This document summarizes the synthesis, isolation, characterization, and electrochemical behavior of some calcium-containing metallofullerenes. Specifically, it describes the first isolation of Ca@C76, Ca@C88, and two isomers of Ca@C90 using an improved arc discharge method and multi-stage HPLC separation. UV-Vis-NIR spectroscopy was used to analyze the electronic structures and possible symmetries. Cyclic voltammetry and differential pulse voltammetry provided information on the electrochemical properties and reversible reduction behaviors compared to other metallofullerenes. The features of the calcium metallofullerenes' electronic structures are also discussed.
This document summarizes research on the role of ascorbic acid concentration in the formation of gold nanorods using a photochemical reduction method. The key findings are:
1) Gold nanorods were only produced if the concentration of ascorbic acid relative to gold ions was above 0.75.
2) Between ratios of 0.75 to 6.2, increasing the ascorbic acid concentration increased the aspect ratio (length to width) of the nanorods.
3) Above a ratio of 6.2, further increasing the ascorbic acid concentration decreased the aspect ratio and led to shorter nanorods.
This suggests there is both a minimum and maximum effective concentration range of ascorbic acid needed to produce
This document summarizes spectroscopic evidence from electronic absorption, magnetic circular dichroism (MCD), and resonance Raman spectroscopies that provide insight into the unique bonding interaction in oxo-molybdenum dithiolate complexes. The data suggests these complexes have low-energy sulfur to molybdenum charge transfer transitions originating from a set of four filled dithiolate orbitals that are primarily sulfur in character. Resonance Raman excitation profiles allowed assignment of an ene-dithiolate in-plane sulfur to molybdenum transition. Three totally symmetric vibrational modes were also identified. The results provide context for understanding electron transfer pathways in pyranopterin dithiolate centers
The document discusses experiments on the stability of SOFC cathodes and the development of a novel test system. It focuses on studying the stability of a barium-based cathode material (La0.5Ba0.5CoO3-δ) when exposed to carbon dioxide through thermodynamic and kinetic analysis. The key reactions, pathways and kinetics of carbonate formation are examined through TGA and HT-XRD experiments. An equilibrium phase diagram is proposed. Additionally, a test system is developed to enable rapid testing of multiple electrodes through a materials printer and micro contact impedance spectroscopy. This allows reproducible fabrication and evaluation of many electrode compositions.
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Alexander Decker
This document describes the synthesis and characterization of a Schiff base ligand and its complexes with various metal ions. The ligand (HL) was prepared in two steps by reacting 3-aminoacetophenone with hydrazine monohydrate to form an intermediate, which was then reacted with salicylaldehyde. The ligand was characterized using various techniques. The metal complexes were prepared by reacting the ligand with metal chlorides in a 1:1 molar ratio. The complexes were characterized using techniques such as elemental analysis, conductivity, IR spectroscopy, UV-Vis spectroscopy, and magnetic susceptibility measurements. Based on the data, the complexes were found to have tetrahedral geometry except for the nickel complex which was square planar.
Carbon corrosion and platinum nanoparticles ripening under open circuit poten...LandimarMendesDuarte
This document discusses a study examining the degradation of platinum nanoparticles supported on Vulcan XC72 carbon under open circuit potential conditions over 3.5 years. Characterization techniques showed that the amorphous domains of the carbon support were preferentially oxidized into CO2 during aging, while the organized domains were more slowly oxidized, producing mostly oxygen-containing surface groups and minor CO2. Over time, platinum nanoparticle aggregation and detachment from the carbon support increased due to platinum-catalyzed carbon corrosion.
The document summarizes the synthesis and characterization of a binuclear Schiff base ligand and its metal complexes with Cu(II), Ni(II), and VO(IV). The ligand was synthesized by reacting 5-bromo-3-fluorosalicylaldehyde and benzidine. The complexes were prepared by reacting the ligand with metal salts. The ligand and complexes were characterized using elemental analysis, IR, NMR, UV-Vis, magnetic susceptibility, and thermal analysis. The ligand behaves as a tetradentate ligand, coordinating through the azomethine nitrogen and deprotonated phenolic oxygen atoms. The complexes exhibit square planar and square pyramidal geometries. Antimicrobial tests found the compounds
The document describes the synthesis of Schiff base ligands derived from citral and valine and their complexes with Cu(II), Ni(II), and Co(II). The structures of the complexes were characterized using IR, UV-vis, and magnetic susceptibility measurements. The Cu(II) and Ni(II) complexes were proposed to have distorted octahedral geometry while the Co(II) complex had square-based pyramidal geometry. Antimicrobial testing showed that the metal complexes had higher activity than the free ligand, with the Co(II) complex being most active.
The document summarizes research on technetium metal and carbide phases. Key findings include:
1) A new orthorhombic phase of technetium metal was discovered with unit cell parameters of a = 2.805(4), b = 4.958(8), c = 4.474(5) Å for samples containing 1.38 wt.% carbon.
2) Softer conditions than previously reported were able to form technetium carbide, with a cubic phase observed at 800°C containing carbon in defective sites within the fcc structure.
3) Technetium carbide has a microhardness that is 2-2.5 times higher than pure technetium
This document summarizes research on the role of ascorbic acid concentration in the formation of gold nanorods using a photochemical reduction method. The key findings are:
1) Gold nanorods were only produced if the concentration of ascorbic acid relative to gold ions was above 0.75.
2) Between ratios of 0.75 to 6.2, increasing the ascorbic acid concentration increased the aspect ratio (length to width) of the nanorods.
3) Above a ratio of 6.2, further increasing the ascorbic acid concentration decreased the aspect ratio and led to shorter nanorods.
