Latest ArticlesPt(Ⅱ)−salophen complexes (S-1~S-4) and 9,10-diphenylanthracene (DPA) tethering pillar[5]arene derivatives (A-1 and A-2) were synthesized to act as sensitizers and annihilators for triplet-triplet annihilation upconversion (TTA-UC), respectively. It turned out that the pyridine cation served as a mask for the excited state of the sensitizer, the triplet states of S-2 and S-3 were significantly quenched by photo-induced electron transfer (PET) with phosphorescence quantum yield quenched from 24.4% for S-4 to 9.3% for S-3, and therefore, both S-2 and S-3 led to negligible UC emissions when traditional annihilator DPA was used as the annihilator. Delightfully, when supramolecular annihilator A-1 and A-2 were employed to include the pyridine cation, PET was significantly inhibited and the triplet states of the sensitizers were activated, TTA-UC emission was therefore boosted. The UC quantum yield of A-2/S-3 system was up to 130 times higher than that of DPA/S-3 system, and the UC emission was switchable by the addition of competitive guests.
A highly sensitive zinc ion fluorescent probe NOD-NY with controlled release of nitric oxide was designed, synthesized and used for tracking intracellular zinc ions in living A549 cells. NOD-NY was prepared from naphthalimide as the fluorophore and N,N-bis(2-pyridylmethyl)amine as the zinc ion recognition receptor, the amide N atom of the naphthalimide was connected to n-butylamine. Under the irradiation of ultraviolet light, NOD-NY can quantitatively release nitric oxide and generate a highly sensitive zinc ion probe Zn-HN, accompanied by a red-shift process of maximum ultraviolet absorption from 350 nm to 450 nm. Upon addition of Zn2+ to the solutions of Zn-HN, a remarkable fluorescence enhancement was observed, which could be attributed to the photo-induced electron transfer (PET) mechanism. By replaced the n-butylamine on NOD-NY with diethylene glycolamine or triphenylphosphine structures, NOD-AY with good biocompatibility and NOD-BY that can target mitochondria were obtained respectively. In addition, the nitric oxide released by NOD-NY enriched in lysosome can diffuse into mitochondria. The released nitric oxide can stimulate metallothionein to release zinc ions, and the light-induced in situ generated zinc ion probe Zn-HN can have a highly sensitive fluorescence response to free zinc ions in living A549 cells.
The construction of triplet-to-singlet Förster resonance energy transfer (TS-FRET) systems has significantly contributed to the advancement of high-performance optoelectronic materials, particularly in the development of metal-free organic environmental afterglow materials. Despite these notable advancements, achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge. In this study, we present the utilization of cation-π interactions as an effective strategy to enhance TS-FRET efficiency, with the ultimate objective of further advancing fluorescence afterglow materials. Our results demonstrate that the cation-π interaction in 1D supramolecular nanorods (1D-SNRs) enhances the dipole-dipole coupling, a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fluorescent acceptor. As a result, we achieved an outstanding TS-FRET efficiency of up to 97%. Furthermore, the 1D-SNRs exhibit a long-lifetime afterglow property, which suggests their potential application as a cost-effective and secure medium for information encryption. Thus, our findings highlight the promising prospects of cation-π interactions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.
Although inductively coupled plasma mass spectrometry (ICP-MS) retains high sensitivity and has been intensively used for the measurement of 99Tc, it usually suffers from tedious, expensive, and time-consuming sample pretreatments due to the isobaric interferences from 99Ru and 98Mo1H. Herein, capillary electrophoresis (CE) was applied as sample introduction system for the sensitive, and interference-free determination of 99TcO4- from RuO4-, and MoO42- by ICP-MS with a simple sample treatment. Compared to the conventional methods, the hyphenated CE-ICP-MS avoids the use of expensive separation resins and reduces the consumption of mineral acid, representing a simpler, more efficient and environmentally benign approach. Moreover, the proposed method exhibits higher accuracy compared with the mathematical correction method using the natural isotope ratio of 99Ru and 101Ru, and significantly reduces sample consumption and the amount of waste, thus remarkably alleviating the radioactive exposure to operators and the pressure of radioactive waste treatment. Under the optimized conditions, the detection limits of 25 µg/L and 0.06 µg/L were obtained for RuO4- and ReO4- (Tc was replaced by Re), respectively, with relative standard deviation (RSD) lower than 5%. In addition, efficient recoveries of RuO4-, ReO4-, and 99TcO4- from simulated Hanford site groundwater were achieved. The method is expected to be a promising candidate for sensitive and accurate analysis of 99Tc from contaminated environmental samples.
