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Dual-action Platinum(II) Schiff Base Complexes: Photocytotoxicity and Cellular Imaging
摘要： Nine photo-stable Pt(II) Schiff base complexes [Pt(O^N^N^O)] (Pt1-Pt9) containing tetradentate salicylaldimine chelating ligands have been synthesized and characterized as potential photosensitisers for photodynamic therapy (PDT). The effects of electron-withdrawing versus electron-donating substituents on their electronic spectral properties are investigated. Pt1-Pt9 show broad absorption bands between 400-600 nm, which makes them useful for green-light photodynamic therapy. The complexes showed intense phosphorescence with emission maxima at ca. 625 nm. This emission was used to track their cellular localization in cancer cells. Confocal cellular imaging showed that the complexes localized mostly in the cytoplasm. In the dark, the complexes were non-toxic to A549 human lung cancer cells, but exhibited high photo-toxicity upon low-dose green light (520 nm, 7.02 J/cm2) irradiation via photo-induced singlet oxygen generation. Thus, these photoactive Pt(II) complexes have the potential to overcome the problem of drug resistance and side effects of current clinical Pt(II) drugs, and to act as both theranostic as well as therapeutic agents.
关键词： Schiff Base,Platinum(II),Photocytotoxicity,Cellular Imaging,Singlet oxygen
更新于2025-11-21 11:08:12
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Transparent Platinum Counter Electrode Prepared by Polyol Reduction for Bifacial, Dye-Sensitized Solar Cells
摘要： Pt catalytic nanoparticles on F-doped SnO2/glass substrates were prepared by polyol reduction below 200 °C. The polyol reduction resulted in better transparency of the counter electrode and high power-conversion efficiency (PCE) of the resultant dye-sensitized solar cells (DSSCs) compared to conventional thermal reduction. The PCEs of the DSSCs with 5 μm-thick TiO2 photoanodes were 6.55% and 5.01% under front and back illumination conditions, respectively. The back/front efficiency ratio is very promising for efficient bifacial DSSCs.
关键词： dye-sensitized solar cell,platinum,bifacial,ethylene glycol,counter electrode
更新于2025-11-21 11:01:37
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Long-lived triplet excited state in a platinum( <scp>ii</scp> ) perylene monoimide complex
摘要： We report the synthesis and solution based photophysical properties of a new Pt(II)-terpyridine complex coupled to a perylene monoimide (PMI) chromophoric unit through an acetylene linkage. This structural arrangement resulted in quantitative quenching of the highly fluorescent PMI chromophore by introducing metal character into the lowest energy singlet state, thereby leading to the formation of a long-lived PMI-ligand localized triplet excited state (τ = 8.4 μs). Even though the phosphorescence from this triplet state was not observed, highly efficient quenching of this excited state by dissolved oxygen and the observation of singlet oxygen photoluminescence in the near-IR at 1270 nm initially pointed towards triplet excited state character. Additionally, the coincidence of the excited state absorbance difference spectra from the sensitized PMI ligand using a triplet donor and the Pt-PMI complex provided strong evidence for this triplet state assignment, which was further supported by TD-DFT calculations.
关键词： singlet oxygen,perylene monoimide,photophysics,platinum(II) complex,triplet excited state
更新于2025-11-19 16:56:42
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Efficient removal of cationic dyes from water by a combined adsorption-photocatalysis process using platinum-doped titanate nanomaterials
摘要： In this study, two types of titanate nanomaterials (TNMs) including titanate nanosheets (TNS) and titanate nanotubes (TNT) were hydrothermally prepared by controlling reaction times, and then the platinum (Pt)-doped TNMs were fabricated. The photocatalytic performance of as-prepared materials was compared with that of the commercially available TiO2 P25. It was revealed that changing the morphology of TiO2 particles could enhance their adsorption ability and photocatalytic activity for the removal of cationic dyes from water. In particular, all prepared materials displayed greater removal of methylene blue than of P25 through the synergy of adsorption and photocatalysis; however, such an effect was not so pronounced for anionic dyes. For cationic dyes (methylene blue and rhodamine B) and anionic dyes (methyl orange and naphthol blue–black), TNT presented higher photocatalytic activity than TNS. The TNMs, after Pt doping, significantly enhanced photocatalytic activity compared to the pristine ones. Remarkably, 0.5% by weight Pt-doped TNS achieved 100% removal of methylene blue and rhodamine B after 120 min and 140 min of UV irradiation, respectively, outperforming P25, although Pt-doped TNMs showed lower photocatalytic performance than P25 for anionic dyes.
