<p> Three cholic acid derived chelating reagents were synthesized. They were synthesized by the attachment of existing chelating ligands onto the side chain of cholic acid via a spacer chain which connects cholic acid and chelate. The incorporation of the ligands EDTA, DTPA and DHPTA onto suitable cholic acid derivatives was performed to produce the respective cholic acid derivatives: cholic acid -EDTA, cholic acid-DTPA, and cholic acid-DHPTA. The synthesis of a fourth chelating reagent was attempted by attaching HEDTA onto the cholic acid side chain but was unsuccessful . A complete account of the three syntheses and one partial synthesis are outlined in this thesis. </p> / Thesis / Master of Science (MSc)

Coordination compounds involving stable radicals represent a promising avenue toward the design of new magnetic materials. In this respect, a series of new metalverdazyl radical complexes has been prepared and their magnetic properties reported. These systems can be envisioned as model systems designed to help elucidate the fundamental electronic interactions between one paramagnetic metal ion and one verdazyl radical that lead to magnetic exchange. A new chelating verdazyl diradical has also been prepared and fully characterised. The electronic ground state of this diradical species has been established through magnetic and variable temperature electron paramagnetic resonance (VT-EPR) studies. In an effort to expand the metal-radical model systems beyond simple 1:1 metal:radical complexes, this verdazyl diradical was employed as a ligand to prepare a succession of first row transition metal complexes. The magnetic properties of the resulting coordination compounds have been studied in an effort to understand how the nature of the metal-diradical magnetic exchange changes with the metal used. In addition to the wide-spread interest in the magnetic properties of stable organic radicals, there is a growing awareness of the redox properties of this class of compounds. Electrochemical and spectroelectrochemical techniques were utilised to probe the redox properties of a verdazyl diradical and a structurally similar verdazyl monoradical. Coordination compounds involving the redox-inert metal zinc were also prepared and their redox properties investigated. While the addition of zinc to the verdazyl diradical had no significant impact on the magnetic properties of the diradical, there is a distinct difference between the redox properties of the diradical itself and its zinc complex. Coordination to zinc also affected the redox properties of the verdazyl monoradical, although to a lesser extent than what was observed for the diradical. / Graduate / 0485

­^¤åºK­n Chapter 1 A new chelating N,N ligand family incorporating an anilido-phosphinimine donor set has been designed. The ligand1-(NHAr)-2-(PPh2=NAr¡¦)C6H4(iPr[NN]DippH: Ar = 2,6-iPr2-C6H3, Ar¡¦ = 2,6-iPr2-C6H3; iPr [NN]MesH: Ar = 2,6-iPr2-C6H3, Ar¡¦ = 2, 4, 6-Me3C6H2; Me[NN]MesH: 2,6-Me2-C6H3, Ar¡¦ = 2, 4, 6-Me3C6H2) were synthesized via a route of reacting amido phosphine ligands with aryl azides. We observed different behaviors of adding n-BuLi in different solvents. In 31P NMR, we found the changed of chemical shift upon the different Ar¡¦ substituents. When substituent on Nphosphinimine was Dipp, there are larger chemical shift change. Addition of [NN]H to ZnMe2 or ZnEt2 in toluene or Et2O at -35oC generated the monomeric, three-coodinate [NN]ZnR (R = Me, Et)(schem 1), while the metathesis reaction of Zn(OAc)2 with iPr[NN]DippLi(Et2O) in THF at -35oC produced iPr[NN]DippZnOAc. But in the same condition, we made the iPr[NP] iPrLi(DME) produced homoleptic {iPr[NP] iPr}2Zn. All of the complexes were characterized by multinuclear NMR spectroscopy or X-ray crystallography. We used [NN]ZnR catalyzed ring-opening polymerization of £`-Caprolactone . The results of catalysis had good yields in 90 to 100% and narrow PDI around 1.5. But they are not a living polymerization catalysis. Chapter 2 We use {[NP]NiCl}2 catalyzed Kumada reactions of alkyl halide or aryl halide with Grignard reagent. In the result, Used {iPr[NP]iPr}2NiCl catalyzed aryl halide with Grignard reagent is better than other {[NP]}2NiCl, but not good catalyzed alkyl halide with Grignard reagent. We do kinetic studies of benzene C-H bond activation by nickel complexes of amido phosphine ligand. By the result, We can defind the benzene C-H bond activation was association rection.