This suggests there is both a minimum and maximum effective concentration range of ascorbic acid needed to produce
This document summarizes spectroscopic evidence from electronic absorption, magnetic circular dichroism (MCD), and resonance Raman spectroscopies that provide insight into the unique bonding interaction in oxo-molybdenum dithiolate complexes. The data suggests these complexes have low-energy sulfur to molybdenum charge transfer transitions originating from a set of four filled dithiolate orbitals that are primarily sulfur in character. Resonance Raman excitation profiles allowed assignment of an ene-dithiolate in-plane sulfur to molybdenum transition. Three totally symmetric vibrational modes were also identified. The results provide context for understanding electron transfer pathways in pyranopterin dithiolate centers
The document discusses experiments on the stability of SOFC cathodes and the development of a novel test system. It focuses on studying the stability of a barium-based cathode material (La0.5Ba0.5CoO3-δ) when exposed to carbon dioxide through thermodynamic and kinetic analysis. The key reactions, pathways and kinetics of carbonate formation are examined through TGA and HT-XRD experiments. An equilibrium phase diagram is proposed. Additionally, a test system is developed to enable rapid testing of multiple electrodes through a materials printer and micro contact impedance spectroscopy. This allows reproducible fabrication and evaluation of many electrode compositions.
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Alexander Decker
This document describes the synthesis and characterization of a Schiff base ligand and its complexes with various metal ions. The ligand (HL) was prepared in two steps by reacting 3-aminoacetophenone with hydrazine monohydrate to form an intermediate, which was then reacted with salicylaldehyde. The ligand was characterized using various techniques. The metal complexes were prepared by reacting the ligand with metal chlorides in a 1:1 molar ratio. The complexes were characterized using techniques such as elemental analysis, conductivity, IR spectroscopy, UV-Vis spectroscopy, and magnetic susceptibility measurements. Based on the data, the complexes were found to have tetrahedral geometry except for the nickel complex which was square planar.
Carbon corrosion and platinum nanoparticles ripening under open circuit poten...LandimarMendesDuarte
This document discusses a study examining the degradation of platinum nanoparticles supported on Vulcan XC72 carbon under open circuit potential conditions over 3.5 years. Characterization techniques showed that the amorphous domains of the carbon support were preferentially oxidized into CO2 during aging, while the organized domains were more slowly oxidized, producing mostly oxygen-containing surface groups and minor CO2. Over time, platinum nanoparticle aggregation and detachment from the carbon support increased due to platinum-catalyzed carbon corrosion.
The document summarizes the synthesis and characterization of a binuclear Schiff base ligand and its metal complexes with Cu(II), Ni(II), and VO(IV). The ligand was synthesized by reacting 5-bromo-3-fluorosalicylaldehyde and benzidine. The complexes were prepared by reacting the ligand with metal salts. The ligand and complexes were characterized using elemental analysis, IR, NMR, UV-Vis, magnetic susceptibility, and thermal analysis. The ligand behaves as a tetradentate ligand, coordinating through the azomethine nitrogen and deprotonated phenolic oxygen atoms. The complexes exhibit square planar and square pyramidal geometries. Antimicrobial tests found the compounds
The document describes the synthesis of Schiff base ligands derived from citral and valine and their complexes with Cu(II), Ni(II), and Co(II). The structures of the complexes were characterized using IR, UV-vis, and magnetic susceptibility measurements. The Cu(II) and Ni(II) complexes were proposed to have distorted octahedral geometry while the Co(II) complex had square-based pyramidal geometry. Antimicrobial testing showed that the metal complexes had higher activity than the free ligand, with the Co(II) complex being most active.
The document summarizes research on technetium metal and carbide phases. Key findings include:
1) A new orthorhombic phase of technetium metal was discovered with unit cell parameters of a = 2.805(4), b = 4.958(8), c = 4.474(5) Å for samples containing 1.38 wt.% carbon.
2) Softer conditions than previously reported were able to form technetium carbide, with a cubic phase observed at 800°C containing carbon in defective sites within the fcc structure.
3) Technetium carbide has a microhardness that is 2-2.5 times higher than pure technetium
Synthesis, characterization and electrocatalytic activity of silver nanorods ...kutty79
This paper describes a simple method of synthesizing silver nanorods using the polyol process, where propylene glycol serves both as a reducing
agent and as a solvent in the presence of a capping reagent such as polyvinylpyrrolidone (PVP). The diameter and length of silver nanorods could be
controlled by changing the AgNO3/PVP ratio. The end-to-end assembly of the silver nanorods was found. The silver nanorods were characterized by
using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and absorption spectroscopy. The catalytic activity of a
glassy carbon electrode with Ag nanorods exhibits extraordinary electrocatalytic activities towards the electro-reduction of benzyl chloride.
- The document reports on the synthesis and characterization of Schiff base ligands derived from L-valine and their Cu(II), Ni(II), and Co(II) complexes.
- Spectroscopic data revealed that the ligands bind as tridentate in the Cu(II) and Ni(II) complexes and bidentate in the Co(II) complex.
- Magnetic susceptibility measurements showed the complexes have a bimetallic structure with antiferromagnetic interactions.
- Antimicrobial testing found the metal complexes to have greater activity than the free ligand, with the Co(II) complex exhibiting the strongest effects.
In this work, I am showing a faithful atomistic process of estimating the oxygen migration energetics within BSCF, oxygen migration energy exhibit a strong dependence on different local atomic structures of this doped perovskites. In addition, DFT calculations exhibit the reason of cubic phase stability of this doped perovskite in variable oxygen concentration.
This document summarizes the synthesis and characterization of new Schiff base ligands and their metal complexes. It describes the synthesis of five Schiff base ligands derived from substituted benzaldehydes and anilines using the reflux method. Copper and nickel complexes were formed from two of the ligands. The ligands and complexes were characterized using infrared spectroscopy, which showed shifts in the C=N and C-O peaks upon complexation. The research aims to synthesize new Schiff bases and their Cu2+ and Ni2+ complexes and characterize them using IR spectroscopy to determine the coordination sites.
Diffusion mechanisms differ in ceramics due to multiple species with varying charges that must balance, often limiting diffusion to the slowest moving species like vacancies. Diffusion is crucial in ceramics for tailoring mechanical properties and enabling ion transport in batteries and fuel cells. Phase diagrams show equilibrium phases and compositions at given temperatures. They are used to understand diffusion effects and interpret final material structures by identifying compounds, solid solutions, and lever rule calculations for multiphase regions.
