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1
Stewart, Peter John. "Metal-ligand multiply bonded complexes supported by amidinate ligands". Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243747.
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Maaß, Christian. "Exploring Metal-Ligand Interactions of Pyrrole Based Pincer Ligands". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5E31-1.
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Baylies, Christian John. "Synthesis of multidentate pyridyl-thiazole ligands and ligand recognition studies". Thesis, University of Huddersfield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399824.
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Yamamoto, Izumi. "Structure-function studies of GABA-C receptor ligands". Thesis, The University of Sydney, 2012. https://hdl.handle.net/2123/28927.
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Throughout the central nervous system (CNS), the Cys-loop superfamily of ligand-gated ion channels {LGICs), including nicotinic acetylcholine, serotonin type-3A, strychnine-sensitive glycine and y-aminobutyric acid A/C receptors, play important roles in synaptic transmission by converting chemical signals into electric signals. Designing potent and subtype-selective ligands with therapeutic value requires knowledge about how ligands interact with their binding sites.
y-Aminobutyric acid (GABA) is the predominant inhibitory neurotransmitter in the mammalian CNS and its binding modes at GABA receptors have not been fully elucidated. GABAc receptors consist of p subunits (p1-p3) and they are known to form homomeric receptors. The five subunits are arranged around a central chloride selective ion channel pore. Each subunit contains a large extracellular N-terminal domain, four transmembrane domains {Ml-M4) of which the second (M2) lines the channel pore and a large M3-M4 intracellular loop. The orthosteric binding site is located at the interface between two subunits in the N-terminal domain and the key residues for ligand binding are found at the five discontinuous loops (A-E).
This thesis describes how ligand binding and receptor gating are closely related and explores the effect of receptor conformational changes upon ligand binding. A series of point mutations in the N-terminal domain of the GABAc p1 receptor were created and expressed in Xenopus oocytes. The mutant receptors were then examined using a range of pharmacological tools to probe function which was measured using the two-electrode voltage clamp method.
The GABA binding mode was explored at GABA receptors using the enantiomers of 3-fluoro-y-aminobutyric acid (3F-GABA) and stereoisomers of 2,3-difluoro-4-aminobutyric acids as conformational probes. Both enantiomers of 3FGABA were full agonists, with the R-3F-GABA being approximately 3-fold more potent than 5-3F-GABA at GABAc receptors. In contrast, both enantiomers were partial agonists with similar efficacy and potency at GABAA receptors. These results suggest a different GABA binding mode at GABAc receptors to that found in the related but pharmacologically distinct GABAA receptors. The effect of the different stereoisomers of 2,3-difluoro-4-aminobutyric acids were also examined at GABAA, GABA8 and GABAc receptors. In the study, two enantiomeric GABAc receptor ligands were identified, one of which is an agonist (25,35-2,3-difluoro-4-aminobutyric acid) while the other is an antagonist (2R,3R-2,3-difluoro-4-aminobutyric acid).
4-Amino-3-hydroxybutanoic acid (GABOB) is an endogenous ligand found in the CNS in mammals and a metabolite of GABA. Homology modeling of the GABAc Pi receptor revealed a potential hydrogen (H-bond) interaction between the hydroxyl group of GABOB and threonine 244 (T244) located on loop C of the ligand binding site. Using site-directed mutagenesis, the effect of mutating T244 on the efficacy and pharmacology of GABOB and various ligands were examined. It was found that mutating T244 to amino acids that lacked a hydroxyl group in the side chain produced GABA insensitive receptors. Only by mutating PiT244 to serine (PiT2445) produced a GABA responsive receptor, albeit 39-fold less sensitive to GABA than Pi wild-type. It was also found that this mutation also changed the activity of GABAc receptor partial agonists, muscimol and imidazole-4-acetic acid (I4AA). At the concentrations tested, both muscimol and I4AA antagonized the currents produced by GABA at PiT2445 mutant receptors (Muscimol: PiWild-type, EC50 = 1.4 µM; PiT2445, IC50 = 32.8 µM. I4AA: Pi wild-type, EC50 = 8.6 µM; PiT2445, IC50 = 21.4 µM). This indicates that T244 is predominantly involved in channel gating.
R-(-)-GABOB and 5-(+)-GABOB are full agonists at Pi wild-type receptors. In contrast, R-(-)-GABOB was a weak partial agonist at PiT2445 (lmM activates 26 % of the current produced by GABA ECso versus Pi wild-type, EC50 = 19 µM; lmax 100%), and 5-(+)-GABOB was a competitive antagonist at PiT2445 receptors (Pi wild-type, EC50 = 45 µM versus PiT2445, IC50 = 417.4 µM, Ks = 204 µM). This highlights that the interaction of GABOB with T244 is enantioselective.
In contrast, the potencies of a range of antagonists tested, 3-aminopropyl(methyl)phosphinic acid (3-APMPA), 3-aminopropylphosphonic acid (3-APA), 5- and R-(3-amino-2-hydroxypropyl)methylphosphinic acid (5-(-)-CGP44532 and R-(+)-CGP44533), were not altered. This suggests that T244 is not critical for antagonist binding. Receptor gating is dynamic and this study highlights the role of loop C in agonist-evoked receptor activation, coupling agonist binding to channel gating.
Ligands acting on receptors are considered to induce a conformational change within the ligand-binding site by interacting with specific amino acids. In this study, tyrosine 102 (Y102) located in the GABA binding site of the Pi subunit of the GABAc receptor was mutated to alanine (piY102A), serine (piY102S) and cysteine (piY102C) to assess the role of this amino acid plays on the action of 12 known and 2 novel antagonists. Of the mutated receptors, piY102S was constitutively active providing an opportunity to assess the activity of the antagonists on Pi receptors with a proportion of receptors existing in the open conformational state compared to those existing predominantly in the closed conformational state (pi wild-type, PiY102C and PiY102A).
It was found that the majority of antagonists studied were able to inhibit the constitutive activity displayed by PiY1025, thus displaying inverse agonist activity. The exception was (±)-4-aminocyclopent-1-enecarboxamide ((±)-4-ACPAM) not exhibiting any inverse agonist activity, but acting explicitly on the closed conformational state of Pi receptors.
It was also found that GABA antagonists were more potent at the closed compared to the open conformational states of Pi receptors suggesting that they may act by stabilizing the closed conformational state and thus reducing activation by agonists. Furthermore, of the antagonists tested, Y102 was found to have the greatest influence on the antagonist activity of gabazine (SR-95531) and its analogue (SR-95813).
Our GABAc Pi receptor homology model identified a novel cavity, which extended beyond the GABA binding site. The model predicted phenylalanine 124(F124), one of the residues lining the cavity, was pointing towards the orthosteric binding site. In this study, F124 was mutated to various amino acids and only a modest effect on receptor pharmacology was observed. However, the mutations had a significant effect on the channel deactivation rate ('toeactivation)- This finding suggests that F124 may play a role in channel gating or stabilizing the open conformation of the receptor.
Designing potent selective agents are the key for the further understanding of the physiological roles of GABAc receptors. Gabazine (SR-95531) is a potent GABAA receptor competitive antagonist. In this study, a series of novel gabazine analogues were tested at GABAA and GABAc receptors. Of the compounds studied, (p)-methoxy analogue without the butyric acid side-chain was 20-fold more potent at GABAc over GABAA receptors. As there was no butyric acid side chain, it is suggested that the carboxylic acid is not important for gabazine activity at this receptor. Establishing the structure-activity relationship based on this analogue will facilitate the development of selective GABAc receptor antagonists with possible physiological effects including memory-enhancement.
Overall, our studies describe agonist and GABAc receptor antagonist induced conformational changes within the ligand binding site. Our findings also highlight the dynamic nature of receptor gating, initiated by ligand binding at a site physically distinct from the ion channel.
5
Badarau, Eduard Guillaumet Gérald Fînaru Adriana. "Conception, synthèse et évaluation biologique de nouvelles classes de ligands sérotoninergiques 5-HT7". S. l. : S. l. : Orléans ; Université de Bacau, 2009. http://intranet.univ-orleans.fr/bibliotheques/theses/eduard.badarau_1653.pdf.
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Thèse de doctorat : Chimie et physicochimie des composés d'intérêt biologique : Orléans : 2009. Thèse de doctorat : Chimie et physicochimie des composés d'intérêt biologique : Université de Bacau : 2009.Titre provenant de l'écran-titre.
6
Duraj-Thatte, Anna. "Fluorescent GFP chromophores as potential ligands for various nuclear receptors". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44764.
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Nuclear receptors are ligand activated transcription factors, where upon binding
with small molecule ligands, these proteins are involved in the regulation of gene
expression. To date there are approximately 48 human nuclear receptors known, involved
in multiple biological and cellular processes, ranging from differentiation to maintenance
of homeostasis. Due to their critical role in transcriptional regulation, these receptors are
implicated in several diseases. Currently, 13% of prescribed drugs in the market are NR
ligands for diseases such as cancer, diabetes and osteoporosis. In addition to drug discovery, the mechanism of function, mobility and trafficking of these receptors is poorly understood. Gaining insight into the relationship between the function and /or
dysfunction of these receptors and their mobility will aid in a better understanding of the
role of these receptors.
