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1
Hogg, John Kirtley. "Conformation of metal chelates". Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259482.
Testo completo
2
Vohra, A. A. "Nickel chelates as dyes". Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601469.
Testo completoAbstract (sommario):
The chelates of seven commercial disperse dyes with nickel, copper and chromium have been formed in cotton and in nylon 6 fabrics. Exhaustion dyeing was satisfactory on nylon 6 and subsequent treatment in the metal salt solution at optimum pH was followed by steaming. The cotton was pretreated with a urea/melamine precondensate with glyoxal formaldehyde, and a polyethylene glycol. Dye was introduced by vapor-transfer from coated paper. Chelation was achieved in a final step. The hue and brightness, fastness to Light, washing and perspiration were assessed for the dyed fabrics. The nickel complexes were in general found to be slightly better than the chromium and copper complexes. Photodegeration of the fibres was reduced by the presence of the nickel complexes. Average stabilisation of nylon 6 was found to be 43% and that of cotton 23%. It may be possible to use selected nickel chelates as dyes that stabilise photodegradabLe fibres. The amount of nickel reacting with the dyed cotton fabric was determined by employing atomic absorption spectroscopy.
3
Mistry, Jayshree. "Oat phytoalexins and magnesium chelates". Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276204.
Testo completo
4
Smith, Raymond John. "New chelates for protein radiolabelling". Thesis, University of Kent, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357228.
Testo completo
5
Wubs, Harm Jan. "Application of iron chelates in hydrodesulphurisation". [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1994. http://irs.ub.rug.nl/ppn/298191733.
Testo completo
6
Boros, Eszter. "Acyclic chelates for imaging with radiometals". Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/44437.
Testo completoAbstract (sommario):
This thesis investigates acyclic chelates containing pyridine, carboxylate and amino groups and their fast and efficient and stable coordination of the (radio-)metals ⁹⁹mTc, Re, Cu, ⁶⁴Cu, Ga, ⁶⁷/⁶⁸Ga. The radiometals mentioned are all of significant interest for SPECT (single photon emission computed tomography) and PET (positron emission tomography) imaging, two of the most important non-invasive diagnostic tools in the clinic. The design, synthesis, radiolabelling, evaluation of stability, and in vivo investigation are presented for three variably charged, novel, short C₈ chain derivatized chelates for the [M(CO)₃]+ core (M = ⁹⁹mTc or Re). Distinct localization of these small amphiphilic molecules in vivo was studied via biodistribution and imaging and was found to be dependent on the charge of the polar moiety. In an attempt to identify a universal chelate applicable to the [M(CO)₃]+ core and ⁶⁴Cu, the synthesis of the dipin bifunctional chelate system, capable of fast coordination of Cu, its radionuclide ⁶⁴Cu, as well as the [M(CO)₃]+ core (M = ⁹⁹mTc, Re) is described. The versatility of the dipin ligand system is based on its ability to adopt a variety of binding modes, tridentate when protected, tetradentate when deprotected. Based on this small, tetradentate scaffold, a series of acyclic chelates with varying bite angle and denticity were synthesized and screened for their ability to coordinate radioisotopes of Ga and Cu under mild conditions within a short period of time. It was found that the linear N₄O₂ chelate H₂dedpa coordinates ⁶⁷/⁶⁸Ga quantitatively to form [⁶⁷Ga(dedpa)]+ after 10 min at room temperature with exceptional kinetic inertness towards human apo-transferrin. The corresponding ⁶⁴Cu complex maintains inertness against serum proteins within 2 h, but shows 23 % transchelation to serum proteins after 24 h. Both potential small molecule perfusion agents, as well as peptide conjugated versions as applications of the H2dedpa scaffold are reported. Both types of derivatives maintained the labelling and radiolabelled complex
(⁶⁷/⁶⁸Ga and ⁶⁴Cu) stability properties found with the non-derivatized versions, further indicating the H₂dedpa scaffold is a useful platform for the development of clinically applicable radiopharmaceuticals.
7
Mitra, Amitabha. "GROUP 13 CHELATES IN PHOSPHATE DEALKYLATION". UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/293.
Testo completoAbstract (sommario):
A series of mononuclear boron halides of the type LBX2 (LH = N-phenyl-3,5-di-tbutylsalicylaldimine,X = Cl (2), Br (3)) and LBX ( LH2 = N-(2-hydroxyphenyl)-3,5-di-tbutylsalicylaldimine,X = Cl (7), Br (8); LH2 = N-(2-hydroxyethyl)-3,5-di-tbutylsalicylaldimine,X = Cl (9), Br (10); LH2= N-(3-hydroxypropyl)-3,5-di-tbutylsalicylaldimine,X = Cl (11), Br (12)) were synthesized from their borate precursorsLB(OMe)2 (1) (LH = N-phenyl-3,5-di-t-butylsalicylaldimine ) and LB(OMe) (LH2 = N-(2-hydroxyphenyl)-3,5-di-t-butylsalicylaldimine (4), N-(2-hydroxyethyl)-3,5-di-tbutylsalicylaldimine(5), N-(3-hydroxypropyl)-3,5-di-t-butylsalicylaldimine (6)). Theborate precursors, 1, 4 - 6, in turn, were prepared by refluxing the corresponding ligandsLH or LH2 with excess B(OMe)3. The boron halide compounds were air- and moisturesensitiveand compound 7 on hydrolysis gave the oxo-bridged compound 13 thatcontained two seven-membered boron heterocycles. The boron halide compoundsdealkylated trimethyl phosphate in stoichiometric reactions to produce methyl halide andunidentified phosphate materials. Compounds 8 and 12 were found to be the mosteffective dealkylating agents. Compound 8 on reaction with t-butyl diphenyl phosphinateproduced a unique boron phosphinate compound LB(O)OPPh2 (14) containing a terminalphosphinate group. Compounds 1-14 were characterized by 1H, 13C, 11B, 31P NMR, IR,MS, EA and MP. Compounds 5, 6, 11, 12 and 13 were also characterized by singlecrystalX-ray diffraction.The alkane elimination reaction between Salen(tBu)H2 ligands and diethylaluminumbromide was used to prepare the four Salen aluminum bromide compounds,salen(tBu)AlBr (15) (salen = N,N'-ethylenebis(3,5-di-tert-butylsalicylideneimine)),salpen(tBu)AlBr (16) (salpen = N,N'-propylenebis(3,5-di-tert-butylsalicylideneimine)),salben(tBu)AlBr (17) (salben = N,N'-butylenebis(3,5-di-tert-butylsalicylideneimine)) andsalophen(tBu)AlBr (18) (salophen = N,N'-o-phenylenenebis(3,5-di-tertbutylsalicylideneimine)).The compounds contained five-coordinate aluminum either in adistorted square planar or a trigonal bipyramidal environment. The bromide group inthese compounds could be displaced by triphenylphosphine oxide or triphenyl phosphateto produce the six-coordinate cationic aluminum compounds [salen(tBu)Al(Ph3PO)2]Br(19), [salpen(tBu)Al(Ph3PO)2]Br (20), [salophen(tBu)Al(Ph3PO)2]Br (21) and[salophen(tBu)Al{(PhO)3PO}2]Br (22). All the compounds were characterized by 1H,13C, 27Al and 31P NMR, IR, mass spectrometry and melting point. Furthermore,compounds 15, 16, 17, 18, 20, 21 and 22 were structurally characterized by single-crystalX-ray diffraction. Compounds 15, 17 and 18 dealkylated a series of organophosphates instoichiometric reaction by breaking the ester C–O bond. Also, they promoted thedealkylation reaction between trimethyl phosphate and added boron tribromide.Stoichiometric reaction of compound 15 with trimethyl phosphate produced thealuminophosphinate compound salen(tBu)AlOP(O)Ph2 (23). Compound 16 on reactionwith tributyl phosphate produced the aluminophosphate compound[salpen(tBu)AlO]2[(BuO)2PO]2 (24). Compounds 23 and 24 were characterized by singlecrystalX-ray diffraction and spectroscopically.
