ChemPhotoChem最新文献

Room temperature afterglow materials have received widespread attention and application in anti-counterfeiting, imaging, and other fields, but the many shortcomings of traditional afterglow materials in terms of cost, environment, and synthesis methods have limited their development. In contrast, carbon dot materials have attracted more and more research due to their numerous advantages and great potential for development. However, the preparation of carbon dot materials with phosphorescence and delayed fluorescence afterglow emission capabilities remains a difficult task. In this study, a series of long life afterglow carbon dot composites with single-mode and dual-mode afterglow emission were successfully prepared by inserting carbon dots synthesized from glucose and glycine into boric acid matrix through a two-step hydrothermal method. This series of carbon dot composites has achieved a transformation from single-mode phosphorescent emission to unique dual-mode afterglow emission, allowing for efficient environmental response color modulation. The composites display different afterglow emissions dominated by either phosphorescent or delayed fluorescence at different temperatures. Based on their excellent temperature sensitivity, a single-mode long phosphorescence with a lifetime of 1.62 seconds was achieved at low temperature. In summary, we have discovered a convenient and efficient method to achieve dual-mode emission by adjusting the matrix proportion.

A systematic investigation of the photoinduced [6π]-electrocyclization reaction of diphenylamine and N-methyldiphenylamine has been carried out under steady-state and time-resolved conditions in homogeneous (cyclohexane, acetonitrile and methanol) and micellar solutions (sodium dodecyl sulfate -SDS, cetyltrimethylammonium chloride-CTAC and polyethylene glycol monododecyl ether-Brij P35). The photolysis of such compounds in both homogeneous and micro-heterogeneous media afforded the corresponding carbazoles in almost quantitative yield under oxidative conditions. Furthermore, the relative rate of formation of the photoproducts increases when moving from homogeneous media to micellar solution, due to the environmental confined and hydrophobic micellar core as highlighted by 1D and 2D NMR (NOESY and DOSY) spectroscopic analyses.

The intensity and handedness of circularly polarized luminescence (CPL) were successfully controlled by dynamic molecular motion in solutions. Bis(boron difluoride) complexes with chiral salen ligands were synthesized and their photophysical properties were investigated. Although these complexes showed rapid molecular rotation about the C−N bond axis in solution at room temperature, two conformers assigned as atropisomers were observed in the NMR spectra at low temperature. Furthermore, the equilibrium of these atropisomers was found to change depending on the external environment, such as the solvent and temperature, allowing precise control of the intensity and handedness of CPL without luminescence color shifts. Theoretical calculations based on density functional theory (DFT) revealed that intramolecular chiral exciton coupling is the key to changes in CPL properties.

The 3-level features of Latent fingerprints (LFPs) are pivotal in linking suspects with problematic or incomplete fingerprint data, constituting one of the most robust forms of evidence. Aggregation-induced emission (AIE) materials, known for their heightened emissive properties in high aggregation states, provide a robust and powerful approach for developing techniques for 3-level details of LFPs. So far, tremendous efforts have been devoted to solving high background fluorescence interference during the 3-level LFPs visualization process. This review commences with an overview of 3-level features and summarizes the interaction and mechanism of visualizing LFPs involving AIE materials and LFPs secretions. Moreover, it encompasses strategies to enhance the contrast and brightness of 3-level LFPs images. We highlight the mechanism of AIE′s physicochemical properties and their effects on the visualization of 3-level LFPs. Additionally, we provide insights into potential challenges and opportunities in this emerging field.

Ryanodine receptor (RyR) is a crucial intracellular Ca²⁺ channel involved in various physiological processes associated with several diseases. This paper presents the synthesis and evaluation of novel photoactivatable caged compounds for the RyR. We used (6-bromo-7-hydroxycoumarn-4-yl)methyl (Bhc) as the photolabile protecting group to develop caged versions of 4-CmC, a broad-spectrum RyR agonist, and FLA365, an antagonist. The synthesized compounds, Bhcmoc-4-CmC and Bhcmoc-FLA365, exhibited photoreactivity that enabled spatiotemporal control over the RyR activity. Bhcmoc-4-CmC presents a quantum yield of 25 % and a photolysis efficiency of 1,075 M⁻¹ cm⁻¹ under 405 nm light, triggering Ca²⁺ release from the endoplasmic reticulum. Conversely, Bhcmoc-FLA365 presents a reduced quantum yield of 0.61 %, which can be attributed to the quenching effects of its tertiary amine structure. We also applied gene-directed caging, synthesizing β-galactosidase (β-Gal) activatable Gal-Bhcmoc-4-CmC and Gal-Bhcmoc-FLA365, and porcine liver esterase (PLE)-activatable CM-Bhcmoc-FLA365, to target these probes to the specific cell types. These caged compounds contribute significantly to photopharmacology, providing tools for the precise analysis and manipulation of the RyR functions. Future research objectives involve further optimization and analysis of the photochemical mechanisms of these caged compounds to enhance their applications in biological and medical research.