The green fluorescent protein (GFP) has revolutionized molecular biology by
providing the ability to monitor protein function and structure via fluorescence. The
fluorescence contribution from this biological marker is the chromophore, formed from
the polypeptide backbone of three amino acid residues, buried inside 11-stranded â-barrel
protein. Synthesis of GFP derivatives of is based on the structure of the
arylmethyleneimidazolidinone (AMI), creating a molecule that is only weakly fluorescent.
Characterizing these AMI derivatives for other proteins can provide a powerful
visualization tool for analysis of protein function and structure. This development could
provide a very powerful method for protein analysis in vitro and in vivo.
Development of such fluorescent ligands will prove beneficial for the nuclear
receptors.
In this work, libraries of AMIs derviatives were synthesized by manipulating
various R groups around the core structure, and tested for their ability to serve as nuclear
receptor ligands with the ability to fluoresce upon binding. The fluorogens are developed
for steroidal and non-steroidal receptors, two general classes of nuclear receptors.
Specific AMIs were designed and developed for steroid receptor estrogen receptor á
(ERá). These ligands are showed to activate the receptor with an EC50 of value 3 ìM and the 10-fold activation with AMI 1 and AMI 2 in comparison to the 21-fold activation
observed with natural ERá ligand, 17â-estradiol. These novel ligands were not able to
display the fluorescence upon binding the receptor. However, fluorescence localized in
nucleus was observed in case of another AMI derivative, AMI 10, which does not
activate the receptor. Such ligands open new avenues for developing fluorescent probes
for ERá that do not involve fluorescent conjugates attached to a known ERá ligand core.
AMIs were also characterized for non-steroidal receptors,specifically the pregnane x receptor (PXR) and retinoic acid receptor á (RARá). To date, fluorogens which turn fluorescence upon binding and activate the receptor have not been developed for these receptors. With respect to PXR, several AMI derivatives were discovered to bind and activate this receptor with a fold-activation better than the known agonist, rifampicin. The best characterized AMI derivative, AMI 4, activates the receptor with an EC50 of value 6.3 ìM and the 154-fold activation in comparison to the 90-fold activation and an EC50 value of 1.3 ìM seen with rifamipicin. This ligand is not only able to activate PXR but also displays fluorescence upon binding to the receptor. The fluroscence pattern was observed around the nucleus. Besides AMI 4, 16 other AMI derivatives are identified that activate PXR with different activation profiles. Thus, a novel class of PXR ligands with fluorescence ability has been developed. The AMI derivatives able to bind and activate RAR, also displayed activation profiles that were comparable to the wild-type ligand, all trans retinoic acid. These ligands activated the receptor with an EC50 value of 220 nM with AMI 109 in comparison to an EC50 value of 0.8 nM with the natural ligand for RARá. When these ligands were tested for fluorescence in yeast, the yeast were able to fluoresce only in the presence of the receptor and the AMI derivative, indicating that these agonists also have the ability to fluoresce.
7
Kandala, Srikanth. "Diphosphine Ligand Substitution in H4Ru4(CO)12: X-ray Diffraction Structures and Reactivity Studies of the Diphosphine Substituted Cluster Products". Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5410/.
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The tetraruthenium cluster H4Ru4(CO)12 has been studied for its reactivity with the unsaturated diphosphine ligands (Z)-Ph2PCH=CHPPh2, 4,5-bis (diphenylphosphino)-4-cyclopenten-1,3-dione, bis(diphenyphosphino)benzene and 1,8- bis(diphenyl phosphino)naphthalene under thermal, near-UV photolysis, and Me3NO-assisted activation. All three cluster activation methods promote loss of CO and furnish the anticipated substitution products that possess a chelating diphosphine ligand. Clusters 1, 2, 3 and 4 have been characterized in solution by IR and NMR spectroscopies, and these data are discussed with respect to the crystallographically determined structures for all new cluster compounds. The 31P NMR spectral data and the solid-state structures confirm the presence of a chelating diphosphine ligand in all four new clusters. Sealed NMR tubes containing clusters 1, 2, 3 and 4 were found to be exceeding stable towards near-UV light and temperatures up to ca. 100°C. The surprisingly robust behavior of the new clusters is contrasted with the related cluster Ru3(CO)10(bpcd) that undergoes fragmentation to the donor-acceptor compound Ru2(CO)6(bpcd) and the phosphido-bridged compound Ru2(CO)6 (µ-PPh2)[µ-C=C(PPh2)C(O)CH2C(O)] under mild conditions. The electrochemical properties have been investigated in the case of clusters 1 and 2 by cyclic voltammetry, and the findings are discussed with respect to the reported electrochemical data on the parent cluster H4Ru4(CO)12.
8
Malgas, Rehana. "The application of novel multinuclear catalysts derived from dendrimeric ligands in the polymerization and oligomerization of unsaturated hydrocarbons". Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7858_1183727432.
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G1 and G2 dendrimeric salicylaldimine ligands containing both substituted and unsubstituted aryl rings were synthesized via a Schiff base condensation of the appropriate salicylaldehyde and the peripheral amino groups of the corresponding G1 and G2 polypropyleneimine dendrimers. The new ligands were characterized using FTIR, 1H NMR and 13C NMR spectroscopy, elemental analysis and ESI mass spectrometry. The dendrimeric ligands were converted to multinuclear nickel complexes by reaction with nickelacetate. The metal complexes were characterized by FTIR spectroscopy, elemental analysis and ESI mass spectrometry.
Some of the dendritic complexes were evaluated as catalyst precursors in the oligomerization of &alpha
-olefins such as ethylene and 1-pentene, using aluminium alkyls such as EtAlCl2 and modified methylaluminoxane (MMAO) as activators. All the dendrimeric catalysts evaluated are active in the oligomerization reactions. From the oligomerization results it was observed that there is a clear dendritic effect, in that both catalyst activity as well as selectivity are impacted by the dendrimer generation. In most cases it was observed that the second generation complexes show higher activity than the corresponding first generation complexes.
The dendrimeric complexes were also evaluated as catalyst precursors in the vinyl polymerization of norbornene. In this case methylaluminoxane (MAO) were employed as an activator. Once again it was noted that a dendritic effect is operative, with second generation metallodendrimers having a higher activity than the first generation complexes.
9
Lewis, William. "Chiral Heterocyclic Ligands". Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/1383.
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This thesis describes the preparation and characterisation of a number of homochiral coordination and metallosupramolecular assemblies. These species were formed from the reaction of chiral pyridine and quinoline containing ligands and metal ions. The combination of traditional coordination chemistry and supramolecular interactions led to a range of polymeric and network structures being formed. The ligands used in this thesis can be divided into two broad categories: alkaloids and ligands derived from them, and amino acid-based ligands. In the first category three new ligands were synthesized, and a variety of routes towards alkaloid-based homochiral ligands were investigated. The second category focused on three ligand motifs, and resulted in the preparation of 16 ligands. These two categories of ligands were reacted with a range of metal salts to investigate their coordination and supramolecular chemistry. The structure of twenty complexes was determined by single crystal X-ray crystallography. The complexes had a range of structures, with discrete and polymeric species being formed. Hydrogen bonding was an important feature in the supramolecular chemistry of the complexes, playing a different role in different series of complexes. Two chiral coordination polymers and one chiral coordination network were synthesized. All three of these structures possessed directionality to some degree: in the coordination network and one of the polymers the directionality is counterbalanced by the opposite directionality being present in the crystal, while the second coordination polymer is generated by the screw axis present and has a high degree of overall directionality.
10
Seymour, L. C. "Chiral organometallic ligands". Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279979.
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Runesson, Johan. "Galanin receptor ligands". Licentiate thesis, Stockholms universitet, Institutionen för neurokemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-59743.
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In the nervous system galanin primarily displays a modulatory role. The galaninergic system consists of a number of bioactive peptides with a highly plastic expression pattern and three different receptors. The lack of receptor subtype selective ligands and antibodies have severely hampered the charac-terization of this system. Therefore, most of the knowledge has been drawn from experiments with transgenic animals, which has given some major conclusions, despite the compensatory effects seen in several animal studies. Therefore, the production of subtype selective ligands is of great importance to delineate the galanin system and slowly experimental data from receptor subtype selective ligand trials is emerging. This thesis aims at studying galanin receptor-ligand interactions and to increase and improve the utilized tools in the galanin research field, espe-cially the development of novel galanin receptor subtype selective ligands. Paper I demonstrates the potential to N-terminally extend galanin ana-logues and the successful development of a galanin receptor 2 (GalR2) selec-tive ligand. In addition, a cell line stably expressing galanin receptor 3 (GalR3) was developed, to improve and simplify future evaluations of sub-type selective galanin ligands. Paper II measures the affinities of M617 and M871 to GalR3 and demon-strates that M871 preferentially binds GalR2. Furthermore, the relatively high affinity of M617 was evaluated by assessing the contribution in recep-tor interaction of individual amino acid residues in the C-terminal part of the M617. In conclusion, this thesis has provided a novel design strategy for galanin receptor ligands and increased the understanding of ligand interactions with the GalR3. Furthermore, M1145 has together with new analogues proven to be highly GalR2 specific, holding promises to future delineation of the galaninergic system as a therapeutic target.