8
Pornsinlapatip, Pornpun. "Flow-injection solvent extraction of metal chelates". Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284394.
Testo completo
9
de, Witt G. Charmaine. "Biodistribution and biospeciation of samarium-153 chelates". Thesis, de Witt, G. Charmaine (1996) Biodistribution and biospeciation of samarium-153 chelates. PhD thesis, Murdoch University, 1996. https://researchrepository.murdoch.edu.au/id/eprint/51690/.
Testo completoAbstract (sommario):
Tumour localisation and biodistribution of several samarium-153 complexes have been investigated by evaluation of the speciation of these complexes in blood plasma using potentiometric titration data and computer modelling. Furthermore, the results of the simulations have been used to propose explanations of the observed biodistributions.
Tissue distribution studies were used to evaluate the localisation of the samarium-153 complexes of the ligands DTPA, HEDTA, HIDA, BZ, PBH, PIH, NTA, citrate and chloride in C57/6J black mice bearing either melanotic or amelanotic B16 melanomas. The mice were sacrificed at 1, 6, 24 or 48 hours after injection and the tumours and other organs of interest removed and measured for radioactivity against a known standard. Tumour imaging studies were also performed.
Appreciable tumour uptake was achieved with all of the complexes, with the exception of Sm-DTPA although the degree of uptake was less than that of gallium-67 citrate. Visualisation of the tumours after administration of many of the samarium-153 complexes was precluded by a high degree of hepatic localisation. The most favourable images were obtained after administration of 153Sm-HEDTA, with the implanted tumour being visible at all times in images performed from 1 to 48 hours.
In order to further understand the bioinorganic chemistry of samarium in the presence of such chelating agents, the protonation constants of citric acid, HEDTA, EDTMP and salicylic acid, as well as the formation constants of their complexes with samarium(III) and yttrium(III), were measured by potentiometric titration and the data analysed using the ESTA suite of programs. The distribution of these complexes as a function of pH was also calculated.
The results obtained from the potentiometric studies were incorporated in blood plasma modelling using the computer program ECCLES to determine both the relative strengths of the complexes in aqueous solution and their speciation in blood plasma. Simulation results indicate that, in aqueous solution, HEDTA is the strongest of the complexing agents for both samarium(III) and yttrium(III) while citrate is the weakest. The complexes of yttrium(III) appear to be generally weaker than those of samarium(III). The ligand HEDTA is also the most effective complexing agent in vivo.
Computer simulations also indicate that samarium is predominantly complexed as the [SmCit]0 and [SmHEDTA]0 species when administered with citrate and HEDTA, respectively. The formation of these neutral species accounts for the high degree of hepatic localisation observed in the biodistribution studies. In contrast, the major samarium species formed with EDTMP appear to be [SmEDTMP]5- [Sm(EDTMP)H-1]6-. The formation of these charged species would explain why the and complex is excreted almost exclusively via the kidneys.
The major competitive interactions for the complexes of Sm-HEDTA in vivo appear to be those of endogenous ligands for the metal ion. In the case of Sm-EDTMP, however, competition for the ligand by endogenous calcium ions takes precedence. This suggests a possible mechanism for the observed localisation of 153Sm-EDTMP in bone metastases.
10
Eapen, M. J. "Solvent extraction of some transition metal chelates". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1986. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3279.
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11
Tran, Anh My. "Synthesis of bifunctional chelates for potential radiopharmaceutical applications". Thesis, University of Essex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247010.
Testo completo
12
Chapman, Heather Mary. "Polymers containing chelates as optically responsive chemical sensors". Thesis, University of Greenwich, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307164.
Testo completo
13
Kim, Yeong-Joon. "Symmetry of hydrogen bonds, metal chelates, and trithiapentalene /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9835379.
Testo completo
14
Suthers, William G. "Regioselective copper (II) mediated protection of trans diols in D glucopyranosides". Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252231.
Testo completo
15
Piyamongkol, Sirivipa. "The design and synthesis of 3-hydroxypyridin-4-one chelators". Thesis, King's College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368849.
Testo completo
16
Ketterman, Joshua K. "Is Zinc a New Class of Neurotransmitter? A Presynaptic Model". Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1156349584.
Testo completo
17
Werner, Andrew J. "Crocidolite dissolution in the presence of Fe chelators : implications for mineral-induced disease /". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07102009-040306/.
Testo completo
18
Faherty, Cathy. "Removal of heavy metals from wastewater using polyelectrolyte chelates". Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252332.
Testo completo
19
Bryson, Nathan John. "Neutral technetium (V) complexes with N,S-donor chelates". Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14586.
Testo completo
20
Griffin, Rowena. "New bifunctional chelates for use in positron emission tomography". Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/29994.
