Dissertations / Theses: 'Metal Nanoparticles - Synthetic Studies'

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Sidhaye, D. S. "Studies on synthesis and assembly of metal nanoparticles." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2009. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2779.

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So, Man-ho, and 蘇文浩. "Nanochemistry, synthesis, characterization and application studies of metal nanoparticles and metalloporphyrin nanowires." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B43703677.

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So, Man-ho. "Nanochemistry, synthesis, characterization and application studies of metal nanoparticles and metalloporphyrin nanowires." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43703677.

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Raffa, Patrizio. "Metal vapour synthesis of stabilized transition metal nanoparticles: characterization, studies on factors affecting particle size and catalytic applications." Doctoral thesis, Scuola Normale Superiore, 2009. http://hdl.handle.net/11384/85791.

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This PhD thesis is focused on the synthesis, characterization and evaluation of catalytic activity of stabilized platinum and gold nanoparticles, generated by use of the metal vaporization technique. Metal vapour synthesis allows to obtain platinum and gold particles with diameters in the range of few nanometers. The introduction of suitable organic molecules at various stage of the synthesis has proven to be useful in order to control the final size of the produced particles. The metal nanoparticles obtained by this new approach are very stable and can be easily handled and characterized in solution. In particular, NMR based measurement of diffusion parameters has proven to be useful for the quick determination of particles size in solution. The choice of organic stabilizing ligand is crucial in determining both the particle size and the catalytic activity and selectivity of the system. Platinum particles characterized by small diameters and good catalytic performances are obtained using vinylsiloxanes and aromatic solvents while, in the synthesis of gold particles, branched thiols and alkylamines demonstrated to be a better choices over linear alkylthiols if catalytic activity is required. A new application of gold nanoparticles in catalytic silane alcoholysis reaction has also been discovered.

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Meduri, Kavita. "Carbon-Supported Transition Metal Nanoparticles for Catalytic and Electromagnetic Applications." Thesis, Portland State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10933285.

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Recently, there has been growing interest in using transition metals (TM) for catalytic and electromagnetic applications, due to the ability of TMs to form stable compounds in multiple oxidation states. In this research, the focus has been on the synthesis and characterization of carbon-supported TM nanoparticles (NPs), specifically palladium (Pd) and gold (Au) NPs, for catalytic applications, and transition metal oxides (TMO) NPs, specifically Fe₃O₄ NPs for electromagnetic applications. Carbon supports have several advantages, such as enabling even distribution of particles, offering large specific surface area with excellent electron conductivity, and relative chemical inertness.

In this dissertation, for catalytic applications, emphasis was on removal of trichloroethylene (TCE) from groundwater. For this application, carbon-supported Pd/Au NP catalysts were developed. Pd was chosen because it is more active, stable and selective for desired end-products, and Au has shown to be a good promotor of Pd’s catalytic activity. Often, commercially available Pd-based catalysts are made using harsh chemicals, which can be harmful to the environment. Here, an environmentally friendly process with aspects of green chemistry was developed to produce carbon-supported Pd/Au NP catalysts. This process uses a combination of sonochemistry and solvothermal syntheses. The carefully designed carbon-supported Pd/Au NP catalyst material was systematically characterized, tested against TCE, and optimized for increased rate of removal of TCE. Electron microscopy and spectroscopy techniques were used to study the material including structure, configuration and oxidative state. The Pd/Au NPs were found mainly to form clusters with an aggregate-Pd_ShellAu_Core structure. Using state-of-the-art direct detection with electron energy loss spectroscopy, the Pd NPs were found to have an oxidative state of zero (0). The formation of the catalyst material was studied in detail by varying several synthesis parameters including type of solvent, sonication time, synthesis temperature etc. The most optimized catalyst was found remove TCE at double the rate of corresponding commercial Pd-based catalysts in a hydrogen headspace. This material was found to catalyze the removal of TCE via traditional hydrodehalogenation and shows promise for the removal of other contaminants such as trichloropropane (TCP), carbon tetrachloride (CT).

This green approach to make and optimize TM materials for specific applications was extended to TMOs, specifically magnetite (Fe₃O₄) and further developed for the application of electromagnetism. As catalysts, Fe₃O₄ is used for removal of p-nitrophenol from water. However, since the carbon-supported Pd/Au material system was developed and optimized for catalysis, here, carbon-supported Fe₃O₄ NPs were developed for electromagnetic applications. There has been growing interest in tuning the magnetic properties of materials at room temperature with the use of external electric fields, for long-term applications in data storage and spintronic devices. While a complete reversible change of material properties has not yet been achieved, some success in partial switching has been achieved using multiferroic spinel structures such as Fe₃O₄. These materials experience a change in magnetic moment at room temperature when exposed to the electric fields generated by electrochemical cells such as lithium ion batteries (LIBs) and supercapacitors (SC). In the past, a 1% reversible change was observed in Fe₃O₄ using LIBs. Here, building on the developments from previous material system, Fe₃O₄ NPs were directly hybridized onto the graphene support in order to increase the observable change in magnetic moment. The material was systematically designed and tested for this application, including a study of the material formation. A simple, environmentally friendly synthesis using the solvothermal process was implemented to make the graphene-supported Fe₃O₄ NPs. This new material was found to produce a reversible change of up to 18% in a LIB. In order to overcome some of the difficulties of testing with a LIB, a corresponding hybrid SC was designed, built and calibrated. The graphene-supported Fe₃O₄ NPs were found to produce a net 2% reversibility in the SC, which has not been reported before. The results from both the LIB and SC were analyzed to better understand the mechanism of switching in a spinel ferrite such as Fe₃O₄, which can help optimize the material for future applications.

