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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Synthesis, radiosynthesis and biological evaluation of novel Re(I) and Tc(I)-metallocarboranes /

Sogbein, Oyebola Olusegun. Valliant, John Fitzmaurice. January 2005 (has links)
Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: John Fitzmaurice Valliant. Includes bibliographical references. Also available online.
32

Synthesis, radiosynthesis and biological evaluation of novel Re(I) and Tc(I)-metallocarboranes /

Sogbein, Oyebola Olusegun. Valliant, John Fitzmaurice. January 2005 (has links)
Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: John Fitzmaurice Valliant. Includes bibliographical references. Also available online.
33

Novel Carborane Derived Semiconducting Thin Films for Neutron Detection and Device Applications

James, Robinson 08 1900 (has links)
Novel carborane (B10C2H12) and aromatic compounds (benzene, pyridine, diaminobenzene) copolymers and composite materials have been fabricated by electron beam induced cross-linking and plasma enhanced chemical vapor deposition (PECVD) respectively. Chemical and electronic structure of these materials were studied using X-ray and ultra-violet photoelectron spectroscopy (XPS and UPS). UPS suggest that the systematic tuning of electronic structure can be achieved by using different aromatic compounds as co-precursors during the deposition. Furthermore, top of valence band is composed of states from the aromatic moieties implying that states near bottom of the conduction band is derived from carborane moieties. Current- voltage (I-V) measurements on the ebeam derived B10C2HX: Diaminobenzene films suggest that these films exhibit enhanced electron hole separation life time. Enhanced electron hole separation and charge transport are critical parameters in designing better neutron voltaic devices. Recently, PECVD composite films of ortho-carborane and pyridine exhibited enhanced neutron detection efficiency even under zero bias compared to the pure ortho-carborane derived films. This enhancement is most likely due to longer electron-hole separation, better charge transport or a combination of both. The studies determining the main factors for the observed enhanced neutron detection are in progress by fabricating composite films of carborane with other aromatic precursors and by altering the plasma deposition conditions. This research will facilitate the development of highly sensitive and cost effective neutron detectors, and has potential applications in spintronics and photo-catalysis.
34

Karboranové strukturní bloky v medicinální chemii / Carborane structural blocks in medicinal chemistry

Nekvinda, Jan January 2018 (has links)
This work deals with carborane and metallacarborane clusters, in terms of their fundamental chemistry and complexation with cyclodextrins, and in the context of emerging pharmacophores applicable in medicinal chemistry. Arguably, the most important part of this work is the preparation of cobalt bis(dicarbollide) sulfamide derivatives. The sulfamido group is attached to the metallacarborane carbon vertex by an alkyl chain that may be modified in its length. This was accomplished by, firstly, the abstraction of the acidic hydrogen, located on the {CH}-vertex from the metallacarborane, by reaction with lithium base, followed by, secondly, reaction with electrophilic agents (PFA, oxirane and oxetane), which leads to a cascade of reactions to give the desired sulfamide derivatives. These compounds were then tested by collaborators in other institutes for in vitro and in vivo activity towards Carbonic Anhydrase IX (CA IX), which is an enzyme associated with tumour growth. In vivo tests on mice have shown that these types of substances are able to effectively reduce tumour size by 30%. The synthetic research continued with the preparation of sulfonamide compounds of the isomers of the carborane series. The reactions began exclusively with propylhydroxy carborane starting materials, which provide optimum...
35

Strukturní studium karboranů s využitím hmotnostní spektrometrie / Structural stury of carboranes by mass spectrometry

Navrátilová, Romana January 2009 (has links)
Boron cluster compounds are substances clearly synthetic, which don't exist outdoors. This group covers boranes, heteroboranes and their derivatives. They are synthesized and examined mostly for their extraordinary structural and bonding properties. Their study also brought many remarkable findings and even allowed practical use of these compounds in science and technology. This thesis is focused on the application of mass spectrometry for the identification of boranes and heteroboranes and on the study of their fragmentation mechanisms using tandem mass spectrometry on spherical ion trap.
36

Samoskládání sloučenin obsahujících borové klastry a jejich spoluskládání s polymery / Self-assembly of boron cluster compounds and their coassembly with polymers

Ďorďovič, Vladimír January 2017 (has links)
This thesis focuses on the self-assembly of the boron cluster compounds and the coassembly of metallacaborane cobalt bis(dicarbollide), COSAN, with hydrophilic polymers. The research was motivated by the discovery of HIV inhibition by COSAN and its conjugates. Therefore, we decided to study in detail the behavior of boron cluster compounds in water. We demonstrated the amphiphilic character of several boranes and carboranes by the study of surface tension and self-assembly despite the absence of classical amphiphilic topology. The behavior of COSAN showed similarities with classical surfactants, such as SDS, whereas the behavior of smaller clusters with high charge density reminded of hydrotropes or chaotropes. Furthermore, we searched for the most suitable carriers of COSAN for drug delivery. Based on the earlier findings that COSAN interacts with both poly(ethylene oxide), PEO, and poly(2-oxazoline), POX, we prepared nanoparticles by mixing COSAN with block copolymers of various types of POX. Comparing linear and star-like block copolymers, we showed that the polymer architecture has a crucial role in the morphology of nanoparticles. In addition, we proved different selectivity of alkaline cations towards PEO and POX, resulting in the different structures of nanoparticles depending on the present...
37

