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Cu-Zn and Cu-Ni Bimetallic Particles Fabricated Using Ascorbic Acid and Its Role in Photodegradation of Methyl Orange
摘要： Chemical reduction of metal salts using ascorbic acid (vitamin C) is a new and green approach in which ascorbic acid serve dual role of reducing and capping agent. Copper, zinc and nickel salts were reduced by ascorbic acid to give bimetallic nanoparticles. SEM images highlight the aggregation of nanoparticles, which is due to the high surface energy of the particles in nano range. Bimetallic particles fabricated are in the weight ratio of 4:1. Subsequent shift of surface plasma resonance band and XRD peaks indicate that the particles are not just a physical mixture of mono metallic particles. UV-visible spectra and XRD result rule out the alloy nature of the particles. Average size of the particles were calculated using XRD data and are in nano scaled. Size of the Cu, Cu-Zn and Cu-Ni particles as calculated by using Scherrer’s equation are 43.47, 38.4 and 43.5 nm, respectively. In this work photo degradation of methyl orange has been studied to demonstrate the catalytic properties of mono and bimetallic particles. Bimetallic particles have superior catalytic application as compared to monometallic particles. These alloying of metals might have result in change of certain electronic configuration, which significantly increase the catalytic application of bimetallic nanoparticles.
关键词： Methyl orange,Ascorbic acid,Bimetallic,Catalytic properties
更新于2025-09-23 15:23:52
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Improvement of the ON/OFF Switching Performance of a pH-Activatable Porphyrin Derivative by the Introduction of Phosphorus(V)
摘要： An activatable photosensitizer for singlet oxygen is of significance due to its potential applications for high tumor-specific photodynamic therapy and diagnosis. In this study, a pH-activatable system that enables the specific photosensitization of singlet oxygen at a low pH was developed based on the complexation of a porphyrin–aniline conjugate with phosphorus(V). As a result of complexation with phosphorus, the water solubility of the porphyrin–aniline conjugate was improved by 100 times. Furthermore, this complexation strongly suppressed the singlet-oxygen-generating activity of the porphyrin photosensitizer under basic conditions, and the quantum yield of the singlet oxygen photosensitization markedly increased under acidic conditions. Based on these improvements, an extremely high ON/OFF switching ratio of the quantum yield was obtained (>400 times).
关键词： pH activatable photosensitizer,ON/OFF switching,singlet oxygen,aniline,phosphorous porphyrin,protonation,fluorescence,acid
更新于2025-09-23 15:23:52
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Electronic mobility and crystal structures of 2,5-dimethylanilinium triiodide and tin-based organic-inorganic hybrid compounds
摘要： We synthesize single crystals of a new 2,5-dimethylanilinium tin iodide organic-inorganic hybrid compound and 2,5-dimethylanilinium triiodide. Single-crystal X-ray diffraction reveals that the hybrid grows as a unique rhombohedral structure consisting of one-dimensional chains of SnI6-octahedra that share corners and edges to build up a ribbon along the [111] direction. Notably, we find that hypophosphorous acid, H3PO2, is of central importance to the formation of this hybrid. In the absence of H3PO2, we synthesize 2,5-dimethylanilinium triiodide from the same starting compounds. We investigate the synthesis routes that drive the growth of these two compounds with distinct crystal structures, appearance and properties. Pulse-radiolysis time-resolved microwave conductivity measurements and density functional theory calculations reveal that both compounds have low charge carrier mobilities and very long lifetimes, consistent with their one-dimensional structural characteristics. Our findings give a better understanding of the relation between synthesis, crystal structures and charge carrier mobilities.
关键词： Tin iodide,Single-crystal XRD,Organic-organic hybrids,Microwave conductivity,Hypophosphorous acid,Triiodide
更新于2025-09-23 15:23:52
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Structural diversity, magnetic properties, and luminescent sensing of four coordination polymers based on 6-(3,5-dicarboxylphenyl)nicotinic acid
摘要： Four coordination polymers (CPs), namely, [Ni(HDNA)(bibp)(H2O)]n (1), [Co(HDNA)(bibp)]n (2), {[Co(HDNA)(bibp)]·H2O}n (3) and {[Zn(HDNA)(bibp)]·H2O}n (4), have been synthesized from the mixed-ligand strategy of 6-(3,5-dicarboxylphenyl)nicotinic acid (H3DNA) and 4,4′-bis(benzimidazo-1-ly)benzene (bibp). Structural analyses revealed that four CPs all feature 2D sheets with diverse nets from {44.62}-sql net (1), {Co2(COO)2} SBUs based {44.62}-sql net (2), to 4-connected {65.8} sheet (3 & 4). Besides, the temperature-dependent magnetic susceptibilities of CPs 1-3 were investigated. And the luminescent sensing indicated CP 4 is a good bifunctional sensor for Fe3+ and Cr2O7 2- ions.
