The Ligand Fields Characterizations within Erbium-Tellurite Glass Network via Gold Nanoparticles Concentration Variation

2016 ◽  
Vol 846 ◽  
pp. 137-141
Author(s):  
Ezza Syuhada Sazali ◽  
M.R. Sahar ◽  
R. Arifin ◽  
S.K. Ghoshal ◽  
Md Supar Rohani
Keyword(s):  
Gold Nanoparticles ◽  
Tellurite Glass ◽  
Glass Network ◽  
Average Diameter ◽  
Visible Range ◽  
Ligand Field ◽  
Racah Parameter ◽  
Crystal Field Strength ◽  
Nanoparticles Concentration ◽  
Ligand Fields

Glass samples of composition 79TeO2 – 15PbO – 5PbCl2 – 1Er2O3 – (x)AuCl3 with (0.0 ≤ x ≤ 0.1 mol%) were successfully synthesized by using melt-quenching technique. The impacts of gold nanoparticles (GNPs) concentration in stimulating the ligand field interaction inside the erbium-tellurite glass network were inspected. Amorphous nature of the sample was confirmed through XRD pattern. TEM images display the existence of GNPs with average diameter ~1.24 nm. Optical absorption spectra were recorded in the UV-Visible range. The absorption displays several prominent peaks corresponding to the transitions from the ground state to the excited states of Er3+ ion. The compositional dependence of the ligand parameters in terms of crystal field strength and Racah parameter were determined.

scholarly journals Effect of Neodymium Nanoparticles on Elastic Properties of Zinc-Tellurite Glass System

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Abdulbaset A. Abdulla Awshah ◽  
Halimah Mohamed Kamari ◽  
Chan Kar Tim ◽  
Nurisya Mohd Shah ◽  
S. H. Alazoumi ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Tellurite Glass ◽  
Glass Network ◽  
Softening Temperature ◽  
Xrd Analysis ◽  
Glass System ◽  
Amorphous Nature ◽  
Nanoparticles Concentration ◽  
Quenching Method ◽  
The Impact

The aim of this work is to determine the effect of neodymium nanoparticles concentration on the elastic properties of zinc-tellurite glass. A series of neodymium nanoparticles doped zinc-tellurite glass systems (NdNPsZT) of composition [(TeO2)0.70(ZnO)0.30]1-x(Nd2O3 NPs)(x), x=0.01, 0.02, 0.03, 0.04, and 0.05, were synthesized by using conventional melt-quenching method. The amorphous nature of the glass system was confirmed by using XRD analysis. The density of the glass system was determined by Archimedes method. The elastic properties were calculated from the measured density and ultrasonic velocity at 5 MHz frequency. The experimental results showed that the elastic properties rely upon the composition of the glass systems and the impact of neodymium nanoparticles (Nd2O3 NPs) within the glass network. The increase in ultrasonic velocities is due to the increase in rigidity and change in structural units of the glass system. The softening temperature and the microhardness increased with the increase in Nd3+ ions concentration from 0.1 to 0.2 mol and decreased when the Nd3+ ions concentration increased from 0.2 to 0.5 mol. Poisson’s ratio and Debye’s temperature decreased with the increase in the Nd3+ ions concentration from 0.1 to 0.2 mol and increased when the Nd3+ ions concentration was increased from 0.2 to 0.5 mol.

Structures and Ligand Field Parameters of Sm3+ Doped Tellurite Glass: Gold Nanoparticles Mediation

2017 ◽  
Vol 268 ◽  
pp. 67-71
Author(s):  
Y.A. Tanko ◽  
Md Rahim Sahar ◽  
Sib Krishna Ghoshal
Keyword(s):  
Gold Nanoparticles ◽  
Tellurite Glass ◽  
Ligand Field ◽  
Electron Microscopic ◽  
Au Nps ◽  
Bonding Parameter ◽  
Resonance Band ◽  
Racah Parameters ◽  
Doped Glasses ◽  
Ligand Field Parameters

Controllable modifications of overall properties of rare-earth doped glasses via gold nanoparticles (Au NPs) mediation prompted gamut research interests. Such glass systems are interesting due to their technological prospects and well as fundamental understanding of surface plasmon resonance effects at metal glass interface responsible for diverse emerging attributes. This motivate us to determine the effects of varying concentration of Au NPs on the structure and ligand field parameters of samarium (Sm3+) doped zinc tellurite glass. Glass samples with composition (79-x)TeO2-20ZnO-1Sm2O3-xAuCl3, where 0 ≤ x ≤ 0.10 mol% are prepared using melt quenching method. X-ray diffraction pattern of all glasses confirmed their amorphous nature. Transmission electron microscopic images verified the existence of Au NPs in a glass matrix matrix with an average size of 10.52 nm. Two surface plasmons resonance band of gold are probed at 652 and 715 nm. Using the UV-Vis absorption spectral data, quantities such as nephelauxetic ratio, bonding parameter and Racah parameters are evaluated. Both bonding parameter and nephelauxetic ratio revealed a reduction with increasing concentration of Au NPs, where decrease in the ionic bonding between Sm3+ and surrounding ligand have clearly indicated an enhancement in the covalency. The values of Racah parameters are decreased as the concentration of Au NPs are increased. The observed reduction in the nephelauxetic function is attributed to the weakening of the localized d-electrons aroused from overlapping d-orbital and ligand orbital. Furthermore, the Raman spectra displayed the structural modification in terms of TeO4 trigonal bipyramidal (tbp) unit, where many TeO4 tbp units are converted into their TeO3 trigonal pyramid (tp) counterparts. Raman bands are found to be located around 102-105 cm-1, 420-424 cm-1, 657-661 cm-1 and 729-736 cm-1. Results are analyzed and compared. Present glass composition is asserted to be useful for the development of photonic devices.

scholarly journals Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 893
Author(s):  
Olufunto T. Fanoro ◽  
Sundararajan Parani ◽  
Rodney Maluleke ◽  
Thabang C. Lebepe ◽  
Jose R. Varghese ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Cell Viability ◽  
Leaf Extract ◽  
Room Temperature ◽  
Klebsiella Oxytoca ◽  
Cost Effective ◽  
Average Diameter ◽  
Antibacterial Activities ◽  
Inhibition Concentration ◽  
First Time

We herein report a facile, green, cost-effective, plant-mediated synthesis of gold nanoparticles (AuNPs) for the first time using Combretum erythrophyllum (CE) plant leaves. The synthesis was conducted at room temperature using CE leaf extract serving as a reducing and capping agent. The as-synthesized AuNPs were found to be crystalline, well dispersed, and spherical in shape with an average diameter of 13.20 nm and an excellent stability of over 60 days. The AuNPs showed broad-spectrum antibacterial activities against both pathogenic Gram-positive (Staphylococcus epidermidis (ATCC14990), Staphylococcus aureus (ATCC 25923), Mycobacterium smegmatis (MC 215)) and Gram-negative bacteria (Proteus mirabilis (ATCC 7002), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13822), Klebsiella oxytoca (ATCC 8724)), with a minimum inhibition concentration of 62.5 µg/mL. In addition, the as-synthesized AuNPs were highly stable with exceptional cell viability towards normal cells (BHK- 21) and cancerous cancer cell lines (cervical and lung cancer).

Ligand field effects on the ground and excited states of reactive FeO2+ species

2018 ◽  
Vol 20 (45) ◽  
pp. 28786-28795 ◽  
Author(s):  
Justin K. Kirkland ◽  
Shahriar N. Khan ◽  
Bryan Casale ◽  
Evangelos Miliordos ◽  
Konstantinos D. Vogiatzis
Keyword(s):  
Iron Oxide ◽  
Quantum Chemical Calculations ◽  
Excited States ◽  
Quantum Chemical ◽  
Ligand Field ◽  
Reactive Iron ◽  
Field Effects ◽  
Ligand Fields

Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.

scholarly journals Exploration of the Antimicrobial and Catalytic Properties of Gold Nanoparticles Greenly Synthesized by Cryptolepis buchanani Roem. and Schult Extract

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Kamonpan Wongyai ◽  
Phitchayapak Wintachai ◽  
Rasimate Maungchang ◽  
Parawee Rattanakit
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Nanoparticles ◽  
Analytical Techniques ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Face Centered

A green, simple, and rapid synthesis of gold nanoparticles using plant extract, Cryptolepis buchanani Roem. and Schult, and their applications are first described in this paper. The formation of gold nanoparticles was visually observed by the appearance of a ruby red color, which was further indicated by an absorption peak at 530 nm in UV-Vis spectroscopy. Optimization of reaction parameters for the gold nanoparticles was also investigated. Various analytical techniques were employed as part of the process of characterizing the resulting gold nanoparticles. Fourier transform infrared (FTIR) analysis revealed that the phenol compounds present in the extract were responsible for gold(III) reduction and stabilization of gold nanoparticles. Transmission electron microscopy (TEM) analysis showed that the gold nanoparticles were spherical in shape with an average diameter of 11 nm. Powder X-ray diffraction (XRD) pattern indicated that the green synthesis approach produced highly crystalline, face-centered cubic gold nanoparticles. Energy-dispersive X-ray spectroscopy (EDS) measurements confirmed the presence of elemental gold in the prepared nanoparticles. The negative zeta potential value of gold nanoparticles was found to be -30.28 mV. The green synthesized gold nanoparticles expressed effective antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii and exhibited an excellent catalytic property in terms of its reduction ability of methylene blue.

Fabrication and In-Situ Thermal Reduction of Gold Nanofibers

2020 ◽  
Vol 12 (8) ◽  
pp. 1109-1115
Author(s):  
Xiaojiao Yang ◽  
Jun Li ◽  
Ying Liu
Keyword(s):  
Thermal Analysis ◽  
Gold Nanoparticles ◽  
Fourier Transform ◽  
Average Diameter ◽  
Thermal Reduction ◽  
Gold Content ◽  
Gold Salt ◽  
One Dimensional ◽  
Nanoelectronic Devices

One-dimensional gold nanofibers are good candidates for next generation nanoelectronic devices. Here, gold nanofibers were synthesized via electrospinning with subsequent in-situ thermal reduction. The thermal behavior of the precursor nanofibers was investigated by thermogravimetric/differential thermal analysis and fourier transform infrared. The polymer parts are decomposed and removed step by step, meanwhile, gold salt is decomposed and in-situ reduced to form gold nanoparticles in air without any reducing agent or gas due to its strong oxidation ability. The effects of gold content, polymers type (PVP, PVA, PAN), calcination atmospheres (Air, H2, H2/Ar) and temperatures (200 °C to 500 °C) on the morphology and structures of gold nanofibers were characterized by XRD, SEM, and TEM. The results shows that PVP is the optimal polymer with the gold content of 6:1 (PVP:Au) to fabricate the continuous gold nanofibers with good morphology and structures. The final gold nanofibers with average diameter of 60 nm and several hundred micrometers long, were fabricated after calcined at 500 °C in air for 2 hours. It was composed of gold nanoparticles that ranged from 5 to 30 nm.

scholarly journals Photoregulation of Gold Nanoparticles Stabilized in a Diacetylenic Nanocapsule

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Saowalak Somjid ◽  
Apiwat Chompoosor ◽  
Somdej Kanokmedhakul ◽  
Saowapak Teerasong
Keyword(s):  
Gold Nanoparticles ◽  
Uv Irradiation ◽  
Irradiation Time ◽  
Spherical Shape ◽  
Average Diameter ◽  
Drug Carriers ◽  
Hydrophobic Core ◽  
Triggered Release ◽  
Hydrophobic Molecule ◽  
Positively Charged Gold Nanoparticle

The results of releasing a drug in a burst are unpredictable and one of the inherent drawbacks of using nanocarriers. Here, photoresponsive cationic gold nanoparticles to stabilize diacetylenic nanocapsules enabling photoregulated release of payloads are reported. The fabrication of these nanocapsules relied on an electrostatic interaction of a negatively charged diacetylenic core and a positively charged gold nanoparticle shell. Gold nanoparticles with photoresponsive ligands on their surfaces act as both hydrophobic core stabilizers and gatekeepers of the nanocapsules, while their polydiacetylene cores serve as hydrophobic drug carriers that can be tuned using UV irradiation. The morphology of nanocapsules was analyzed using TEM and dynamic light scattering. The resultant nanocapsules had a spherical shape with an average diameter of 152.9 ± 6.7 nm. Upon UV irradiation, the nanocapsules lost their integrity and an encapsulated model compound was released through diffusion. The release of a hydrophobic molecule was irradiation time dependent and thereby controllable. This light-triggered release provides an alternative strategy for controlled drug delivery.

Self-Assembled Nano-Needles of Polyaniline, Efficient Structures in Controlling Electrical Conductivity

2011 ◽  
Vol 1312 ◽  
Author(s):  
Michael I. Ibrahim ◽  
Maria J. Bassil ◽  
Umit B. Demirci ◽  
Georges El Haj Moussa ◽  
Mario R. El Tahchi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Oxidative Polymerization ◽  
Weight Ratio ◽  
High Mobility ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Visible Range ◽  
Mobility Of Charge Carriers ◽  
Vis Spectroscopy ◽  
Size And Morphology

ABSTRACTPolyaniline (PANI) is one of the most interesting conducting polymers with a wide and controllable conductivity range, synthesized easily via chemical or electrical route, stable chemically and environmentally, having high absorption in the visible range and high mobility of charge carriers. Under different conditions, PANI morphology can be controlled yielding to the creation of nano-tubes, belts, rods, fibers and particles.In this study, the chemical oxidative polymerization which consists of mixing aniline hydrochloride (A-HCl) with ammonium peroxydisulfate (APS) was used to synthesize HCl doped PANI. Fixing the weight ratio A-HCl/APS defined by the IUPAC while varying their quantities leads to the formation of PANI nanoparticles with variable diameters. In addition, PANI nano-needles of 60 nm average diameter at the center are also obtained. Different methods are used to investigate of 1-D morphologies. The electrical conductivity of bulk PANI pellets is measured using the four-point probe technique. The absorption in the visible range of PANI particles and nano-needles is determined by UV-Vis spectroscopy. XRD analysis was performed to study the effect of PANI particle size and morphology on the crystallinity of the powder. Such structures could be used in hybrid solar cells for higher conversion efficiencies.

scholarly journals Retention of Activity by Antibodies Immobilized on Gold Nanoparticles of Different Sizes: Fluorometric Method of Determination and Comparative Evaluation

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3117
Author(s):  
Dmitriy V. Sotnikov ◽  
Nadezhda A. Byzova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Gold Nanoparticles ◽  
Average Diameter ◽  
Measurement Procedure ◽  
Antigen Binding ◽  
Reactive Protein ◽  
Gold Salts ◽  
Tryptophan Residues ◽  
Analytical Reagents ◽  
Citrate Reduction ◽  
Sequential Measurements

Antibody–nanoparticle conjugates are widely used analytical reagents. An informative parameter reflecting the conjugates’ properties is the number of antibodies per nanoparticle that retain their antigen-binding ability. Estimation of this parameter is characterized by a lack of simple, reproducible methods. The proposed method is based on the registration of fluorescence of tryptophan residues contained in proteins and combines sequential measurements of first the immobilized antibody number and then the bound protein antigen number. Requirements for the measurement procedure have been determined to ensure reliable and accurate results. Using the developed technique, preparations of spherical gold nanoparticles obtained by the most common method of citrate reduction of gold salts (the Turkevich–Frens method) and varying in average diameter from 15 to 55 nm have been characterized. It was shown that the number of antibodies (immunoglobulins G) bound by one nanoparticle ranged from 30 to 194 during adsorptive unoriented monolayer immobilization. C-reactive protein was considered as the model antigen. The percentage of antibody valences that retained their antigen-binding properties in the conjugate increased from 17 to 34% with an increase in the diameter of gold nanoparticles. The proposed method and the results of the study provide tools to assess the capabilities of the preparations of gold nanoparticles and their conjugates as well as the expediency of seeking the best techniques for various practical purposes.

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