12
Bates, George Benjamin. "Tetrahedrally coordinating ligands". Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5123/.
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Selective ligand coordination of zinc over other metals such as copper (II) and iron (III) is desirable and has potential commercial uses in hydrometallurgy. With this in mind ligands have been synthesised that impart a tetrahedral donor array. Binding to zinc which prefers a tetrahedral binding geometry may achieve selectivity over other non-tetrahedrally coordinating metals. Di-N-alkylated bisbenzimidazole-4,4'-dicarboxylic acids have been synthesised and shown by proton NMR, ESMS and IR analysis to bind zinc as an [L(_2)Zn(_2)] species with selectivity over copper, nickel, lead and cadmium. Hence a reversal of the Irving- Williams sequence is observed. Aqueous extraction tests using a lipophilic N-alkylated derivative indicated that the observed selectivity over copper and iron (III) was not reproduced under these experimental conditions. The ligand began to extract in the pH 2.3-3.8 region.2,9-Diphosphinoxymethyl phenanthroline derivatives were synthesised and shown to bind nickel, copper and zinc with similar stability constants, with only marginal enhancement over that of the parent phenanthroline. The 1:1 complexes were produced at acidities below pH 2. Increasing the length of the pendent arm donor groups by using phenylacetic acid moieties did not enhance zinc selectivity. The donor group was not ideal and [ML(_2)] species were generated (i.e. an N(_4) donor set)Two phenol substituted 12N(_3) ligands were synthesised (N-linked and β-C- linked). Complex stability order followed die Irving-Williams sequence Cu > Zn > Ni. The N-linked derivative formed a six membered chelate on binding and had larger metal-ligand stability constants than for the C-linked derivative which formed an eight membered chelate. The N-linked derivative bound the copper (II) cation in a near tetrahedral arrangement and imparted some copper (I) character to the metal
13
Teng, Su Fern. "Immunoglobulins binding ligands". Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627345.
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Gorman, Adam David. "New inorganophosphorus ligands". Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.730904.
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Chai, Jianfang. "Synthesis, structure and reactivity of manganese complexes supported by carbon or nitrogen donor ligands". Doctoral thesis, [S.l. : s.n.], 2004. http://webdoc.sub.gwdg.de/diss/2004/chai/chai.pdf.
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Magqi, Nceba. "Studies towards the development of novel multidentate ligands". Thesis, Rhodes University, 2007. http://eprints.ru.ac.za/867/.
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Proctor, Lavinia M. "Pharmacological activity of C3a and C3a receptor ligands /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18423.pdf.
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Brèque, Anne. "Application en catalyse homogène de ligands phosphole, phosphanorbornadiène et phosphinine dans des réactions d'hydrogénation de dérivés insaturés". Paris 11, 1988. http://www.theses.fr/1988PA112299.
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Les phospholes, les phosphanorbornadiènes et les phosphines sont des hétérocycles phosphorés aujourd'hui aisément accessibles qui présentent par rapport aux phosphanes, couramment utilisés en catalyse homogène des propriétés stériques et électroniques tout à fait particulières. Les activités catalytiques de ces ligands associés à un complexe cationique de Rhodium sont évaluées dans la réaction d'hydrogénation d'un néhydroaminoacide en aminoacide et comparées aux activités obtenues dans les mêmes conditions à partir de systèmes catalytiques de référence. Si les activités des phosphinines restent, dans tous les cas, voisines de celles du catalyseur de Wilkinson, celles des phospholes sont généralement supérieures à l'activité de ce catalyseur. Les phosphanorbornadiènes, quant à eux, donnent dans certains cas des activités très supérieures aux précédentes, voisines de celles du diphosphane de Kagan : la DIOP. Ainsi, le système catalytique phosphanorbornadiénique le plus performant a été testé dans diverses réactions d'hydrogénation de dérivés insaturés. Il révèle notamment dans la réduction de fonctions carbonyle, de dérivés nitrés et aromatiques, un comportement inattendu par rapport aux systèmes homogènes décrits dans la littérature. La dernière phase de ce travail a consisté à l'élaboration de deux voies de synthèses simples conduisant à des phosphanorbornadiènes chiraux dans le but d'étudier leurs applications en hydrogénation asymétrique de substrats prochiraux. Les premiers tests réalisés donnent des excès enantiomeriques voisins de 50% dans l'hydrogénation asymétrique de l'acide à (N-Acétamido) cinnamique-Z.
19
Daubinet, André. "Design, synthesis and evaluation of silver-specific ligands". Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1004966.
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Several series of ligands, designed to chelate silver(I) specifically in the presence of base metals, have been synthesised. The ligands include: - dithiodiamide compounds, prepared by the condensation of acetanilide derivatives with 1,2-dibromoethane; propanenitrile and propanoic ester derivatives prepared from pyridine-2-carbaldehyde via the Morita-Baylis-Hillman reaction; and novel malonamide ligands from the reaction of diethyl malonate with a range of primary amines. The malonamide derivatives were prepared under both conventional thermal and microwave-assisted conditions, the latter proving to be highly efficient. The ligands were all characterised using a combination of spectroscopic and, where appropriate, elemental analysis; in one case, the structural assignment was confirmed by single-crystal X-ray analysis. The fragmentation patterns in the electron-impact mass spectra of the malonamide derivatives have been explored using high-resolution and meta-stable peak scanning techniques. Complexes of the malonamide ligands with copper(II) and silver(I) have been synthesised, and examination of these complexes has revealed distinct differences in their co-ordination preferences towards silver(I) and copper(II). Tentative, computer-modelled structures for the complexes have been proposed using the available spectroscopic and elemental analysis data. Computer modelling, at the Molecular Mechanics level, has also been used to assess the capacity of the ligand systems to adopt conformations suitable for the chelation of tetrahedral silver(I). Solvent extraction studies have been undertaken using aqueous metal ion solutions and various organic solvents. The dithiodiamide derivatives typically presented solubility problems, but one of the ligands, N,N´-bis(3-chlorophenyl)-3,6-dithiaoctanediamide, exhibited significant but slow extraction of silver(I) into toluene. The malonamide derivatives, however, proved to be readily soluble in ethyl acetate and, in some cases, exhibited good to excellent selectivity for silver(I) in the presence of the base metals copper and lead. Atomic absorption analysis revealed rapid equilibration times (<15 min) and high extraction efficiencies over a wide pH range (2.78 - 9.0). Metal selectivity has been determined by ICP-MS analysis of the residual silver, copper and lead present in the aqueous phase after 15 min, and one of the ligands, N,N´-bis(2-benzylsulfanylethyl)malonamide, exhibits excellent (≥ 96 %) silver(I) specificity.
20
Boudier, Adrien. "Design, synthesis and characterization of new ligands and activators for the oligomerization of ethylene by iron complexes". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00868786.
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This thesis describes the development of new catalytic systems based upon iron complexes and their reactivity toward ethylene. First, we focused our interest on the synthesis of iron(III) precursors chelated by monoanionic ligand. Those complexes were obtained either by reaction of the monoanionic ligand with FeCl3 or through oxidation of the iron(II) complex. The second reaction led to binuclear complexes. Then, another aim of the thesis was to design new well-defined cocatalysts for the activation of iron complexes. The study of the reaction between an alcohol and the trimethylaluminum allowed us to reach this aim. Aluminum complexes adopted either a binuclear framework or a trinuclear one, depending on the nature of alcohol reagent. Besides this work, new iron(II) and nickel(II) complexes chelated by imino-imidazole ligands bearing a pendant donor function L were synthesized. All complexes have been evaluated for the oligomerization of ethylene in the presence of EtAlCl2 or MAO as cocatalyst. Only nickel complexes were active toward ethylene transformation.
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Juneja, Alok [Verfasser]. "Exploring theoretically ligands and polymeric linkers to make multivalent ligands / Alok Juneja". Berlin : Freie Universität Berlin, 2010. http://d-nb.info/1024743276/34.
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Chen, Yang. "The syntheses and reactivity of polydentate PNNP ligands and macrocyclic polyphosphine ligands". HKBU Institutional Repository, 1998. http://repository.hkbu.edu.hk/etd_ra/220.
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Mazaud, Louis. "Ligands pinceurs mixtes à base d'iminophosphorane pour des systèmes Métal-Ligands coopératifs". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX070.