The focus of this dissertation was on the development of a methodology for carbon-supported TM and TMO NPs for specific applications. It is envisioned that this approach and strategy will contribute towards the future optimization of similar material systems for a multitude of applications.

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Ray, Priyanka. "Calixarenes and Nanoparticles : Synthesis, Properties and Applications." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112131.

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Le travail présenté dans ce manuscrit inclut la synthèse organique des différents types de calixarènes, l'étude de leurs propriétés optiques, des simulations théoriques pour déterminer leurs conformations favorables et leurs utilisations pour stabiliser des nanoparticules. Des nanoparticules d’argent, d’or, de platine et des nanoparticules bimétalliques (Ag-Au) ont été synthétisées en utilisant par réduction radiolytique ainsi que la synthèse la photochimique. Ces nanoparticules sont stabilisées en utilisant des calixarènes et divers polymères. Les nanomatériaux ont été caractérisés par spectroscopie d’absorption UV-Visible et spectroscopie de fluorescence et par des observations en microscopie électronique en transmission. Comme les nanoparticules métalliques sont connues pour leurs applications dans divers domaines, des propriétés antibactériennes de nanoparticules d'argent et des propriétés électrocatalytiques des nanoparticules d'or ont été testées
The work presented in this manuscript includes the organic synthesis of different types of calixarenes, the study of their optical properties, computational studies for determination of their favourable conformations and their use in the stabilisation of nanoparticles. Silver, gold, platinum and bimetallic (Ag-Au) nanoparticles were synthesised using radiolytic reduction as well as photochemical method. These nanoparticles were stabilised by calixarenes and also other ligands which included several polymers. The nanomaterials were characterised using UV-Visible absorption and fluorescence spectroscopy and transmission electron microscopy (TEM) measurements. As metal nanoparticles are known for their applications in various fields, the antibacterial properties of silver nanoparticles and the electrocatalytic properties of gold nanoparticles were tested

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Zimmermann, M., and G. Garnweitner. "Formation Studies on the Nonaqueous Synthesis of Metal Oxide Nanoparticles in a 1.5 L Reactor System." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34891.

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In the last years, the nonaqueous synthesis has been demonstrated as a highly versatile method for the simple synthesis of highly crystalline metal oxide nanoparticles and nanomaterials. Thereby, we have presented the synthesis of a multitude of different metal oxides (e.g., TiO2, ZrO2, BaTiO3, Fe3O4). The mechanisms of particle formation as well as the influence of process parameters on the particle properties however remain largely unknown so far, as the molecular mechanisms are rather complex. In this paper, we show that the synthesis of metal oxide nanoparticles is feasible also on a multi-gram reactor scale on the example of anatase TiO2 nanoparticles. Using a reactor system equipped with a sampling system for with-drawal of samples at different stages of the reaction, the kinetics of particle formation could be determined and compared to the formation of organic side products and water. Additionally, insights into the influence of different process parameters on the particle properties are shown and can be utilized to tailor size and morphology of the product nanoparticles. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34891

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TRASATTI, Andrea. "New heteroscorpionate and macrocyclic ligands, related metal complexes and novel Gold nanoparticles: synthesis, structure analysis and biological studies." Doctoral thesis, Università degli Studi di Camerino, 2013. http://hdl.handle.net/11581/401702.