关键词： Photocatalysis,Cationic dyes,Titanate nanomaterials,Adsorption,Platinum doping
更新于2025-11-14 15:13:28
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X-ray photoelectron spectroscopy and Raman microscopy of a ferroan platinum crystal from the Kondyor Massif, Russian Far East
摘要： X-ray Photoelectron Spectroscopy was used to study a ferroan platinum crystal from the Kondyor Massif, Russian Far East. Prior to the X-ray Photoelectron Spectroscopic analyses, the nature of the crystal was confirmed by X-ray diffraction. The survey scan showed mainly the presence of Pt and Fe, with smaller amounts of O and Si. The high resolutions spectra of the Pt 4f and Fe 2p showed 18.3 atom% Fe in the crystal, which puts the composition on the lower boundary for ferroan platinum and confirms earlier analyses using other methods such as Scanning Electron Microscopy-Energy Dispersive X-ray analysis/microprobe. The binding energy of the Pt 4f5/2 was 74.0 eV and Pt 4f7/2 70.5 eV, while the Fe 2p3/2 for metallic Fe was observed at 707.2 eV. The Fe 2p3/2 for metallic Fe was significantly sharper than that of Fe 2p3/2 at 710.7 eV associated with surface material. The Raman spectrum was dominated by the Pt–Pt stretching mode at 253 cm?1. Changed orientation resulted in the observation of two bands at 127 and 139 cm?1, interpreted as being due to stretching modes of two Pt–Pt bonds with the third bond to Fe and Pt fixed. The presence of Ca-Fe-Al-Mg-Si-O on the surface was probably associated with the presence of a clinopyroxene. These minerals can be expected since the crystal came originally from a clinopyroxenite-dunite matrix. The spectra showed a variety of interferences, e.g. Al 2p with Pt 4f, Mg 2p with Fe 3p, and Ca 2p1/2 with Mg Auger, making exact determinations of the ratios of these elements difficult.
关键词： surface chemistry,platinum group minerals,X-ray photoelectron spectroscopy,Raman spectroscopy,Platinum
更新于2025-09-23 15:23:52
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Effect of the Chirality of Counter Anions on the Vapochromic Behavior of Luminescent Pt(II) Complexes
摘要： New luminescent Pt(II) complexes with the chiral counter anions [PtCl(tpy)](L-Hta) (1-L) and [PtCl(tpy)](DL-Hta) (1-DL; tpy = 2,2’:6’,2’’-terpyridine; L-H2ta = L-tartaric acid; DL-H2ta = racemic tartaric acid) were synthesized and their vapochromic behavior was evaluated. Single crystal X-ray analysis revealed that the stacked square-planar Pt(II) molecules in anhydrous 1-DL formed a one-dimensional columnar structure with weak intermolecular Pt···Pt interactions, while in anhydrous 1-L the Pt(II) molecules were dimerized with Pt…Pt interactions to form a zig-zag stacked column. These differences were attributed to the different hydrogen bonding in the DL- and L-Hta? ions. The dihydrates of 1-DL and 1-L displayed near-identical crystal structures with comparable emission spectra derived from 3π–π* ligand emission. Both dihydrates exhibited MeOH-vapor-induced dehydration to form the anhydrous complexes. These presented broad 3MMLCT emission (549 and 565 nm, respectively), affected by the degree of intermolecular Pt···Pt interactions.
关键词： luminescence,chromophores,platinum
更新于2025-09-23 15:23:52
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A novel on-line electrochemical transmission infrared spectroscopy to?study the current efficiency of carbonates for?ethanol oxidation reactions in alkaline media
摘要： Research on the reaction mechanism of ethanol oxidation reaction (EOR) is important for the development of highly active EOR electro-catalysts. One of the main difficulties in the EOR study is the quantitative analysis of the non-volatile products. Conventional on-line electrochemical flowing transmission infrared spectroscopy (ETIRS) can only collect a part of the carbonate products of EOR in alkaline media, making the further quantitative study impossible. Herein, a new ETIRS system has been designed and prepared by employing a cation-exchange membrane (Nafion) in the sampling hood. The using of the Nafion membrane can prevent the anions crossing over by confining the generated carbonates in the sampling hood without diffusing into the bulk electrolyte. Therefore, the collection efficiency of the carbonate products as well as the test accuracy of the carbonate current efficiency has been significantly improved. The result of CO stripping reaction shows that ca. 100% of the carbonate product is able to be collected in alkaline media by this new system. The influence of the experimental temperature to the carbonate current efficiency has been further studied on Pt/C toward EOR in alkaline media.