Schiff base is a compound formed by the condensation reaction of a carbonyl group with a primary amine. The document discusses various methods for preparing Schiff base ligands and complexes, and techniques for characterizing them including UV-visible spectroscopy, IR spectroscopy, NMR, EPR, mass spectrometry, TGA/DTA, and elemental analysis. Schiff base ligands and their complexes have applications in areas like biology, catalysis, materials science, and more.
This document summarizes a research project on the synthesis, characterization, and biological activity of piperonal-based Schiff bases and their metal complexes. The objectives were to synthesize Schiff bases from piperonal and various amines, form complexes by adding metals, and test the complexes for antibacterial activity. Key steps included preparing the Schiff bases and their metal adducts, using various techniques to characterize the compounds, and evaluating the complexes against gram-positive and gram-negative bacteria to determine antibacterial potential. The research aims to contribute to the development of new antibacterial agents.
This document summarizes a presentation on solid electrolytes. It discusses how solid electrolytes exhibit ionic conductivity through mobile anions or cations, with maximum conductivity between 0.1-10 Ohm-1cm-1. Examples of solid electrolytes mentioned include AgI, β-alumina, and zirconia. Applications discussed include use in batteries, oxygen sensors, and solid oxide fuel cells. The proposed work is to synthesize and characterize Sr and Cu doped LaAlO3 as a potential solid electrolyte material.
A detailed study of Transition Metal Complexes of a Schiff base with its Phys...Abhishek Ghara
The many activities of metal ions in biology have stimulated the development of metal based therapeutics. It has been found that biologically active compounds become more effective and bacteriostatic upon chelation with metal ions also the biological activity of many drugs has been shown to be enhanced on complexing with metal ions, hence promoting their use in Pharmacology. The present work deals with the synthesis of metal complexes derived from a novel Schiff base drug synthesized from urea and salicylaldehyde and its physico-chemical analysis to find out ligand- metal ratio of this complex in solution. For the structure elucidation of these complexes “Monovariation method (Mole ratio method/ Yoe-Jones Method)” has been used to ascertain the ligand-metal ratio in the complex. The stability constant of the formed complex was calculated by molar conductance measurement using Modified Job’s method (Method of Continuous Variations). The analysis has been carried out using conductometry. To confirm metal-ligand ratio, conductometric titrations were carried out at room temperature using analytical grade metal salts. Titrations were carried out with “systronics conductivity-meter” using dip type conductivity cell having cell constant 1 at room temperature.
Development Of Non Aqueous Asymmetric Hybrid Supercapacitors Part IiiNakkiran Arulmozhi
The document describes research on developing asymmetric hybrid supercapacitors based on lithium-ion intercalated compounds. Specifically, it discusses synthesizing cathode materials of pure LiCoO2 and LiCo1-xAlxO2 with varying amounts of aluminum doping (x=0, 0.2, 0.4, 0.6). The materials were characterized using techniques like thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Electrochemical characterization of the materials was also performed through cyclic voltammetry and charge/discharge testing to evaluate their performance in supercapacitors.
This document describes research on using carbon dots as both reducing agents and stabilizing agents in the synthesis of palladium nanoparticle-carbon dot composites. The carbon dots were able to reduce palladium chloride to form palladium nanoparticles coated with an ultrathin carbon dot shell. These palladium@carbon dot composites showed high catalytic activity for carbon-carbon bond formation reactions like Heck and Suzuki couplings. The document provides details on the synthesis and characterization of the carbon dots and palladium@carbon dot composites, as well as evaluation of their catalytic activity.
This document provides a checklist of important experiments in chemistry for SPM (Sijil Pelajaran Malaysia) students. It lists 14 chemistry topics and the key experiments students should be able to describe for each topic. These include experiments on the structure of the atom, chemical formulae and equations, the periodic table of elements, electrochemistry, acids and bases, salts, rate of reaction, carbon compounds, oxidation and reduction, and thermochemistry. For each experiment, students are expected to describe the apparatus, materials, procedure, observations, analysis, and interpreting data. The document also analyzes which chemistry topics were examined in SPM Paper 3 from 2003 to 2011.
This document summarizes the synthesis and study of transition metal complexes of benzaldimino-1,3,4-thiadiazole-2-thiol (BTT). The author synthesized the ligand BTT and its copper, nickel, cobalt, and zinc complexes. The complexes were characterized using infrared spectroscopy, electronic spectroscopy, ESR, cyclic voltammetry, NMR, and magnetic susceptibility measurements. Spectroscopic data indicated the ligand behaves as a bidentate ligand, forming octahedral complexes with the metals. The author thanks advisors and colleagues and concludes the spectral studies support an octahedral geometry for the complexes.
Synthetic antibacterial agent assisted synthesis of gold nanoparticles chara...Expand_Lives
In this study, we report synthesis of water-soluble gold nanoparticles (Au-NPs), having an average
diameter of ca. 20 nm, using ciprofloxacin (CF) as a reducing/stabilizing agent. The synthesized
Au-NPs have been characterized by scanning electron microscopy (SEM), EDX, TEM, UV–visible
spectroscopy (UV–vis), X-ray diffraction and cyclic voltammetry. TEM and SEM combined with EDX
analysis confirmed that spherical-shaped Au-NPs were formed. UV–vis spectra of the Au-NPs showed
two absorption bands corresponding to the capping agent ciprofloxacin and surface plasmon absorption
bands at 274 and 527 nm, respectively. The synthesized Au-NPs are used to modify a glassy carbon
electrode (GCE) and its electrochemical and electrocatalytic properties are investigated. The Au-NPs
modified electrode showed excellent electrocatalytic activity towards the oxidation of methanol at
+0.33 V in alkaline solution, which was not observed on the unmodified GCE. Further, electrocatalytic
reduction of oxygen was also studied using the Au-NPs modified electrode at lower potential. Here, CF
was used as a reducing agent for the preparation of Au-NPs dispersion. This Au-NPs dispersion is highly
stable, and can be stored for more than three months in air at room temperature.
