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Bezuidenhout, Charl Xavier. "Polar ordering of guest molecules in host-guest inclusion complexes." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/18107.
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Thesis (MSc)--Stellenbosch University, 2011.ENGLISH ABSTRACT: 2,7-dimethylocta-3,5-diyne-2,7-diol forms inclusion complexes with various guests molecules, where the guest molecules are polar-ordered. A Cambridge Structural Database (CSD) search revealed ten inclusion complexes where the guest molecules were polar-ordered. Using Density Functional Theory (DFT) computational methods (in the absence of the host), we evaluated the intra-channel and lateral guest-guest interactions between the guest molecules. Two polar-ordered inclusion complexes ((1,4,7-cyclohexane-1,2,4,5,7,8-hexaoxonane)·CHCl3 and (2,4,6-(endolongifolyl)-1,3,5-trioxane)·CDCl3) were singled out in the CSD search for further studies along with 2,7-dimethylocta-3,5-diyne-2,7-diol. Synthesis of any 1,2,4,5,7,8-hexaoxonane and 1,3,5-trioxane derivatives was attempted to establish whether the polar-ordering ability extends into the family of compounds. We managed to produce three new polar-ordered inclusion complexes with 2,7-dimethylocta-3,5-diyne-2,7-diol (ClC(CH3)3, BrC(CH3)3 and IC(CH3)3), thus extending the series to six guest polar-ordered systems. We were only able to synthesise 1,4,7-cyclohexane-1,2,4,5,7,8-hexaoxonane and produce the CHCl3 inclusion complex and one new polar-ordered inclusion complex (CHBr3). Three 1,3,5-trioxanes was synthesised (the cyclohexyl, cyclohex-3-en-1-yl and cyclopentyl derivatives), which did not include any solvents. However, these 1,3,5-trioxanes also form polar-ordered crystals. These compounds and inclusion complexes were analysed by means of single crystal X-ray diffraction to determine their crystal structures. All the crystal structures could be solved and refined to adequate accuracy (except for 2,4,6-tri(cyclopentyl)-1,3,5-trioxane) with no disorder of the guest molecules (where applicable) and their polar-ordering property investigated. Due to their vast molecular differences, these compounds were studied separately by means of visual crystal structure analysis and computational modelling techniques (Density functional theory, molecular mechanics, molecular dynamics and molecular quench dynamics).
AFRIKAANSE OPSOMMING: 2,7-dimetielokta-3,5-diyn-2,7-diol vorm insluitingskomplekse met verskeie molekules as gaste, waar die gas-molekules polêr georden is. 'n Cambridge Struktuur Databasis (CSD) soektog lewer tien insluitings komplekse waarvan die gas-molekules polêr georden is. Deur gebruik te maak van Digtheidsfunksionele teorie (DFT) berekeninge (in die afwesigheid van die gasheer) het ons die inter-kanaal en wedersydse gas-gas interaksies tussen die gas molekules geëvalueer. Twee polêr geordende insluitingskomplekse ((1,4,7-sikloheksaan-1,2,4,5,7,8-heksaoksonaan)·CHCl3 en (2,4,6-(endolongifolyl)-1,3,5-trioksaan)·CDCl3) is uitgesonder uit die CSD soektog vir verdere studies saam met 2,7-dimetielokta-3,5-diyn-2,7-diol. Aanslag was gemaak om enige 1,2,4,5,7,8-heksaoksonaan en 1,3,5-trioksaan derivate te sintetiseer en vas te stel of die polêre ordensvermoë oor die familie van verbindings strek. Ons het daarin geslaag om drie nuwe polêr geordende insluitingskomplekse op te lewer met 2,7-dimetielokta-3,5-diyn-2,7-diol (Cl(CH3)3, BrC(CH3)3 en I(CH3)3), en sodoende die reeks uitgebrei na ses gaste wat polêr geordende insluitingskomplekse vorm. Net 1,4,7-sikloheksaan-1,2,4,5,7,8-heksaoksonaan kon gesintetiseer word en dit lewer twee polêr geordende insluitingskomplekse (CHCl3 en CHBr3 (nuut)). Drie 1,3,5-trioksane is gesintetiseer (die sikloheksiel, sikloheks-3-een-1-iel en siklopentiel derivate) en het nie enige oplosmiddels (gaste) ingesluit nie. Nietemin vorm hiedie 1,3,5-trioksane ook polêr geordende kristalle. Hierdie verbindings en insluitingskomplekse is geanaliseer deur middel van enkelkristal X-straal diffraksie om hul kristalstrukture te bepaal. Alle kristalstrukture was opgelos en verwerk tot voldoende akkuraatheid (behalwe vir 2,4,6-tri(siklopentiel)-1,3,5-trioxane) met geen wanorde in die gas molekuul posisies nie (waar van toepassing) en hul polêre ordensvermoë is ondersoek. As gevolg van groot verskille in hul molekulêre strukture, is hierdie verbindings afsonderlik bestudeer deur middel van molekulêre modellerings metodes (Digtheidsfunksionele teorie, molekulêre meganika, molekulêre dinamika en molekulêre stakings dinamika).
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Kundu, Mitali. "Exploration of inclusion complexes between host and guest molecules and solvation effect of some vital molecules in various environments." Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2689.
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Bouanga, Boudiombo Jacky Sorrel. "Molecular selectivity by host-guest methods." Doctoral thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33667.