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The synthesis, the structural and the biological analysis of a series of new macrocyclic, heteroscorpionate ligands and related copper complexes are reported in the first two parts of this PhD thesis. In the third part the study of the internalization processes of new gold nanoparticles in the HeLa cells were showed. In the first part the coordination environment and the stability behavior of the new macrocyclic ligands 1,10-dithia-4,7-diazacyclododecane-3,8-dicarboxylic acid (NEC-SE), 1,10-dithia-4,7-diazacyclotridecane-3,8-dicarboxylic acid (NEC-SP), 1,10-dithia-4,7-diazacyclotetradecane-3,8-dicarboxylic acid (NEC-SB), 4-methyl-1,7-ditihia-4,10,13-triazacyclopentadecane-9,14-dicarboxylic acid (NEC-SN-Me) and of the corresponding Cu(II) complexes were investigated both in the solid state and in aqueous solution. The Cu2+ complexation constants for NEC-SE were determined in aqueous solution. The behavior of the copper complexes in presence of the strong copper chelating bioagent human serum albumin was also examined, to gain information on the stability of these compounds in biological fluids. The corresponding 64Cu(II) labeled complexes were produced in major98% radiochemical purity in collaboration with Prof. J. S. Lewis (Memorial Sloan-Kettering Cancer Center, NY). Rats were injected with complexes and were euthanized at 1, 4 and 24 h. All three complexes were cleared from the blood over the first hour following injection but there was poor clearance of this activity over 24 h. In the second section the syntheses by direct coupling of preformed side chain acid and amine components of new nitroimidazole and glucosamine conjugated heteroscorpionate ligands, namely 2,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide (LMN) and 1,3,4,6-tetra-O-acetyl-2-{[bis(3,5-dimethyl-1H-pyrazol-1-yl)acetyl]amino}-2-deoxy-b-D-glucopyranose (LDAC), respectively, were reported. The related copper(II) complexes {[(LMN)2Cu]Cl2} and {[(LDAC)2Cu]Cl2} were prepared from the reaction of CuCl2*2H2O with LMN or LDAC in methanol solution. XAS and EXAFS were used to determine the local environment of the two copper(II) complexes. The new copper(II) complexes and the uncoordinated ligands were evaluated for their cytotoxic activity towards a panel of several human tumour cell lines. The results indicated that both copper(II) complexes show similar spectra of cytotoxicity and very low resistance factors (RF minus 2) against C13* ovarian cancer cells which have acquired resistance to cisplatin. In the last part only partial results were reported because the study is still in progress. This part of PhD work was carried out in collaboration with the research groups of Prof. Stellacci in the Department of Materials Science and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland, during my abroad 6 months stage. The synthesis of a series of mixed-ligand gold nanoparticle (NPs) obtained varying the lengths of both the hydrophobic and hydrophilic ligand length were carried out. The synthesized NPs were studied using 1H-NMR (first and before the decomposition with potassium cyanide), TEM and GC-MS analysis. The NPs with a size between 4 and 10 nm were recovered using the fractionation by centrifugation, which is a technique that uses the principle that larger particles sediment faster than smaller ones. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to explore how the temperature of the system, the size of NPs and their shell composition affect the internalization processes in the analyzed cell.

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Tran, Kristina L. "Synthesis, Characterization, and Self-Assembly of Gold Nanorods and Nanoprisms." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3446.

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The unique properties of gold nanoparticles make them excellent candidates for applications in electronics, sensing, imaging, and photothermal therapy. Though abundant literature exists for isotropic gold nanoparticles, work on nanoparticles of different shapes has been gaining interest recently. Anisotropic gold nanoparticles, such as nanorods and nanoprisms, have tunable optical properties in the visible and near-infrared regions. Through synthesis and surface modification, the production of various shapes of these gold nanoparticles can be controlled to meet different applications. Two different types of gold nanorods were used in this thesis. The first type was stabilized with cetyltrimethylammonium bromide (CTAB) and had aspect ratios of 3-4 (defined as the nanorod length divided by the diameter). The second type was synthesized using CTAB and benzyldimethylhexadecylammonium chloride (BDAC) in a binary surfactant system which produced aspect ratios greater than 4. The nanorods were characterized with UV-Vis spectroscopy and transmission electron microscopy (TEM). Two types of bowl-shaped macrocyclic compounds called resorcinarenes were used to direct self-assembly of the nanorods. The first type of resorcinarene (R2S) consisted of thiol(SH)-terminated alkyl chains on both rims. The second type (R1S) contained thiol-terminated alkyl chains on only one rim. The monolayer formation of these resorcinarenes on planar gold surfaces was studied and characterized by FTIR spectroscopy. Resorcinarene-mediated assembly of gold nanorods was monitored with UV-Vis spectroscopy, dynamic light scattering (DLS), and TEM. In addition to gold nanorods, gold nanoprisms were synthesized through a kinetically-controlled reduction route in the presence of CTAB. The linking of nanoprisms using resorcinarenes was also explored.

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Weerathunga, Kaluarachchige Don H. "Metal nanoparticle and semiconductor heterogeneous catalysis for synthetic organic oxidation reactions." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228677/1/Kaluarachchige%20Don_Weerathunga_Thesis.pdf.

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This thesis investigated new metal nanoparticle and semiconductor catalyst and photocatalyst systems for achieving fine chemical synthesis from both fossil-fuel sourced reactants and biomass carbohydrate-derived reactants. Photocatalysts for industrially important organic oxidation reactions were developed that efficiently worked with the aid of solar light irradiation, at low temperature and pressure, that avoided the use of hazardous chemicals. The effects on the organic reaction mechanisms of different noble metal nanoparticle and metal oxide nanostructures were explored for these chemical transformations. Success in developing the nanomaterial photocatalysts has contributed to the field of sustainable green chemical synthesis.

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Freeman, David J. "Synthetic and metal binding studies of cyclic peptides." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299566.

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Cartwright, P. S. "Synthetic and spectroscopic studies of transition metal complexes." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380302.

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Wellington, Kevin Wayne. "Synthetic and analytical studies of biomimetic metal complexes." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005042.

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Several series of novel diamido, diamino and diimino ligands containing different spacers and heterocyclic donors have been synthesised. The spacers include the flexible biphenyl, the rigid 1,1 O-phenanthroline and various acyclic moieties, while the heterocyclic donors comprise pyridine, imidazole or benzimidazole groups. These ligands have been designed to complex copper and act as biomimetic models of the active site of the enzyme, tyrosinase, and their complexes with copper, cobalt, nickel and platinum have been analysed using microanalytical, IR, UV-Visible and cyclic voltammetric techniques. Attempted reduction of the biphenyl-based diimino ligands resulted in an unexpected intramolecular cyclisation affording azepine derivatives, the structures of which were elucidated with the aid of single crystal X-ray analysis of cobalt and nickel complexes. Computer modelling methods have been used to explore the conformational options of the copper complexes, and to assess the accessibility of the dinuclear copper site to substrate molecules. Computer modelling has also been used, in conjunction with the available analytical data, to visualise the possible structures of selected ligands and complexes. The copper complexes, although predominantly polymeric, were evaluated as biomimetic catalysts using 3,5-di-t-butylphenol and 3,5-di-t-butylcatechol as substrates. Some of the complexes clearly displayed biomimetic potential, exhibiting both phenolase and catecholase activity.