A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized, allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively mild conditions. Valuable chiral 1,2,3,4-tetrahydroquinoxalines could be obtained with high yields and excellent enantioselectivities (35 examples, up to > 99% ee).
In this work, we put forward a new and universal approach, i.e., cyanine ketone method, for fabricating meso–aryl heptamethine indocyanines, which is so simple that the treatment of the easy-to-get cyanine ketones with various aromatic lithium (ArLi), followed by acidification, could straightforwardly give rise to the products in one-pot way. Importantly, due to the strong nucleophilicity of ArLi, a series of bulky hydrophilic aromatic groups can be facilely integrated into the meso–position of heptamethine indocyanines, not only effectively inhibiting the undesired dye self-aggregation but also largely improving the water-solubility. Using one of anti-aggregation meso–aryl heptamethine indocyanines, we fabricated a dye-antibody conjugate for in vivo imaging tumor in a mouse model and achieved a high tumor-to-normal tissue ratio. The work laid a chemical foundation for constructing various meso–aryl heptamethine indocyanines, facilitating the advanced imaging and therapeutic applications in future.
Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties. Consequently, the development of host–guest molecular recognition systems for these compounds serves a dual-purpose: enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation. This study investigated the host–guest recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules, 1-chloro-2,4-dinitrobenzene and picric acid. Various techniques including 1H NMR, 2D NOESY NMR, and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro guests in solution. Moreover, valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these guests with different pillararenes. The assembled solid-state supramolecular structures observed encompassed a 1:1 host–guest inclusion complex, an external binding complex, and an exo-wall tessellation complex. Furthermore, based on the findings from these systems, a pillararene-based test paper was developed for efficient picric acid detection, and the removal of picric acid from solution was also achieved using pillararenes powder. This research provides novel insights into the development of diverse host–guest systems toward hazardous compounds, offering potential applications in environmental protection and explosive detection domains.
For nano-collision, regulating the interaction between nanoparticles (NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes (UMEs) suffer from narrow electrochemical window and poor electrode interface adhesion, severely hindering the application of precise single NP analysis. Here, we propose a simple and effective interface modification strategy. By electrochemically self-assembling poly(diallyldimethylammonium chloride) (PC) on the surface of carbon nanocone electrodes (CNCEs), we successfully prepared PC-modified CNCEs (PC‑CNCEs). These electrodes not only possess sufficiently wide electrochemical window but also exhibit strong adhesion to negatively charged Ag NPs on their surfaces. Surface physical analysis and electrochemical molecule detection validated the high-density loading of PC on the modified electrodes. Furthermore, the working principle of PC‑CNCEs for single Ag NP collision detection was further verified through the techniques of nano-collision and double-potential steps. Leveraging these significant advantages, PC‑CNCEs not only achieved precise measurements of single or mixed-sized Ag NPs but also detected Ag NP solutions at concentrations as low as fmol/L levels. This advancement offers a new strategy for the rapid and precise analysis of NP colloids.
Selective separation of phenanthrene (PHE) from aromatic isomer mixtures poses a significant challenge in industry due to the similar physical properties of PHE and its isomer anthracene (ANT). Herein, we report the self-assembly of a water-soluble Pd2L2 cage 1 with a large hydrophobic cavity, formed from novel macrocyclic ligands (L) and cis-Pd(Ⅱ). Cage 1 can selectively encapsulate PHE instead of ANT. Based on host-guest recognition followed by extraction, we achieve a remarkable 99% purity of PHE separation from an equimolar mixture of PHE and ANT using cage 1 in aqueous solution. Importantly, the separation performance of PHE using cage 1 remains unaffected even after five extraction cycles, demonstrating its robustness. This work highlights the potential of supramolecular cages for efficient and cost-effective PHE separation from the isomer ANT in aqueous solutions using such promising host-guest strategy.
Inspired by the light-dependent signal transduction in nature, we herein report a fully synthetic receptor AZO with the capacity of transmembrane signaling, working by photo-induced change of molecular conformation. Our receptor has an anchoring group, a rigid and photoresponsive transmembrane unit and a precatalyst tailgroup. After doping in lipid membranes, AZO is membrane anchored and the extended trans-isomer enables the tailgroup to bind with intravesicular Zn2+, thereby achieving enzyme activation and triggering downstream events (ester hydrolysis). However, the shortened cis-isomer pulls the tailgroup into lipids, thereby preventing the complexation and all transduction processes. Upon alternative irradiation of ultraviolet (UV) and visible light, the transduction process can be reversible switch between "ON" and "OFF", achieving light signal transduction. This study provides a new strategy for future design of artificial signal transduction receptors.
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