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This thesis presents investigations related to interactions of chelating ligands (macrocyclic and acyclic) with neutral and ionic species in solution. Following a brief introduction on coordination chemistry, each topic is presented separately in three chapters. In Chapter I, thermodynamic studies on drug cyclodextrin interactions in water and in chloroform at 298.15 K are discussed in relation to the effect of the macrocycle on the transfer of N1-substituted sulphonamides from water to chloroform. It is concluded that the transfer of the drug in this solvent system is thermodynamically more favoured in the absence than in the presence of cyclodextrin. Chapter II concerns thermodynamic aspects on calixarenes and their ester derivatives. As far as calixarenes are concerned, thermodynamic parameters of complexation of tert-butylamine and p-tert-butylcalix[4]arene in benzonitrile suggest that two processes are involved; the formation of the adduct followed by that of an endo-calix complex. The interaction of alkyl-p-tert-butylcalix[4]arene tetraethanoates with alkali-metal cations in acetonitrile and in benzonitrile at 298.15 K was studied by titration calorimetry. The limitation of this technique to derive stability constant data for highly stable complexes led to the development of a double competitive potentiometric method. Thermodynamic data are discussed in terms of the solvation of host, guest and resulting complex in these solvents. Chapter III discusses synthesis, characterisation and acid-base properties of ethylenedinitrilo-N,N1-diacetic-N,N1-bis(1-phenylethylacetamido) acid (edtamba) and ethylenedinitrilo-N,N1-diacetic-N,N'bis(pyridylacetamidoacetamioe)acid (edtapa) This is followed by the thermodynamics of complexation of these ligands with metal cations (Pb(II), Cd(II), Cu(II), Ni(II), Zn(II) and Co(II) in water at 298.15 K. These results show that unlike EDTA, edtamba and edtapa do not interact selectively with these cations as a result of a remarkable enthalpy-entropy compensation effect. Computer programs written during the course of these investigations are appended.

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by Wong Yin Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 105-115). / Abstract also in Chinese. / Title page --- p.i / Acknowledgements --- p.ii / Table of contents --- p.iii / Abbreviations --- p.v / Abstract --- p.vi / 摘要 --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Assay Development for Ciprofloxacin / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- HPLC Assay --- p.24 / Chapter 2.3 --- Microbiological Assay --- p.29 / Chapter 2.4 --- Discussion --- p.30 / Chapter Chapter 3 --- The Effects of Oral Ferrous Sulfate on Pharmacokinetics and Pharmacodynamics of Intravenous Ciprofloxacin / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Materials and Methods --- p.45 / Chapter 3.3 --- Results --- p.49 / Chapter 3.4 --- Discussion --- p.51 / Chapter Chapter 4 --- The Effects of Oral Ferrous Sulfate on Pharmacokinetics and Pharmacodynamics of Oral Ciprofloxacin / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.2 --- Materials and Methods --- p.62 / Chapter 4.3 --- Results --- p.66 / Chapter 4.4 --- Discussion --- p.68 / Chapter Chapter 5 --- Influence of Mineral Rich Traditional Chinese Medicines on the Pharmacokinetics of Oral Ciprofloxacin / Chapter 5.1 --- Introduction --- p.77 / Chapter 5.2 --- Materials and Methods --- p.81 / Chapter 5.3 --- Results --- p.85 / Chapter 5.4 --- Discussion --- p.86 / Chapter Chapter 6 --- General Conclusion --- p.98 / References --- p.105