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The Host-Guest inclusion crystallization method has long been used for the separation of closely related compounds. Especially for the separation of isomers which presented difficulties in techniques like distillation or chromatography. In this study, different host systems were used to separate isomers of trimethoxybenzenes, lutidines, methylacetophenones and xylenols. Isomers are compounds with the same molecular formula but different arrangement of their atoms. They are often produced as mixtures when synthesised in large quantities by various industries and are more valuable as purified single components. Thus, it is important to separate them into their individual components. The process of Host-Guest method is dependent on the phenomenon of molecular recognition between the host and guest molecules, and this, in turn, relies on the sum of non-bonded, secondary interactions which impinge on the final crystalline product. This is especially the case for enantiomers which are isomers with the same boiling points and melting point. However, enantiomers differ by their ability to diffract polarised light. Although countless methods have been used for their separation, one method that has been proven to be certainly successful on this path was the “family method”. The “Dutch resolution method” or the “family method” makes use of the crystallization technique by mixing similar host compounds to separate enantiomers. However, the improvement of the end results was not understood. In fact, the whole process has been done just on results and no analysis of the actual activity occurring at the molecular level was investigated. In this research, the Host-Guest chemistry method was applied with the aim of separating several isomers compounds in the intention of understanding the selectivity characteristics of a particular host. For the purpose of the analysis, structural isomers with close boiling points were selected. Competition experiments were set to survey which of the isomers were a better fit for a particular host. After analysis of the different crystal material obtained from crystallization experiments with NMR techniques, various trends were observed. X-Ray crystallography was employed to elucidate the crystal structures of the different compound formed by Host-Guest chemistry. The new complexes were further analysed by thermal analysis (TGA, DSC), kinetics of desolvation, Hirshfeld surface analysis, and activation energy of desolvation-analysis techniques. During the separation of the trimethoxybenzene (TMB) isomers, cholic acid and deoxycholic acid' hosts were used in chapter 3. It was found that each host separated the isomers differently. That was independent of the closeness of their molecular structures. The difference in selectivity was attributed to the arrangement of each host in the structure obtained with the guest compounds. Separation of lutidines was carried out in chapters 4 and 5. The first separation consisted of the study of the fifteen pairwise combinations of the isomers with 3,3′-bis(9-hydroxy-9- fluorenyl)2−2′- binaphthyl which is presented in chapter 4. The second analysis was carried out with host 2,2'bis(1-hydroxy-4,5-dihydro-2,3:6,7-dibenzocycloheptatrien-1-yl)-biphenyl. Nevertheless, both hosts preferred 3,4-lutidine. Four additional hosts were used to simulate the “Dutch resolution method” in chapter 5. Further analysis of torsion angles was performed over the five hosts for the complexes formed with 2,4-lutidine and 3,5-lutidine. The host characterized by unbridged phenyl moieties and the one characterized by bulky tert-butyl groups was found to prefer 3,5-lutidine. In chapter 6, deoxycholic acid resolved the 2-methylcyclohexanone (2MCH) but not 3- methylcyclohexanone (3MCH) during the separation of methylcyclohexanone isomers. However, during the competition experiment, it was found that when 2MCH was mixed with 3MCH, the latter was resolved as an S-enantiomer. Kinetics of desolvation studied resulted in the determination of the activation energies of the Host-Guest complexes and was like the trend observed by 1H NMR analysis. Chapter 7 was focused on the synergistic effect of mixed hosts system. This was to emphasize the impact that a mixture of compounds with similar structural composition may provide. Competition experiments were done with the 15 pairs of xylenol isomers with 4,4'- isopropylidene Bisphenol. Three of these pairs were selected for further analysis with two similar bisphenol hosts. One interesting structure was obtained with 4,4-isopropylidene Bisphenol and 4,4'-(9-Fluorenylidene) Bisphenol with a guest mixture. This is an unusual result as crystal structures comprising two hosts with two guests are rare.
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Yasmin, Ananya. "Investigation of Host Guest Inclusion Complexations and Diverse Interactions of Some Industrially and Biologically Potent Molecules in Assorted Phases by Physicochemical Methodologies." Thesis, University of North Bengal, 2019. http://ir.nbu.ac.in/handle/123456789/2854.
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Lacy, Stephen Michael. "Redox-active cyclophane host molecules for the inclusion of cationic and neutral guest species." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333410.
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HOUSE, BRIAN EDWARD. "HOST-[2] ROTAXANES: GUEST RECOGNITION AND CELLULAR TRANSPORT." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1155826127.
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Roy, Aditi. "Study to explore molecular inclusion complexes of cyclic hosts with vital guests in various environments." Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2633.
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Grotzfeld, Robert M. (Robert Martin). "Studies in molecular recognition : self-assembling molecular host-guest sytems." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10865.
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Saha, Binoy Chandra. "Host guest inclusion complexes and thermodynamic properties of some imperative molecules with the manifestation of diverse interections by physiochemical investigation." Thesis, University of North Bengal, 2020. http://ir.nbu.ac.in/handle/123456789/3966.
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Barman, Siti. "Investigation on solvation behaviour and host guest inclusion complexes of some significant molecules with diverse cyclic compounds." Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2588.
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Iwamoto, Takahiro. "Studies on Synthesis and Host-Guest Chemistry of Cycloparaphenylenes." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188613.
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Moncelsi, Giulia. "Stimuli-responsive host-guest systems decorated with hemithioindigo and spiropyran units." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668163.