关键词： Structural diversity,Coordination polymers,Luminescent sensing,Magnetic property,Polycarboxylic acid ligand
更新于2025-09-23 15:23:52
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Observation of Site-Resolved Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater
摘要： Allosteric information transfer in proteins has been linked to distinct vibrational energy transfer (VET) pathways in a number of theoretical studies. Experimental evidence for such pathways, however, is sparse because site-selective injection of vibrational energy into a protein, i.e. localized heating, is required for their investigation. Here, we solve this problem by the site-specific incorporation of the non-canonical amino acid β-(1-azulenyl)-L-alanine (AzAla) via genetic code expansion. Being an exception to Kasha′s rule, AzAla undergoes ultrafast internal conversion and heating after S1 excitation while upon S2 excitation it serves as a fluorescent label. We endowed PDZ3, a protein interaction domain of postsynaptic density protein 95, with this ultrafast heater at two distinct positions. Using ultrafast IR spectroscopy, we could indeed observe VET from the incorporation sites in the protein to a bound peptide ligand on a picosecond timescale. This approach based on genetically encoded AzAla paves the way for detailed studies of VET and its role for function in a wide range of proteins.
关键词： protein modification,energy transfer,non-canonical amino acid,time-resolved spectroscopy,mutagenesis
更新于2025-09-23 15:23:52
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Ag/Ag2O/BiNbO4 structure for simultaneous photocatalytic degradation of mixed cationic and anionic dyes
摘要： In principle, n-type and p-type semiconductors are respectively responsible for photo-catalytic degradation of cationic dyes (e.g., methylene blue) and anionic dyes (e.g., acid red 1), governed by photoelectrons in the former and photo-holes in the later system. Hence, we present a new strategy: design and fabrication of photocatalytic structures to match the redox potentials of mixed basic/acidic dyes as well as the reactive oxygen species (ROS). For the ?rst time Ag/Ag2O/BiNbO4 structure is (1) designed to match the redox potentials of basic/acidic dyes as well as ROS, (2) fabricated using photoreduction to control the Ag/Ag2O/BiNbO4 interfaces, and (3) able to simultaneously degrade 84% methylene blue dye (MB) in 240 min and 88% acid red 1 (AR) in 25 min under LED light irradiation, corresponding to 7 wt% Ag loading. To the best of our knowledge, this is the ?rst photocatalytic degradation study on mixed basic and acidic dyes using a single catalyst. We also tested the new redox potential matching strategy in mixed basic dyes (MB and rhodamine B (RhB)). As expected our experimental results reproduced well our model predictions: in particular, results support our proposed hydroxyl radical (?OH) mechanism, which is initiated by photo-holes. Therefore, this new design strategy, which consists of matching band structures of the photocatalyst with redox potentials of dyes and ROS, has immediate implications to general photocatalytic applications beyond dye degradation and water-splitting.
关键词： Methylene blue,Nanostructures,Rhodamine B,Photocatalysis,Dye degradation,Acid red,Mixed dyes
更新于2025-09-23 15:23:52
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Boron doped carbon dots as a multifunctional fluorescent probe for sorbate and vitamin B12
摘要： Boron doped carbon dots (B-CD) were synthesized by a one-step hydrothermal method using phenylboronic acid as the starting material. They have an average size of about 3.3 nm, with excitation/emission wavelength of 247/323 nm and a quantum yield of 12%. The B-CD is shown to be viable fluorescent probe for sorbate (PS) and vitamin B12 (VB12). The fluorescence (FL) of the B-CD is quenched in the presence of PS or VB12 mainly coming from inner filter effect (IFE), but F?rster resonance energy transfer (FRET) from the B-CD (as a donor) to PS/VB12 (as an acceptor) cannot be excluded. The probe enables PS to be detected by fluorometry with a linear response in the 0.20–24 μM concentration range and a 6.1 nM detection limit (at 3σ/slope). For VB12, the data are 0.20–30 μM and 8.0 nM.