A novel CVO/TiO₂ heterojunction material has been prepared and used to catalyze the oxidative aromatization of amines and cyclohexenones under visible light irradiation, avoiding the use of noble metal catalysts and providing an environmentally friendly alternative for the synthesis of aromatic amines. The catalytic reaction uses oxygen as the final oxidant and provides good yields over a wide range of substrates. Notably, the recyclable heterogeneous semiconductor photocatalyst can be readily recovered and reused for at least four cycles. In addition, several biologically active molecules were successfully synthesized using the photocatalytic method.

We describe the synthesis, full photophysical study, and ab initio calculations of 2-(2’-hydroxyphenyl)benzazole (HBX) fluorophores substituted, at the meta position of the phenol group, by pyridine derivatives. HBX are commonly used as model dyes to study the stimuli-induced modulation of the Excited State Intramolecular Proton Transfer (ESIPT) process. The meta-substituted fluorophores reported herein, display a photophysical profile different from the previously reported ortho- and para-substituted HBO pyridine isomers. Indeed, while all dyes undergo spontaneous deprotonation in neutral conditions, leading to highly emissive anionic species; upon protonation, ortho- and para-pyridine substitution leads to resonance-stabilized keto isomers, formed after ESIPT. Protonated meta derivatives, unable to stabilize their excited structure by such electronic delocalization process, display sizable intramolecular charge transfer (ICT) processes, translating into significantly redshifted emission. In addition, all dyes present a strong emission intensity, not only in neutral and acidic solutions, but also in the solid-state. The nature of the emissive transitions was confirmed in each case by theoretical calculations combining Time-Dependent Density Functional Theory (TD-DFT) and second-order Coupled Cluster (CC2) methods.

BOIMPY (bis- (borondifluoride)-8-imidazodipyrromethene) photosensitizers were developed for imaging-guided photodynamic therapy (PDT). The introduction of heavy atoms (Br and I) to the β-positions of BOIMPY combined with the twisted structure of the molecule was the strategy to enhance the intersystem crossing process of the BOIMPYs and reduce intermolecular π–π interactions of BOIMPY core. To clarify the electronic features of BOIMPY derivatives, their optical properties were studied using UV-vis absorption, fluorescence spectroscopy, electrochemistry, and density functional theory (DFT) computing. The halogenated BOIMPYs exhibited a high absorption coefficient with high singlet oxygen generation ability (Φ_Δ=0.46 and 0.94 for brominated and iodinated BOIMPY, respectively). More significantly, an in vitro investigation showed that all derivatives displayed fluorescence in cancer cells and that the halogenated BOIMPYs increased the effectiveness of tumor inhibition upon exposure to 660 nm red LED light radiation. The half-maximal inhibitory concentrations for the iodinated and brominated BOIMPYs were 2.14 μM and 14.78 μM, respectively. Consequently, iodinated BOIMPY has been shown to represent a new class of photosensitizers with potential use in imaging-guided photodynamic therapy.

Cancer cells change their glucose metabolism towards lactic acid production for various defensive and proliferative advantages. Dichloroacetate (DCA) is an inhibitor of a key enzyme and thus, changes back the OX-PHOS to glycolysis ratio. We designed and synthesized a singlet oxygen triggered source of dichloroacetate which releases this inhibitor during photodynamic singlet oxygen generation. Synergistic action of DCA and singlet oxygen results in significant enhancement of photocytotoxicity. The results suggest that this approach could offer significant improvement in the therapeutic outcome of PDT.

The development of greener methods for the preparation of three-membered rings has increased in the last decade, not only due to their biological activity but also to the ring strain of those heterocycles that make them useful precursors of more complex molecules. In this work, the visible-light-promoted synthesis and ring-opening of aziridines and epoxides, reported in the last five years, were reviewed. Both homogeneous and heterogeneous catalysts were discussed and, in addition, the plausible mechanism pathways were highlighted.