C3N5: A Low Bandgap Semiconductor Containing an Azo-linked Carbon Nitride Fra...Pawan Kumar
Modification of carbon nitride based polymeric 2D materials for tailoring their optical, electronic and chemical properties for various applications has gained significant interest. The present report demonstrates the synthesis of a novel modified carbon nitride framework with a remarkable 3:5 C:N stoichiometry (C3N5) and an electronic bandgap of 1.76 eV, by thermal deammoniation of the melem hydrazine precursor. Characterization revealed that in the C3N5 polymer, two s-heptazine units are bridged together with azo linkage, which constitutes an entirely new and different bonding fashion from g-C3N4 where three heptazine units are linked together with tertiary nitrogen. Extended conjugation due to overlap of azo nitrogens and increased electron density on heptazine nucleus due to the aromatic π network of heptazine units lead to an upward shift of the valence band maximum resulting in bandgap reduction down to 1.76 eV. XRD, He-ion imaging, HR-TEM, EELS, PL, fluorescence lifetime imaging, Raman, FTIR, TGA, KPFM, XPS, NMR and EPR clearly show that the properties of C3N5 are distinct from pristine carbon nitride (g-C3N4). When used as an electron transport layer (ETL) in MAPbBr3 based halide perovskite solar cells, C3N5 outperformed g-C3N4, in particular generating an open circuit photovoltage as high as 1.3 V, while C3N5 blended with MAxFA1–xPb(I0.85Br0.15)3 perovskite active layer achieved a photoconversion efficiency (PCE) up to 16.7%. C3N5 was also shown to be an effective visible light sensitizer for TiO2 photoanodes in photoelectrochemical water splitting. Because of its electron-rich character, the C3N5 material displayed instantaneous adsorption of methylene blue from aqueous solution reaching complete equilibrium within 10 min, which is significantly faster than pristine g-C3N4 and other carbon based materials. C3N5 coupled with plasmonic silver nanocubes promotes plasmon-exciton coinduced surface catalytic reactions reaching completion at much low laser intensity (1.0 mW) than g-C3N4, which showed sluggish performance even at high laser power (10.0 mW). The relatively narrow bandgap and 2D structure of C3N5 make it an interesting air-stable and temperature-resistant semiconductor for optoelectronic applications while its electron-rich character and intra sheet cavity make it an attractive supramolecular adsorbent for environmental applications.
This document summarizes research on the optical and structural properties of tenorite (CuO) nanopowders doped with silicon (Si) and zirconium (Zr). Nanopowders were synthesized using a sol-gel method and calcined at temperatures from 400-700°C. X-ray diffraction analysis showed the samples crystallized in a tenorite structure and doping affected crystallinity and particle size. Optical absorption spectroscopy indicated undoped CuO has a direct bandgap of 1.78eV, while doped CuO (15% Si, 15% Zr) has a wider bandgap of 3.75-3.95eV. Scanning electron microscopy and other characterization techniques
Electrochemical Synthesis of MoO3 Nanoparticles Effect of Temperature Convert...IJERA Editor
MoO3 nanorods were prepared by electrochemical reduction method using the tetra propyl ammonium bromide (TPAB) was structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio and at current density 14mA &18 mA. The reduction process takes place under atmospheric condition over a period of 2 h. Dried sample was calcinated in muffle furnace at 500ºC. The parameters such as current density and concentration of stabilizers were used to control the size of nanorods. The synthesized MoO3 nanorods were characterized by using UV-Visible, FT-IR, XRD, SEM-EDS and TEM analysis techniques.
Graphene oxide was synthesized from graphite powder and functionalized with ethanolamine to produce GO-EA. GO-EA was successfully redispersed in an ethylene glycol solution. X-ray photoelectron spectroscopy analysis showed the expected functional groups on GO and the appearance of new peaks indicating successful functionalization of GO-EA. Future work will verify the increased thermal conductivity of the solution and explore GO-EA's catalytic properties.
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
This document describes a study investigating V and Mn incorporated mesoporous molecular sieves for the vapor phase oxidation of o-xylene. Mesoporous monometallic V-MCM-41, Mn-MCM-41, and bimetallic V-Mn-MCM-41 molecular sieves were synthesized and characterized. Their activity was measured for the gas phase oxidation of o-xylene to phthalic anhydride. Among the catalysts, V-MCM-41 with Si/V = 50 exhibited the highest activity and selectivity towards producing phthalic anhydride under the experimental conditions. The physico-chemical properties of the catalysts, including metal content, surface area,
Fujian Bailong Lace Manufacture Co., Ltd is a lace manufacturer located in Changle City, Fujian Province with over 15 years of experience making lace trims and fabrics. They have 200 staff including 10 designers and supply lace to major brands like H&M, ZARA, and Walmart. The company utilizes advanced equipment from Karl Mayer and has created over 10,000 lace designs for customers to choose from. They have certifications like Oeko-tex 100 and focus on quality control and research and development.
SlideShare es una plataforma gratuita para compartir presentaciones en formato PowerPoint u OpenOffice de forma online. Los usuarios pueden subir presentaciones de hasta 20 MB, comentar los trabajos de otros y crear grupos. SlideShare permite compartir presentaciones de manera fácil sin necesidad de enviar archivos pesados por correo electrónico, y ofrece opciones de privacidad. Para usarla, basta con registrarse, buscar la presentación en el computador y cargarla a la cuenta personal en SlideShare.
Ryan Lee has over 15 years of experience in various fields including warehouse management, delivery driving, security, and the military. He has a proven track record of learning quickly, working well under pressure, and being a team player. His most recent role was as a Warehouse Manager where he oversaw operations including shipping, receiving, scheduling pickups/deliveries, and pulling orders.
Synthesis, characterization and electrocatalytic activity of silver nanorods ...kutty79
This paper describes a simple method of synthesizing silver nanorods using the polyol process, where propylene glycol serves both as a reducing
agent and as a solvent in the presence of a capping reagent such as polyvinylpyrrolidone (PVP). The diameter and length of silver nanorods could be
controlled by changing the AgNO3/PVP ratio. The end-to-end assembly of the silver nanorods was found. The silver nanorods were characterized by
using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and absorption spectroscopy. The catalytic activity of a
glassy carbon electrode with Ag nanorods exhibits extraordinary electrocatalytic activities towards the electro-reduction of benzyl chloride.