关键词： Fluorescent probe,Sorbic acid,Fluorescence quenching ratios,Intra-day precision,Selectivity,Inter-day precision,Quenching mechanism,Real sample analysis
更新于2025-09-23 15:23:52
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5-aminolevulinic acid induced protoporphyrin IX (ALA-PpIX) fluorescence guidance in meningioma surgery
摘要： Introduction 5-aminolevulinic acid induced protoporphyrin IX (5-ALA-PpIX) fluorescence guidance has emerged as a valuable surgical adjunct for resection of intracranial tumors. Methods Here we present a focused review on 5-ALA-PpIX fluorescence guidance for meningiomas. Results We discuss the clinical studies and specific applications to date as well as the two main intraoperative fluorescence technologies applied to meningiomas. Conclusions The use of 5-ALA-PpIX in meningiomas holds promising potential so neurosurgeons can improve surgical outcomes for patients with meningiomas as well as be pioneers in developing improved fluorescence imaging technologies.
关键词： Meningioma,Quantitative fluorescence,5-Aminolevulinic acid,Fluorescence-guided surgery,Protoporphyrin IX,Spectroscopy
更新于2025-09-23 15:23:52
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A fluorescent Eu(III) MOF for highly selective and sensitive sensing of picric acid
摘要： A metal-organic framework [Eu3L3(CH3COO)2(H2O)2(μ3-OH)]?3DMF, (EuL, H2L=9H-carbazole-2,7-dicarboxylic acid, DMF=N,N-dimethylformamide) has been synthesized under solvothermal conditions and structurally characterized. In EuL, Eu6O8 clusters are four-bridged by carboxylates to form parallel-aligned Eu–O–C chains, which are further linked by the carbazole moieties of L2? ligands to form the three-dimensional framework with rhombic channels. The EuL material with characteristic emission of Eu3+ ion exhibits significant luminescence quenching response for picric acid (PA) and the linear Stern-Volmer plot was observed in the concentration range of 0.05–0.15 mM with Ksv of 98074 M?1. As far as we know, this Ksv is among the highest values for COFs and MOFs in detection of PA. The excellent anti-interference ability and repeatability were also verified by experiments. Lastly, we investigated the luminescence quenching mechanism in the EuL sensing system.
关键词： europium,picric acid,sensor,metal-organic frameworks
更新于2025-09-23 15:23:52
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ROS dependent antitumour activity of photo-activated iron(III) complexes of amino acids
摘要： Several amino acid-based photo-active monomeric iron(III) complexes of the general formula, [Fe(L)2]?, where L = Schiff base ligands (salisalidene arginine, salicylidenetryptophan, 3,5-di-tert-butyl benzalidine arginine and salicylidene tryptophan) were synthesized, characterized and explored for photo-activated anticancer activity to Chang Liver Cells, HeLa and MCF-7 cells. Complexes exhibited remarkable photo-cytotoxicity with IC50 value to the extent of 0.7 μM to Chang Liver Cells in visible light and there was a 40-fold enhancement in cytotoxicity in comparison to the cytotoxicity in dark. Complexes were non-toxic to MCF-10A (normal cells) in dark and visible light (IC50 > 100 μM in dark; IC50 > 80 μM in visible light) signifying target-speci?c nature of the anti-tumour activity of the complexes. Increased ROS concentration, as probed by DCFDA assay, in the cancer cells was responsible for apoptotic cell death. Decarboxylation or phenolate-Fe(III) charge transfer of photo-activated iron(III) complexes generating ?OH radicals (ROS) were responsible for the apoptosis. Overall, the tumour-selective photo-activated anticancer activity of the amino acid-based iron(III) complexes have shown a promising aspect in developing iron-based photo-chemotherapeutics as the next generation PDT agents.
关键词： ROS generation,photo-activation,Iron(III) complexes,amino acid,photocytotoxicity
更新于2025-09-23 15:23:52