Karboranové strukturní bloky v medicinální chemii / Carborane structural blocks in medicinal chemistry

Nekvinda, Jan January 2018 (has links)
This work deals with carborane and metallacarborane clusters, in terms of their fundamental chemistry and complexation with cyclodextrins, and in the context of emerging pharmacophores applicable in medicinal chemistry. Arguably, the most important part of this work is the preparation of cobalt bis(dicarbollide) sulfamide derivatives. The sulfamido group is attached to the metallacarborane carbon vertex by an alkyl chain that may be modified in its length. This was accomplished by, firstly, the abstraction of the acidic hydrogen, located on the {CH}-vertex from the metallacarborane, by reaction with lithium base, followed by, secondly, reaction with electrophilic agents (PFA, oxirane and oxetane), which leads to a cascade of reactions to give the desired sulfamide derivatives. These compounds were then tested by collaborators in other institutes for in vitro and in vivo activity towards Carbonic Anhydrase IX (CA IX), which is an enzyme associated with tumour growth. In vivo tests on mice have shown that these types of substances are able to effectively reduce tumour size by 30%. The synthetic research continued with the preparation of sulfonamide compounds of the isomers of the carborane series. The reactions began exclusively with propylhydroxy carborane starting materials, which provide optimum...
38

Carborane-Based Analog of Rev-5901 Attenuates Growth of Colon Carcinoma In Vivo

Paskas, Svetlana, Murganic, Blagoje, Kuhnert, Robert, Hey-Hawkins, Evamarie, Mijatovic, Sanja, Maksimovic-Ivanic, Danijela 27 October 2023 (has links)
Lipoxygenases convert polyunsaturated fatty acids into biologically active metabolites such as inflammatory mediators—prostaglandins and leukotrienes. The inhibition of lipoxygenases is increasingly employed in the treatment of cancer. We evaluated the anticancer potential of two novel 5-lipoxygenase inhibitors, named CarbZDNaph and CarbZDChin, which are analogues of the commercially available inhibitor Rev-5901. The in vitro segment of this study was conducted on a mouse colorectal carcinoma cell line—CT26CL25. For an in vivo model, we induced tumors in BALB/c mice by the implantation of CT26CL25 cells, and we treated the animals with potential inhibitors. A 48 h treatment resulted in diminished cell viability. Calculated IC50 values (halfmaximal inhibitory concentrations) were 25 µM, 15 µM and 30 µM for CarbZDNaph, CarbZDChin and Rev-5901, respectively. The detailed analysis of mechanism revealed an induction of caspasedependent apoptosis and autophagy. In the presence of chloroquine, an autophagy inhibitor, we observed an increased mortality of cells, implying a cytoprotective role of autophagy. Our in vivo experiment reports tumor growth attenuation in animals treated with CarbZDChin. Compounds CarbZDNaph and Rev-5901 lacked an in vivo efficacy. The results presented in this study display a strong effect of compound CarbZDChin on malignant cell growth. Having in mind the important role of inflammation in cancer development, these results have a significant impact and are worthy of further evaluation.
39

Syntéza nových karboranových matallakarboranových a strukturní bloků pro vývoj biologicky aktivní látek / Synthesis of new carborane and metallacarborane bulding blocks appliable in design of biologically active compounds

Nekvinda, Jan January 2014 (has links)
Compounds with carboxylic and amidic functions belong to basic structural blocks, which are used for construction of functional molecules in organic, organometallic and also in carborane chemistry. However, considering cobalt bis(dicarbollide)(1-) ion, the synthetic ways to these derivatives have been virtually unknown. A published procedure on lithiation in THF and reaction with CO2 leading to mono- and dicarboxylic acids had failed in our hands. Nevertheless, a detailed revision of the experimental conditions provided finally good yields of mixture of both acids, which could be separated by chromatography and crystallization, and compound of general formulation [(1-HOOC-1,2-C2B9H10)(1',2'-C2B9H10)-3,3'-Co(III)]- and stereoisomeric mixture of [(HOOC)2-(1,2-C2B9H10)2-3,3'-Co(III)]- were characterized for the first time by combination of NMR, MS and HPLC. Also, the carboxylic acid derivatives with methylene and ethylene connectors of the general formula [(1-HOOC-(CH2)n-1,2- C2B9H10)(1',2'-C2B9H10)-3,3'-Co(III)]- were prepared by lithiation of Cs1 in DME at low temperatures followed by reaction with BrCH2COOEt and subsequent hydrolysis of the resulting ester or by oxidation of the respective propylhydroxy derivative. The acids were converted to reactive p-nitrophenyl esters...

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