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Namura, Kyoko. "Studies on Photothermal Conversion by Noble Metal Nanoparticles." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199303.

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Jones, Robert Edward. "Synthetic and structural studies on early transition metal siloxides." Thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/23079.

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[Super- and subscripts in abstract] n-Bu3SiOH was prepared from both n-Bu3SiH and n-Bu3SiCI. Reactions of n-Bu3SiOH with NaH, LiBun, MC15 (M = Ta or Mo) and Cp2MCl2 (Cp = 115-C5H5, M = Ti or Zr) were investigated, in some cases using the base Et3N as a hydrogen chloride acceptor. Na+(QSiPh3r was prepared from the reaction of Ph3SiOH with NaH, but in poor yield. Ph3SiOH was reacted with TaCI5, but the product, if formed at all, was intractable. When Ph3SiOH was reacted with Cp2MC12 (M = Ti or Zr) products were isolated and characterised, viz. [Cp2 TiCl(OSiPh3)]n (n = 1 or 2) and Cp2Zr(OSiPh3)2. Single crystals Cp2Zr(OSiPh3h were studied using X-ray photographic techniques. They crystallise in the monoclinic system with a = 35. 7, b = 10.4, c = 21.1 A, f3 = 97.7 °, V= 7763 A3. A full crystal structure analysis was not possible due to failure of the diffractometer software to locate the monoclinic unit cell determined by photographic methods. Ph3 SiOH was also reacted with Cp 2ZrC12 (Cp = 115-C5Me5) and the product was tentatively assigned to be Cp 2Zr(OSiPh3h as a pure sample could not be obtained. An interesting spirocompound, Ti[OSiPh2(0SiPh2)30h, was prepared from Ph2Si(0Hh and Ti(n-Bu0)4 and the crystal structure determined by X-ray crystallography. It crystallises in the monoclinic system, space group P21/n, a = 13.805(5), b = 27.545(5), c = 23.476(9) A, f3 = 94.41(3) 0 , V= 8901(5) A3, Z = 4, R = 0.0831 for 5528 reflections with Ire/> 2a(Iref).

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Alwaaly, Ahmed Ali Swadi. "Protonation of metal-sulfur complexes : synthetic and mechanistic studies." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2958.