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L’objectiu del treball de recerca d’aquesta tesis doctoral és el disseny i síntesis de contenidors moleculars que responguin a estímuls externs mitjançant la incorporació d’unitats foto-isomeritzables (photoswitchable units (PUs) en anglès) a les estructures tant del receptor com de la molècula reconeguda. S’han utilitzat dos tipus de PUs amb propietats diferenciades, hemitioindigos i espiropirans, incorporats a dos tipus de macrocicles, calix[4]arè i calix[4]pirrole. S’ha estudiat la isomerització de les PUs mitjançant la irradiació amb llum i el tractament àcid-base així com l’efecte d’aquesta en les propietats d’enllaç i encapsulació tant dels receptors unimoleculars com de les capsules supramoleculars. Primerament es descriu la síntesis i la caracterització fotoquímica de dos hemitioindigos que presenten un grup N-òxid terminal. S’ha demostrat la isomerització Z/E sota llum visible (λ = 450 nm) i s’ha estudiat en detall la constant d’enllaç dels dos isomers Z/E en la cavitat aromàtica polar d’un receptor calix[4]pirrole super aril-extès en dissolvents orgànics. Seguidament, s’han dissenyat i sintetitzat dos calixarens tetra-urea decorats amb quatre unitats hemitioindigo al cèrcol superior. S’ha descrit la seva síntesis i s’ha investigat la seva dimerització en dissolvents orgànics no-polars en presència de salts de tetrametilfosfoni. També es descriuen els intents de foto-isomerització tant dels monòmers com dels agregats de les tetra-ureas. Finalment, s’ha sintetitzat un calixarè tetra-urea amb quatre grups espiropirà al cèrcol superior. S’ha estudiat el seu auto-assemblatge en capsules homo- i hetero- dimèriques, aquesta última en presència d’un calix[4]pirrole i un N-òxid. S’han realitzat estudis d’auto-assemblatge, “self-sorting”, estudis foto- i acido- cròmics de les capsules en dissolvents clorats. Els resultats suggereixen que els tractaments àcid-base de les capsules són reversibles i pronostiquen bons resultats en el transport i alliberament controlat de molècules.El objetivo del trabajo de investigación incluido en esta tesis es el diseño y síntesis de sistemas receptor-huésped capaces de responder a estímulos externos. Estos sistemas cuentan con interruptores moleculares fotosensibles unidos covalentemente al receptor o al huésped. Los interruptores moleculares presentados son hemitioindigos y espiropiranos, mientras que las estructuras macrocíclicas están basadas en calix[4]arenos y calix[4]pirroles. Se estudió cómo la irradiación con luz y el tratamiento acido-base inducen la isomerización del interruptor molecular, así como el efecto que este proceso tiene en la afinidad de enlace y las propiedades de encapsulación de los receptores unimoleculares y las cápsulas supramoleculares. Se describe la síntesis de dos hemitioindigo N-oxidos. Se investigó su fotoisomerización reversible Z/E con luz visible (λ = 450 nm) al mismo tiempo que se realizó un estudio detallado de la interacción 1:1 y su efecto en la isomerización Z- y E-HTI en la cavidad aromática polar de un calix[4]pirrol super aril-extendido en disolvente orgánico. A continuación, se diseñaron y sintetizaron dos calix[4]arenos tetraurea decorados con cuatro hemitioindigos en su parte superior. Se describen los intentos de sintetizar dichos receptores y su dimerización en una variedad de disolventes orgánicos apolares y en presencia de tetrametil fosfonio. También se describe la fotoisomerización de las tetraureas en su estado monomérico y formando agregados. Finalmente, se sintetizó un calix[4]areno con unidades tetraurea capaz de responder a estímulos externos que cuenta con cuatro espiropiranos en su parte superior. Este receptor se auto ensambla formando capsulas homo- y heterodiméricas, esta última en presencia de un calix[4]pirrol similar y un N-oxido adecuado. Se discuten los estudios de auto-ensamblaje, “self-sorting”, foto- y acidocrómicos de dichos sistemas capsulares en disolventes clorados. Los resultados apuntan a que el tratamiento acido-base es reversible y predicen un buen comportamiento para su uso como transportadores y liberación de moléculas.
The aim of the research work included in this doctoral thesis is the design and synthesis of stimuli-responsive host-guest systems in which photoswitchable units are covalently incorporated into either the receptor’s or the guest’s scaffold. We use two photoswitches with distinct properties, hemithioindigos and spiropyrans, and two types of macrocyclic scaffolds based on calix[4]arene and calix[4]pyrrole. We study how light-irradiation and acid-base treatments induce the isomerization of the molecular switch. We were especially interested in coupling the isomerization processes with the binding affinity and the encapsulation properties of unimolecular receptors and supramolecular capsules, respectively. First, we describe the synthesis and photochemical characterization of two hemithioindigos featuring a terminal N-oxide moiety. We probe their Z/E reversible photoisomerization with visible light (λ = 450 nm) and we provide a detailed study of the 1:1 binding and its effect on the switching of the Z- and E-HTI isomers into the polar aromatic cavity of a super aryl-extended calix[4]pyrrole receptor in organic solvent. Next, we design and synthesize two tetraurea calix[4]arenes decorated with four hemithioindigo units at the upper rim. We describe the synthetic efforts to obtain these receptors and we investigate their dimerization in a variety of non-polar organic solvents and in the presence of tetramethyl phosphonium salts. We also report the tentative photoisomerization of the tetraureas in the monomeric state and involved in aggregates. Finally, we synthesize a stimuli-responsive tetraurea calix[4]arene featuring four appended spiropyran groups at its upper rim, which self-assembles into a homo- or heterodimeric capsule, the latter in the presence of a calix[4]pyrrole counterpart and a suitable N-oxide templating guest. The self-assembly, self-sorting, photo- and acidochromic studies of the capsular systems in chlorinated solvents are discussed. Our results suggest that the acid-base treatments are reversible and augur well for the transport and release of molecular cargo.
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Biplab, Rajbanshi. "Investigation of host- guest inclusion complexation of some biologically potent molecules and solvent consequences of some food preservations with the manifestation of synthesis, characterization and innovative applications." Thesis, University of North Bengal, 2020. http://ir.nbu.ac.in/handle/123456789/3963.
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Windsor, Hunter Jackson. "Spin State Modulation of Nanoporous Frameworks by Guest Molecule Encapsulation." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/27415.
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The targeted engineering of multifunctional devices displaying facile switching behaviours is a pervasive yet difficult problem to solve. One solution is to develop spin crossover (SCO) nanoporous metal–organic frameworks (MOFs) that couple a reversible and fatigue-resistant electronic rearrangement with other modalities such as redox activity, luminescence, or molecular recognition, thereby producing multistimuli responsive switches. Materials which display such dynamic responsiveness to a range of stimuli have already seen widespread use as nanomechanical actuators, thermochromic pigments, optical display devices, and pressure sensors within materials science.
2,1,3-Benzothiadiazole (2,1,3-BTZ) is one heterocyclic unit known to be redox-active and exhibit high fluorescence quantum yields. The aim therefore of this thesis is to synthesise a family of nanoporous SCO MOFs that incorporate pillaring ligands based on the 2,1,3-BTZ moiety; to then characterise their thermal spin-state dependence via magnetometry and diffraction techniques; and to probe the interplay between spin, redox, and fluorescent states. The study also seeks to investigate the effect that guest molecule encapsulation within the pore structures of these MOFs has on their SCO behaviour. These will primarily include electron-rich polycyclic aromatic hydrocarbons (PAHs) and perfluorinated aryliodides. Such guest molecule encapsulation in other host–guest systems has been proven to be an effective methodology towards modulating the electronic band and resonance structures of the host compound and has applications within designing new semiconductors
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Roy, Niloy. "Synthesis, characterization and innovative applications of inclusion complexes and nanocomposites of some biologically potent molecules." Thesis, University of North Bengal, 2022. http://ir.nbu.ac.in/handle/123456789/4754.
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Montalvo, Acosta Joel José. "Computational approaches to molecular recognition : from host-guest to protein-ligand binding." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF051/document.