Testo completoAbstract (sommario):
This project has focussed on synthesising a range of bifunctional chelators (BFCs) for use in nuclear medicine, in particular positron emission tomography (PET). When such BFCs are complexed to a M(III) ion the overall charge on the complex varies between -1 and -3; this is expected to affect the renal clearance and biodistribution of these complexes.;A range of novel BFCs were produced; the synthesis of each requiring the use of new di-ester pendant arms. The BFCs were coupled to a range of moieties, including a patented biologically active peptide designed to locate at the site of angiogenesis, in order to allow the imaging of tumours to take place. The ultimate aim of the project was to couple the biologically active peptide to a tert-butyl deprotected BFC. This was achieved using various methodologies and reagents. The solution behaviour of the corresponding Eu(III) complex was studied. The hydration state of the peptide-coupled BFC was found to be q = 1, with 1 H NMR spectroscopy indicating a 4:1 mixture of square antiprismatic (SAP) : twisted square antiprismatic (TSAP) geometric isomers in solution.;Complexes of Ga(III), Eu(III), Y(III) and In(III) were synthesised with various benzylamine and N-Benzoyl-Gly-Lys coupled and tert-butyl protected BFCs. These were studied by 1H NMR and fluorescence spectroscopy where possible to provide an insight into their solution behaviour. Luminescent lifetime measurements indicated that the hydration state of all Eu(III) complexes was q = 1, indicating an 8-coordinate complex (with respect to ligand) with the ninth site occupied by a water. 1H NMR spectroscopy revealed the predominant geometric isomer in solution to be SAP, usually with a 4 : 1 ratio of SAP:TSAP. Selected benzylamine and N-Benzoly-Gly-Lys coupled BFCs were radiolabelled with 68Ga, using microwave heating for 1 min in order to illustrate their potential use in PET. This proved to be a superior method of radiolabelling on a small scale when compared to conventional heating.
21
Ballard, Beau Jurisson Silvia S. "Synthesis and evaluation of ¹⁰⁵Rhodium (III) complexes of phosphine chelate systems". Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/6693.
Testo completoAbstract (sommario):
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 25, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Silvia Jurisson. Vita. Includes bibliographical references.
22
Selvaranjan, Selvadurai. "Processable molecular lanthanide chelates for organic light emitting diodes (OLEDs)". Thesis, London South Bank University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618667.
Testo completo
23
Warren, Richard L. "Studies on 3-oxo-N-phenylbutanamides and their metal chelates". Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/33977.
Testo completoAbstract (sommario):
Ten compounds of the type CH3.CO.CHR.CO.NH.C6H5 have been prepared where R = -CH3, -C2H5, -n-C3H7, -i-C3H7, -n-C4H9, -i-C4H9, -Cl, -Br, -I and -SCN. Of these, only the -Cl, -Br, -I and - SCN derivatives and the parent compound (R = H) are capable of forming metal chelates, and the reasons for this are discussed. Metal chelates have been prepared with copper (II), iron (III) and chromium (III) ions. Proton nuclear magnetic resonance, infra-red and ultra-violet/visible spectroscopic techniques have been used to study the keto-enol equilibria of the compounds together with solvent and substituent effects and the crystal field spectra of the metal chelates. The decomposition of the compounds and some of the metal chelates have been investigated under the gas phase conditions of the mass spectrometer and under aqueous alkaline conditions. Similarities between the decomposition routes and the effect of the 2-substituent are discussed.
24
Cross, Jason Patrick. "The development of luminescent lanthanide chelates for cellular based assays". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/773020/.
Testo completoAbstract (sommario):
In order for luminescent lanthanide complexes to be used in fluoroimmunoassays, a number of criteria must be adhered to, such as high quantum yield, high stability in aqueous media and insensitivity to the surrounding environment. In this thesis, a number of new ligand systems, designed with regard to achieving novel sensitising ligands of europium and terbium for use in cellular assays are discussed. A new ligand based upon a macrocyclic polyaminocarboxylate incorporating a single bipyridine chromophore and its complexes of europium and terbium are reported. Luminescence properties of both complexes are very good, with the terbium analogue displaying more complex behaviour, which suggest a back energy transfer mechanism from the emissive metal centre to the bipyridine triplet. The development of a different ligand incorporating the bipyridine chromophore as the binding groups based on a macrocyclic backbone are also reported. Simple intramolecular europium and terbium complexes of salicylaldehyde and ohydroxybenzophenone were prepared and their photophysical properties recorded. These chelates showed poor stability in solution which led to the investigation of azacrown appended version of these ligands with the aim to improve stability. Europium chelates of these sensitisers displayed poor emissive properties at room temperature postulated to be due to a ligand to metal charge transfer deactivation mechanism. Finally, with the aim of developing charge neutral, fat-soluble luminescent lanthanide complexes capable of cell loading, donors of mixed pyrido-phenol sensitisers were developed. The luminescent properties were found to be poor for the europium complex due to ligand to metal charge transfer. Terbium complexes of these ligands showed sensitivity towards oxygen and temperature, indicating the presence of back energy transfer from the metal centre to the aryl triplet. Complexes of 8- hydroxyquinoline with europium are also reported.
25
Monzittu, Francesco Matteo. "Main group and transition metal-based chelates for PET applications". Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422231/.
