Made available in DSpace on 2014-10-09T12:32:25Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:31Z (GMT). No. of bitstreams: 1 03134.pdf: 2064767 bytes, checksum: 2ee561f5c7d60b299f3f1a26c7b85831 (MD5) / Tese(Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The main purpose of this work is to determine the characteristics of the thiourea carrier in human erythrocytes taking into consideration the two parameters of transfer (half-saturation constant and maximum transport rate) and the energy of dissociation of the carrier complex. In the president experiment, the problem has been approached by observing the exit of thiourea, from cells previously equilibrated with thiourea, into a saline medium containing different concentrations of thiourea. The most important advantages of this method are the rapidity of the exit process and the fact that it can be easily measured.

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: A series of di- and mono-substituted acyl(aroyl) thioureas were examined for the extraction and transportation of Au(III). Two-phase metal ion extraction experiments were employed to investigate the extraction behaviour of these ligands. The effect of varying ligand concentration on the extraction trend of these ligands was investigated. The results show that the different substituent groups on the benzoyl ring can affect the extraction pattern of the metal. Furthermore, the alkyl substituents on the thiourea moiety and varying the ligand concentration have an influence on the percentage of metal ion extracted. With the exception of the H2L2(N,N-di-propyl-N'- benzoylthiourea ) ligand the di-alkyl substituted thioureas were more efficient for the metal ion extraction than the mono-alkyl ligands. In almost all the experimental set ups there was reduction of the Au(lIl) to Au(l) and Au(O) but it was more pronounced with HL3 (N,N-di-(2-hydroxyethyl)-N'-benzoylthiourea). Transport experiments were also conducted, the experimental set up for transportation was a concentric type cell involving a 3-phase system - 2 aqueous phases ( source and receiving phase) separated by a chloroform membrane incorporating the ligand. The transport results however only gave a satisfactory result of about 5% of gold transported by the HL1 (N,N-dibutyl-N'-benzoylthiourea). All other ligands attempted resulted in metal ion being present in the organic phase, but no metal ion present in the receiving phase. To help drive the transport of the metal ion to the receiving phase CN-, S203 2- and perchloric acid were incorporated into the receiving phase. The transport results were not enhanced with these substances being present in the aqueous receiving phase. The aqueous source and receiving phases were analyzed by flame atomic absorption spectroscopy (FAAS). Finally the N,N-diethyl-N'-camphanoylthiourea (HL10) ligand and its complex with Au(l) were synthesised. Single crystals of the complex were grown for X-ray crystallography and the crystal and molecular structure of the complex was determined. The complex crystallizes in the monoclinic space group P21. The cell parameters are a = 10.7356(7)A b = 16.3443(11)A c = 10.9268(7)A f3 = 103.1450(10t , and final R-factor of 1.76%. The coordination sphere around Au(l) shows a nearly linear arrangement of sulphur and chloride. / AFRIKAANSE OPSOMMING: In hierdie proefskrif is In aantal mono- en di-gesubstitueerde asiel(ariel) thioureums ondersoek vir die transportasie en ekstraksie van Au(III). Twee-fase metaalioon vloeistof-vloeistof ekstraksie eksperimente is gebruik om die ekstraksie patroon van hierdie ligande te ondersoek. Die effek van verskillende ligand konsentrasies op die ekstraksie neiging van hierdie ligande is ondersoek. Resultate toon dat die verskillende substituente op die benziel ring die ekstraksie patroon van die metaalioon beïnvloed. Verder, is gevind dat die alkiel substituente op die thioureum saam met varierende ligand konsentrasies geensins die metaalioon ekstraksie beïnvloed nie. Met die uitsondering van H2L2 (N,N-dipropiel-N'-benzielthioureum) is die di-alkiel gesubstitueerde ligande meer effektief vir metaalioon ekstraksie in vergelyking met die mono-alkiel ligande. In baie van die eksperimente is In reduksie van Au(llI) na Au(l) en Au(O) gesien en dit is baie duidelik met ligand HL3 (N,N-di(2- hidroksie-etiel)N'-benzielthioureum). Alle waterige fases is ge-analiseer met gebruik van Atoomabsorpsie Spektroskopie (AAS). Transportasie eksperimente is ook uitgevoer met gebruik van In drie-fase selsisteem. Twee waterige fases (bron- en ontvang-fase) is geskei met die chloroform membraan fase wat die ligande bevat. Hierdie eksperimente het net In 5% Au(lll) transportasie getoon met HL1(N,N-dibutiel-N'-benzielthioureum). Daar was geen transportasie van Au(lIl) met enige van die ander ligande. Analise van die twee waterige fases het getoon dat die metaalioon eindelik goed ge-ekstraeer is en is teenwoordig in die membraan fase. Om die transportasie van Au(lIl) aan te spoor, is CN-, s2ol- en perchloorsuur in die ontvang-fase geinkorporeer. Die resultate was geensins beïnvloed nie. N,N-di-etiel-N'-kamfonielthioureum (HL10)ligande en die kompleks daarvan met Au(l) is ook gesintetiseer. Enkel-kristalle van die kompleks is verkry en X-straal kristallografiese analiese is onderneem. Hierdie kompleks kristalliseer in die monokliniese ruimtegroep P21,met a =10.7356(7)Á, b=16.3443(11)Á, c=10.9268(7)Á en ~=103.1450(10t. Die finale R-faktor is 1.76%. Die koordinasie om Au(l) toon In liniêre geometrie met swael en chloor.