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La reconnaissance moléculaire est un problème très intéressant et surtout un défi actuel pour la chimie biophysique. Avoir des prévisions fiables sur la reconnaissance spécifique entre les molécules est hautement prioritaire, car il fournira un aperçu des problèmes fondamentaux et suscitera des applications technologiques pertinentes. La thèse présentée ici est centrée sur une analyse quantitatif de la reconnaissance moléculaire en solution pour la liaison l'hôte-invité, la liaison protéine-ligand et la catalyse. Le cadre de la mécanique statistique utilisé pour décrire l'état de la technique de liaison récepteur-ligand est un point d'inflexion pour le développement de nouvelles méthodes améliorées. En fait, un modèle très performant et précis a été obtenu pour l'analyse de la liaison hôte-invité. Enfin, les modèles présentés ont été utilisés comme outils prédictifs fiables pour la découverte de nouvelles entités chimiques destinées à améliorer la catalyse en solutionMolecular recognition is a very interesting problem, and foremost, a current challenge for biophysical chemistry. Having reliable predictions on the specific recognition between molecules is highly priority as it will provide an insight of fundamental problems and will raise relevant technological applications. The dissertation presented here is centered on a quantitative analysis of molecular recognition in solution for host-guest, protein-ligand binding and catalysis. The statistical mechanics framework used to describe the state-of-the-art for receptor-ligand binding is an inflection point for the developing of new improved and methods. In fact, a highly performanced and accurate model was obtained for the analysis of host-guest binding. Finally, the presented models were used as a reliable predictive tools for discovering new chemical entities for enhance catalysis in solution
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White, Tim Chemistry Australian Defence Force Academy UNSW. "Supramolecular chemistry and synthesis of Cucurbit[n]uril." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Chemistry, 2003. http://handle.unsw.edu.au/1959.4/38643.
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The recently discovered cucurbit[n]uril are a range of macrocyclic hosts which have enormous potential in industrial, medical and academic applications. Cucurbit[n]uril have a rigid repeating structure of methylene bridged glycouril, which give cucurbit[n]uril their gourd like shape of a cavity with two carbonyl fringed portals. In this thesis the host-guest binding abilities of three cucurbit[n]uril (n = 6, 7, 8) have been examined for a range of potential guests. These guests ranged from simple alkyl amines through globular alkyl and carboranyl amines to bipyridyl systems. In total 45 guest molecules where examined. Most of the guests examined where either cationically charged, capable of hydrogen binding, contained a substantial molecular dipole, or a combination of these. Furthermore, all of the potential guests examined had some solubility in an acidified aqueous sodium sulfate solution within which the host-guest properties were examined. It was generally found that the larger guests did have selectivity for the larger hosts. However, when the host became too large weaker complexes would form and for the range of materials examined here cucurbit[7]uril was found to be the 'best' host system. In one example, p-xylene diamine, a 2:1 complex with cucurbit[8]uril was observed. While not the focus of this work a new rapid purification method was developed for the cucurbit[n]uril using different metal ions to either solubilise or precipitate the different cucurbit[n]uril. In the second part of this work these same guest molecules where used as potential templates in the synthesis of cucurbit[n]uril. Surprisingly the guests that bound strongly to an individual host did not seem to template the cucurbit[n]uril synthesis at all. Rather these strong binders inhibited the reaction such that little or no cucurbit[n]uril formed under the reaction conditions studied. However, several examples provided excellent template results. Indeed the results indicate that guests which bound with intermediate rates of exchange are the best templates and using templates under these conditions we have been able to produce cucurbit[7]uril as 46% by mass of the total cucurbit[n]uril product. This is the highest yield ever recorded for cucurbit[7]uril and it is the first example of cucurbit[7]uril being the major product of this condensation reaction. In an another example cucurbit[8]uril formed 18% of the product an increase of 150% over the standard reaction conditions. While studying both the template reactions and the host-guest binding properties of the cucurbit[n]uril a new supramolecular form, an 'inverse rotaxane' was discovered. Inverse rotaxanes are not held in place by large blocking groups, rather the molecular structure encapsulated by the cucurbit[n]uril host prevents decomplexation of the axle.
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ZEHNDER, DONALD WILLIAM. "HOST-[2]ROTAXANE: A NOVEL MOLECULAR MACHINE." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1051188602.
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MacGillivray, Leonard R. "Self-assembly for the construction of discrete and infinite host-guest architecture /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924903.
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Norrehed, Sara. "Modulation of Molecular Properties : Host–Guest Interactions for Structural Analysis and Chemical Reactions." Doctoral thesis, Uppsala universitet, Syntetisk organisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-207138.
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This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems. Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined. To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted. Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation. Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.
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García, Simón Cristina. "Synthesis of molecular nanocapsules for supramolecular host-guest chemistry and enzyme-like catalysis." Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/289567.
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Coordination-driven self-assembly has led to the realization of an increasing number of elegant and sophisticated functional structures, the structural complexity of which would be difficult to achieve using conventional covalent chemistry. The synthesis of three-dimensional coordination capsule-like structures is of particular interest due to their multiple potential applications, particularly their use in selective molecular recognition (host-guest chemistry), reactivity modulation (nanoreactors), molecular sensors or biological applications.
The main goal of this doctoral thesis, performed in the QBIS-CAT group from the University of Girona, is the preparation of coordination nanocapsules of different sizes (1 and 2) and their application in the selective recognition of specific molecular substrates. On one hand, the smaller capsule (1) displays high selectivity towards anionic, planar-shaped -guests, whilst on the other hand, the larger nanocapsule (2) is able to encapsulate fullerenes in a rapid manner at room temperature, by simply soaking a solid sample of the capsule in a fullerene containing solution. Strikingly, the larger nanocapsule is shown to be effective for the selective separation of C60 from a mixture of fullerenes using a straightforward washing protocol of a solid sample of fullerene containing nanocapsule. Nowadays, the applications of fullerenes (i.e. in solar cells or in medicine) are limited in origin by their purification which is often tedious and expensive. The results of this investigation may pave the way for the future development of new methodologies for the purification of fullerene mixtures.