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Nickel and iron are present in certain metalloenzymes (e.g. nitrogenases, hydrogenases and carbon monoxide dehydrogenase) and also in some industrial catalysts (e.g. isomerization and hydrocyanation catalysts) where the substrate transformations also involve reactions with acids. Understanding the protonation of simple nickel and iron complexes is important in establishing the mechanisms of these natural and industrial catalysts, this thesis will focus on kinetic studies of the protonation mechanisms of various nickel and iron complexes. The complexes [Ni(S2CR)(triphos)]BPh4 {R = Me, Et or Bun; triphos = PhP(CH2CH2PPh2)2} and [Ni(S2CC6H4R′-4)(triphos)]BPh4 (R′ = H, Me, Cl or OMe) were synthesised and characterised by spectroscopy, and for R = Et; R′ = Me, H, Cl or OMe the X-ray crystal structures were determined. The crystallography shows that the nickel is trigonal bipyramidal with the dithioate ligand being bidentate and spanning equatorial and axial positions. The protonation reactions of all [Ni(S2CR)(triphos)]+ and [Ni(S2CC6H4R′-4)(triphos)]+ with HCl to form [Ni(HS2CR)(triphos)]+, [Ni(HS2CC6H4R′-4)(triphos)]+ in MeCN have been studied . In all cases the rates of protonation are slow and the rate law is complicated. The kinetics are consistent with two coupled equilibria where initially the HCl binds to a sulfur through hydrogen bonding, and this is followed by intramolecular proton transfer to the sulfur. For the alkyl derivatives the rates of protonation are dependent on the electronic nature of the R group while the affect of the 4-Rʹ-substituent on the aryl derivatives is small. The overall isotope effects for transfer of the proton from HCl to [Ni(S2CR)(triphos)]+ {(KR/1kR/2)H / (KR/1kR/2)D} are all small (0.94 – 0.25). The protonation of each sulfur in [Ni(S2CR)(triphos)]+ (R = Me or Ph) has been explored using molecular mechanics calculations (GAUSSIAN09 package, geometries optimized at the B3LYP/Lanl2dz levels of theory). The calculations indicate that the protonation of the sulfur in the equatorial position results in chelate ring-opening, but protonation of the sulfur in the axial position does not. The calculated pKaRs of the coordinated carboxydithioic acid are rather insensitive to the R-substituent (pKaR = 7.2 – 8.3). The analogous [Ni(O2CR)(triphos)]BPh4 (R = Et or Ph) have also been prepared and studied. The protonation of these complexes is much more rapid than the dithioate 5 analogues and so the kinetics of the protonation reactions were studied with the weak acid lutH+ (lut = 2,6-dimethylpyridine). . The complexes [Ni(OC6H5R-4)(triphos)]BPh4, [Ni(SePh)(triphos)]BPh4 and [Ni(XRʹ)(triphos)]BPh4 (R = H, CH3, Cl or OCH3X = S, R = Et, But or Cy) have been synthesised and characterised. For [Ni(SeC6H5)(triphos)]BPh4 and all [Ni(XRʹ)(triphos)]BPh4 the X-ray crystal structures have been determined. The protonation reactions of all these derivatives have been studied using the weak acid lutH+. The kinetics of the protonation reactions is consistent with an equilibrium mechanism in which the acid initially hydrogen bonds to the O or Se site and then undergoes intramolecular proton transfer. In the reaction of [Ni(SePh)(triphos)]+, the hydrogen bonded intermediate accumulates at high concentrations of lutH+, but for the reactions of [Ni(OC6H4R-4)(triphos)]+ the hydrogen bonded intermediate never attains a sufficient concentration to complicate the kinetics. The reason for the slow and similar rates of protonation of [Ni(XPh)(triphos)]+ (X = O, S or Se) have been studied using DFT calculations which indicate that the slow proton transfer is because of steric interactions between lutH+ and the phenyl group on triphos. [Ni(SRʹ)2(dppe)] (Rʹ = Et, But or Cyh) have been synthesised and characterised using spectroscopy. The kinetics of the protonation reactions of all the derivatives with lutH+ in MeCN is described. The rate law is complicated and the kinetics is consistent with two coupled equilibria where firstly the acid hydrogen bonds to sulfur and this is followed by intramolecular proton transfer to the sulfur. In the last section of this thesis, the substitution reactions of two types of Fe-S-based clusters [Fe4S4(OR)4]2- and[{MoFe3S4(OPh)3}2(-SPh)3]3- have been studied with PhS- in the presence of NHEt3+. The clusters were characterised using 1H NMR spectroscopy. The kinetics of the reactions of the clusters with PhS- is consistent with a mechanism involving an initial rapid protonation step followed by the dissociation of phenoxide in the rate-limiting step. The mechanistic interpretations of these results are discussed in the light of studies on other Fe-S-based clusters and recent DFT calculations which suggest there is an elongation of a Fe-S bond after protonation.

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Davies, Ian Wain. "Stereochemical and synthetic studies on transition metal-catalysed cyclisations." Thesis, University of Bath, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306358.

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MUZZI, BEATRICE. "Investigation of synthetic strategies for enhancing the energy product of spinel ferrite nanoparticles." Doctoral thesis, Università di Siena, 2021. http://hdl.handle.net/11365/1126979.

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This work was focused on the development of synthesis strategies for enhancing the energy product of spinel ferrite nanoparticles. The final goal was that of finding the best conditions to realize novel materials with improved magnetic properties, which could be used as building blocks for the realization of rare earth free - permanent magnet with higher energy products than commercial ferrites (i.e. strontium ferrite). To this aim, we focused on quasi-zero-dimensional magnetic materials and as possible strategies to enhance their performances we explored the coupling at the nanoscale with magnetic components endowed with complementary properties, and the modification of the intrinsic core properties by solvent mediated post-synthetic treatment. In the first part of this work, hybrid nanocomposite magnets were designed, where the effective exchange-coupling through the interface between hard and soft magnetic constituents or between AFM and a F(i)M phases is exploited to increase the energy product of the material. In particular, metal/ferrite nano-heterostructures, NHSs, were synthesized by an optimized one-pot thermal decomposition method, which allowed us to tune the composition of the final product by tuning the synthetic parameters. The best NHSs obtained by this approach had energy product of 19 kJm-3, higher than that of the commercial hexagonal ferrite. With the aim of developing a system able to display exchange bias at room temperature, iron oxide AFM|FiM core|shell (CS) NPs doped with two divalent cations (Co(II) and Ni(II)) were also synthetized. The co-doping with cobalt and nickel revealed to be a good compromise for obtaining nanocrystals stable to further oxidation processes, and with increased anisotropy, bias and Néel temperature (260 K) than the standard CS iron oxide NPs. The second part of the thesis was devoted to the improvement of the magnetic performances of the prepared CS AFM|F(i)M hybrid NPs and of standard cobalt ferrites NPs, by solvent mediated post-synthesis treatments. In the first case a mild oxidation of the Fe0.95O|Fe3O4, Co0.3Fe0.7O|Co0.8Fe2.2O4 and Ni0.17Co0.21Fe0.62O|Ni0.4Co0.3Fe2.3O4 CS NPs was realized by solvent mediated annealing in the presence of air, with the aim of investigating the role of the nature of the divalent ions on the structure and room temperature magnetic behaviour of the oxidized product. The Ni(II) and Co(II) amount during the oxidation process was found to play a crucial role in the formation of crystalline antiphase boundaries, leading to a mosaic texturing of the spinel structure in the NPs, characterized by enhanced exchange bias and high field magnetization with respect to the standard AFM|F(i)M NPs. The second investigated approach was the solvent mediated annealing treatment of standard cobalt ferrites NPs. This approach has proven to be an excellent strategy for increasing of the 48 % the BHmax value of the material thanks to the reduction of the lattice microstrain generated during the crystallites’ growth. The presented results provide indications on the validity of the proposed approaches. A further investigation is required to obtain materials characterized by exchange effect at room temperatures through a synthesis that can be carried out on a large scale.