- The document reports on the synthesis and characterization of Schiff base ligands derived from L-valine and their Cu(II), Ni(II), and Co(II) complexes.
- Spectroscopic data revealed that the ligands bind as tridentate in the Cu(II) and Ni(II) complexes and bidentate in the Co(II) complex.
- Magnetic susceptibility measurements showed the complexes have a bimetallic structure with antiferromagnetic interactions.
- Antimicrobial testing found the metal complexes to have greater activity than the free ligand, with the Co(II) complex exhibiting the strongest effects.
In this work, I am showing a faithful atomistic process of estimating the oxygen migration energetics within BSCF, oxygen migration energy exhibit a strong dependence on different local atomic structures of this doped perovskites. In addition, DFT calculations exhibit the reason of cubic phase stability of this doped perovskite in variable oxygen concentration.
This document summarizes the synthesis and characterization of new Schiff base ligands and their metal complexes. It describes the synthesis of five Schiff base ligands derived from substituted benzaldehydes and anilines using the reflux method. Copper and nickel complexes were formed from two of the ligands. The ligands and complexes were characterized using infrared spectroscopy, which showed shifts in the C=N and C-O peaks upon complexation. The research aims to synthesize new Schiff bases and their Cu2+ and Ni2+ complexes and characterize them using IR spectroscopy to determine the coordination sites.
Diffusion mechanisms differ in ceramics due to multiple species with varying charges that must balance, often limiting diffusion to the slowest moving species like vacancies. Diffusion is crucial in ceramics for tailoring mechanical properties and enabling ion transport in batteries and fuel cells. Phase diagrams show equilibrium phases and compositions at given temperatures. They are used to understand diffusion effects and interpret final material structures by identifying compounds, solid solutions, and lever rule calculations for multiphase regions.
Schiff base is a compound formed by the condensation reaction of a carbonyl group with a primary amine. The document discusses various methods for preparing Schiff base ligands and complexes, and techniques for characterizing them including UV-visible spectroscopy, IR spectroscopy, NMR, EPR, mass spectrometry, TGA/DTA, and elemental analysis. Schiff base ligands and their complexes have applications in areas like biology, catalysis, materials science, and more.
This document summarizes a research project on the synthesis, characterization, and biological activity of piperonal-based Schiff bases and their metal complexes. The objectives were to synthesize Schiff bases from piperonal and various amines, form complexes by adding metals, and test the complexes for antibacterial activity. Key steps included preparing the Schiff bases and their metal adducts, using various techniques to characterize the compounds, and evaluating the complexes against gram-positive and gram-negative bacteria to determine antibacterial potential. The research aims to contribute to the development of new antibacterial agents.
This document summarizes a presentation on solid electrolytes. It discusses how solid electrolytes exhibit ionic conductivity through mobile anions or cations, with maximum conductivity between 0.1-10 Ohm-1cm-1. Examples of solid electrolytes mentioned include AgI, β-alumina, and zirconia. Applications discussed include use in batteries, oxygen sensors, and solid oxide fuel cells. The proposed work is to synthesize and characterize Sr and Cu doped LaAlO3 as a potential solid electrolyte material.
A detailed study of Transition Metal Complexes of a Schiff base with its Phys...Abhishek Ghara
The many activities of metal ions in biology have stimulated the development of metal based therapeutics. It has been found that biologically active compounds become more effective and bacteriostatic upon chelation with metal ions also the biological activity of many drugs has been shown to be enhanced on complexing with metal ions, hence promoting their use in Pharmacology. The present work deals with the synthesis of metal complexes derived from a novel Schiff base drug synthesized from urea and salicylaldehyde and its physico-chemical analysis to find out ligand- metal ratio of this complex in solution. For the structure elucidation of these complexes “Monovariation method (Mole ratio method/ Yoe-Jones Method)” has been used to ascertain the ligand-metal ratio in the complex. The stability constant of the formed complex was calculated by molar conductance measurement using Modified Job’s method (Method of Continuous Variations). The analysis has been carried out using conductometry. To confirm metal-ligand ratio, conductometric titrations were carried out at room temperature using analytical grade metal salts. Titrations were carried out with “systronics conductivity-meter” using dip type conductivity cell having cell constant 1 at room temperature.
Development Of Non Aqueous Asymmetric Hybrid Supercapacitors Part IiiNakkiran Arulmozhi
The document describes research on developing asymmetric hybrid supercapacitors based on lithium-ion intercalated compounds. Specifically, it discusses synthesizing cathode materials of pure LiCoO2 and LiCo1-xAlxO2 with varying amounts of aluminum doping (x=0, 0.2, 0.4, 0.6). The materials were characterized using techniques like thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Electrochemical characterization of the materials was also performed through cyclic voltammetry and charge/discharge testing to evaluate their performance in supercapacitors.
This document describes research on using carbon dots as both reducing agents and stabilizing agents in the synthesis of palladium nanoparticle-carbon dot composites. The carbon dots were able to reduce palladium chloride to form palladium nanoparticles coated with an ultrathin carbon dot shell. These palladium@carbon dot composites showed high catalytic activity for carbon-carbon bond formation reactions like Heck and Suzuki couplings. The document provides details on the synthesis and characterization of the carbon dots and palladium@carbon dot composites, as well as evaluation of their catalytic activity.
This document provides a checklist of important experiments in chemistry for SPM (Sijil Pelajaran Malaysia) students. It lists 14 chemistry topics and the key experiments students should be able to describe for each topic. These include experiments on the structure of the atom, chemical formulae and equations, the periodic table of elements, electrochemistry, acids and bases, salts, rate of reaction, carbon compounds, oxidation and reduction, and thermochemistry. For each experiment, students are expected to describe the apparatus, materials, procedure, observations, analysis, and interpreting data. The document also analyzes which chemistry topics were examined in SPM Paper 3 from 2003 to 2011.
This document summarizes the synthesis and study of transition metal complexes of benzaldimino-1,3,4-thiadiazole-2-thiol (BTT). The author synthesized the ligand BTT and its copper, nickel, cobalt, and zinc complexes. The complexes were characterized using infrared spectroscopy, electronic spectroscopy, ESR, cyclic voltammetry, NMR, and magnetic susceptibility measurements. Spectroscopic data indicated the ligand behaves as a bidentate ligand, forming octahedral complexes with the metals. The author thanks advisors and colleagues and concludes the spectral studies support an octahedral geometry for the complexes.
Synthetic antibacterial agent assisted synthesis of gold nanoparticles chara...Expand_Lives
In this study, we report synthesis of water-soluble gold nanoparticles (Au-NPs), having an average
diameter of ca. 20 nm, using ciprofloxacin (CF) as a reducing/stabilizing agent. The synthesized
Au-NPs have been characterized by scanning electron microscopy (SEM), EDX, TEM, UV–visible
spectroscopy (UV–vis), X-ray diffraction and cyclic voltammetry. TEM and SEM combined with EDX
analysis confirmed that spherical-shaped Au-NPs were formed. UV–vis spectra of the Au-NPs showed
two absorption bands corresponding to the capping agent ciprofloxacin and surface plasmon absorption
bands at 274 and 527 nm, respectively. The synthesized Au-NPs are used to modify a glassy carbon
electrode (GCE) and its electrochemical and electrocatalytic properties are investigated. The Au-NPs
modified electrode showed excellent electrocatalytic activity towards the oxidation of methanol at
+0.33 V in alkaline solution, which was not observed on the unmodified GCE. Further, electrocatalytic
reduction of oxygen was also studied using the Au-NPs modified electrode at lower potential. Here, CF
was used as a reducing agent for the preparation of Au-NPs dispersion. This Au-NPs dispersion is highly
stable, and can be stored for more than three months in air at room temperature.
C3N5: A Low Bandgap Semiconductor Containing an Azo-linked Carbon Nitride Fra...Pawan Kumar
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1. Synthesis, isolation, spectroscopic and electrochemical
characterization of some calcium-containing metallofullerenes
Ya Zhang a,b
, Jianxun Xu a
, Ce Hao b
, Zujin Shi a,*, Zhennan Gu a
a
State Key Laboratory of Rare Earth Materials Chemistry and Applications, Department of Chemistry, Peking University, Beijing 100871, PR China
b
State Key Laboratory of Fine Chemicals, Department of Chemistry, Dalian University of Technology, Dalian 116024, PR China
Received 10 March 2005; accepted 17 August 2005
Available online 3 October 2005
Abstract
A few Ca-containing mono-metallofullerenes, i.e. Ca@C76, Ca@C88, Ca@C90 (I, II), were synthesized by an improved DC arc dis-
charge method and isolated by a multi-stage HPLC method for the first time. These isomer-separated metallofullerenes were character-
ized by LD-TOF MS and UV–vis–NIR spectrometry. Their HOMO-LUMO band gaps and possible molecular geometries are discussed
according to the absorption spectra in this report. In addition, the cyclic and differential pulse voltammetry of Ca@C76 was conducted in
MeCN/C6H5CH3 (1:4 v/v). The voltammograms of Ca@C82 (II, III) and Ca@C84 (II) were also recorded. Their electrochemical behav-
iors are discussed compared with those of corresponding ytterbium metallofullerenes. The features of the Ca metallofullerenesÕ electronic
structures are also discussed.
Ó 2005 Elsevier Ltd. All rights reserved.
Keywords: Metallofullerenes; Arc discharge; Absorption spectrometry; Electrochemistry
1. Introduction
Endohedral metallofullerenes have attracted much
attention because of their unique structures and novel
properties [1]. This kind of materials are expected to show
promising applications in diverse areas, such as material
and biology science. The so-called divalent metallofulle-
renes are of special attraction because of their abundant
isomers based on different cages (usually ranging from 72
to 84), for example, Ca@C2n, Sm@C2n, Yb@C2n and
Eu@C2n [2–7]. In contrast, the trivalent metallofullerenes
are mostly based on C82 and C84 cages. Up to now, quite
a few Ca-containing metallofullerenes have been isolated
and characterized. In 1995, kubozono et al. succeeded in
isolating the first Ca-containing metallofullerene, i.e.
Ca@C60, using aniline as the extractant [8]. In 1997, Cao
et al. observed a series of Ca-containing metallofullerenes
from Ca@C58 to Ca@C100 in CS2 extract [9]. In addition,
Shinohara and co-workers obtained some isomer-separated
Ca-containing metallofullerenes, namely, Ca@C2n
(2n = 72, 74, 80, 82, 84) by a multi-step HPLC method
[2–4]. Furthermore, Ca@C82 (III) was determined to be
C2 symmetry by 13
C NMR [10]. However, the synthesis
and isolation of some other cage-based Ca-containing
metallofullerenes were neglected in previous work.
Here we present the first isolation and characterization
of some Ca-containing metallofullerenes, i.e. Ca@C76,
Ca@C88 and Ca@C90 (I, II). They were synthesized by
an improved arc discharge method and isolated in iso-
mer-free form by multi-step HPLC. The purities (>98%)
were determined by LD-TOF MS. In addition, the UV–
vis–NIR spectroscopy, cyclic voltammetry (CV) and differ-
ential pulse voltammetry (DPV) were conducted for these
‘‘new’’ species. The valence state of the endohedral calcium
ion, the possible molecular symmetries and the electronic
structures were discussed according to the absorption spec-
tra and electrochemical voltammograms.
0008-6223/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carbon.2005.08.018
*
Corresponding author. Tel.: +861062751495; fax: +861062751708.
E-mail address: zjshi@pku.edu.cn (Z. Shi).
www.elsevier.com/locate/carbon
Carbon 44 (2006) 475–479
2. 2. Experimental Section
Soot containing calcium metallofullerenes was produced
by the DC arc discharge method. The anode is a
B6 · 150 mm graphite rod with a drilled B4 · 120 mm
hole, filled with a powder mixture of graphite, CaC2 and
Ni (10:1:1, atomic ratio). The cathode was a B10 mm
graphite rod with a tapered end to prevent the formation
of deposit. The arc was generated at 65 A in 720 Torr he-
lium static atmosphere, while the gap between the anode
and cathode was kept as large as possible by adjusting
the anode. Usually, a 12-cm long anode rod yields 4.5 g
soot. The raw soot was collected under the protection of
nitrogen to avoid air degradation. The soot was extracted
with o-dimethylbenzene for several times under sonication
until the extract was colorless. The LD-TOF mass spec-
trum of the o-dimethylbenzene extract showed that, under
our experimental conditions, the relative abundance of
each isomer was much different compared with previous re-
port. Especially, Ca@C76 was much more abundant, which
was not isolated in isomer-free form in prior work.
Isolation was conducted by multi-stage HPLC (LC-908-
C60, Japan Analytical Industry) equipped with three differ-
ent columns: 5PYE, Buckyprep, and Buckyprep-M
(20 · 250 mm, Cosmosil Nacalai Tesque). Toluene was
used as mobile phase at a flow rate of 15 mL/min detected
at 335 nm. The detail isolating process can be seen in
supporting materials.
The purities of the isolated Ca-containing metallofulle-
renes were determined to be above 98% by MALDI-TOF
mass spectrometry (BIFLEX III, Bruker Inc.) with radia-
tion pulses (10À8
s) from a N2 laser operating at 337 nm.
UV–vis–NIR spectra of the isolated Ca metallofulle-
renes were recorded between 400–2000 nm in toluene solu-
tion with Shimadzu UV-3100 spectrophotometer.
A BAS-100B Electrochemical Analyzer was used to
record cyclic and differential pulse voltammograms of the
Ca metallofullerenes, i.e. Ca@C76, Ca@C82 (II, III),
Ca@C84 (II) and Ca@C88. All the measurements were con-
ducted in MeCN/C6H5CH3 (1:4 v/v) containing 0.1 M
(n-Bu)4NClO4 with a three-electrode configuration, a glass
carbon disk (4 mm in diameter) as the working electrode, a
platinum wire as the auxiliary electrode and a Ag wire
coated with AgCl as the reference electrode. All the exper-
iments were performed in an ice-water bath. Cyclic voltam-
mograms were recorded at 50 mV/s and DPV were
obtained at 10 mV/s using a pulse amplitude of 50 mV, a
pulse width of 50 ms, and a pulse period of 200 ms. The
electrochemical cell was purged with high purity nitrogen
for about ten min. before each measurement. All the poten-
tials in this report are with respect to the ferrocene/ferro-
cenium redox couple.
3. Results and discussion
3.1. UV–vis–NIR absorption spectroscopy
The absorption spectrum of Ca@C76 and Ca@C88 are
shown in Fig. 1a. There are several characteristic peaks
around 465, 608 and 710 nm and a broad absorption band
between 800 and 1300 nm. The onset arises from 1700 nm.
The onset of the absorption spectrum of a fullerene is a
good measure of its band gap energy. The band gap of
Ca@C76 is estimated to be about 0.7 eV according to
the onset of its absorption spectrum. As can be seen in
the absorption curve, Ca@C88 shows characteristic peaks
at around 705, 786, 1097 nm, relative weak peaks at
495, 530, 579, 933 nm and a board absorption band at
1400 nm. The absorption onset of Ca@C88 is around
1700 nm, indicating a small HOMO-LUMO gap. The
absorption spectrum of Ca@C88 is quite similar to that
of Eu@C88 (I), which was the first report of the spectro-
scopic characterization of the C88-based metallofullerenes
[7]. But there are still some small differences between the
two spectra. For example, there is a distinct peak at
1097 in the absorption spectrum of Ca@C88, but this
region is featureless in the absorption spectrum of
Eu@C88 (I).
400 600 800 1000 1200 1400 1600 1800 2000
Absorbance/a.u.
Ca@C88
Wavelength / nm
Ca@C76
(a)
400 600 800 1000 1200 1400 1600 1800 2000
Ca@C90(II)
Wavelength / nm
Ca@C90(I)
Absorbance/a.u.
(b)
Fig. 1. The absorption spectra of the isomer-separated (a) Ca@C76, Ca@C88 and (b) Ca@C90 (I, II).
476 Y. Zhang et al. / Carbon 44 (2006) 475–479
3. The absorption spectra of Ca@C90 (I, II) are given in
Fig. 1b. Compared with the absorption spectra of
Dy2@C90 (I, II) and Er2@C90 (I, II), the spectra of
Ca@C90 (I, II) are much different [11,12]. However, the
absorption spectra of Ca@C90 (I) and Eu@C90 are very
similar, even though the absorption peaks of Eu@C90 are
not as visible as those of Ca@C90 (I) [7]. The similarity be-
tween the two absorption spectra indicates the same sym-
metry of these two species. In addition, in our work there
was a second isomer, i.e. Ca@C90 (II), isolated and charac-
terized spectroscopically. The absorption spectrum of the
second isomer differs remarkably from that of the first
one. As can be seen in the absorption curve of Ca@C90
(I), there are two broad bands around 800, 110 nm and
two distinct peaks at 569 and 670 nm. For the second iso-
mer, several absorption peaks are observed at 1128, 972,
874, 834, 606 and 554 nm. The different absorption spectra
of Ca@C90 (I, II) indicate their different molecular
symmetries.
3.2. Cyclic and differential pulse voltammograms
The cyclic and differential pulse voltammograms of
Ca@C76, Ca@C82 (II, III) and Ca@C84 (II) were recorded
in the potential range from À3.0 to 1.3 V in our experi-
ments. None of oxidation peak was been observed within
such potential range, which was attributed to the closed
shell electronic structures of these isomers. Meanwhile, five
reduction peaks for each isomer were observed. The fifth
one (E = À2.23 V) was assigned to an impurity original
from the toluene used as HPLC solvent. The correlative
discussion was demonstrated elsewhere [13]. In addition,
there is a tiny peak to be observed between the second
and third reduction in each of the differential pulse voltam-
mograms of Ca@C82 (II, III) and Ca@C84 (II), which can
be attributed to a coexisted ‘‘isomer impurity’’.