Testo completoAbstract (sommario):
[AlCl3(BnMe2-tacn)] was radiolabelled by Cl/18F halide exchange reactions in the presence of 2.99 mol. equiv. of KF at pH 4 CH3CO2Na buffer solution with addition of 18F-target water, to give [Al18F19F2(BnMe2-tacn)] with RCY up to 24 %. The radio-product was purified through a simple SPE purification protocol in 99 % RCP and it shows excellent stability in 50 % EtOH/PBS solution for >3h. [GaF3(BnMe2-tacn)] can be successfully 18F-radiolabelled using a precursor concentration as low as 27 nM through 18F/19F isotopic exchange reactions, using 18F-target water in a 75 % MeCN/H2O solution, in good RCYs (37 ± 5 %) within 10 minutes. The RCY of the reaction starting with a precursor concentration of 268 nM and 2.68 μM were 66 ± 4 % and 73 ± 4 %, respectively. [Ga18F19F2(BnMe2-tacn)] was purified through an SPE cartridge and formulated in 20 % EtOH/water solution showing a RCP of 99 % at t = 0 which decreases to 77-88 % after 2 h. The effect on the RCP of temperature, pH, addition of ascorbic acid, an excess of Cl− or OH− in solution were investigated. The coordination chemistry of Group 13 metal fluorides towards O-donor ligands was developed. The MF3·3H2O (M = Al, Ga, In) were synthesised and the more readily soluble molecular species [MF3(OH2)2(DMSO)] (M = Al, Ga) were used as synthons for reactions with other ligands. The complexes were characterised by 1H, 19F{1H}, microanalysis and IR spectroscopy. The stability of [GaF3(OH2)2(dmso)] was tested to determine whether it could be used as a radiolabelling precursor. The coordination chemistry of the Group 3, Sc(III), Y(III), and lanthanides, La(III) and Lu(III), trichlorides and trifluorides (Sc only) towards neutral N-donor ligands was developed. The complexes were characterised by 1H, 19F{1H} and 45Sc NMR spectroscopy, as appropriate, together with IR spectroscopy and microanalysis. The crystal structures of [ScCl3(terpy)], [MCl3(terpy)(OH2)] (M = Y, Lu), [YI3(Me3-tacn)]·MeCN, [{YI2(Me3-tacn)}2(μ-O)]·MeCN, [{La(terpy)(OH2)Cl2}2(μ-Cl)2], [ScF2Cl(Me3-tacn)] and [ScF2(Me3-tacn)(μ-F)SnMe3Cl] are reported. The first three examples of scandium fluoride complexes with neutral ligands are reported, [ScF3(BnMe2-tacn)], [ScF3(Me3-tacn)] and [ScF3(terpy)]. These complexes were obtained by halide exchange reactions using the trichloride analogues, by reaction with [Me4N]F or Me3SnF as the fluoride source. The first row transition metal fluorides chemistry with terpy and Me3-tacn was explored in order to identify promising systems for 18F radiolabelling. The complexes [MF3(L)] (M = Cr, Mn, Fe, Co; L = Me3-tacn, terpy) were synthesised and fully characterised by UV-vis and IR spectroscopy, microanalysis, and, for the diamagnetic [CoF3(L)], using 1H, 19F{1H} and 59Co NMR spectroscopy. Single crystal X-ray analyses are reported for [MF3(Me3-tacn)] (M = Mn, Co). Stability tests on [MF3(Me3-tacn)] (M = Cr, Mn, Fe, Co) and [CrF3(terpy)] were performed and the Cl/19F halide exchange reactions using [CrCl3(Me3-tacn)] and [FeCl3(Me3-tacn)] were also carried out with added [Me4N]F. The halide exchange reactions allowed partial Cl/F exchange for the Cr(III) systems, and proved to be successful in forming [FeF3(Me3-tacn)] cleanly.
26
Hindocha, Sheena. "Towards the synthesis of novel chelates for technetium-99m imaging". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/29369.
Testo completoAbstract (sommario):
This thesis details the synthesis of tetradentate ligand systems for use with technetium-99m with a focus on sulphur donors. The synthesis of a series of S4 tetradentate ligands is detailed (Chapter 3). The ligands with general formula Me2PS(CH2)2S(CH2)nS(CH2)2PSMe2 where n = 2-4 (3.1-3.3). The ligands were reacted with technetium-99m, [ReO2(py)4]Cl and [ReOCl3(PPh3)2] unfortunately evidence for complexation was not obtained. In order to gain an understanding of the coordination chemistry of the ligands 3.1-3.3 were successfully complexed to Cu(I), Ag(I) and Pd(II) centres, the compounds and structures are discussed in chapter 3. The synthesis of ligands containing 1-methyl-2H-imidazole-2-thione units, which act as S donors is featured in chapter 4. Challenges met during the synthesis of the S4 and N2S2 ligands are discussed. P2S2 (4.12 and 4.16) ligands were synthesised by the reaction of the imidazole unit with 1,3-propanebis(phenyldihydroxymethylphosphine) dichloride. This led to the subsequent synthesis of an analogous P2O2 (4.17) ligand using 1-ethyl-2H-imidazolin-2-one. The P2S2 and P2O2 chelates were reacted with PdCl2 to produce Palladium(II) complexes. Reactions with [ReOCl3(PPh3)2] were also completed and although pure samples were not isolated, there is evidence that [ReO2L]+ complexes were synthesised. The synthesis of a tetradentate phosphine oxime (P2N2) ligand system is the focus of chapter 5. The synthetic challenges encountered during the proposed synthesis are detailed along with alternative synthetic routes. The synthesis of analogous P2N2 compounds is also reported. Whilst evidence for the target chelate (5.2) was obtained its synthesis could not be fully confirmed.
27
Apicella, Pietro. "Process innovation in the production of chelates for agricultural uses". Doctoral thesis, Universita degli studi di Salerno, 2016. http://hdl.handle.net/10556/2186.
Testo completoAbstract (sommario):
2014 - 2015Analyzing the literature available on the production of iron chelates, it is clear as these extremely diffused products are produced according to processes developed in the second part of last century which involve the enormous use of organic solvents, chlorinated substances and water. Although these processes have been optimized, they are not environmentally sustainable and imply high costs of post processing operations and disposal of dangerous substances. Based on this scenario, it is clear the necessity to develop a production process environmentally friendly, based on the elimination of chlorinated substances and the reduction of organic solvents use... [edited by author]
XIV n.s.
28
Kreisel, Kevin Allen. "Organochromium chemistry with formally neutral, chelating ancillary ligands". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 292 p, 2008. http://proquest.umi.com/pqdweb?did=1456289501&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Testo completo
29
Li, Niya, e 李妮婭. "Meta-analysis of the safety of iron chelating agents". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208520.
Testo completoAbstract (sommario):
Background:
Thalassaemia is a genetic disorder disease, one of the most clinically relevant haemoglobinopathies in paediatric population. It interferes with the synthesis of haemoglobin chain. For the sake of maintaining the serum haemoglobin at a normal level, regular blood cell transfusion is required to the patients with thalassaemia. In general, patients with thalassaemia are often diagnosed at an early age and need to take a life-long iron chelating therapy to prevent the multi-organ failure caused by iron-overload. The safety issue is considered a very importance aspect in the treatment among paediatric population and young people.
In the past decades, numerous randomised controlled trials (RCTs) and meta-analysis regarding the efficacy and safety of iron chelating agents including deferoxamine, deferiprone, deferasirox, in reducing iron accumulation among patients with thalassaemia had been published, yet limited meta-analysis reveal the same issue among paediatric population and young adults. Further evidence and understanding are therefore needed to confirm whether or not the iron chelating agents are safe among young patients with thalassaemia.