关键词： Transmission infrared spectroscopy,Ethanol oxidation reaction,Platinum,Alkaline media
更新于2025-09-23 15:23:52
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Surfactant templated oriented 1-D nanoscale platinum and palladium systems on a modified silicon surface
摘要： A templating method has been improved to form oriented one-dimensional metal nanostructures on a silicon surface. To achieve this, the silicon surface is modified with 3-aminopropyl trimethoxysilane. The cationic surfactant cetyltrimethylammonium bromide is used as a micellar template. The average width of the obtained Pt strips is 35 nm, the average width of the obtained Pd strips is 60 nm.
关键词： Platinum group,Atomic force microscopy,Surface modification,Nanostructured materials,Micelle templates
更新于2025-09-23 15:23:52
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Precision Plating of Human Electrogenic Cells on Microelectrodes Enhanced with Precision Electrodeposited Nano-Porous Platinum for Cell-Based Biosensing Applications
摘要： Microelectrode Arrays are established platforms for biosensing applications; however, limitations in electrode impedance and cell-electrode coupling still exist. In this paper, the SNR of 25 μm diameter gold (Au) microelectrodes was improved by decreasing the impedance with precision electrodeposition. SEM determined that N-P Pt. microelectrodes had nano-porous structures that filled the insulation cylinders. EIS, CV, and RMS noise measurements concluded that the optimized electrodeposition of N-P Pt. led to a lowered impedance of 18.36 kΩ ± 2.6 kΩ at 1 kHz, a larger double layer capacitance of 73 nF, and lowered RMS noise of 2.08 ± 0.16 μV as compared to the values for Au of 159 kΩ ± 28 kΩ at 1 kHz, 17nF, and 3.14 ± 0.42 μV, respectively. Human motoneurons and human cardiomyocytes were cultured on N-P Pt. devices to assess their biocompatibility and signal quality. In order to improve the cell-electrode coupling, a precision plating technique was used. Both cell types were electrically active on devices for up to 10 weeks, demonstrated improved SNR, and expected responses to precision chemical and electrical stimulation. The modification of Au microelectrodes with nanomaterials in combination with precision culturing of human cell types provides cost effective, highly sensitive, well coupled and relevant biosensing platforms for medical and pharmaceutical research.
关键词： Biosensing,human motoneurons,precision plating of cells,MEA,human cardiomyocytes,nano-porous platinum,precision plating of nanomaterials,microelectrodes,human electrogenic cells
更新于2025-09-23 15:22:29
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Infrared Spectroscopy on Electronic Structures of Platinum-group Metal Pernitrides MN2 (M = Ru, Rh, Ir, and Pt)
摘要： The electronic structures of platinum-group metal pernitrides MN2 (M = Ru, Rh, Ir, and Pt) were investigated via synchrotron radiation infrared spectroscopy and first-principles calculations. Measured reflectance spectra of marcasite-type RuN2 and RhN2 showed Drude-like responses, approaching 1 as the photon energy was decreased, whereas reflectance of arsenopyrite-type IrN2 and pyrite-type PtN2 became ~0.3 in the low photon energy region with a few features. These findings agreed well with the predictions of the metallic nature of marcasite-type RuN2 and RhN2 and the semiconducting properties of arsenopyrite-type IrN2 and pyrite-type PtN2, respectively. The measured reflectance spectra were also reasonably consistent with the calculated optical responses. The band gaps of IrN2 and PtN2 were estimated to be 0.8 and 2.1 eV, respectively, via first-principles calculation with a modified Becke–Johnson (MBJ) potential for the exchange potential.
关键词： first-principles calculation,platinum-group metal pernitride,infrared reflectance spectra,valence band electronic structure
更新于2025-09-23 15:22:29