1. Benzene C-H Activation by Nickel(II) and Platinum(II) Complexes of Chelating Diarylamido Phosphine Ligands We have demonstrated an efficient intermolecular benzene C-H activation process mediated by Ni(II) complexes of ([Me-NP-iPr]Ni(L)(R)(L = Pyridine, 2,4-Lutidine, PMe3) and [iPr-NP-Ph]Ni(PMe3)(R) (R = Me, CH2SiMe3). When Lewis base is PMe3 or substituent is CH2SiMe3 more reactivity is observed. The amido diphosphine complexes [iPr-PNP]PtOTf effectively activate the benzene C-H bond in the presence of an appropriate Lewis base(NEt3 or DABCO). 2. Metal Complexes of Amido Phosphine Ligand Bearing Unsymmetric Donor Atom: Syntheses, Structures and Reactivities A series of [Ph-PNN]Ni(II)R (R = Me, Et, Ph, CH2Ph) complexes containing £]-hydrogen atoms have been prepared and characterizated. We have demonstrated an efficient intermolecular arene C-H activation process mediated by Ni(II) complexes of [Ph-PNN]NiEt at elevated temperature. A series of nickel(II) complexes featuring an unsupported, covalently bound p-donor ligand including anilide, phenolate, thiophenolate and tert-butoxide derivatives have been prepared and characterizated. Novel unsymmetric tridentate ligands (H[R-PNO], R = iPr, Ph) have been prepared and characterized. The reaction of [iPr-PNO]NiCl with Na/Hg in thf or ether at room temperature induced C-O bond activation followed by the generation of {[iPr-PNO]Ni}{[iPr-PNO*]NiMe}. 3. Amido Diphosphine Complexes of Cobalt: Syntheses, Structures and Reactivities A series of paramagnetic divalent cobalt complexes ([R-PNP]CoCl, R = iPr, Cy) supported by tridentate diarylamido phosphine ligands have been prepared and characterized. The diamagnetic monovalent cobalt-dinitrogen complexes ([R-PNP]Co(N2), R = iPr, Cy) are accessible from the reaction of [R-PNP]CoCl with LiHBEt3 in THF solution. The dinitrogen complex [Cy-PNP]Co(N2) reacts in THF with terminal alkynes, HC¡ÝCR, yielding vinylidene complexes ([Cy-PNP]Co=C=C(H)(R), R = Ph, SiMe3). The dinitrogen complex [Cy-PNP]Co(N2) and {[iPr-PNP]Co}2(£g-N2) reacts in THF with diphenylacetylene (PhC¡ÝCPh) yielding p complexes ([R-PNP]Co(h2-PhC¡ÝCPh), R = iPr, Cy). 4. Fluorinated Mono- and Diarylamido Complexes of Lithium and Group 4 Metals The synthesis of bis-ligand Group 4 metal complexes ([iPrAr-NF]2MCl2, M= Zr, Hf) are utilizing [iPrAr-NF]Li and MCl4(THF)2. The alkylation of [iPrAr-NF]2MCl2 with RMgCl (R= Me, iBu, PhCH2, Me3SiCH2) produced a series of group 4 metal complexes ([iPrAr-NF]2MR2, M= Zr, Hf) which are catalyst precursors for olefin polymerization. Deprotonation of H[iPr-NF] and H[Cy-NF] with n-BuLi in ethereal solutions at -35 ¢XC produced the lithium complexes {[iPr-NF]Li(solv)}2 (solv = THF, Et2O) and {[Cy-NF]Li(Et2O)}2, respectively. The metathetical reaction of [iPr-NF]Li(Et2O) with 1/3 equiv TiCl4(THF)2 in toluene solution produced the trianilide titanium complex [iPr-NF]3TiCl. A series of novel fluorinated bidentate (H[Mes-NP-RF], R = iPr, Ph) and tridentate ligands (H2[Mes-NPNF]) have been prepared and characterizated.

Potential arsenic toxicity in different geologic environments is dependent on total arsenic concentration and arsenic bioavailability. It is important to identify the geologic environments that may sequester arsenic because these systems can act as long-term sources for arsenic as well as retard transport and limit toxicity. Bioavailability is defined as the readiness of a compound or element to be taken up by organisms (Gregorich et al., 2001), while potential bioavailability is possible uptake of a compound or element by organisms. The objective of this research is to quantify the potential bioavailability of arsenic in laboratory microcosms and in different geologic environments in the Nueces and San Antonio River Watersheds, Texas, using a chelating resin as an infinite sink. To assess the applicability of chelating resins to estimate potential arsenic bioavailability in the field, iron-loaded DOWEX M4195 resin was used to extract arsenic from solutions and sediments (pond sediment, river sediment, and ephemeral stream sediment). The average percentage of arsenic sorbed from solution was 66% ± 0.16. Competition studies between arsenate, phosphate, and vanadate suggest there is moderate competition, reducing overall arsenic sorption to the resin in the presence of competing ions. Iron-loaded resin was then exposed to sediment samples spiked with increasing amounts of arsenic over 15, 30, 60 and 90 days. Results of the sediment study showed 1) increased arsenic sorption to the resin over time, 2) small variations of potential bioavailable arsenic among geologically different sediments, and 3) evidence of arsenic sequestration. Field devices that housed iron-loaded resin were used to extract potentially bioavailable arsenic from sediment in six different geologic environments (i.e. lake, river, perennial stream, ephemeral stream, pond, and wetland) in the watersheds over a twenty-eight day period. The wetland (15.7 mmol As/g wet resin) and perennial stream sediments (11.0 mmol As/g wet resin) represented the maximal and minimal calculated potential bioavailability, respectively. However, the potentially bioavailable index calculated from mmol As/g wet resin extracted from field environments and mmol As/ g sediment in digested samples showed sequestration would be high in the wetland environment and high bioavailability in the perennial stream and river environments.