Objective:
To conduct a meta-analysis to evaluate the safety of iron chelating agents in paediatric population and young adults with thalassaemia.
Methods:
Literature search was carried out in PubMed, EMBASE, BIOSIS Previews, Science Citation Index Expanded and Cochrane Library databases. This meta-analysis of observational studies was conducted following the PRISMA and MOOSE statements.
Selection Criteria
All prospective uncontrolled cohort studies were eligible to include. Articles were assessed according to the age range of its participants and the quality of the reported adverse effects. All enrolled studies should record countable cases of adverse effects of paediatric population and young patients up to 25 years of age, diagnosed with alpha/beta thalassaemia or sickle cell disease and under the treatment of iron chelating agents.
Data Collection and analysis
Two reviewers independently retrieved the data and conducted the quality assessment for each of the included studies. Agency for healthcare research and quality assessment tool was used to evaluate the general risk of bias, whilst the quality of harms was assessed with the Mcharm question criterions. Meta-analysis was carried out for detecting the entire proportion value of six adverse effects including liver abnormality, renal abnormality, rash, abdominal pain/discomfort, nausea and neutropenia, and the forest plot was generated accordingly. The I2 was estimated to assess the methodological quality of each outcome. Random or fixed model was used for the analysis. The sensitivity analysis was conducted to assess the robust of the result.
Results
A total of 8199 articles were identified in the initial database search. After removal of duplications, update from other sources and exclusion based on the exclusion criteria, 25 full articles were retrieved and 14 uncontrolled cohort studies were included in this review. Eight hundred and fifty-four patients up to 25 years of age were included in the analysis. The general quality of the studies was moderate while the quality of adverse effects was low to moderate. Out of the 14 included studies, nine were under the deferasirox treatment; five for deferiprone therapy. No study included deferoxamine. Most adverse effects were observed among the paediatric patients under deferasirox treatment. The meta-analysis of pooled proportion under deferasirox were 17.23% (95%CI, 8.78-25.68%) for liver abnormality, 11.58% (95%CI, 5.91-17.25%) for renal abnormality, 5.41% (95%CI, 3.23-7.58%) for rash, 11.03% (95%CI, 1.83-20.22%) for abdominal pain/discomfort and 5.77% (95%CI, 1,50-10.03%) for nausea. Only one study reported case of neutropenia in the patients under deferasirox, whereas more cases were recorded within the paediatric patients with deferiprone, estimated proportion of 5.98% (95%CI, 2.79-9.16%). However, the meta-analysis of estimated proportion for liver abnormality in paediatric patients with deferiprone was 10.08% (95%CI, 2.67-17.49%), abdominal pain/discomfort was 4.31% (95%CI, 1.65-6.98%). Only one study reported case of renal abnormality, rash and nausea respectively in the patients with deferasirox, which a meta-analysis could not be conducted.
Conclusions
Among paediatric population and young patients with thalassaemia disease, most drug-related adverse effects were liver injury among patients under both deferasirox and deferiprone. For patients under deferasirox, the proportions of the risk of abdominal pain/discomfort and renal abnormality were in a secondary high-level, whereas the proportions of the risk of rash and nausea were comparatively very low. Few adverse effects were detected among young patients with deferiprone. In addition, the proportion of liver abnormality and abdominal pain/discomfort were lower for deferiprone than deferasirox. Further investigation is needed to assess the safety and efficacy between different dosage of iron chelating agents and the risk of other adverse effects among paediatric population, which are necessary to guide the clinical practice in the treatment of paediatric patients with thalassaemia.published_or_final_version
Pharmacology and Pharmacy
Master
Master of Medical Sciences
30
Buist, David. "The geometry of the bisimidazole chelate ringand [i.e. ring and] its selectivity for the largest metal ions". View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-3/buistd/davidbuist.pdf.
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31
Whetstone, Paul Andrew. "Bifunctional metal chelates as tools for imaging, therapy and biomolecular study /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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32
Morale, Francesca. "Metallomesogens derived from Schiff-base chelates and related co-ordination chemistry". Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269486.
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Gad, A. M. M. "Metal chelates as flame retardants and photostabilisers for some vinyl polymers". Thesis, City University London, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356010.
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Auzeloux, Philippe. "Pharmacomodulation de chelates techneties : application potentielle au diagnostic du melanome malin". Clermont-Ferrand 1, 1998. http://www.theses.fr/1998CLF1MM02.
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35
ADELAERE, BRUNO. "Ligands et chelates issus d'aryl-4 3h-dithiole-1,2 thiones-3". Nantes, 1989. http://www.theses.fr/1989NANT2066.
Testo completoAbstract (sommario):
La polycondensation de diols, de diacides et d'un chelate de ligand s,n-tetradentes bifonctionnalise, permet d'obtenir un heteropolymere de type resine polyester insature comportant dans sa structure intime, un chelate metallique. La preparation des metaux chelates presentant des extremites susceptibles d'etre copolymerisees, a necessite la fonctionnalisation en para du noyau aromatique d'aryl-4 3h-dithiole-1,2 thiones-3, produits de depart de la synthese. L'action des monoamines primaires et secondaires, et des diamines primaires, sur les sels de dithiolylium prepares a partir d'aryl-4 3h-dithiole-1,2 thiones-3, conduit a des ligands heterodieniques de type -aminopropenethials et -aminopropenedithioates. La complexation de metaux (ii) par les ligands s,n-tetradentes derivant de l'ethylenediamine et de l'o-phenylenediamine, donne des chelates metalliques
36
Osinski, Allen Jordan. "Re(CO)3 Template Formation of Diiminoisoindoline Based Chelates". University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522967085282879.
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Resetar, Lorri. "Characterization of chromophoric dissolved organic matter with iron chelates in rain water /". Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/resetarl/lorriresetar.html.
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Habarurema, Gratien. "Rhenium complexes with multidentate imine-, amine-, thione-, thiol-, hydroxy- and carboxamide chelates". Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/12679.