Finally, the confined inner cavity of the larger nanocapsule, 2, was used to encapsulate a chiral rhodium catalyst which gave amongst the highest selectivities in the asymmetric hydroformylation of styrene for a monoligated rhodium catalyst. The results obtained demonstrate a substantial increase in stereoselectivity upon encapsulation of the catalyst, providing evidence of a selectivity-inducing effect by the secondary coordination sphere reminiscent of enzymatic active sites.La química d’autoacoblament dirigida per enllaços de coordinació ha facilitat l’obtenció d’una gran varietat d’estructures químiques molt sofisticades, la complexitat de les quals hagués estat molt difícil d’aconseguir mitjançant la convencional química covalent. La síntesis de càpsules de coordinació tridimensionals rep un interès especial degut a la multitud d’aplicacions que aquestes ofereixen, destacant la seva aplicació en el reconeixement selectiu de molècules (química receptor-substrat), modulació de la reactivitat (nanoreactors), sensors moleculars o les seves aplicacions biològiques. El principal objectiu d’aquesta tesi doctoral, que ha estat realitzada al grup QBIS-CAT de la Universitat de Girona, és la preparació de nanocàpsules de coordinació de diferents mides (1 i 2), i la seva aplicació en el reconeixement selectiu de substrats moleculars específics. Per una banda, la nanocàpsula més petita (1) és altament selectiva per substrats plans, aniònics amb sistemes . Per altra banda, la nanocàpsula de majors dimensions (2) pot encapsular ful·lerens de manera ràpida i a temperatura ambient, simplement amarant una mostra sòlida de la nanocàpsula en una dissolució de ful·lerens. A més, la nanocàpsula més gran es va emprar amb èxit en la separació selectiva de C60 d’una barreja de ful·lerens utilitzant un senzill protocol experimental basats en rentats del sistema nanocàpsula-ful·lerè en estat sòlid. Actualment, les aplicacions dels ful·lerens (ex. en cel·les solars o en medecina) es veuen limitades per la purificació d’aquestes molècules, que generalment s’aconsegueix mitjançant processos tediosos i costos. Els resultats d’aquesta investigació podrien facilitar el desenvolupament de noves metodologies per la purificació de barreges de ful·lerens. Finalment, la cavitat interior de la nanocàpsula de majors dimensions, 2, es va utilitzar per encapsular un catalitzador de rodi quiral que va donar alts valors de selectivitat, dels més alts que s’han observat per a un catalitzador de rodi monolligat. Els resultats obtinguts demostren que l’encapsulació del catalitzador incrementa notablement l’estereoselectivitat de la reacció, i indiquen que el confinament del catalitzador dins la caixa causa un efecte d’inducció de la selectivitat similar al que té lloc en els centres catalítics dels enzims.
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Shin, Du Hyun. "Host-Guest Assemblies for Functional Interfaces via Langmuir-Blodgett and Self-Assembly Technique." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/54573.
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Various technologies depend on interfacial events that are influenced by various molecular interactions at a solid-liquid interface. The functionality of a surface plays an important role in many applications such as catalysis, sensing, and bio-compatibility, which can benefit from distinctive chemical and physical surface properties. To create tailor-made functional surfaces, surface host-guest assemblies based on Langmuir-Blodgett and self-assembly technique have been employed as a model system as they may offer the potential ability to regenerate surface properties via intercalation of various functional guest molecules. This thesis ranges over the development and characterization of host-guest assemblies and their feasibilities for the regeneration of surface properties via intercalation of functional guests. In our work, 3-dimensional host structures with cavities are constructed on a targeted solid substrate using Langmuir-Blodgett and self-assembly techniques. In particular, by adopting the fundamental concept of host-guest interaction in supramolecular chemistry, we expect that structurally homologous guest molecules where functional groups are anchored can be intercalated into the cavities between hydrophobe arrays at the liquid-solid interface from solution under well-controlled conditions. This approach offers the potential of separating the functional of the monolayer from the inherent structure of the host.
The first part of this thesis details two-dimensional host-guest assemblies consisting of guanidinium (G), octadecylsulfonate (S) and various functional alkane guests at the air-aqueous interface and following deposition onto solid substrates via the Langmuir-Blodgett technique. In particular, we evaluated the stability of the host-guest assemblies and the feasibility of exchanging molecular guests under exposure to various organic solvent environments. Analysis of X-ray reflectivity measurements of the thin films showed that good stability of the host-guest assembly could not be achieved due to weak interactions between the host monoalyer and the solid surface. In addition, no evidence of intercalation of guest molecules into guest-free host-cavities was observed.
The second part of this thesis discusses the effective methodologies to prepare low-density self-assembled monolayers (LDSAMs) with cavities on silicon substrates. We employed a step-wise reaction based on hydrolytic or silane chemistry: integral spacer molecules such as anthracene-derivatives were anchored to the Si substrate and then long alkane chains were appended to the spacer molecules. The results showed that LDSAMs using an anthryl spacer are attached at the SAM/Si interface via a Si-O-C linkage, and the films do not exhibit a densely packed monolayer quality as would be expected for a non-sterically hindered alkyltrichlorosilane on Si. Thus, the resulting LDSAMs (with cavities) may be capable of accommodating other guest molecules with hydrocarbon chains through intercalation in order to form host-guest assemblies.
The third part of this thesis demonstrates the ability of LDSAMs to produce functional surfaces via the intercalation of various functional guest molecules. Self-assembled monolayers of (10-octadecyl)-9-anthracenethiol (host-SAMs) on Au substrates were prepared. Quartz crystal microbalance with dissipation (QCM-D) measurements was used to demonstrate the capacity of LDSAMs to confine guest molecules in the cavities and to probe the structural changes of the host-guest assembly during guest intercalation from ethanol solution. X-ray photoelectron spectroscopy (XPS) measurements were then used to probe host-guest monolayers formed by immersing the host monolayer in solutions in a variety of other solvents. A combined study of QCM-D and XPS showed that guest molecules were intercalated into host-cavities. The reversibility of the intercalation process allows a guest already situated in a host-cavity to be replaced with second guest under well-regulated solvent conditions.Ph. D.
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SMUKSTE, INESE. "ARTIFICIAL RECEPTORS FOR MOLECULAR RECOGNITION OF AMINO ACIDS, PEPTIDES AND CARBOHYDRATES." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029757614.
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Rieth, Stephen E. "An Investigation into the Effects of Gating in Artificial Host Systems." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1308098752.
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Chiba, Yusuke. "Template Synthesis of Structure-Controlled Porphyrin Tubes and Those Inclusion and Optical Properties." Kyoto University, 2018. http://hdl.handle.net/2433/232050.
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Kai, Sze-fai Alex. "Design and synthesis of luminescent Rhenium(I) and Ruthenium(II) Diimine complexes for the recognition of ions and small molecules by host-guest interactions /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20567091.
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Saha, Subhadeep. "Study to explore the formation of host - guest inclusion complexes of cyclodextrins with biologically active moleculars and crown ethers with ionic liquids by spectroscopic and physicochemical techniques." Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2648.
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Laughery, Zachary. "Synthesis of Molecular Baskets and Introduction of Inward Facing Functionality." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/328.
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As a first step to producing a shape selective catalysts or enzyme mimic, two preorganized host molecules were synthesized. Binding studies of the two hosts with a variety of guests in three solvents demonstrated that an important driving force in the association was the formation of C-H???X-R hydrogen bonds (X = halogen). A deuterated host was utilized to further examine the formation of the C-H???X-R hydrogen bonds. In an effort to place functionality in the hydrophobic pocket of these hosts, two methods were developed. The first utilized directed ortho metallation to place electrophiles above and/or directed into the cavity. Perlithiation of the host could lead to sixty-nine products but reaction conditions and host rigidity limited product formation. This reaction technique led to the placement of carboxylic acid groups onto the host and the isolation of twelve products. Two different positions of the carboxylic acids (endoand exo-) direct the orientation of the guest. 1D- and 2D-NMR were utilized to examine how the was orientated inside the host. The second method employed to place functionality on the host, sited a tripodal zinc binding ligand on the side of the hydrophobic pocket of the host. The synthesized host was able to bind zinc strongly and in a 1:1 manner.
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Sun, Liansheng. "Studies on the Syntheses and Properties of Cycloparaphenylenes Having Heteroatom Functionalities and New Topology." Kyoto University, 2020. http://hdl.handle.net/2433/253506.
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Blom, Magnus. "Light-Triggered Conformational Switches for Modulation of Molecular Recognition : Applications for Peptidomimetics and Supramolecular Systems." Doctoral thesis, Uppsala universitet, Syntetisk organisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267845.
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The main focus of this thesis is on photochemical modulation of molecular recognition in various host-guest systems. This involves the design, synthesis and integration of light-triggered conformational switches into peptidomimetic guests and molecular tweezer hosts. The impact of the switches on guest and host structures has been assessed by spectroscopic and computational conformational analysis. Effects of photochemical structure modulation on molecular recognition in protein-ligand and supramolecular host-guest systems are discussed. Phototriggerable peptidomimetic inhibitors of the enzyme M. tuberculosis ribonucleotide reductase (RNR) were obtained by incorporation of a stilbene based amino acid moiety into oligopeptides between 3-9 residues long (Paper I). Interstrand hydrogen bond probability in the E and Z forms of the peptidomimetics was used as a tool for predicting conformational preferences. Considerable differences in inhibitory potency for the E and Z photoisomers were demonstrated in a binding assay. In order to advance the concept of photomodulable inhibitors, synthetic routes towards amino acid derivatives based on the more rigid stiff-stilbene chromophore were developed (Paper II). The effect of E-Z isomerization on the conformational properties of peptidomimetic inhibitors incorporating the stiff-stilbene chromophore was also assessed computationally (Paper III). It was indicated that inhibitors with the more rigid amino acid derivative should display larger conformational divergence between photoisomers than corresponding stilbene derivatives. Bisporphyrin tweezers with enediyne and stiff-stilbene spacers have been synthesized, and the conformational characteristics imposed by the spacers have been studied and compared to a glycoluril linked tweezer. The effects of spacers on tweezer binding of diamine guests and helicity induction by chiral guests have been investigated (Paper IV). Connections between spacer flexibility and host-guest binding strength have been established. The structural properties of the stiff-stilbene spaced tweezer made it particularly susceptible to helicity induction by both monotopic and bitopic chiral guests. Finally, the possibility of photochemical bite-size variation of tweezers with photoswitchable spacers has been assessed. Initial studies have shown that photoisomerization of the tweezers is possible without photochemical decomposition. Conformational analyses indicate that isomerization should impact binding characteristics of the tweezers to a significant extent (Paper V).
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Peñuelas, Haro Guillem. "Towards Recognition of Polar Molecules in Water Using Calix[4]pyrrole Based Receptors." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670758.
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Aquesta tesi s’ocupa del disseny, síntesi i estudis d’unió de receptors amfifílics solubles en aigua per a la unió selectiva de molècules o residus polars neutres relacionats amb la salut humana. Amb aquesta finalitat, es van seleccionar receptors basats en calix[4]pirrol aril-estesos. Aquests andamis presenten una cavitat còncava tancada en un extrem per quatre grups polars (NHs de pirrol) i oberta al seu extrem oposat. Aquestes característiques permeten que les interaccions polars i no polars operin en sinergia per obtenir alts nivells d’afinitat i selectivitat. Específicament, es descriu el disseny, la síntesi i els estudis d’unió de tres generacions d’una nova família d’andamis calix[4]pirrols aril-estesos cavitats mitjançant grups fosfonat per a la unió selectiva de creatinina. Es descriuen les modificacions estructurals i les conclusions extretes de cada generació. Tot i que no es va aconseguir la selectivitat esperada, es van obtenir valors rellevants de constants d’unió per a alguns dels receptors estudiats (Ka ≈ 1000 M-1). Per a comprendre millor com funcionen aquests tipus de receptors en aigua, es va realitzar un estudi exhaustiu de les seves propietats d'unió utilitzant una sèrie d’hostes polars neutres. Els resultats derivats d’aquests estudis mostren que els receptors calix[4]pirrol son excel·lents amfitrions d’amides, urees i N-òxids de piridina en aigua, obtenint valors de constant d’unió majors que 100000 M-1. Es va demostrar que els receptors calix[4]pirrol són millors donadors d’enllaç d’hidrogen que l’aigua. També es descriu el disseny i la síntesi de dos nous receptors calix[4]pirrol amb tirants que presenten terminacions dendrítiques ionitzables per a la unió selectiva de monosacàrids. L’estratègia sintètica optimitzada es discuteix en detall. Es van realitzar estudis d’unió amb un dels receptors sintetitzats amb octil-D-glucòsid en medi orgànic. Els resultats extres d’aquests experiments representen un bon auguri per a la seva transferència a solució aquosa.Esta tesis se ocupa del diseño, síntesis y estudios de unión de receptores anfifílicos solubles en agua para la unión selectiva de moléculas o residuos polares neutros relacionados con la salud humana. Con este fin, se seleccionaron receptores basados calix[4]pirrol aril-extendido. Estos andamios presentan una cavidad cóncava cerrada en un extremo por cuatro grupos polares (NHs de pirrol) y abiertos en su extremo opuesto. Estas características permiten que las interacciones polares y no polares operen sinérgicamente para obtener altos niveles de afinidad y selectividad. Específicamente, describimos el diseño, síntesis y estudios de unión de tres generaciones de una nueva familia de andamios calix[4]pirroles aril-extendidos cavitados mediante grupos fosfonato para la unión selectiva de creatinina. Se describen las modificaciones estructurales y las conclusiones extraídas de cada generación. Aunque no se logró la selectividad esperada, se obtuvieron valores relevantes de constantes de unión para algunos de los receptores estudiados (Ka ≈ 1000 M-1). Para comprender mejor cómo funcionan estos tipos de receptores en el agua, realizamos un estudio exhaustivo de sus propiedades de unión utilizando una serie de huéspedes neutros polares. Los resultados derivados de estos estudios mostraron que los receptores calix[4]pirrol son excelentes anfitriones de amidas, ureas y N-óxidos en agua, obteniendo valores de constante de unión mayores de 100000 M-1. Pudimos demostrar que los receptores calix[4]pirrol son mejores dadores de enlaces de hidrógeno que el agua. También describimos el diseño y la síntesis de dos nuevos receptores calix[4]pirrol con tirantes que presentan terminaciones dendríticas ionizables para la unión selectiva de monosacáridos. La estrategia sintética optimizada se discute en detalle. Realizamos estudios de unión con uno de los receptores sintetizados en medio orgánico con octil-D-glucósido. Los resultados extraídos de estos experimentos representan un buen augurio para su transferencia a solución acuosa.
This thesis deals with the design, synthesis and binding studies of water-soluble amphiphilic receptors for the selective binding of polar neutral molecules or residues related to human health. To do so, we selected aryl-extended calix[4]pyrrole based receptors. These scaffolds deliver a concave cavity closed at one end by four polar groups (pyrrole NHs) and opened at their opposite end. These features allow polar and non-polar interactions to operate synergistically to obtain high levels of affinity and selectivity. Specifically, we describe the design, synthesis and binding studies of three generations of a novel family of phosphonate cavitands based on aryl-extended calix[4]pyrrole scaffolds for the selective binding of creatinine. The structural modifications and the conclusions extracted from each generation are described. Although the expected selectivity was not accomplished, large binding constants were obtained for some of the studied receptors (Ka ≈ 1000 M-1). In order to better understand how these types of receptors function in water, we performed a thorough study of their binding properties using a series of polar neutral guests. The results derived from this studies showed that calix[4]pyrroles are excellent hosts for amides, ureas and N-oxides in water, reaching binding constant values larger than 100000 M-1. We could demonstrate that calix[4]pyrrole receptors are better hydrogen bonding donors than bulk water. We also report the design and synthesis of two novel strapped calix[4]pyrroles featuring ionizable dendritic terminations for the selective binding of mono-saccharides. The optimized synthetic strategy is discussed in detail. We performed binding studies with one of the synthesized receptors in organic media with octyl-D-glucoside. The extracted results from these experiments augur well for its transfer to aqueous solution.
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Chaffee, Kathleen Elizabeth. "'Amplifying' the NMR signatures of host-guest interactions and molecular structure using liquid-crystalline matrices and polarization enhancement of nuclear spins." OpenSIUC, 2008. https://opensiuc.lib.siu.edu/dissertations/250.
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Nuclear magnetic resonance (NMR) spectroscopy has been extensively used to investigate the structure and dynamics of host-guest systems. NMR spectroscopy has gained attention because of its high spectral information content for studies of molecules in the solid state and in solution. However, the main weakness of NMR is the inherent low detection sensitivity. Host-guest interactions are weak; therefore these interactions can be particularly difficult to study due to weak spectral response. NMR methods are currently the best solution for measuring these responses with atomic-scale precision. Improving upon these limitations is the main goal of this dissertation research using laser-polarized xenon, liquid crystals, and polarization exchange pulse sequences. The first five chapters review the basics of NMR spectroscopy that is used throughout this dissertation. Chapters one and two concern the fundamental elements of liquid-state and liquid-crystal NMR spectroscopy. The third chapter deals with the properties of organic thermotropic and lyotropic liquid crystals including the ZLI 1132 and PBLG. Chapter four presents the theoretical and experimental aspects of optical pumping laser-polarized xenon and properties of xenon. An overview of the dissertation research is described in chapter six. Chapter seven describes the procedures for synthesizing many of the cryptophanes used in the NMR experiments in this dissertation. The cryptophanes synthesized include cryptophane-A, cryptophane-223, and cryptophane-E as well as the water-soluble derivatives of each. The eighth and ninth chapters investigate the binding kinetics of hydrocarbon and hydrogen gases to cryptophane-111 in organic solutions. Chapter ten illustrates the utility of liquid crystalline-aligned cryptophanes (bis- and cryptophane-A) reintroducing dipolar couplings in solution. Chapter eleven describes the exploitation of the reintroduced dipolar coupling of the guest molecule to transfer the abundant 1H nuclear spin magnetization to the rare 13C spins to enhance NMR detection sensitivity using an adiabatic Hartmann-Hahn cross polarization pulse sequence. Chapter twelve describes cryptophanes of varying cavity size to probe the host-guest dynamic coupling (with chloroform as a guest ligand) aligned in PBLG. Finally, chapter thirteen introduces preliminary xenon @ cryptophanes aligned in liquid crystals to achieve intermolecular polarization transfer.
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Grommet, Angela B. "Coordination cages for the separation and transportation of molecular cargo." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274998.
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The first chapter of this thesis introduces the fundamental concepts governing the design and synthesis of supramolecular complexes. By illustrating the synthesis of several coordination cages reported in the literature, the principles underlying the construction of coordination cages by subcomponent self-assembly are elucidated. Ionic liquids are then proposed as solvents for cage systems; general methods for the preparation and synthesis of these solvents are described. The second chapter explores the use of ionic liquids as solvents for existing coordination cages. Potential methods of characterising these cages in ionic liquids are discussed; cages are demonstrated to be stable and capable of encapsulating guests in these ionic environments; and systems in which cages have good solubility in ionic liquids are designed. Building upon these observations, a triphasic sorting system is presented such that each of three different host-guest complexes are soluble in only one of three immiscible liquid phases. In contrast to the static triphasic system described in the second chapter, the third chapter explores directed phase transfer of coordination cages and their cargos from water, across a phase interface, and into an ionic liquid phase. The host-guest complex can then be recycled from the ionic liquid layer back into water after several additional steps. Furthermore, phase transfer of cationic cages is used to separate a mixture of cationic and anionic host-guest complexes. In the fourth chapter, fully reversible phase transfer of coordination cages is developed. Using anion exchange to modulate the solubility of three different cationic cages, reversible transport between water and ethyl acetate is demonstrated. Sequential phase transfer can also be achieved such that, from a mixture of cubic (+16) and tetrahedral (+8) cages, the cubic cage transfers from water to ethyl acetate before the tetrahedral cage. This process is fully reversible; upon the addition of a hydrophilic anion, the tetrahedral cage returns from ethyl acetate to water before the cubic cage.
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Lavendomme, Roy. "Development of strategies for the highly selective functionalization of calixarenes and study of host–guest properties of calixarene-based molecular boxes." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/241320.
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Ce travail s’inscrit dans le cadre de l’étude de plateformes polyphénoliques et, plus spécifiquement, des calixarènes. Des macrocycles oligomériques tels que les calixarènes, cyclodextrines, cyclotrivératrylènes, pillararènes, etc. sont fortement utilisés dans de nombreuses applications telles que la reconnaissance moléculaire, la détection, la séparation, le greffage sur surface, etc. Le développement de telles applications requiert toutefois modification sélective de ces macrocycles pour leur conférer des propriétés utiles aux applications visées (e.g. affinité envers certaines espèces chimiques, hydrosolubilité, activité photoluminescente). La modification sélective de tels macrocycles oligomériques est cependant loin d’être triviale car, en plus de requérir un contrôle des chimio- régio- et stéréosélectivités classiques, la réaction d’un nombre défini de fonctions identiques est une problématique clé qui doit être résolue. En effet, la fonctionnalisation des oligomères cycliques tels que les calixarènes passe par la formation de produits mono-, di-, tri-fonctionnalisés, et ainsi de suite de manière itérative. Par analogie avec des processus itératifs, nous avons proposé le terme « itérosélectivité » pour décrire la sélectivité qui gouverne le nombre de transformations chimiques répétées. Dans ce contexte, nous avons proposé des stratégies rationnelles et hautement sélectives pour la fonctionnalisation de calixarènes. Ces stratégies exploitent principalement des réactions de carbamatation pour introduire sélectivement des groupements tert-butylaminocarbonyle (Bac) sur les positions phénoliques des calixarènes. Citons notamment la carbamatation « all-but-one » qui permet d’introduire itérosélectivement des groupements Bac sur tous les phénols sauf un pour une grande variété de calixarènes. De plus, l’utilisation de ces groupements Bac comme groupe protecteur nous a permis de synthétiser de nombreux dérivés calixaréniques jusqu’alors inaccessibles suivant les voies de fonctionnalisation connues. Certains de ces composés présentent notamment une chiralité inhérente. En dehors de nos travaux, aucune voie de fonctionnalisation sélective de calixarènes décrite à ce jour n’est aussi générale et efficace. Nous avons également présenté une nouvelle voie d’oxydation de calixarènes en calixquinones. Cette voie présente moins de risques pour la santé et l’environnement que la méthode la plus couramment utilisée à ce jour employant un sel de thallium, métal extrêmement toxique. Les différents aspects synthétiques développés ont permis de synthétiser des boites moléculaires originales dérivées de calixarènes qui ont été étudiées pour leurs propriétés intéressantes dans le cadre de la reconnaissance sélective de petites molécules dont l’eau et le DMSO, ainsi que le piégeage de gaz à l’état solide dont l’hexafluorure de soufre qui est le gaz à effet de serre le plus puissant répertorié à ce jour. Pour finir, la caractérisation poussée d’une bibliothèque de dérivés calixaréniques par spectroscopie de résonance magnétique nucléaire a permis de décrire une méthode générale pour la caractérisation structurale et conformationnelle des calixarènes.This work concerns the study of polyphenolic platforms, and more particularly, of calixarenes. Oligomeric macrocycles such as calixarenes, cyclodextrins, cyclotriveratrylenes, pillararenes, etc. are widely used as molecular platforms in supramolecular chemistry and in particular for the design of sensors, catalysts, multivalent systems, biomimetic receptors, etc. In general, the synthesis of such supramolecular systems requires the controlled introduction of functional groups on the precursor platform. However, the development of efficient methods for selective modification of macrocyclic oligomers remains extremely challenging. Indeed, in addition to the control of the classical chemo-, regio-, and stereoselectivities, the reaction of a defined number of identical functional groups is a key issue that must be solved. Indeed, the functionalization of oligomeric macrocycles such as calixarenes goes through the formation of mono-, di, tri-functionalized products and so on, iteratively. By analogy with iterative processes, we proposed to name “iteroselectivity” the kind of selectivity that governs the number of repeating chemical transformations. In this context, we proposed rational and highly selective strategies for the functionalization of calixarenes. These strategies are mainly based on the carbamatation of calixarene phenolic functions to introduce tert-butylaminocarbonyl groups (i.e. Bac groups). Our leading example is the “all-but-one” carbamatation which can be used to introduce Bac groups on all but one phenol of a large variety of calixarenes. Moreover, using Bac groups as protecting groups led to the synthesis of numerous calixarene derivatives which were, until now, not accessible through conventional means. It is noteworthy that some of these compounds are inherently chiral. No other selective functionalization method described for calixarenes is as general and efficient than this “all-but-one” carbamatation. Besides, we also described a new oxidation method to synthesize calixquinone starting from calixarenes. This method is less risky and more environment-friendly than the most commonly used method which rely on thallium salts, an extremely toxic metal. Through the various synthetic methods developed herein, we also developed calixarene-based molecular boxes. The host–guest properties of these molecular boxes were studied revealing their ability to include small molecules such as water or DMSO. We also developed a method to sequester gases in the solid state relying on an original concept involving calix[6]arene-based molecular boxes. This was exemplified with the sequestration of SF6, known as the most potent greenhouse gas. At last, the extensive characterization of a library of calixarene derivatives by nuclear magnetic resonance spectroscopy led to the development of a general method for the structural and conformational characterization of calixarenes.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Chaffee, Kathleen E. "'Amplifying' the NMR signatures of host-guest interactions and molecular structure using liquid-crystalline matrices and polarization enhancement of nuclear spins /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1674093171&sid=7&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (Ph. D.)--Southern Illinois University Carbondale, 2008."Department of Chemistry and Biochemistry." Keywords: Cross-polarization, Cryptophanes, Host-guest chemistry, Liquid crystals, Supramolecular, Host-guest interactions, Polarization, Nuclear spins. