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Extended π-Conjugated Structures via Dehydrative C–C Coupling
摘要： We describe a methodology for the synthesis of extended aromatic structures through dehydrative C?C coupling from readily accessible diols. Treatment of the diols with a Br?nsted acid (para-toluenesulfonic acid) induces the nucleophilic addition of an arene or heteroarene, yielding fully aromatic products in high to quantitative yields with thiophenes, furan, indole, and N,N-dimethylaniline as coupling partners. The C?C coupling reactions proceed under mild, open flask conditions and offer high atom economy, while providing an attractive alternative approach to metal-catalyzed cross-coupling.
关键词： metal-catalyzed cross-coupling,extended aromatic structures,atom economy,para-toluenesulfonic acid,dehydrative C?C coupling,Br?nsted acid
更新于2025-09-04 15:30:14
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A Novel Solid-State Electrochemiluminescence Sensor Based on poly(3-amino-4 hydroxybenzenesulfonic acid) /Ru(bpy)32+ Modified Electrode for Determination of Malachite Green
摘要： The poly(3-amino-4-hydroxybenzenesulfonic acid)/Ru(bpy)3 2+ modified glassy carbon electrode (PAHBS/Ru(bpy)3 2+/GCE) is a novel solid-state electrochemiluminescence (ECL) sensor. It was prepared by electropolymerization of 3-amino-4-hydroxybenzenesulfonicacid (AHBS) followed by soaking into Ru(bpy)3 2+ solution. Ru(bpy)3 2+ was entrapped on the electrode via the electrostatic interactions between sulfonic acid groups and Ru(bpy)3 2+ cation. The morphology and composition of the modified electrodes were analysed using scanning electron microscope and energy-dispersed spectrum. Cyclic voltammetry and electrochemical impedance spectroscopy were used to compare the electrochemical behavior of the electrodes before and after modification. Under the optimal conditions, the ECL intensity of the quenching value (ΔECL) versus the logarithm of the concentration of malachite green (MG) was linear over a concentration range from 5.0 × 10-8 to 1.0 × 10-5 mol L-1 (r = 0.9931) and the limit of detection (LOD) was 2.5 × 10-8 mol L-1. This method has been successfully applied to the determination of MG in pond water.
关键词： Ru(bpy)3 2+,electrochemiluminescence,malachite green,sensor,3-amino-4-hydroxybenzenesulfonic acid
更新于2025-09-04 15:30:14
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PHOTOELECTROCHEMICAL ANALYSIS OF TITANIUM DIOXIDE BY USING OXALIC ACID AS A SACRIFICIAL DONOR
摘要： Photoelectrochemical (PEC) water splitting is a very promising green method to produce solar fuel. Titanium dioxide (TiO2) has been widely used as photocatalyst for this type of reaction. Improving the performance of TiO2 for PEC water splitting has been ongoing and addition of sacrificial donor especially from waste is an attractive option to achieve this. Oxalic acid is one component in organic waste stream that can be used as sacrificial donor. The TiO2 thin films has been fabricated by coating TiO2 paste on Fluorine Tin oxide (FTO) glass surface. The morphology of the TiO2 thin films were porous and rough with uniform particles size with crystallite size of about 20 nm and dominant anatase peak. The TiO2 photoelectrode undergo PEC testing to measure its photolectroactivity by using oxalic acid as a sacrificial donor in two different type of electrolytes which are distilled water and sodium sulfate (NA2SO4) aqueous solution. The photocurrent produced without addition of oxalic acid is much lower than with the acid. The saturation photocurrent for aqueous NA2SO4 solution and water electrolyte is 0.1 mA/cm2 and negligible respectively. While the photocurrent for addition of oxalic acid in NA2SO4 aqueous solution is 0.5 mA/cm2 and the photocurrent for oxalic acid in water only is 0.9 mA/cm2, which is almost double compared to in NA2SO4 and tenfold in water only. The highest photocurrent produced by TiO2 photoelectrode is by addition of oxalic acid in aqueous (H2O) electrolyte.
关键词： photoelectrochemical cell,titanium dioxide,donor,oxalic acid,Water splitting
更新于2025-09-04 15:30:14
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Iron Oxide Nanoparticles as Potential Scaffold for Photocatalytic and Sensing Applications
摘要： Herein, we report photocatalytic and ?uorescence sensing applications of iron oxide (α-Fe2O3) nanoparticles synthesized by facile low-temperature simple solution process. The synthesized nanoparticles were characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) attached with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-visible spectroscopy and ?uorescence spectroscopy. The detailed analysis revealed that the synthesized nanoparticles were well-crystalline, grown in very high density and possessing rhombohedral α-Fe2O3 crystal structure. The prepared nanoparticles were used as ef?cient scaffold for photocatalytic and sensing applications. The detailed photocatalysis results revealed that in presence of an appropriate amount of α-Fe2O3 nanoparticles as photocatalyst, a signi?cant dye degradation of methyl orange (MO) was observed in 140 min. In addition, the fabricated ?orescence sensor based on α-Fe2O3 nanoparticles exhibited a low detection limit of ～3.33 μM/L towards picric acid. The observed results clearly con?rmed that the synthesized α-Fe2O3 nanoparticles are potential scaffold for photocatalysis and sensing applications.
关键词： Picric Acid,Photocatalysis,Methyl Orange,α-Fe2O3 Nanoparticles
更新于2025-09-04 15:30:14
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Porous TiO <sub/>2</sub> Nanotube Arrays for Drug Loading and Their Elution Sensing
摘要： Porous TiO2 nanotube arrays have been attracting much attention as optical sensing layers and surface layers of dental implants because they are stable in acid and biocompatible. To use them as the optical sensing layers, TiO2 nanotube arrays with various structures were fabricated and obtained an optimized microstructure at 50 V, 50 min and 0.5 wt% of NH4F, 7.4 vol% deionized water in ethylene glycol. TiO2 nanotube arrays which had diameters of ～73.54 nm and lengths of ～3.39 μm showed the best sensing performance. A Ti implant was also anodized at 60 V for 4 hr in an ethylene glycol electrolyte and TiO2 nanotube arrays showed the pore diameter of 156.01 nm and the thickness of 6.87 μm. Recombinant human bone morphogenetic protein-2 (rhBMP-2), isobutylphenyl propionic acid, and sodium alendronate were loaded into the TiO2 nanotube arrays on the surface of the Ti implant. For elution of these drugs, optical thickness changes of 2.4 nm, 3.5 nm and 3.1 nm were respectively observed for about 2.2 hr, 3.6 hr and 3.1 hr. The TiO2 nanotube arrays were useful for drug loading and their elution interferometric sensing.
关键词： Dental Implant,Porous TiO2 Nanotube Arrays,Interferometric Sensor,Isobutylphenyl Propionic Acid,Drug Delivery,rhBMP-2,Sodium Alendronate
更新于2025-09-04 15:30:14
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The application of fluorescence techniques in meningioma surgery—a review
摘要： Surgical resections of meningiomas, the most common intracranial tumor in adults, can only be curative if radical resection is achieved. Potentially, the extent of resection could be improved, especially in complex and/or high-grade meningiomas by fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA), indocyanine green (ICG), or fluorescein. This review aims to summarize and evaluate these fluorescence-guided meningioma surgery techniques. PubMed and Embase were searched for relevant articles. Additionally, we checked reference lists for further studies. Forty-eight articles were included in the final analysis. 5-ALA fluoresced with varying sensitivity and selectivity in meningiomas and in invaded bone and dura mater. Although ICG was mainly applied for video angiography, one report shows tumor fluorescence 18–28 h post-ICG injection. Lastly, the use of fluorescein could aid in the identification of tumor remnants; however, detection of dural tail is highly questionable. Fluorescence-guided meningioma surgery should be a reliable, highly specific, and sensitive technique. Despite numerous studies reporting the use of fluorescent dyes, currently, there is no evidence that these tools improve the radical resection rate and long-term recurrence-free outcome in meningioma surgery without neurological deficits. Evidence regarding the effectiveness and increased safety of resection after the application of these fluorophores is currently lacking. Future research should focus on the development of a meningioma-targeted, highly sensitive, and specific fluorophore.
关键词： Fluorescence-guided surgery,Meningioma,Indocyanine green,5-Aminolevulinic acid,Intraoperative imaging,Fluorescein
更新于2025-09-04 15:30:14
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Salicylic acid complexed with TiO2 for visible light-driven selective oxidation of amines into imines with air
摘要： The interplay of salicylic acid (SA) and reactive oxygen species (ROS) can modulate biotic and abiotic stress of plants, essential biological aerobic oxidation processes. Meanwhile, ROS plays a critical role in TiO2 photocatalytic system for the degradation of organic species. Herein, we developed a system consisted of SA and TiO2 aiming at the selective oxidation of organic molecules by ROS. Interestingly, SA complexed with TiO2 leads to ligand-to-metal charge transfer (LMCT) under visible light irradiation. The charge transfer from ligand (chemically adsorbed SA) to metal (conduction band of TiO2) activates O2 to ROS, superoxide (O2?). The positive charge located at ligand SA is connected with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) catalysis for direct two-electron oxidation of amines and later regenerated by O2. SA and its derivatives were screened as ligands of TiO2 for the selective aerobic oxidation of amines into imines under blue light-emitting diode (LED) irradiation in which 5-CH3O-SA (5-methoxysalicylic acid, 0.8 mol%) complexed with anatase TiO2 and coupled with TEMPO (5 mol%) confers significantly better results than the others. By this visible light LMCT route, both primary amines and secondary amines can be selectively oxidized into corresponding imines with atmosphere O2 as the terminal oxidant. Importantly, the desired product of N-benzylidenebenzylamine can be isolated in 92% yield.