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Ce projet vise la synthèse de différentes familles de ligands pinceurs associant la fonction iminophosphorane (P=N) à d’autres fonctions azotées ou phosphorées. Les ligands pinceurs sont des ligands tridentés, dont la versatilité des structures possibles permet une modulation fine des propriétés électroniques et stériques des complexes formés. L’introduction de fonctions spécifiques permet également d’envisager une coopérativé du ligand.Le premier chapitre décrit la synthèse et la caractérisation de différents complexes ruthénium-hydrure qui différent par la nature des ligands ancillaires. Les complexes obtenus et leurs propriétés ont été comparés à leurs analogues phosphine(s)/amines décrits dans la littérature en particulier pour la catalyse de processus hydrogénants et déshydrogénants. Dans le contexte économique et écologique actuel, la catalyse par des complexes de ruthénium n’apparait pas comme une solution pertinente à long terme. Des complexes de fer analogues ont donc également été développés.Une seconde famille de ligands, différant par la position de la fonction iminophosphorane, a été également synthétisée. Sa coordination à un métal de transition du groupe 11 tel que le cuivre(I) a été étudiée. Les propriétés catalytiques et la réactivité des différents complexes formés ont ensuite été décrites au travers, par exemple, de la réaction d’Huisgen.Enfin, une nouvelle famille de ligands pinceurs triazotés à motif amidoquinoline a ensuite été développée. Sa synthèse est décrite dans ce manuscrit, ainsi que les complexes préparés avec différents métaux du groupe 8 tels que le palladium et le nickel. La réactivité du ligand possédant des substituants phényles avec le nickel(0) a conduit à réarrangement original du ligandThis research project aims at the synthesis of various types of pincer ligands associating iminophosphorane (P=N) and different nitrogen and phosphorous containing functions. Pincer ligands are tridentate ligands with high degree of synthetic variability allowing a fine tuning of the electronic and steric properties. Cooperativity can also be allowed by introducing specific functions.First chapter deals with the synthesis and characterizations of various ruthenium-hydride complexes which differ by the nature of the ancillary ligands. The obtained complexes and their properties have been compared to their phophine(s)/amine analogues known in the literature, in particular for hydrogenating or dehydrogenating processes. Nevertheless, inthe global economic and ecologic context, ruthenium catalysis does not appear as a sustainable candidate. Therefore iron analogs have also been developed.The modification of the iminophosphorane position led us to synthesize a new family of ligands. Its coordination with a group 11 transition metal such as copper(I) has also been studied. The catalytic properties of those complexes for the Huisgen reaction have also been probed.Finally a new family of pincer ligands containing three coordinating nitrogen atoms with an amidoquinoline moiety has been developed afterwards. Its synthesis is described in this manuscript as well as the complexes formed with group 8 transition metals such as palladium and nickel. An unusual reactivity has been observed when the ligand which includes phenyl substituents on the iminophosphorane reacted with nickel(0)
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Roscoe, Jane Caroline. "Unsymmetrical tridentate phosphine ligands". Thesis, University of Central Lancashire, 1991. http://clok.uclan.ac.uk/20127/.
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A general synthetic route, via phosphonium salts and phosphine oxides has been developed for the preparation of unsymmetrical triphosphine ligands, which necessarily contain one central chiral phosphorus atom. The ttparent" tridentate phosphine is (2- diphenylphosphinoethyl)(3-diphenylphosphinopropyl) phenylphosphine, Ph2P(CH2)3PPh(CH2)2PPh2, "eptp". Other tridentates were prepared by varying the substituents at one phosphorus atom to form the analogous ligands with a general formula of R2P(CH2)3PPh(CH2)2PPh2 where R=p-FC6H4, p-C1C6H4, o-CH30C6H4. The ligands were found to complex readily with nickel(Il) and palladium(ll) to form air-stable complexes containing square planar species such as [NiI(eptp)]+ in solution. Complexes were isolated using C104, PF6- and 1 as counterions, and were characterised by elemental analysis, magnetic and conductance measurements, infrared spectroscopy, and especially by 31 P nmr spectroscopy where the three non-equivalent phosphorus nuclei, all coupled to one another, provided a wealth of useful data. Crystals were grown for a single-crystal X-ray crystallographic study of the Ni12 complex of eptp, which showed one weakly bonded iodo ligand at the apex of a square pyramid. This is the site at which a substrate molecule would be expected to coordinate in any asymmetric homogeneous catalytic application; the other side of the square plane was sterically crowded. The unit cell contained four molecules, two of each enantiomer. The nickel(II)-triphosphine complexes were screened for catalytic activity in the hydrogenation of alkenes. In this investigation they were all found to be inactive for hydrogenation at ambient conditions. However addition of a little NaBH4 produced colourless solutions, presumably nickel(0) complexes, which in air were found to be excellent oxidation catalysts, rapidly oxidising added phosphines to phosphine oxides. The phosphine oxide intermediate in the tridentate phosphine ligand synthesis, Ph2P(0)(CH2)3P(0)Ph(CH2)2PPh2, teptp02, provided an attractive stage at which to investigate resolution of the two enantiomers, since the final trichlorosilane reduction stage of the phosphine oxides to phosphines is known to be stereospecific. 31P nmr studies showed strong chiral recognition between eptp02 and (+)-camphorsulphonic acid in CDCI3. The novel mixed phosphine/phosphine oxide ligand eptp02 was found to coordinate exclusively via phosphorus to palladium(Il) in [PdC12(eptpO2)21 or via the phosphine oxide groups to lanthanum(lII). It would also coordinate simultaneously to both, and so is ideally suited to the preparation of very unusual heterobinuclear complexes containing one oxophilic f-block metal ion (e.g. La 3 ) and one 'soft' d-block metal ion (e.g. Pd2+). Such complexes presumably contain macrocyclic rings involving both types of metal ion. Various other routes to unsymmetrical tridentate ligands were investigated which involved some unusual mixed bidentate ligands. A new route to bisphosphine monoxides, Ph2P(CH2)P(0)Ph2, has been developed in this programme. These monoxides provided a simple route to new tn- and tetra- phosphine oxides such as eptp03 and the "2,3,2"-tetraoxide , Ph2P(0)(CH2)2P(0)Ph(CH2)3P(0)Ph(CH2)2P(0)Ph2. In collaboration with The University of Barcelona, (Campus of Tarragona), the bisphosphine monoxides with -(CH2)2- and -(CH2)4- backbones were converted to ligands containing both a phosphine sulphide and a phosphine oxide group e.g. Ph2P(S)(CH2)2P(0)Ph2. This ligand and the bisphosphine monoxide, were found to coordinate to tin(II) chloride through the phosphine oxide only. Whereas various alkyl and aryl substituents at phosphorus have been extensively investigated in polyphosphine ligands by previous workers, the pyridyl substituent has not been used in this way. This would be an interesting substituent as it is sterically similar to phenyl but electronically quite different. New routes to a pyridyl substituent at phosphorus were investigated, producing the previously unknown pyridyltriphenyiphosphonium salt [PPh3(2-py)]Br and the ligand 6-bromo-2(diphenylphosphino)pyridine. When hydrolysed phosphonium salts containing a pyridyl group were found to lose the pyridyl group in preference to phenyl, so elaboration to di- and tri-phosphines was not possible.
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Speak, Anneliese Odette. "Invariant NKT cell ligands". Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504596.
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Salek, Spencer N. "Macrocyclic tridentate phosphathia ligands". Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242928.
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Royall, Sophie C. "Anti-inflammatory SSTR2 ligands". Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/51776/.
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Broad-Spectrum Chemokine Inhibitors (BSCIs) are a novel type of anti-inflammatory drug, discovered by Fox and colleagues, which act through the receptor SSTR2. Chapter 1 consists of the story of the development of current BSCIs and a literature review of existing SSTR2 ligands. In Chapter 2 a series of receptor probes were synthesised based on existing SSTR2 ligands, BSCIs and a hybrid of the two. Biological data were gained determining their SSTR2 binding ability and their extent of leukocyte migration inhibition. In Chapter 3 a series of small molecules were synthesised based on the structure of highly potent BSCIs. Once again biological data were gained determining their SSTR2 binding ability and their extent of leukocyte migration inhibition. In Chapter 4 a series of BSCIs were synthesised which contained substituted aromatic groups using an iron-cross coupling reaction. Biological data were gained to determine these compounds SSTR2 binding ability. Further iron cross-coupling reactions were carried out to determine the scope of these reactions and their applications in medicinal synthetic chemistry. This works has gained evidence to support a split binding site theory for SSTR2. Somatostatin and BSCIs bind in slightly different area of the binding site, and through functional selectivity somatostatin structural analogues can exert an anti-inflammatory effect while somatostatin does not.
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Shuttleworth, Timothy A. "Pyridylphosphine ligands for methoxycarbonylation". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702891.
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O'Brien-Brown, James. "Novel P2X7 Receptor Ligands". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21280.
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The P2X7 receptor (P2X7R) is a purinergic receptor that plays a central role in the inflammatory response. Activation of the P2X7R releases pro-inflammatory cytokines such as interleukin 1β (IL-1β), which have been shown to underlie the pathogenesis of a number of neurodegenerative disorders. Consequently, the development of a CNS penetrant P2X7R antagonist is considered a promising target for the inhibition of neurodegenerative diseases. A series of P2X7R antagonists were synthesised to investigate which structural features of the hydrophobic moiety dictated binding site selectivity (orthosteric vs allosteric), and potency data are available for derivatives synthesised; assays to assess binding site selectivity have not currently been undertaken. To assist future pharmacological analyses, fluorescent probes based on lead compounds from the aryl cyanoguanidine and adamantyl benzamide P2X7R antagonist series were synthesised, and antagonist potency and binding affinity data for a number of derivatives are reported. Based on the original structure-activity relationship (SAR) study of the adamantyl cyanoguanidine series, a range of heterobicyclic adamantyl cyanoguanidine analogues were synthesised in order to refine the pharmacophore for potent P2X7R antagonism. The adamantyl indazoles 302 and 303 (IC50 = 18.6 ± 0.5 nM and 22.2 ± 6 nM respectively) were equipotent to the lead 19, and SAR data from this series has identified several structural requirements for potent P2X7R antagonism. Attempts to develop radioligands for visualising P2X7R expression in vivo are reported. The trifluorinated adamantyl benzamide [11C]SMW139 was progressed into first-in-human studies as a radiodiagnostic probe for identifying active areas of neuroinflammation in patients with relapsing-remitting multiple sclerosis (RRMS), with data from the small cohort suggesting it did so successfully. Further studies in larger cohorts are currently in progress.
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Speidel, Joshua A. "Computational approaches to structure based ligand design : an illustration for P/CAF bromodomain ligands /". Access full-text from WCMC, 2007. http://proquest.umi.com/pqdweb?did=1453183061&sid=21&Fmt=2&clientId=8424&RQT=309&VName=PQD.
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Kissel, Daniel Stephen. "Metal ion complexing properties of two dimensional sulfur ligands and their use in neurodegenerative disease". View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-3/kisseld/danielkissel.pdf.
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Wade, R. C. "Ligand-macromolecule interactions". Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:576ce119-6a93-4eb0-a7e4-1f2513736dbd.
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The optimisation of ligand-macromolecule interactions is fundamental to the design of therapeutic agents. The GRID method is a procedure for determining energetically favourable ligand binding sites on molecules of known structure using an empirical energy potential. In this thesis, it has been extended, tested, and then applied to the design of anti-influenza agents. In the GRID method, the energy of a hydrogen-bond is determined by a function which is dependent on the length of the hydrogen-bond, its orientation at the hydrogen-bond donor and acceptor atoms, and the chemical nature of these atoms. This function has been formulated in order to reproduce experimental observations of hydrogen-bond geometries. The reorientation of hydrogen atoms and lone-pair orbitals on the formation of hydrogen-bonds is calculated analytically. The experimentally observed water structures of crystals of four biological molecules have been used as model systems for testing the GRID method. It has been shown that the location of well-ordered waters can be predicted accurately. The ability of the GRID method to assist in the assignment of water sites during crystallographic refinement has been demonstrated. It has also been shown that waters in the active site of an enzyme may be both stabilized and displaced by a bound substrate. Ligands have been designed to block the highly conserved host cell receptor site of the influenza virus haemagglutinin in order to prevent the attachment of the virus to the host cells. The protein was mapped energetically by program GRID and specific ligand binding sites were identified. Ligands, which exploited these binding sites, were then designed using computer graphics and energy minimization techniques. Some of the designed ligands were peptides and these were synthesised and assayed. Preliminary results indicate that they may possess anti-influenza activity.
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Pchalek, Karin Chemistry Faculty of Science UNSW. "Design and synthesis of new ligands and heterocycles from activated indoles". Awarded by:University of New South Wales. School of Chemistry, 2004. http://handle.unsw.edu.au/1959.4/20584.
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For the purpose of incorporating indoles into organometallic complexes for catalysis, as well as in the generation of new heterocyclic systems, various reactions have been carried out at C2, C6 and C7 of the indole system. In order to achieve this, 3-substituted 4,6-dimethoxyindoles and 6-hydroxy- 4-methoxyindoles were necessary as starting materials. Consequently, a lithium-bromide-templated one-pot procedure for the synthesis of some 3-substituted 4,6-dimethoxyindoles and a selective demethylation procedure for 3-substituted 6-hydroxy-4-methoxyindoles were developed. Various kinds of novel methylene-bridged bi-, tri-, and tetradentate pyridyl-indole ligands were synthesised via Vilsmeier-Haack, Friedel-Crafts or electrophilic addition reactions on the indole heterocycle. However, their metal complexing properties were generally weak and variable. Nevertheless, some of the tridentate pyridylindole ligands showed strong anion binding to halides, whereas a remarkable ligand transformation occurred with a bidentate 2-pyridylindole ligand and zinc(II), giving a substituted indolo[2,3-c]pyrrolo-[3,2,1-ij]quinoline system. Two new types of tetradentate Schiff base ligands were prepared from 2-formyl-indoles and 7-formyl-6-hydroxyindoles, and diamines. These preformed ligands were reacted with first- and second-row transition metals to give neutral metal complexes. Novel heterocyclic systems such as 4H-pyrrolo[3,2,1-ij]quinolines, 3H-pyrrolo-[1,2-a]indoles, and 1H-furo[2,3-g]indoles were synthesised from 2-formyl-, 7-formyl-, and 6-hydroxyindoles, utilising mainly intra-molecular Wittig reactions, Claisen-Schmidt condensations or acid- and base-catalysed cyclisations. A common feature of the prepared 4H-pyrrolo[3,2,1-ij]quinolines and 3H-pyrrolo-[1,2-a]indoles was their intense fluorescent character, which was examined as well.
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Akyol, Ceyhun. "Tetracarbonyl[n,n". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605941/index.pdf.
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N,N&rsquo-bis(ferrocenylmethylene)ethylenediamine was prepared from the reaction of ferrocenecarboxaldehyde and ethylenediamine and characterized by IR, Raman, 1H and 13C-NMR spectroscopy. The electrochemical behaviour of this ligand was also studied for the first time by cyclic voltammetry. Diferrocenyl diimine ligand was used in the thermal substitution of 1,5-cyclooctadiene in Cr(CO)4(2:2-1,5-cyclooctadiene) at 38°
C in toluene for two hours to form the tetracarbonyl[N,N&rsquo
-bis(ferrocenylmethylene)ethylenediamine]chromium(0), [Cr(CO)4(BFEDA)]. This complex was succesfully isolated and crystallized from its 1:1 toluene/dichloromethane solution and characterized by elemental analysis, MS, IR, 1H, 13C-NMR spectroscopy. Electrochemical behaviour of the complex was also studied by cyclic voltammetry and the mechanism of electrode reaction was investigated by in-situ UV-VIS and IR spectroscopy measurements. This new complex has the iron atom of ferrocene unit in conjugation with the chromium metal center and, therefore, shows an electronic communication between two metal atoms.
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McGregor, Lynn Marie. "Methods for the Identification of Ligand-Target Pairs from Combined Libraries of Targes and Ligands". Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11370.
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Advances in genome and proteome research have led to a dramatic increase in the number of macromolecular targets of interest to the life sciences. A solution-phase method to simultaneously reveal all ligand-target binding pairs from a single solution containing libraries of ligands and targets could significantly increase the efficiency and effectiveness of target-oriented screening efforts. Here, we describe interaction-dependent PCR (IDPCR), a solution-phase method to identify binding partners from combined libraries of small-molecule ligands and targets in a single experiment. Binding between DNA-linked targets and DNA-linked ligands induces formation of an extendable duplex. Extension links codes identifying the ligand and target into one selectively amplifiable DNA molecule. In a model selection, IDPCR resulted in the enrichment of DNA encoding all five known protein-ligand pairs out of 67,599 possible sequences.
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Mutti, Marcello. "Crystal engineering of mixed-ligand metal-organic frameworks based on simple carboxylate and bipyridyl ligands". Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29726.
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Over the last few decades research in supramolecular chemistry and crystal engineering have seen an exponential growth. The synthesis of metal-organic frameworks (MOFs) has attracted much interest worldwide due to the possibility of obtaining a large variety of structures with a wide range of applications in fields pertaining to storage, separation and catalysis. This work focuses on the crystal engineering of MOFs based on mixed ligands which may ultimately be used in the gas storage of pollutants, greenhouse gases or fuel. Two novel 2D mixed-ligand MOFs, both based on manganese, 4,4’-bipyridine and 1,3,5- benzenetricarboxylic acid, have been prepared and fully characterized. The employment of dimethylformamide or dimethylacetamide, as the solvent, results in two isostructural MOFs. Another novel MOF, similar in structure to the previous two, with 5-nitroisophthalic acid instead of 1,3,5-benzenetricarboxylic acid has been also prepared and characterized. This MOF has the same metal and ligand combination as, and is largely isostructural to, a literature example, but differs in method of preparation and solvent content. These Mnbased MOFs have potential voids in the structure making them candidates for gas sorption experiments. A novel 2D mixed-ligand MOF based on cobalt, 4,4’-bipyridine and 5-nitroisophthalic acid has been synthesized and fully characterized. Its structure is the same of another MOF, based on manganese, present in this work and like its manganese analogue it exhibits potential void spaces in the framework that make it a candidate for gas sorption experiments. Finally, a novel 2D MOF based on 1,3,5-benzenetricarboxylic acid and cadmium bromide has been synthesized and fully characterized. Dehydration and rehydration studies performed by combining powder X-ray diffraction with thermogravimetric analysis show that it can lose coordinated water, that comes from the reaction solvent, upon heating, and reabsorb water from the atmosphere, ultimately regaining its original structure. All MOFs were synthesized via the solvothermal method and characterized with X-ray diffraction (single crystal and powder) and thermal analyses (hot stage microscopy, differential scanning calorimetry and thermogravimetric analysis).