Testo completoAbstract (sommario):
This study entails the synthesis, spectroscopic and structural characterization of new rhenium complexes with multidentate imine-, amine-, thione-, thiol-, hydroxy- and carboxamide chelates in various oxidation states. Rhenium(I) and (V) complexes with imidazolidine, pyrimidine and bridging pyridyl derivatives are reported in Chapter 3. The reactions of the potential tridentate N,N,Odonor ligand 2,2'-dipyridylketone (dpk) with trans-[ReOCl3(PPh3)2], (n-Bu4N)[ReOCl4] and trans-[ReOI2(OEt)(PPh3)2] led to the isolation of cis-[ReOCl2(edpm)], cis-[ReOCl2(dpk.OH)] and [ReO3(dpk.OH)] respectively (see Scheme 1). The reaction of (E)-N-((pyridine-2-yl)methylene)benzo[d]thiazol-2-amine (pbt) with trans- [ReOCl3(PPh3)2] produced a mononuclear oxorhenium(V) complex cis- [ReOCl2(epm)(PPh3)]. Both dpk and pbt exhibited a nucleophilic attack by acetonitrile (for Hedpm), water (for dpk) and ethanol (for pbt) leading to chelates that act as uninegative tridentate N,N,O- and bidentate N,O-donor chelates respectively. The reaction of [Re(CO)5Cl] with 2,3-dihydro-2,2-di(pyridin-2-yl)-1H-benzo[d]imidazole (H2dpb), (2,6-diaza-cyclohex-1-enylolonium)2-aza-benzoate (H2den) and 2-(2-(pyridine-2-yl)imidazolidin-2-yl)pyridine (H2pip) (see Scheme 1) gave rise to novel rhenium(I) complexes fac-[Re(CO)3(H2dmb)Cl], fac-[Re(CO)3(Hhdm)] and fac-[Re(CO)3(H2pip)]Cl respectively. The monomeric cationic salt fac-[Re(CO)3(H2salbam)]Br and ligand-bridged dimer fac- (μ-H2salet)[Re(CO)3]2 complexes were formed by the reactions of [Re(CO)5X] (X = Br or Cl) with the potentially heptadentate Schiff base 2,2,2-tris (salicylideneimino)- triethylamine (H3salet; Scheme 2) respectively. The reactions of the potentially hexadentate ligands acting as tridentate monoanionic N,N,O- or N,O,O-donor chelates N1-(3-(2-hydroxy enzylideneamino) propylamino) ethyl)benzylidenepropane-1,3-diamine (H2salpd) and N,N -bis(salicylidene) -3,6-dioxa-1,8-diaminooctane (H2saldane) (Scheme 2) with [Re(CO)5Cl] led to the isolation of the mononuclear and dinuclear complexes fac-[Re(CO)3(Hsaldane)] and fac-(μ-salpd)[Re(CO)3]2 respectively. The reactions of [Re(CO)5Cl] with the tetradentate ligands 2-{[2-hydroxy-3-{[(E)-(2- hydroxyphenyl)-methylidene]amino}propyl)imino]methyl}phenol (H2hmp), 6-((6E)- ((3E)-3-((oxocyclohexa-2,4-dienyl)methyleneamino)-2-hydroxypropylimino)methyl)- cyclohexa-2,4-dienone (H2hcd.H2O) zwitterion and 2-((1E)-1-((E)-3-(2-hydoxyphenylmethylideneamino)propylimino)methyl)phenol (H2hdp) (see Scheme 2) resulted in the formation of the neutral fac-[Re(CO)3(Hamp)], fac-[Re(CO)3(Hhetp)] and fac- [Re(CO)3(Happ)] respectively. The treatment of 2-((3-(2-hydroxybenzylamino)-propylamino)methyl)phenol (H2hbp) with [Re(CO)3Cl] and trans-[ReOCl3(PPh3)2] gave the fac-[Re(CO)3(Hhbp)] and (μ-O)[ReO(hbp)]2 complexes. The reactions of the ligands H2hmp, H2hdp and H2hap (see Scheme 2) with trans-[ReOBr3(PPh3)2] and trans-[ReOI2(OEt)(PPh3)2] produced dinuclear oxo-bridged rhenium(V) complexes (μ-O)[ReO(hmp)]2, [(μ-O)[ReO(hdp)]2 and (μ-O)[ReO(hap)]2 respectively. The neutral and anionic binding modes of thiosemicarbazones to the fac-[Re(CO)3]+, cis- [ReO2]+ and trans-[ReO2]+ cores have been investigated in Chapter 6. The reactions of the potentially tridentate ligand 1-{1-(2- hydroxyphenyl)ethylidene}-4- phenylthiosemicarbazide (H2hpt) (see Scheme 3) with [Re(CO)5Cl], cis-[ReO2I(PPh3)2]cand trans-[ReO2(py)4]Cl led to the isolation of the complexes fac-[Re(CO)3(H2hpt)2]Cl, [Re(hipt)(Hipht)(PPh3)] and trans-[ReO(hpt)(Hhpt)] respectively. The X-ray crystal analysis of the complexes show that the ligand H2hpt exhibits decomposition, thiol-enol tautomerism and a thiolate-iminium zwitterionic process, and coordinates in the neutral form via its thione sulfur and nitrogen and anionic through the azo nitrogen, thiolate sulfur and acetophenolic oxygen. A series of nitrogen-heterocyclic amide-, acid-, thiol- and diol-based ligands as well as their related monomeric rhenium(III) and (V) complexes have also been studied (see Chapter 7). The reaction of N-(2-(pyrazine-2-carboxamido)phenyl)pyrazine-2- carboxamide (H2ppc) (Scheme 3) with trans-[ReOBr3(PPh3)2] yielded the complex trans- [ReBr2(Hppca)(PPh3)2]. The reactions of trans-[ReOX3(PPh3)2] (X = Cl, Br) with pyridine-2,6-dicarboxylic acid (H2pda) produced the neutral oxorhenium(V) complexes [ReOX2(epca)(PPh3)]. The treatment of trans-[ReOBr3(PPh3)2] with 2-mercaptopyridine- 3-carboxylic acid (H2mpc) gave rise to the rhenium(III) complex [Re(empc)3(PPh3)]. The reaction of 2,6-bis(hydroxymethyl)pyridine (H2bhp) with trans-[ReOI2(EOt)(PPh3)2], trans-[ReOBr3(PPh3)2] and [Re(CO)5Cl] gave the complexes [ReO(Hbhp)2(PPh3)]I.PPh3, cis-[ReOBr2(Hbhp)(PPh3)] and fac-(μ- O)2[Re(CO)3(Hbhp)]2 respectively. Their X-ray crystal structures indicate that the ligand acts as a bidentate monoanionic N,O-donor chelate leaving a free aliphatic hydroxyl group.