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Fogg, Andrew Michael. "Structural, kinetic and synthetic studies of intercalation compounds." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297906.

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Prangige, Erandi Sakunthala Peiris. "Product selectivity control in synthetic organic reactions by metal nanoparticle photocatalysis." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/132075/1/Erandi_Prangige_Thesis.pdf.

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In this thesis, an in-depth study on alloying effect of non-plasmonic metals with gold nanoparticles to selectively control product formation under light and dark conditions was done. Overall, it was demonstrated that fine tuning the alloying effect could enhance product selectivity switch. This may open up a new research pathway for many important organic syntheses.

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McAslan, Ewan Blyth. "Synthetic, structural and spectroscopic studies on some platinum group metal complexes." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/28560.

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Westbrook, Georgina. "Synthetic and electrochemical studies of novel transition metal and lanthanide complexes." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436811.

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Crossley, John Gordon. "Synthetic and structural studies of stacked square planar transition metal complexes." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317920.

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Page, Nicola Alison. "Synthetic and structural studies of transition metal organometallic complexes and polymers." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627581.

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Nogueira, Helena Isabel Seguro. "Synthetic, spectroscopic and catalytic studies on transition metal complexes with oxygen." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244195.

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Johnston, Karl Anthony Andrew. "Experimental and theoretical studies of transition metal impurities in synthetic diamond." Thesis, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392528.

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This thesis is concerned with the properties of transition metals in High Pressure High Temperature synthetic diamond. They have been studied using the following techniques: optical and electron paramagnetic resonance spectroscopies, and a local density approximation code to model various defect centres. Experimental studies of recently-discovered lines, attributed to Co-N complexes in diamond, are presented. Under uniaxial stress, it is found that a zero-phonon line at 2.367 eV has its optical transition from an E- to A_1-ground state at a defect with trigonal symmetry. Another line at 2.135 eV arises at a defect with monoclinic I symmetry. EPR work has revealed the first Co-related EPR centre - O4. This has monoclinic I symmetry, and, because of hyperfine interaction that results in a broadening of the spectral features, it is concluded that nitrogen is also present. Next, cobalt in diamond has been modelled. Using the ab-initio local density code, AIMPRO, many different cobalt-related structures in diamond have been examined, ranging from the isolated atom to complexes with several nitrogens. The empirical model developed by Ludwig and Woodbury is useful in describing these defects. The defects that have been studied experimentally have also been modelled theoretically. For the 2.367 eV system, a Co-N complex with spin zero has been found to be the most likely candidate for the defect centre. Finally, some optical and modelling work have been combined on nickel-nitrogen complexes in diamond. The S2 and S3 luminescence systems are present in natural and synthetic diamond and have been tentatively correlated with the EPR NE3/2 defect systems. Uniaxial stress results indicate that the centres are of low symmetry - typically triclinic. This agrees with the EPR work. Some complementary modelling investigating these systems further supports these results. The thesis is concluded with some discussions and suggestions for further work.

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27

Nakano, Koji. "Synthetic studies on metal-catalyzed carbonation and carbonylation reactions of epoxides." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144859.

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Kyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第11664号
論工博第3856号
新制||工||1352(附属図書館)
23477
UT51-2005-D582
京都大学大学院工学研究科材料化学専攻
(主査)教授檜山爲次郎, 教授大嶌幸一郎, 教授中條善樹
学位規則第4条第2項該当

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28

Fluch, Ulrike [Verfasser]. "Noble Metal Nanoparticles and their Application in Electrochemical Studies / Ulrike Fluch." München : Verlag Dr. Hut, 2014. http://d-nb.info/1060587920/34.

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29

Lawlor, Fiona Jayne. "Synthetic and structural studies involving the elements boron, antimony and bismuth." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320603.

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30

Fisher, George Ayrton. "Synthetic and catalytic studies of organo and organo transition metal bismouth compounds." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357646.

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31

Badahdah, Khadija Omer. "Studies of quinone monooximes and of their metal complexes and synthetic applications." Thesis, London Metropolitan University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300686.

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32

Moss, I. "Synthetic and spectroscopic studies on transition metal complexes of sulphur-containing ligands." Thesis, University of Exeter, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374940.

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33

Jones, A. G. "Synthetic, structural and catalytic studies of metal carbonyl clusters of Group VIII." Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374567.

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34

Cook, S. L. "Structural and synthetic studies on homo- and heterogeneous transition metal carbonyl cluster." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303890.

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35

Angeloni, Alessandro. "Synthetic studies of hydrogen bonding in crystal structures of metal chloride complexes." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399876.

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36

Williams, I. D. "Structural and synthetic studies of transition metal complexes with unsaturated organic ligands." Thesis, University of Bristol, 1985. http://hdl.handle.net/1983/7447913d-4afc-419a-ac89-d8de8e14c77e.