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Rönnmark, Jenny. "Affibody ligands in immunotechnology applications". Doctoral thesis, KTH, Biotechnology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3369.
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This thesis describes the development and use ofnon-immunoglobulin affinity proteins denoted affibodies asalternatives to antibodies in different immunotechnologyapplications. A 58 aa IgG Fc binding three-helix bundle domainZ, derived from staphylococcal protein A has been used asframework for library constructions, in which the face of themolecule involved in the native binding activity has beenengineered by combinatorial protein engineering. Recruting 13surface-located positions for simultanenous substitutionmutagenesis, using degenerated oligonucleotides for libraryassembly at the genetic level, two libraries differing in thechoice of codons were constructed to serve as general sourcesof novel affinity proteins. The libraries were adapted fordisplay onE. colifilamentous phage particles allowingin vitroselection of desired variants capable ofbinding a given target molecule. In selections using human IgAas target, several new IgA specific affibodies could beidentified. One variant ZIgA1, was further investigated and showed binding toboth IgA1 and IgA2 human subclasses as well as to secretoryIgA. This variant was further demonstrated uesful as ligand inaffinity chromatography purification for recovery of IgA fromdifferent samples including unconditioned human plasma.Affibodies of different specificities were also fused to otherprotein domains to construct fusion proteins of relevance forimmunotechnology applications. Using Fc of human IgG as genefusion partner, "artificial antbodies" could be produced inE. colias homodimeic proteins, where the antigenbinding was confered by N-terminally positioned affibodymoieties of different valencies. One area of application forthis type of constructs was demonstrated through specificdetection of the target protein by Western blotting. Exploitingthe uncomplicated structure of affibody affinity proteins, genefusions between affibodies and the homotetrameric reporterenzyme β-galactosidase were constructed, which could beproduced as soluble proteins intracellularly inE. coli. The potential use of such recombinantimmunoconjugates in immunotechnology was demonstrated in ELISAdot-blot and immunohistochemistry, where in the latter case IgAdepositions in the glomeruli of a human kidney biopsy could bespecfically detected with low background staining ofsurrounding tissues. In a novel format for sandwich ELISA, thepossible advantage of the bacterial origin of the affibodyclass of affinity proteins was investigated. As a means tocircumvent problems associated with the presence of humanheterophilic antibodies in serum, causing bakground signals dueto analyte-independent crosslinking of standard capture anddetection antibody reagents, assay formats based oncombinations of antibody and affibody reagents for capture anddetection were investigated and found to be of potentialuse.
Keywords:phage display, combinatorial, affinity, IgAligand, immunohistochemistry, affibody-fusions
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Ramogida, Caterina Fortunata. "Acyclic chelating ligands for radiometals". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54053.
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This thesis presents studies on a class of acyclic (open chain) chelating ligands based on the picolinic acid moiety. Our recent reports of the promising hexadentate chelator H₂dedpa and octadentate analogue H₄octapa for Ga(III) and In(III)/Lu(III) complexation, respectively, have spurred our interest in further developing this class of chelators, which have subsequently been dubbed the “pa” family of ligands. These ligands possess the potential to bind a variety of clinically relevant radiometal ions, such as ⁶⁸Ga, ⁶⁴Cu, ¹¹¹In, ¹⁷⁷Lu, or ⁸⁶/⁹⁰Y. When harnessed properly, the radiative emissions of these radiometals can be utilised in radiopharmaceuticals for imaging (via γ-rays for single photon emission computed tomography (SPECT) or β+ particles for positron emission tomography (PET)) or therapy (via highly ionizing radiation from α, β-, or Auger electron emission). A key component of these radiometal-based radiopharmaceuticals is the chelating ligand, used to securely bind the radiometal which ensures proper delivery the radioactive dose to the area of interest in vivo. This work focuses on further exploiting the H₂dedpa (N₄O₂) and H₄octapa (N₄O₄) scaffolds that possess ideal properties for ⁶⁷/⁶⁸Ga and ¹¹¹In radiopharmaceuticals, respectively – such as mild room temperature radiolabeling in 10 min, and the ability to form kinetically inert complexes – rare manifestations for acyclic ligands. Herein, efforts were made to incorporate dedpa²- into a small molecule imaging agent for ⁶⁸Ga PET. A variety of dedpa²- (and one octapa⁴-) analogues were synthesized, characterized, and evaluated through thermodynamic stability, in vitro kinetic inertness, and radiolabeling studies to assess their “usefulness” as ligands in radiopharmaceutical design. The chiral ligands H₂CHXdedpa and H₄CHXoctapa are highlights of this work; [Ga(CHXdedpa)]+ and [In(CHXoctapa)]- were found to be more, or equally, stable versus their achiral counterparts H₂dedpa and H₄octapa. Nitroimidazole-containing H₂dedpa and H₂CHXdedpa derivatives were also studied as potential ⁶⁸Ga PET imaging agents of tumour hypoxia. The radio-tracers showed exceptional in vitro stability (86 to >99% intact), and promising preferential uptake in hypoxic cell lines suggesting these ligands would be ideal candidates for further testing in vivo.Science, Faculty of
Chemistry, Department of
Graduate
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Black, Cory A., i n/a. "Supramolecular complexes of multimodal ligands". University of Otago. Department of Chemistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070518.091104.
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This thesis describes the synthesis and X-ray crystallographic analysis of a series of supramolecular architectures prepared using seven flexible multimodal ligands with Ag(I), Cu(I), Cd(II), Co(II), Ni(II) and Pd(II) metal salts.
Chapter one introduces some examples of fundamental supramolecular systems with particular focus on metallo-supramolecular motifs, specifically coordination polymers. Topological analysis is discussed as a method for the simplified description and comparison of network structures.
Chapter two describes the design, synthesis and characterisation of the symmetrical ligands bis(2-pyrazylmethyl)sulfide (psp), bis(4-pyrimidylmethyl)sulfide (msm) and 5,5�-(thiodimethylene)di-pyrazine-2-carboxylic acid methyl ester (csc) as well as the asymmetrical ligands 2-benzylsulfanylmethyl-pyrazine (psb), 2-pyridylsulfanylmethyl-pyrazine (psd), 3-pyridylsulfanylmethyl-pyrazine (psn) and 4-pyridylsulfanylmethyl-pyrazine (psy).
Chapter three presents a literature review of ligands related to psp, msm and csc, followed by the synthesis and characterization of thirteen Ag(I), Cd(II), Co(II), Ni(II) and Pd(II) complexes. The X-ray crystal structures of nine of these complexes are reported and compared. The structures were present as either one- or two-dimensional coordination polymers. The {[Ag(psp)](PF₆)}[infinity] and {[Ag₂(psp)(C₆H₆)(CH₃CN)₂](PF₆)₂�CH₃CN}[infinity] structures demonstrated a solvent dependence by forming a 1-D twisted ladder with a [eta]�-bound benzene and a 2-D undulating sheet with a 4.8� topology respectively. Six of the structures {[Cd₂(psp)(CH₃CN)(H₂O)(NO₃)₄]�H₂O}[infinity], {[Co(psp)(CH₃CN)₂](ClO₄)₂}[infinity], {[Ni(psp)(NO₃)₂]}[infinity] and {[Ag(msm)](X)}[infinity] (X = BF₄⁻, ClO₄⁻, PF₆⁻) displayed anion-[pi] interactions between multi-atomic anions and [pi]-acidic ring centres. A novel N[pz]���cent[pz] T-shaped [pi]-[pi] interaction was also identified in the {[Ni(psp)(NO₃)₂]}[infinity] structure. A 2-D sheet with 6� topology was observed in the X-ray structure of {[Ag₂(csc)](NO₃)₂}[infinity].