39
Hutchison, Aaron Robert. "THE DESIGN AND SYNTHESIS OF NOVEL CHELATES FOR THE PRECIPITATION OF MERCURY". UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/519.
Testo completoAbstract (sommario):
Mercury has been an element of great industrial importance since early times.This wide utilization of the element has led to pervasive mercury contamination in theglobal environment. Due to mercury's high toxicity, this is a matter of great concern. Anumber of methods, includ ing phytoremediation, filtration, and precipitation/chelation,have been investigated to remove mercury from the environment. Unfortunately, thesemethods are not entirely satisfactory for the in-situ remediation of mercury from aqueousenvironments.The hypothesis of this dissertation is that this can best be accomplished by theaddition of a large and flexible sulfur-based chelate, that will bind mercury in atetracoordinate and presumably tetrahedral environment, to mercury-contaminatedwaters. Although this proved difficult due to the tendency of these ligands to decomposeinto smaller, sulfur-containing rings, the synthesis and characterization of such a chelatewas achieved. Several potential mercury-binding ligands were eventually synthesizedsignificant amounts of mercury (91-100%) from the contaminated solutions, in one caselowering the mercury levels in the water to below the CVAF detection limits. Theresulting solids lost little (andlt;15 ppb) of their mercury during leaching studies.This work demonstrates the use of tetradentate chelates in precipating Hg2+ fromwater to produce stable mercury- ligand precipitates. A calculation for the quantification ofthe geometry of a four-coordinate compound was also developed and applied to aluminum,gallium, and mercury compounds. This calculation could also be applied to the mercurycompounds described in this thesis once X-ray structures become available
40
Jones, R. M. "Kinetics of the reactions of peroxyacids with metal ions, chelates and complexes". Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381880.
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Elshewy, Ahmed. "Alpha hydroxy acid-containing chelates and their homo and hetero metallic complexes". University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563876435270199.
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42
Ndibewu, Peter Papoh. "A commercial process development for plant food formulation using polyprotic acids from natural extracts as chelating agents". Thesis, Nelson Mandela Metropolitan University, 2005. http://hdl.handle.net/10948/153.
Testo completoAbstract (sommario):
The citrus industry is one of South Africa's largest agricultural sectors in terms of export earnings with lemon fruits and juice as a trendsetter due to their high grade quality. According to growers, the Eastern Cape Province of South Africa alone produces an excess of about 10-14,000 tons of lemon juice which is presently of no economic value due to the sour taste and “bitterness”. As a result of this excess and in order to make use of the polyprotic acids naturally occurring in the lemon juice, four fertilizer nutrient mixtures are formulated, using lemon juice as base. From a conceptual scientific approach, characterization (physico-chemical and functional properties determinations) of Eureka Lemon fruit juices were undertaken, followed by smaller scale batch formulation experiments. On the basis that these lemon juice-based fertilizer mixtures are prepared following standard liquid fertilizer formulation guidelines, a field test was conducted to evaluate their potential effectiveness to influence plant growth. A growth chamber testing on tomato plants revealed high growth response (> 99.9 % certainty) potential in two of the semi-organic mixtures formulated while the organic mixture showed a relatively good growth rate as compared to the control (pure tap water). According to statistical analysis (ANOVA) comparison, two of the semi-organic mixtures performed considerably better than the two commercial samples evaluated. Potential benefits profoundly associated with these nutrient mixtures as compared to similar liquid fertilizer products on the market is that most nutrients are chelated and dissolved in solution. Also, the mixtures contain all necessary nutrients including plant growth substances required for healthier plant growth. The most important socioeconomic impact is the value addition to the technology chain in the citrus industry. The use of fluid fertilizers in significant quantities is less than twenty years old. Nevertheless, growth has been so rapid that in South Africa demand for mixed liquid fertilizer has greatly increased from 90 000 tons NPK & blended micronutrients in 1955 to more than 600 000 per annum tons today (Report 41/2003, Department of Minerals and Energy). The liquid fertilizers market is sparsely specialized with major competitors like Omnia, Kynoch and Foskor supplying more than 50 % of the market demand. Amongst the nutrient mixtures formulated, mixture one is an NPK (1-1-2) based nutrient mixture containing both secondary nutrients (0.5 % Mg & 1.0 % Ca) and seven micronutrients (0.1 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co). The composition of this mixture offers the formula a potential to be used as a general purpose (all stages of plant growth) fertilization mixture in view of its balanced composition (containing all essential plant nutrients). Mixture two contains essentially the micronutrients and in higher concentrations (0.3 % Fe, 0.3 % Cu, 0.1 % Zn, 0.2 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co) as compared to mixture one except for boron, molybdenum and cobalt. The concentration of the micronutrients contained in this mixture is adequately high which offers a potential for it to be used in supplementing nutrition in plants with critical micronutrient-deficient symptoms. Mixture three is very similar to mixture two (1.0 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 Mn, 0.05 % B, 0.0005 % Mo and 0.0005 % Co) except that the concentrations of all seven micronutrients are considerably less than those of contained in mixture two. However, the concentration of iron in this mixture is as high as 1.0 %. The mixture has a potential to be used in high iron-deficient situations. Mixture four is an organic formula with relatively low nutrient concentrations (NPK-0.02-0.02-1, 0.27 % Mg, 0.02 % Ca, 0.008 % Fe, 0.26 % Cu, 0.012 % Zn, 0.009 % Mn). Nevertheless, this mixture is appealing for organically grown crops where the use of chemicals is prohibited by standards. These lemon juice-based nutrient mixtures were further characterized and tested for stability and storability over a period of eight weeks. This study revealed no major change in the physical quality (colour, pH and “salt out” effect). The basic formulation methodology is a two-step procedure that involves filtration of the lemon juice to remove membranous materials, mixing at ambient temperature and stabilization of the nutrient mixtures. However, for the organic nutrient formula mix, filtration follows after extraction of nutrients from plant materials using the lemon juice.
43
Qi, Weihong. "Characterization of Biochelators, Membrane Redox Systems, and Quinone Reductases from Wood Degrading Basidiomycetes". Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/QiW2001.pdf.
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Legge, Matthew. "Structural studies of organometallic complexes". Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263821.
Testo completo
45
Nichols, Kristine Ann. "Role of iron in the accumulation of glomalin, an arbuscular mycorrhizal fungal glycoprotein". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1178.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains viii, 85 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
46
Howard, Maury Elizabeth. "Characterization of synthetic biopolymeric chelators for trace metal extraction and recovery /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Benitez, Tenoch. "Salsola kali (tumbleweed) a possible biomonitoring device for the detection of airborne heavy metals /". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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48
Payne, Katherine Marie. "Investigations into the Effects of Water Exchange and the Structure of Lanthanide Chelates". PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/3284.
Testo completoAbstract (sommario):
Lanthanide chelates are effective agents for improving contrast in MR images. Optimizing the relaxation of inner sphere water molecules is a common focus of research in this field. However, the efforts to design an optimal contrast agent have commonly over-looked the relationship of water position and water exchange kinetics. This work explores structural conformation, the impact of very fast water exchange kinetics on hydration, and differing tumbling rates for regioisomers of a number of lanthanide chelates. We have grown crystals of LnDOTMA and obtained structural data by X-ray diffraction that provide a picture of the chelate during water exchange and demonstrate that chelate conformation is associated with water position. We observe increased population of the major isomer with increased water exchange rates in variable temperature 1H NMR studies of HoDOTMA. This suggests that water position and water exchange rates are linked. We therefore recommend that accurate water exchange data be included in the application of the SBM equations when interpreting experimental data. As further support of this recommendation, we measured water exchange kinetics with 17O NMR for the rigid GdNB-DOTMA chelates. These results were used in the fitting of 1H NMRD profiles to establish tumbling parameters. Similar results were also observed in the less rigid GdNB-DOTA, establishing the first identification of regioisomers in these chelates and their biphenyl derivatives. Binding studies of GdBP-DOTA indicate that the side isomer is a more effective agent, but it is the minor species in solution. Our work herein shows that predicting efficacy of contrast agents with SBM equations requires a more complete consideration of chelate hydration (q/r6).
49
Potgieter, Kim Carey. "Complexes of the ReO³⁺/Re(CO)₃cores with multidentate N,O-Donor chelates". Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1225.
Testo completoAbstract (sommario):
This study investigates the coordination modes of multidentate N,O-donor ligands toward the [ReVO]3+ and fac-[ReI(CO)3]+ cores. The reactions of trans-[ReOX3(PPh3)2] (X = Cl, Br) with 4-aminoantipyrine (H2pap) were studied, and the complexes cis-[ReX2(pap)(H2pap)(PPh3)](ReO4) were isolated. The X-ray crystal structures show that both complexes display a distorted octahedral geometry around the central rhenium atom, and are mirror images of each other. The ligand pap is coordinated monodentately through the doubly deprotonated amino nitrogen as an imide, and H2pap acts as a neutral bidentate chelate, with coordination through the neutral amino nitrogen and the ketonic oxygen. The attempted synthesis of the potentially hexadentate Schiff base ligand 1,2-bis(2-{(Z)- [(2-hydroxyphenyl)imido]methyl}phenoxy)benzene from the condensation reaction of 2- (2-((2-aminophenoxy)methyl)benzyloxy)benzenamine and salicylaldehyde produced the zwitterion derivative (H2ono) of 2-{(Z)-[2-(hydroxyphenyl)imino]methyl}phenol. The tridentate Schiff bases (Z)-2-(2-aminobenzylideneamino)phenol (H3onn) and (Z)-2-(2- (methylthio)benzylideneamino)phenol (Hons) were prepared in a similar manner. The reaction of H2ono with trans-[ReOBr3(PPh3)2] surprisingly led to the isolation of the rhenium(III) complex [ReBr(PPh3)2(ono)], in which ono acts as a dianionic tridentate ligand. The reaction of H3onn with trans-[ReOBr3(PPh3)2] produced the imidorhenium(V) complex salt [ReBr(PPh3)2(onn)]Br, in which onn is coordinated as a trianionic tridentate imidoiminophenolate. The reaction of Hons with [Re(CO)5Br] led to the further decomposition of the Hons ligand, and the rhenium(I) product fac- [Re(CO)3(ons)(Hno)] (Hno = 2-aminophenol) was isolated, with ons coordinated as a monoanionic bidentate chelate (with a free SCH3 group), and Hno present as a neutral monodentate ligand with coordination through the amino nitrogen atom. Abstract Nelson Mandela Metropolitan University vi The reactions of the potentially hexadentate ligand N,N’-{ethane-1,2- diylbis[nitrilomethylidenebenzene-1,2-diyl]}bis(2-aminobenzeneimine) (H2ted) with rhenium(V) starting materials resulted in the decomposition of the H2ted molecule to give different coordinated multidentate ligands coordinated to the rhenium(V) centers. In the reaction of H2ted with trans-[ReOBr3(PPh3)2] in ethanol, the highly unusual ‘3+3’ complex cation [Re(tnn)(Htnn)]Br2 was isolated, in which tnn is coordinated as a tridentate imido-imino-amine, and Htnn is present as a tridentate monoanionic amidoimino- amine chelate (H2tnn = N-(2-aminophenylmethylidene)ethane-1,2-diamine). With trans-[ReO2(py)4]Cl as starting material, the neutral complex [ReO(dne)] was found, in which the tetradentate chelate dne acts as a triamido-imine. The reaction of cis- [ReO2I(PPh3)2] with H2ted led to the formation of the monocationic complex salt [ReO(ane)]PF6, with ane acting as a tetradentate dianionic diamidodiimine (H2ane = N,N’-bis[(2-aminophenyl)methylidene] ethane-1,2-diamine). The seven-coordinate rhenium(III) complex cation [Re(dhp)(PPh3)2]+ (H2dhp = 2,6-bis(2- hydroxyphenyliminomethyl)pyridine) was isolated as the iodide salt from the reaction of cis-[ReO2I(PPh3)2] with H2dhp in ethanol and as the perrhenate salt from the reaction of trans-[ReOBr3(PPh3)2] with H2dhp in methanol. Both products result from a disproportionation reaction with perrhenate also being produced in the process. The complex fac-[Re(CO)3(H2dhp)Br] was prepared from [Re(CO)5Br] and H2dhp in toluene, where the H2dhp ligand acts as a neutral bidentate NN-donor chelate. The metal is coordinated to three carbonyl donors in a facial orientation, to a neutral imino nitrogen, a pyridinic nitrogen and a bromide.
50
ABEY, JANE E. "SYNTHESIS, CHARACTERIZATION AND RELAXIVITY OF POLYMERIC GADOLINIUM CHELATES AS POTENTIAL MRI CONTRAST AGENTS". University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1084460201.
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