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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.
51

Structure and bonding in some mono- and bisfluorosulfates

Mailer, Kathleen O'Sullivan January 1970 (has links)
The single crystal X-ray analyses of KSO(3)F and NH(4)SO(3)F are reported. Both are orthorhombic (space group: Pnma) with cell dimensions a =8.62 Å, b =5.84, c = 7.35 and a = 8.97 Å, b = 5.99, c = 7.54 respectively. Two of the anion ligand positions are completely disordered in KSO(3)F (i.e. SO(2)X(2)¯, X = 50% F and 50% O). A hydrogen bond between NH(4)+ and one of the SO(3)F ¯ disordered positions causes that ligand position to be occupied preferentially by oxygen in NH(4)SO(3)F. The laser Raman spectrum of CH(3)C(OH)(2)SO(3)F is determined. The vibrational spectra and SO(3)F¯ dimensions are compared in NK(4)SO(3)Fr KSO(3)F, CH(3)C(OH)(2)SO(3)F, and (CH3)2 Sn(SO3F)2. The SO(3)F¯ dimensions are surprisingly constant with only S-F in (CF3)2Sn(SO3F)2 (in which there is greatest X-OSO(2)F interaction) shorter than in the others. vS-F increases with increasing cation-anion interaction. The vibrational spectra of the fluorosulfates of Li+, Na+ , K+, NH4+, Rb+, Cs+, (CH3)4N+, and (C6H5)4As+ are reported. vS-F increases 108 cm(-1) with polarizing power of the cation (from (C6H5)4As+ to Li+) and vS-O (average) increases in the same series by 35 cm(-1). The preparation and conductivity in HSO(3)F of Sn(SO3F)2 and Pb(SO3F)2 are reported. Both are weaker bases than Ca(SO3F)2. The Mössbauer parameters of Sn(SO3F)2 (ὁ= +4.17 mm/sec, ∆ = 0.73 mm/sec) indicate it is one of the most ionic SnII compounds yet reported. A new preparative route for obtaining M(SO3F)2 {M(OOCC6H5)2 + HSO3F} is reported. The vibrational spectra of the bis-fluorosulfates of Mg(II), Ca(II), Sr(II), Ba(II), Sn(Il), Pb(II), Cu(II), Zn(II), Cd(II), Mn(II), and Hg(II) are reported. vS-O (average) and vS-F cannot be correlated with polarizing power of the cation or M2+ ionization potential but are in all cases higher than for the mono-fluorosulfates. The differences among the spectra are explained in terms of polarizing power of the cation, some multiple bonding to fluorine and different site-symmetries for the SO3 F¯ anion. / Science, Faculty of / Chemistry, Department of / Graduate
52

New access to difluoromethylphosphonate-containing molecules : via a copper-mediated approach / Nouveaux accès à des molécules contenant le motif difluoromethylphosphonate : une approche médiée par le cuivre

Ivanova, Maria 20 October 2017 (has links)
Depuis des décennies, la chimie du fluor est un domaine suscitant un fort intérêt. Bien que de nombreuses méthodologies originales et élégantes aient été développées pour introduire des groupements fluorés variés, le résidu CF2PO(OEt)2 reste encore peu étudié. Cela contraste avec ses propriétés uniques et à hautes valeurs ajoutées. En effet, le motif CF2PO(OEt)2 s'est avéré être un bioisostère métaboliquement stable du groupement phosphate, ce dernier étant particulièrement instable in vivo en comparaison. En conséquence, des approches pour incorporer ce motif au sein de molécules ont été développées bien qu'encore limitées à un nombre restreint de transformations. Dans le cadre de cette thèse, nous souhaitons proposer une méthode générale et directe pour accéder à des molécules contenant le groupement CF2PO(OEt)2. La première partie de cette thèse a été dédiée à l'introduction du motif CF2PO(OEt)2 sur des sels d'iodonium comportant un substituant aryle, heteroaryle, ou dérivés d'alcènes et d'alcynes, mettant en jeu la génération d'une espèce de type CuCF2PO(OEt)2 (Chapitre II). Puis, l'utilité et la généralité de cette transformation a été démontrée lors de la fonctionnalisation de dérivés de type R-X (R = vinyle, allyle et benzyle) ainsi que des disulfures en tant qu'électrophiles. Par ailleurs, une réaction de couplage de type Ullmann réalisée à température ambiante a été étudiée. Finalement, la réactivité divergente de l'espèce CuCF2PO(OEt)2 envers les α-diazoesters, par un simple changement du sel de cuivre, a été examinée (Chapitre III). Cette approche a été étendue par la suite aux dérivés d'α-bromocétones afin d'offrir une voie d'accès aux cétones contenant un motif SCF2PO(OEt)2 en position α (Chapitre IV). / Since several decades, the organofluorine chemistry is a research area of strong interest. While plenty of original and elegant methodologies were developed to introduce various fluorinated groups, the CF2PO(OEt)2 residue was scarcely spotlighted. This contrasts with its unique and highly valuable properties. Indeed, the CF2PO(OEt)2 moiety proved to be a metabolically stable bioisoster of the in vivo unstable phosphate group. As a result, approaches to incorporate this motif onto molecules were developed albeit still restricted to few transformations. In this PhD thesis, we would like to propose a general and straightforward method to access CF2PO(OEt)2-containing molecules. A first part was dedicated to the introduction of the CF2PO(OEt)2 motif on aryl, heteroaryl, vinyl and alkynyl iodonium salts, by generating the CuCF2PO(OEt)2 species (Chapter II). Then, the utility and the generality of this transformation were further demonstrated using R-X (R = vinyl, allyl and benzyl) as well as disulfides as the electrophiles. Besides, a Ullmann-type cross-coupling reaction proceeding at room temperature was also studied. Finally, the divergent reactivity of the CuCF2PO(OEt)2 species toward α-diazoesters, by a simple change of copper salt, was investigated (Chapter III). This approach was then extended to α-bromoketone derivatives to access the a-SCF2PO(OEt)2 ketones (Chapter IV).
53