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37

Li, Zheng. "Structural Studies of Natural and Synthetic Macromolecules Stabilized by Metal Ion Binding." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1295646060.

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38

Nelson, Janet E. Bercaw John E. Bercaw John E. "Synthetic, structural, and mechanistic studies in early transition metal and actinide chemistry /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-07192007-074200.

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39

Machell, Jonathan Charles. "Structural and synthetic studies of compounds containing tin and the noble metals." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253417.

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40

Hegde, V. R. "Development of homogeneous and heterogeneous transition metal based catalytic organic synthetic methodologies and synthetic studies towards bioactive molecules." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1996. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2910.

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41

Clarkson, Lucy Mary. "Synthetic and structural studies in organotransition metal complexes of gallium, indium and thallium." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315678.

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42

Poole, Mark Charles. "Synthetic and spectroscopic studies of organic sulphides, sulphoxides, sulphones, and their metal complexes." Thesis, University of Exeter, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332281.

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43

Che, Lah Nurul Akmal. "Conductivity studies of the size-induced metal-insulator transition (SIMIT) in silver nanoparticles." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:a2337bd5-0502-4bc0-a565-971e0fa8f6fc.

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In his tenth decade, Professor Sir Nevill Mott, in a letter to Professor Peter P. Edwards, reminiscenced about the fundamental difference between metals and non-metals; thus he wrote of the situation at the absolute zero of temperature (T = 0 K) '... there a metal conducts, and a non-metal doesn't'. This simple but amazingly powerful commentary stands as a powerful abiding description of the challenge of the fascinating question as to what makes a metal conduct. Many years of experimental studies of metals and nonmetals, targeted at the experimental verification in divided-metal systems ranging from transition mesoscopic metal compounds to microscopic colloidal metals, the occurrence of the electronic transition between these two canonical states of matter have always an enduring fascination where the possibility of a Size-Induced Metal-Insulator Transition (SIMIT) within a small particle of a bulk metal is accessed. In contrast to the situation of a discontinuous Metal-to-Insulator Transition (MIT) in macroscopic systems containing huge numbers of interacting particles and electrons (i.e. a doped semiconductor), the onset of the SIMIT in a single, isolated microscopic particle of a metallic element of the Periodic Table is expected to be a continuous metal-insulator transition. Here, we report an experimental study on the microwave electrical conductivity across the possible SIMIT in particles of the most conductive of all metals in Periodic Table - silver (Ag). Particular emphasis has been placed on the development and application of a non-intrusive microwave measurement technique, taken across a broad range microwave frequencies. The aim is to look for, and interrogate the nature of the SIMIT in such ultra-fine Ag particles. We have attempted to develop a coherent description of the different dielectric responses that yield electrical conductivity over a wide range of mesoscopic and microscopic Ag particles, from which the SIMIT is identified and rationalised. We find that, at 294 K, the mesoscopic Ag particles approximately 5 nm exhibit an 'effective' microwave conductivities which is reduced by some two orders-of-magnitude below that of bulk metallic Ag.

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44

Teng, Die. "Computational studies of transition metal nanoclusters on metal-supported graphene moiré." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51830.

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The graphene moiré superstructure formed on Ru(0001) (g/Ru(0001)) has shown the potential as a template to self-assemble super-lattices of metal nanoparticles as model catalysts. To explore the possibility of rational catalyst design on g/Ru(0001), detailed density functional theory (DFT) calculations have been performed to investigate the adsorption and diffusion of Rh and Au adatoms on g/Ru(0001). The consequences of different hopping rates for cluster nucleation have been explored by performing Monte Carlo-based statistical analysis, which suggests that diffusing species other than adatoms need to be taken into account to develop an accurate description of cluster nucleation and growth on this surface. DFT calculations have also been carried out to investigate the adsorption and diffusion of 18 4d (Y-Ag) and 5d (La-Au) transition metal adatoms on g/Ru(0001). Given the necessity to study larger diffusing species than adatoms, DFT calculations have been performed to study the adsorption and diffusion of Rh and Au dimers and trimers on g/Ru(0001). It was shown that the mobility of Rh clusters decreases with the increase of cluster size, while for Au, dimers diffuse faster than monomers and trimers on the moiré surface. We then used a genetic algorithm combined with DFT calculations to predict the lowest energy structure of a Au8 cluster on g/Ru(0001). Our prediction leads us to propose that Au clusters aggregates through Oswald ripening with Au dimer being the major diffusing species. Finally, we examined the morphology of a Cu19 cluster on g/Cu(111) using MD simulations with COMB3 potential. We also studied the mobility of Cu clusters on g/Cu(111) at elevated temperatures. The analysis suggests that g/Cu(111) may not be a suitable substrate for the formation and growth of isolated Cu clusters. All these calculation results have provided us a better understanding and useful insights into the nucleation and growth mechanism of metal clusters on graphene moiré.

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Wood, Barry Alan. "Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants." Thesis, University of Aberdeen, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540437.