关键词： Salicylic acid,Titanium dioxide,Amines,Photocatalysis,Surface complex
更新于2025-09-04 15:30:14
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Light regulation of vitamin C in tomato fruit is mediated through photosynthesis
摘要： Higher levels of irradiance result in higher accumulation of ascorbate in leaves and fruits. Photosynthesis and respiration are an integral part of the physiological mechanism of light regulation of ascorbate in leaves, but little is known about the light regulation of ascorbate in fruit. The aim of this study was to investigate whether fruit illumination alone is sufficient for ascorbate increase in tomato fruit and whether this light signal is mediated by respiration and photosynthesis. First the changes of ascorbate with the progress of fruit development were investigated and subsequently detached fruit of different tomato genotypes were exposed to different irradiances and spectra. Measurements were performed on ascorbate, respiration, photosynthesis and chlorophyll content of the fruit. When attached to the plant, there was no effect of development on ascorbate from the mature green to the red stage. Detached fruit stored in darkness did not accumulate ascorbate. However, when exposed to 300-600 μmol m-2 s-1 light detached mature green fruit (photosynthetically active) substantially accumulated ascorbate, while mature red fruit (non-photosynthetically active) did not respond to light. Photosynthesis correlated with this increase of ascorbate while no correlation between respiration and ascorbate was found. Spectral effects on ascorbate in detached tomato fruit were limited. These results indicate that the signal for light regulation of ascorbate is perceived locally in the fruit and that fruit illumination alone is sufficient for a considerable increase in ascorbate levels for as long as the fruit contains chlorophyll. It is shown that photosynthetic activity of the fruit is an integral part of the response of ascorbate to light in tomato fruit. The light induced increase in ascorbate levels occurred in a range of genotypes, indicating a universal effect of light to ascorbate in tomato fruit.
关键词： photosynthesis,respiration,vitamin C,irradiance,ascorbic acid,spectrum
更新于2025-09-04 15:30:14
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Photocatalytic activities using a nanocomposite of mesoporous SiO2 and CdInSe-graphene nanoparticles under visible light irradiation
摘要： The new novel ternary mesoporous SiO2/CdInSe-graphene composites with diameters of approximately 8.08 nm have been fabricated through a self-assembly method. All physical tests demonstrated that the CdInSe-graphene was successfully uniformly distributed onto the surface of the ordered mesoporous silica particles. The obtained mesoporous SiO2/CdInSe-graphene composites exhibited good photocatalytic activity for degradation of both cationic-anionic organic dye groups, as well as the decomposition of the representative phenol group of the compound under visible light irradiation. Moreover, the photocatalytic evolution of hydrogen was studied for establishing a wider application of the as-fabricated SiO2/CdInSe-graphene catalyst in the case of energy conversion. This work indicated that the combination of the mesoporous silica and CdInSe-graphene enables achievements such as an enhancement photocatalytic performance, which has potential in industrial waste management and energy conversion.
关键词： Dye decomposition,CdInSe nanoparticles,Graphene-based nanocomposite,Gallic acid degradation,Mesoporous silica,Hydrogen production
更新于2025-09-04 15:30:14
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Citric acid-modulated in situ synthesis of 3D hierarchical Bi@BiOCl microsphere photocatalysts with enhanced photocatalytic performance
摘要： 3D hierarchical Bi@BiOCl microspheres were successfully synthesized by a facile solvothermal method using citric acid as a modulating agent and the growth process was revealed. The modulation of citric acid not only reduced the size of BiOCl nanosheets, finally transforming BiOCl microflowers into microspheres, but also induced the in situ reductive deposition of metallic Bi on the surface of the microspheres. Consequently, Bi@BiOCl microspheres showed larger specific surface areas and total pore volumes, higher absorptivity to the visible light and better charge transfer ability than BiOCl microflowers. As a result, Bi@BiOCl microspheres exhibited much better photocatalytic performance than BiOCl microflowers. Bi@BiOCl microspheres modulated by 2.8 g citric acid showed the highest photocatalytic activity, which was 4.4 and 2.5 times higher than BiOCl microflowers in degrading RhB under visible light and salicylic acid under UV light, respectively. This work may provide a new insight into simultaneous size control and in situ metal deposition for Bi-containing photocatalysts and other materials.
关键词： solvothermal method,Bi@BiOCl microspheres,photocatalytic performance,citric acid modulation,in situ reductive deposition
更新于2025-09-04 15:30:14