drug carrying, they can execute precise drug delivery targeting unknown sites in a collaborative sensing-navigating-cargo dropping sequence, demonstrating significant potential for precise tumor treatment. These findings highlight the critical roles of attribute differences and hierarchical organization in designing efficient swarming micro/nanorobots for biomedical applications.
PubMed: 38868929
DOI: 10.1002/advs.202401711 -
ChemSusChem Jun 2024The sulfoxide moiety is one of the most commonly utilized groups in pharmaceutical and industrial chemistry. The need for sustainability and easy accessibility to...
The sulfoxide moiety is one of the most commonly utilized groups in pharmaceutical and industrial chemistry. The need for sustainability and easy accessibility to sulfoxide moieties is deemed necessary, due to its ubiquity in natural products and potentially pharmaceutically active compounds. In this context, we report herein a sustainable, aerobic and environmentally friendly photochemical protocol based on the use of a benzothioxathene imide as the photocatalyst to selectively oxidise sulfides under mild irradiation (456 nm), in very low catalyst loading (0.01 mol%) and on water. In addition, to demonstrate the compatibility of our protocol with wide scope of substrates, the latter was successfully applied to the synthesis of the biologically-active Sulforaphane and Modafinil.
PubMed: 38867402
DOI: 10.1002/cssc.202400903 -
Environmental Science & Technology Jun 2024Hydrogen peroxide (HO) plays a crucial role as an oxidizing agent within the tropospheric environment, making a substantial contribution to sulfate formation in hydrated...
Hydrogen peroxide (HO) plays a crucial role as an oxidizing agent within the tropospheric environment, making a substantial contribution to sulfate formation in hydrated aerosols and cloud and fog droplets. Field observations show that high levels of HO are often observed in heavy haze events and polluted air. However, the source of HO remains unclear. Here, using the droplets formed by the deliquescence of hygroscopic compounds under a high relative humidity (RH), the formation of HO by the photochemistry of imidazole-2-carbaldehyde (2-IC) under ultraviolet irradiation was explored. The results indicate that 2-IC produces IM-C-OH and IM-C═O radicals via H transfer itself to its excited triplet state and generates HO and organic peroxides in the presence of O, which has an evident oxidizing effect on SO, suggesting the potential involvement of this pathway in the formation of atmospheric sulfate. HO formation is limited in acidic droplets or droplets containing ammonium ions, and no HO is detected in droplets containing nitrate, whereas droplets containing citric acid have an obvious promotion effect on HO formation. These findings provide valuable insights into the behaviors of atmospheric photosensitizers, the source of HO, and the formation of sulfate in atmospheric droplets.
Topics: Hydrogen Peroxide; Oxidation-Reduction; Imidazoles; Photochemistry; Sulfur Dioxide; Air Pollutants; Ultraviolet Rays
PubMed: 38865480
DOI: 10.1021/acs.est.3c11113 -
Journal of the American Chemical Society Jun 2024Titanium-oxo clusters can undergo photochemical reactions under UV light, resulting in the reduction of the titanium-oxo core and oxidation of surface ligands. This is...
Titanium-oxo clusters can undergo photochemical reactions under UV light, resulting in the reduction of the titanium-oxo core and oxidation of surface ligands. This is an important step in photocatalytic processes in light-absorbing Ti/O-based clusters, metal-organic frameworks, and (nano)material surfaces; however, studying the direct outcome of this photochemical process is challenging due to the fragility of the immediate photoproducts. In this report, titanium-oxo clusters [TiO(OPr)(L)] ( = 4, L = OPPh, or = 6, L = OCCHBu) undergo a two-electron photoredox reaction in the single-crystal state via an irreversible single-crystal to single-crystal (SC-SC) transformation initiated by a UV laser. The process is monitored by single crystal X-ray diffraction revealing the photoreduction of the cluster with coproduction of an (oxidized) acetone ligand, which is retained in the structure as a ligand to Ti(3+). The results demonstrate that photochemistry of inorganic molecules can be studied in the single crystal phase, allowing characterization of photoproducts which are unstable in the solution phase.
PubMed: 38865257
DOI: 10.1021/jacs.4c04068