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This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic. Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued. The role of PCs in the arsenic translocation system in plants was monitored firstly by statistical analysis, then by monitoring arsenic translocation of L-BSO-poisoned and mutant plants. Whilst protected PC₂ was synthesised in good yield, subsequent isolation of deprotected PC₂ was not achieved via SEC or RP chromatography. Statistical analysis showed that differential transport of iAs(V) and DMA(V) in planta between two plant groups was not due to PC/As(III)-PC speciation difference, but this was far from conclusive. Plants exposed to iAs(V) and the PC synthase inhibitor L-BSO showed increased arsenic translocation with decreasing As(III)-PC levels, but the trend was not statistically significant. Analysis of Arabidopsis thaliana mutants with differing PC levels confirmed that arsenic translocation increased with reduced PC and As(III)-PC complex levels. HR-ICP-MS quantified unbound PC species on m/z 32 (S⁺), whilst HR-ESI-MS identified the (GS)₃-As(III) complex for the first time in vivo. Whilst significant levels of iAs(III) and PC₂ exist within seaweeds, no As(III)-PC complex formation was observed. This indicates a transient role, if any, for PCs during the in vivo detoxification of arsenic within seaweeds. The development of a thiol tag based upon a polybrominated-pyrrole moiety was unsuccessful, owing to the greater-than-anticipated complexity of the chemistry exhibited by pyrrole.

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46

Sumida, Yuto. "Studies on New Synthetic Reactions via sp3C-sp3C Bond Cleavage under Transition Metal Catalysis." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120875.

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47

Waikar, Smruti. "Metal complexes of oxygen-, nitrogen-, and sulphur-containing macrocyclic ligands : synthetic and structural studies." Thesis, London Metropolitan University, 1992. http://repository.londonmet.ac.uk/3388/.

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It was at the turn of this century, within the area of co-ordination chemistry that the interdependence of structure and reactivity was first realised. The understanding of interactions between metal and ligand has become more complex progressing from simple unidentate to the more complicated multidentate systems and in some instances, ligand designs have imposed unusual co-ordination geometrics around metal atoms. Such offsets are particularly evident in macrocyclic ligands. Their intrinsic properties as ligands gives them the potential to behave as catalysts, semiconductors and sequestering agents for use in pollution control and hydrometallurgy. In addition, they have impinged on the biomedical field, where they have become likely candidates for therapeutic reagents required for the treatment of metal intoxication, or used as diagnostic agents in the form of radio-labelled macrocycle-conjugated antibodies for better tumor imaging while their specificity and efficacy prove excellent for enzyme modelling. In 1987, achievements in this expanding field culminated in the form of a Nobel prize, awarded to C. J. Pedersen, J. M. Lehn and D. J. Cram and marked the scientific world's recognition of the importance of macrocyclic chemistry. Having briefly outlined the wealth of research associated with macrocyclic ligands currently being undertaken, one aspect is of special interest to this work. The objective of this project has been to design new selective complexing agents for the toxic heavy metal ions cadmium(II), mercury(II) and lead(II). Resulting observations on the properties of such systems should provide a better insight of how and why certain ligands 'discriminate' or appear selectively to complex with only certain metal ions. In addition, the project supplements an ongoing study of related work which forms part of a series within a matrix of similar macrocyclic ligands.

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Carew, Alexander Jon. "Fundamental studies into the catalytic properties of metal-oxide supported gold and copper nanoparticles." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367710.

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Navas, M. P. "Pulsed laser ablation of composite metal nanoparticles: studies on growth, plasmonic sensing and catalysis." Thesis, IIT Delhi, 2017. http://localhost:8080/iit/handle/2074/7229.

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50

Nouar, Farid. "Design, Synthesis and Post-Synthetic Modifications of Functional Metal-Organic Materials." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1725.

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Porous solids are a class of materials of high scientific and technological significance. Indeed, they have the ability to interact with atoms, ions or molecules not only at their surface but also throughout the bulk of the solid. This ability places these materials as a major class involved in many applications such as gas storage and separation, catalysis, drug delivery and sensor technology. Metal-Organic Materials (MOMs) or coordination polymers (CPs) are crystalline compounds constructed from metal ions or clusters and organic components that are linked via coordination bonds to form zero-, one-, two or three-periodic structures. Porous Metal-Organic Materials (MOMs) or Metal-Organic Frameworks (MOFs) are a relatively new class of nanoporous materials that typically possess regular micropores stable upon removal of guests. An extraordinary academic and industrial interests was witnessed over the past two decades and is evidenced by a fantastic grow of these new materials. Indeed, due to a self-assembly process and readily available metals and organic linkers, an almost infinite number of materials can, in principle, be synthesized. However, a rational design is very challenging but not impossible. In theory, MOMs could be designed and synthesized with tuned functionalities toward specific properties that will determine their potential applications. The present research involves the design and synthesis of functional porous Metal-Organic Materials that can be used as platforms for specific studies related to many applications such as for example gas storage and particularly hydrogen storage. In this manuscript, I will discuss the studies performed on existing major Metal-Organic Frameworks, namely Zeolite-like Metal-Organic Frameworks (ZMOFs) that were designed and synthesized in my research group. My research was also focused on the design and the synthesis of new highly porous isoreticular materials based on Metal-Organic Polyhedra (MOP) where desirable functionality and unique features can be introduced in the final material prior and/or after the assembly process. The use of hetero-functional ligands for a rational design toward binary or ternary net will also be discussed in this dissertation.

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Dissertations / Theses on the topic 'Metal Nanoparticles - Synthetic Studies'

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