Following a review of related ligands, chapter four focuses on seven Ag(I), Cd(II), Co(II) and Cu(I) complexes formed using the asymmetric pyrazine-benzene ligand psb. In total six 1-D coordination polymer chains are reported. Two structurally disparate supramolecular isomers were formed in [Ag(psb)NO₃][infinity] and {[Ag₂(psb)₂NO₃]NO₃�H₂O}[infinity]. The compound {[Ag(psb)](BF₄)}[infinity] was similar to the former isomer [Ag(psb)NO₃][infinity]. The structurally similar coordination polymers {[Cd(psb)(H₂O)(NO₃)₂]}[infinity] and {[Co(psb)(H₂O)₃](ClO₄)₂�H₂O}[infinity] formed structures that showed anion-[pi] interactions using coordinated and non-coordinated anions respectively. The [Cu₂(psb)I₂][infinity] chain consisted of ligands linked together by a Cu₄I₄ stepped cubane tetramer.
Chapter five presents seventeen Ag(I) and Cu(I) complexes prepared using three asymmetric pyrazine-pyridine ligands psd, psn and psy. A review of asymmetric pyrazine-pyridine ligands is provided. Seventeen X-ray crystal structures are described. Four psd complexes using AgBF₄, AgClO₄, AgNO₃ and AgPF₆ crystallised as discrete dimers with three types of crystal packing and ligand-supported Ag���Ag interactions. The complexes {[Ag₂(psd)₂CF₃SO₃]CF₃SO₃}[infinity] and {Cu₂(psd)I₂}[infinity] were a 1-D X-shaped chain and a 2-D 6� net respectively. The isostructural 2-D sheets in {[Ag(psn)]ClO₄}[infinity] and {[Ag(psn)]PF₆�CH₃CN}[infinity], had 4.8� topologies whereas a thicker sheet was formed in {[Ag₂(psn)₂](BF₄)₂}[infinity] with a complicated (4�.6�.8�)₂(4.6.8)₂ topology. The {[Ag₃(psn)₂](CF₃SO₃)₃�CH₃CN}[infinity] chain polymer displayed three different coordination geometries around the three Ag(I) centres with two ligand-unsupported Ag���Ag interactions. The complex [Cu₂(psn)₂I₂] crystallised as a discrete dimer with a different ligand arrangement than those found in the psd dimers. Six Ag(I) 3-D networks were formed using psy. The complexes {[Ag(psy)]X}[infinity] (X = BF₄, ClO₄, PF₆) formed as isostructural non-interpenetrated (10,3)-d networks. An unprecedented tri-nodal (4.6.8)₂(6.8�)₂(4.6.8�.10)₂ topology was observed in the {[Ag₂(psy)₂](CF₃SO₃)₂}[infinity] structure. The suprarmolecular isomers {[Ag₃(psy)₂(NO₃)₂]NO₃]}[infinity] and {[Ag₃(psy)₂(NO₃)₃]�H₂O}[infinity] formed inclined interpenetrated 6� sheets and a (4�.6)₂(4⁴.6�.8⁸.10) 3-D network respectively. The structures in this chapter showed a general trend of increasing dimensionality when progressing from psd to psn to psy.
Chapter six presents a summary of the more significant results and concluding remarks.
40
Fern, Glen Matthew. "Ferrocenes of Substituted Indenyl Ligands". Thesis, University of Canterbury. Chemistry, 2005. http://hdl.handle.net/10092/1266.
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This thesis describes the preparation and characterization of a variety of methyl-, trimethylsilyl-, and diphenylphosphino-substituted indenes. The indenes were then used in the preparation of bis(indenyl)iron(II) complexes. The bis(indenyl)iron(II) complexes were characterized by ¹H, ¹³C, and ³¹P-NMR, UV/visible spectroscopy, cyclic voltammetry, and mass spectrometry. The cyclic voltammetry shows an approximately linear relationship between the oxidation potential and the type of substituent and its ring position, but with increasing substitution leads to lower than expected oxidation potentials. The UV/visible spectra show two absorption bands in the visible region. The position of the bands are essentially unaffected by methyl-substitution, but the low energy band red-shifts with trimethylsilyl- and diphenylphosphino-substitution. Di(2-methylindenyl)iron(II), bis(4,7-dimethyl-indenyl)iron(II), bis(1,3-bis(trimethylsilyl)indenyl)iron(II), rac-bis(1-diphenyl-phosphinoindenyl)iron(II), rac-bis(1-diphenylphosphino-3-methylindenyl)iron(II), and rac-bis(1-diphenylphosphino-2,3-dimethylindenyl)iron(II) were characterized by X-ray crystallography.The planar chiral ferrocenylphosphine bis(1-diphenylphosphinoindenyl)iron(II) is observed to undergo a facile ring-flipping isomerization from the meso isomer to the racemic isomer in THF at ambient temperature. The isomerization is slowed by the addition of the noncoordinating solvent chloroform, but is accelerated by the addition of LiCl. Rate and activation parameters for the isomerization have been determined to be: kobs = 1.6 x 10⁻⁵ s⁻¹ at 23 ℃, ΔH‡ = 58 ± 4 kJ mol⁻¹, ΔS‡ = −140 ± 15 J mol⁻¹ K⁻¹. Deuterium labeling of bis(1-diphenylphosphinoindenyl)iron(II) in the 3- and 3ʹ-position ruled out the isomerization proceeding by [1,5]-proton shifts or dissociative mechanisms. The proposed mechanism for the isomerization proceeds via coordination of two THF ligands with ring-slippage of one of the indenyl ligands until it is coordinated through the phosphine. Coordination of the indenyl ligand by the other face leads to the formation of the other isomer.The heterobimetallic complexes (bis(1-diphenylphosphinoindenyl)iron(II))-cis-dichloropalladium(II), (bis(1-diphenylphosphinoindenyl)iron(II))-cis-dichloro-platinum(II), and [(cyclooctadiene)(rac-bis(1-diphenylphosphinoindenyl)iron(II))-rhodium(I)] tetraphenylborate were prepared. Attempts to prepare dichloro(bis(1-diphenylphosphinoindenyl)iron(II))nickel(II) lead to the formation of trans-dichloro(bis(1-diphenylphosphinoindene))nickel(II). The complex (bis(1-diphenyl-phosphinoindenyl)iron(II))-cis-dichloropalladium(II) is able to catalyze the cross-coupling of bromobenzene with n-/sec-butylmagnesium chloride. However. the reaction is not selective with isomerization of the alkyl group and reduction of the halide occurring via a β-hydride elimination mechanism.
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LeSauteur, Lynne. "TrkA ligands : development and uses". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0019/NQ44493.pdf.
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Burton, Nicolas Paul. "Novel ligands for affinity chromatography". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359769.
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Oxlade, David Philip. "Approaches to novel fluorophilic ligands". Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398237.
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Prabagar, Jasotha. "Synthesis of bulky phosphine ligands". Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437012.
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Moss, Andrew James. "Engineering novel angiopoietin receptor ligands". Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/27654.
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Angiopoietin-1 is a multimeric glycoprotein which signals through the vascular endothelial Tie2 receptor to protect against inflammation and leakage, an effect antagonised by the selectively upregulated antagonist angiopoietin-2. In many pathologies this destabilisation by angiopoietin-2 is excessive or inappropriate, and here angiopoietin-1 has a promising role in therapeutic application. However angiopoietin-1 is difficult to purify and administer, its large multimeric structure rendering it prone to aggregation and insolubility. In this work the abilities of two small heptameric Tie2 binding peptides, VTSRGNV and NLLMAAS, multimerised using the established oligomeric scaffold cartilage oligomeric matrix protein (COMP), to bind and activate Tie2 were investigated. cDNAs for synthetic ligands were created by PCR, and protein synthesis was carried out in mammalian and bacterial expression systems. Ligands were expressed as stable, soluble pentamers and tetramers which showed similar abilities to bind Tie2 in vitro. Both ligands activated Tie2 similarly in Eahy926 and HUVEC endothelial cells. Both ligands were also able to activate two important downstream signalling mediators of Tie2 in HUVECs, namely Akt and ERK, in a dose-dependent fashion. However, the kinetics of ERK appeared different between the two ligands, implying possible differences in signalling of the two ligands through Tie2. This work is proof of principle and is among the first work to demonstrate that Tie2 binding elements other than the ang1 FRD can be used to activate Tie2. Additionally, kinetics work suggests that the two ligands, presumed to bind to different areas on Tie2, might induce slightly different patterns of receptor activation.
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Hassan, Hani Mutlak Abdullah. "Chemical Synthesis of Protein Ligands". Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501975.
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Wikaira, Jan. "Polynuclear complexes with macrocyclic ligands". Thesis, University of Canterbury. Chemistry, 1996. http://hdl.handle.net/10092/8063.
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A series of polynuclear macrocyclic complexes has been prepared by the Schiff-base condensation of 1,5-diaminopentan-3-ol with 2,6-diformyl-4-methyl-R-phenol (where R = Me or tBu) in the presence of transition metal template ions. The (2 + 2) macrocyclic complexes, containing two or four metal ions, have been characterised by a variety of methods including microanalysis, infrared spectroscopy, cyclic voltammetry, E.I. and FAB mass spectrometry and X-ray crystallography.