by Qi Li. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 192-199). / Acknowledgment --- p.i / Abstract --- p.ii / Table of Contents --- p.iii / Index of Componds --- p.iv / List of Tables --- p.v / List of Figures --- p.vi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- General Survey of Inclusion Chemistry --- p.1 / Chapter 1.2. --- The Importance of Hydrogen Bonds --- p.5 / Chapter 1.3. --- "Classical Inclusion Compounds of Urea, Thiourea and Selenourea" --- p.8 / Chapter 1.4. --- Research Strategy --- p.12 / Chapter 2. --- Description of Crystal Structures --- p.16 / Chapter 2.1. --- Urea-Anion Inclusion Compounds --- p.16 / Chapter 2.1.1. --- Halide complexes --- p.18 / Chapter 2.1.2. --- Bicarbonate complexes --- p.30 / Chapter 2.1.3. --- Allophanate complexes --- p.36 / Chapter 2.1.4. --- Borate and pentaborate complexes --- p.44 / Chapter 2.1.5. --- Complex featuring both host-host and host-guest hydrogen bonding --- p.60 / Chapter 2.1.6. --- Tetraethylammonium and phosphonium chloride complexes --- p.65 / Chapter 2.2. --- Thiourea-Anion Inclusion Compounds --- p.71 / Chapter 2.2.1. --- Halide Complexes --- p.73 / Chapter 2.2.2. --- Bicarbonate Complexes --- p.76 / Chapter 2.2.3. --- Nitrate Complexes --- p.87 / Chapter 2.2.4. --- Formate Complexes --- p.101 / Chapter 2.2.5. --- Acetate Complexes --- p.113 / Chapter 2.2.6. --- Oxalate and Fumarate Complexes --- p.127 / Chapter 2.2.7. --- Unsymmetrical quaternary ammonium ions as guests --- p.138 / Chapter 2.3. --- Selenourea-Anion Inclusion Compounds --- p.152 / Chapter 3. --- Summary and Discussion --- p.161 / Chapter 3.1. --- Structural Features and Relationships --- p.161 / Chapter 3.2. --- Hydrogen Bonding in Urea/Thiourea/Selenourea-Anion Inclusion Compounds --- p.164 / Chapter 3.3. --- Linkage Modes of Urea and Thiourea Molecules --- p.168 / Chapter 3.4. --- Comolecular Aggregates of Urea and Other Host Components --- p.173 / Chapter 3.5. --- Comolecular Aggregates of Thiourea and Other Host Components --- p.175 / Chapter 4. --- Experimental --- p.177 / Chapter 4.1. --- Preparation --- p.177 / Chapter 4.2. --- Crystallography --- p.182 / Chapter 5. --- References --- p.192 / Appendix A: Tables of Atomic coordinates and thermal parameters --- p.200 / Appendix B: Publication Based on Results Reported in This Thesis --- p.243

Contaminants in aqueous environments exist in phases that are sorbed to suspended or colloidal material and that are dissolved in solution. Polymer flocculants can be used to remove suspended or colloidal material along with sorbed contaminants, but they remove little of the dissolved contaminants. In the study presented here, development of polymers to sorb contaminants from aqueous solution during the flocculation process was investigated. Atrazine and phosphate (H₂PO₄ ̄) were chosen as test contaminants. For a given test contaminant, multiple copies of a functional group that interacted with that contaminant were inserted into the polymer backbone of a polyacrylamide flocculant. The functional groups inserted into the polymer structure acted as a trap for the dissolved contaminant. The traps were a cyclic secondary amine that interacted with atrazine, and a thiourea that interacted with phosphate. Modified flocculants with different configurations and densities of trapping groups were made and evaluated for removal of the test contaminants from aqueous suspensions. The suspensions consisted of bentonite or kaolinite in water with a known concentration of a test contaminant. The atrazine source was labeled with ¹⁴C and concentrations were measured using a scintillation counter. The source of phosphate used was NaH₂PO₄ and ion chromatography was used to measure the aqueous concentrations of phosphate. In general, the modified polymer flocculants containing trapping groups removed significantly more atrazine and phosphate from suspension compared to the control polymer flocculants ([alpha] =0.05). While the amount of modified polymers needed to achieve significant removal of the test contaminant were higher than the Environmental Protection Agency limit for concentration of polyacrylamide flocculants in water, it was possible to enhance the polymers sorbtion and removal of contaminants from solution during the flocculation process.

Thesis (Ph.D.)--Michigan State University. Dept. of Chemistry, 2008. / Title from PDF t.p. (viewed on Mar. 27, 2009) Includes bibliographical references (p. 214-219). Also issued in print.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xvii, 289 p. : ill. Includes abstract. Includes bibliographical references.

See Abstract in on Page 9 / Dissertation (MSc (Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

4 ABSTRACT This diploma thesis is focused on the synthesis of new bifunctional thiourea organic catalysts containing a carbohydrate moiety, in particular D-glucose with modification on the primary hydroxyl group. The first part of this diploma thesis describes a modification of synthesis of the known bifunctional thiourea catalyst with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranose and (1R,2R)-diaminocyclohexane. The second part is dedicated to the synthesis of new bifunctional thiourea catalysts with modification of the carbohydrate moiety. We focused on per-O-acetyl-β-D-glucopyranose derivatives with pefluoroalkyl moiety on the primary hydroxyl group. We examined different ways of the preparation of 6-O-perfluoroalkylated glucose derivatives. These perfluoroalkylated carbohydrate compounds were transformed into corresponding glycosyl isothiocyanates. Those derivatives upon treatment of (1R,2R)-diaminocyklohexane or 3,5- bis(trifluormethyl)aniline afforded new bifunctional thiourea organocatalysts.