The first four reduction potentials of the Ca metallo-
fullerenes are listed in Table 1. Both DPV and CV peak
potentials are given. All the reductions are reversible,
which are estimated from the cyclic voltammograms.
The cyclic and differential pulse voltammograms of
Ca@C76 are present in Fig. 2. As can be seen, there are four
reduction peaks observed within the potential window. The
four reversible couples appear as sets of two (E1 and E2, E3
and E4). This is consistent with the prediction that Ca@C76
has a closed-shell electronic structure. Our early report
showed the electrochemical behaviors of Yb@C76 (I, II)
[13]. The voltammograms of Ca@C76 resemble those of
Yb@C76 (II) to some extent, which indicates their similar
electronic structures.
Fig. 3 shows the cyclic and differential pulse voltam-
mograms of Ca@C82 (II, III). Four reduction peaks can
be seen in both voltammograms of these two isomers. To
be notable, the first reduction of Ca@C82 (III) is followed
immediately by the second one. The similar case was also
observed for Yb@C82 (II) [13]. In fact, these two metallo-
fullerenesÕ voltammograms are almost the same. This
means that the two isomers have the same electronic and
cage structures, i.e. C2. Dennis and Shinohara determined
the symmetry of Ca@C82 (III) to be C2 from the NMR
spectrum [10]. Our above discussion is in agreement with
the NMR result. The voltammograms of Ca@C82 (II) is
different from those of M@C82 (I, II, III) (Ms = Yb, Sm,
Tm), indicating its new cage structure [13–15]. The UV–
vis–NIR of Ca@C82 (I, II, III, IV) were given by Xu
et al. [4]. By comparing the absorption spectra of Ca@C82s
and M@C82s, one can see that Ca@C82 (I, III, IV) corre-
spond to M@C82 (I, II, II) respectively. That is to say,
Ca@C82 (II) is the ‘‘fourth’’ isomer. This new cageÕs struc-
ture is still unknown. But from its voltammograms, it can
be deduced that the electron affinity of Ca@C82 (II) is com-
parative with that of Ca@C82 (III). And all the four reduc-
tion peaks of Ca@C82 (II) are negatively shifted compared
with those of Ca@C82 (III), indicating the higher levels of
the front molecular orbitals of Ca@C82 (II).
The cyclic and differential pulse voltammograms of
Ca@C84 (II) are given in Fig. 4. The voltammograms of
Table 1
Half-cell potentialsa
and DPV peak potentialsb
of the Ca metallofulle-
renes, versus Fc/Fc+
(in volts)
red
E1
red
E2
red
E3
red
E4
Ca@C76 DPV À0.58 À0.94 À1.51 À1.93
CV À0.61 À0.99 À1.57 À1.97
Ca@C82 (II) DPV À0.63 À0.94 À1.52 À1.87
CV À0.65 À0.96 À1.55 À1.90
Ca@C82 (III) DPV À0.55 À0.70 À1.25 À1.66
CV À0.59 À0.74 À1.30 À1.70
Ca@C84 (II) DPV À0.59 À0.84 À1.22 À1.60
CV À0.64 À0.90 À1.27 À1.65
a
The voltammetry experiments were conducted in MeCN/C6H5CH3
(1:4 v/v) containing 0.1 M (n-Bu)4NClO4; scan rate: 50 mV/s.
b
Pulse amplitude: 50 mV; pulse width: 50 ms; pulse period: 200 ms; scan
rate: 10 mV/s.
0 -500 -1000 -1500 -2000 -2500 -3000
Current
E (mv) vs Ferrocene
Ca@C76
1 µA
Fig. 2. The cyclic and differential pulse voltammograms of Ca@C76
recorded in MeCN/C6H5CH3 (1:4 v/v) solution containing 0.1 M
(n-Bu)4NClO4. The peak (Es = 2.23 V) is assigned to an impurity.
Y. Zhang et al. / Carbon 44 (2006) 475–479 477
4. Ca@C84 (II) are quite similar to those of Yb@C84 (II),
which indicates their similar cage structures and electronic
structures [13]. On the other hand, these two metallofulle-
renesÕ absorption spectra are also almost identical. This is
consistent with the above conclusion. The ‘‘impurity’’ peak
is very high due to that the concentration of Ca@C84 (II)
toluene solution is extra low. In addition, there is a reduc-
tion peak around À2.65 V. This peak is poorly definitive
due to that it is of a low intensity and the reduction poten-
tial is near the potential window. This reduction process
was also observed in the voltammograms of Yb@C84 (II).
4. Conclusion
In summary, a few Ca-containing metallofullerens,
namely Ca@C76, Ca@C88, Ca@C90 (I, II), were synthe-
sized and successfully isolated under our improved experi-
mental conditions for the first time. These isomer-separated
metallofullerenes were characterized by LD-TOF MS and
UV–vis–NIR spectrometry. Their HOMO-LUMO band
gaps and possible molecular geometries are discussed
according to the absorption spectra in this report. In addi-
tion, the cyclic and differential pulse voltammetry of
Ca@C76 was conducted in MeCN/C6H5CH3 (1:4 v/v).
The voltammograms of Ca@C82 (II, III) and Ca@C84
(II) were also recorded. Their electrochemical behaviors
are discussed compared with those of corresponding ytter-
bium metallofullerenes. The features of the Ca metallo-
fullerenesÕ electronic structures are also discussed.
Acknowledgements
This work was supported by National Natural Science
Foundation of China (Nos. 20151002, 50272004 and
50472023), and Scientific Research Foundation for the Re-
turned Overseas Chinese Scholars, State Education Minis-
try of China.
Appendix A. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.carbon.
2005.08.018.
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