When the template ion is copper, tetranuclear complexes are obtained. The structures of [Cu₄(μ₄-OH)L1(CH₃CN)₃(ClO₄)₂]⋅ClO₄⋅H₂O and [Cu₄(H₂LVS)(dfmp) ₂Cl(H₂O)₂]⋅BF₄ have been determined; both complexes contain planar tetracopper cations with an exogenous hydroxo donor in the centre of the cavity, bound to all four copper ions. Under appropriate conditions the tetra copper complexes dimerise to form octacopper assemblies and the structure of one of these [{Cu₄(μ₄-O)LV5(ClO₄)}₂]⋅(ClO₄)₂⋅4H₂O is reported. Ligand binding to the exposed faces of these arrays was investigated.
Tetranuclear cobalt complexes have also been prepared. The X-ray structure of [Co₄(μ₄-O)LV5(CH₃COO)₄]Cl⋅3H₂O shows that, in contrast to the copper complexes, the cation is not planar and the central exogenous donor is an oxo rather than a hydroxo ligand. Tetracobalt complexes can be obtained at various oxidation levels between Co(II)₄ and Co(III)₄.
A series of dicobalt complexes has been synthesised. In contrast to the familiar Robson dinuclear complexes, the cobalt ions are not bridged by phenolate donors but are diagonally disposed in the cavity and bridged by two chloride ions. X-ray crystal structure determinations have been carried out on five of these complexes, each having a core structure of [Co₂(H₄L)Cl₂]. These complexes offer a potential route to the formation of tetra nuclear complexes containing mixed metal ions.
Synthetic organic work directed towards the development of new ligands was also undertaken.
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Tei, Lorenzo. "Studies on functionalised macrocyclic ligands". Thesis, University of Nottingham, 2001. http://eprints.nottingham.ac.uk/12386/.
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The work presented in this thesis hinges on three main topics: a) the coordination chemistry of symmetric and asymmetric derivatives of [9]aneN3 towards lanthanide ions; b) the transition metal co-ordination chemistry of nitrile and amino derivatives of [9]aneN3 and [15]aneN3O2; c) the use of macrocyclic ligands for the synthesis of polymeric Ag' complexes. Chapter 3 describes the Ln"' complexes of the ligand obtained by Schiffbase condensation of 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane (L) with three molar equivalents of sodium pyruvate using the Ln0' ion as templating agent. The mononuclear complexes [Ln(La)] (Ln"' = Y10, Sm"', Gd"', Dy"', Eu", Yb"', La"') have been prepared and characterised, and in most cases the crystal structure has also been determined. NMR spectroscopic studies on the diamagnetic [Y(La)] and [La(La)] complexes and on paramagnetic [Yb(La)] and [Sm(La)] complexes have been carried out. Variable temperature 1H NMR behaviour of the [Y(La)] and [Yb(La)] complexes has also been investigated. Hydrolysis experiments on the [La(La)] complex in D20 at neutral and acidic pH have been performed in order to determine the stability of such a complex in in vivo conditions. Moreover, lanthanide properties such as relaxivity of the Gd"' complex and Dysprosium Induced Shift (DIS) have been determined in order to obtain information either about the efficiency as contrast agent of the Gd"' complex and the number of water molecules bound to the metal centre. After the study on the nine co-ordinate complexes [Ln(La)] discussed in Chapter 3, Chapter 4 reports the Ln°1 complexes obtained by changing the ketone employed for the Schiff-base condensation with the triamine L. Two different acetylphosphonate monoesters have been used in order to form novel nine co-ordinate Ln"' complexes: the synthesis of [Ln(Lb)] (Ln"' = Y"', Gds", Yb"', La'y') and [Ln(Lc)] (Ln"' = Y"", Gd"', Eu") complexes has been achieved by Schiffbase condensation of the triamine (L) with methyl sodium acetyl phosphonate and methoxybenzyl sodium acetyl phosphonate, respectively, using the Ln01 ion as templating agent. These Ln"' complexes have been studied again by X-ray crystallography and NMR spectroscopy. Since the nine co-ordinate lanthanide complexes such as [Ln(Lb)] and [Ln(L`)] contain three chiral phosphorus centres, four possible diastereomers, each of them with two enantiomers, could be distinguished and NMR spectroscopic studies have been carried out in order to determine the four different diastereomers present in solution. As in Chapter 3, hydrolysis experiments on the Y" complexes with Lb and Lc and relaxivity ofthe Gd1° complexes have been determined. The ligands discussed in Chapter 5 have been synthesised in order to provide a set of seven or eight donor atoms for the co-ordination of lanthanide ions, leaving one or two co-ordination sites available for the binding of water molecules. Therefore, 4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (L2), 1-(carboxymethyl)-4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (HL3) and 1-(2-hydroxyethyl)-4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (HL4) have been synthesised and then reacted with two equivalents of sodium pyruvate, methyl sodium acetyl phosphonate or methoxybenzyl sodium acetyl phosphonate using the Ln" ion as templating agent. A large number of lanthanide complexes with formulations [Ln(L2a)(CH3CO2)], [Ln(L2b)(CH3CO2)], [Ln(L2°)(CH3CO2)], [Ln(L3a)] [Ln(L3b)], [Ln(L4a)] and [Ln(L4b)] have been synthesised and characterised. The single crystal X-ray diffraction analysis of [Gd(L2a)(CH3CO2)]"CH30H, the 1H and 13C NMR spectra and the hydrolysis experiments on the V" complexes with L 2a, L2b, L2c, L3a, L3b, L 4a and L 4b are reported. Relaxivity of the Gd" complexes and Dysprosium Induced Shift on [Dy(L2a)(CH3CO2)], [Dy(L3a)] and [Dy(L4a)] have been determined. Chapter 6 describes the co-ordination chemistry of symmetric and asymmetric derivatives of [9]aneN3 towards transition metal ions. The two ligands tris(cyanomethyl)- and tris(2-cyanoethyl)-1,4,7-triazacyciononane (L' and L5, respectively) form peculiar complexes with Cull: using Cu(BF4)2.4H20 in MeOH at 65°C, the methanolysis of two nitriles with formation of imino-ether groups have produced square-based pyramidal Cull complexes. However, from the reaction of L5 with CuC12.2H2O in CH3CN at room temperature, the distorted square-based pyramidal Cull complex [Cu(L5)C12] with the nitrite pendant arms left uncoordinated has been formed. Cull and Zn" complexes with 1-(2-aminoethyl)-1,4,7-triazacyclononane (L7), Mn", Nil', Cull and Zn" complexes with L2, Mn", Cull and Zn" complexes with 1,4,7-tris(3-aminopropyl)-1,4,7 triazacyclononane (L) and Mn" and Zn" complexes with HL3 and HL4 have been prepared and characterised, and in most cases the crystal structure has also been determined. Furthermore, the EPR spectra of the Cull complexes and the 13C NMR spectroscopic data for the Zn" complexes are reported. Synthesis, solution studies and structural characterisation of complexes with [15]aneN302 derivatives are the topics of Chapter 7. The two ligands 1,4,7-tris(cyanomethyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L8) and 1,4,7-tris(2-aminoethyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L9) have been synthesised and their co-ordination chemistry towards transition and posttransition metal ions (Cull, Zn°, Cd" and Pbll) has been studied. Most of the complexes have been structurally characterised and they all show interesting structures: the pendant nitrile arms of L8 are not involved in co-ordination of the metal except for the Pbl' crystal structure and with L9 only larger metal ions such as Cd" and Pbll are bound to all the donor atoms of the ligand. The protonation equilibria of the two ligands and the formation of the Cu", Zn", Cd" and Pb" complexes with L8 and L9 have been studied by means of potentiometric measurements. The protonation constants of the ligands and the stability constants of the complexes are reported and compared to other ligands with similar macrocyclic framework and donor atoms. In order to further investigate the structural features of the complexes in solution, 'H NMR spectra of diamagnetic complexes have also been recorded at various temperatures. In Chapter 8, the nitrite pendant arm derivatives L', L5, L8 and L1° have been used as building blocks for the synthesis of extended inorganic architectures by reaction with Ag'. The complexes {[Ag(L')]PF6},,,, {[Ag(L')]BF4}oo, {[Ag(L8)]BF4}. and [Ag(L10)]PF202 have been prepared and structurally characterised. Analogously to other complexes of the same type prepared in the Schröder group, these compounds show nuclearity and dimensionality strictly dependent upon the number and length of the nitrite functionalised pendant arms present in the ligand: these act as linkers between different metal centres. Ag' complexes of [9]aneN3 and [15]aneN302 derivatives bearing three 7-methylquinoline pendant arms have also been prepared and characterised. The crystal structure of the Ag' complex with 1,4,7-tris(7-methylquinolyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L12) shows theformation of a dimer {[Ag2.5(L12)(PF202)2.5"CH3CN]2w}i th one Ag' co-ordinated linearly by two heterocyclic N-donors and bridging the two units.
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Guindy, Christina Irene. "Cobalt complexes of radical ligands". Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408058.
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Devlin, Edward Charles. "New ligands for asymmetric synthesis". Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428366.
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