Fluorinated esters : synthesis and identification

Schaff, Jilla 01 January 1988 (has links)
Reactions of different alcohols with 2-hydroxy - 1- trifluoromethyl -1,2,2-trifluoroethanesulfonic acid sultone were studied. Six new esters were prepared: C6F5OC(O)CF(CF3)SO2F, CH3CH2OC(O)CF(CF3)SO2F, CF3CH2OC(O)CF(CF3)SO2F, (CF3)2CHOC(O)CF(CF3)SO2F, CH2=CHCH20C(O)CF(CF3)SO2F, (CH2OC(O)CF(CF3)SO2F)2. Analytical data, infrared, nmr and mass spectra are presented supporting the proposed structures for these new compounds.
54

The availability of fluorine as measured by its deposition in the tibiae of young growing rabbits.

Triandafillou, Joan Margaret. January 1964 (has links)
No description available.
55

The effects of fluorine on the closure-to-cleavage ratios of 1,4 biradicals /

McConnell, James Russell January 1984 (has links)
No description available.
56

The critical properties of binary systems of certain fluorocompounds with alkanes /

Abd El Hafeez, Nureldayim Mousa January 1970 (has links)
No description available.
57

Catalytic Fluorination of Dichloromethane with Hydrofluoric Acid

Myers, Michael O. 01 January 1977 (has links) (PDF)
The catalytic, vapor-phase fluorination of dichloromethane to chlorofluoromethane with 38% hydrofluoric acid was investigated as a model system for possible direct utilization of hydrofluoric acid in the production of fluorocarbons and chlorofluorocarbons. Catalysts consisting of Cr or Ni supported on alumina and Ni, Cr, Ag, Co, La, Sn, Hg(I), Hg(II), Cu, Fe, Ru, Zn, Na, or Ca supported on activated charcoal were utilized at various reaction temperatures and reactor residence times. Alumina-supported catalysts were found to have low activities for fluorination in comparison to catalysts utilizing anhydrous HF reported in the patent literature. The low activities were attributed to low catalyst surface areas resulting from the fluorination of the catalyst with aqueous HF. Carbon-supported catalysts were found, in general, to promote thermal cracking of the CH2Cl2 feed as well as the fluorination reaction. This thermal cracking was usually sufficiently severe to result in drastically lowered yields of the desired product and low catalyst lifetime due to coking. The greatest selectivities for the desired product, CH2ClF, relative to the difluorinated product, CH2F2, at reasonably high conversions, were obtained with Sn, Cu, or Co fluorides on an activated charcoal support, although overall yields were relatively low due to thermal cracking.
58

Fluorine-18 as a tracer in inorganic and organic syntheses and its application to positron emission tomography.

Chirakal, Raman V. Schrobilgen, Gary J. Unknown Date (has links)
Thesis (Ph.D.)--McMaster University (Canada), 1991. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5707. Supervisor: Gary J. Schrobilgen.
59

The dental implications of fluorine a thesis submitted in partial fulfillment ... Master of Public Health ... /

Bellinger, Willard R. January 1946 (has links)
Thesis (M.P.H.)--University of Michigan, 1946.
60

The dental implications of fluorine a thesis submitted in partial fulfillment ... Master of Public Health ... /

Bellinger, Willard R. January 1946 (has links)
Thesis (M.P.H.)--University of Michigan, 1946.

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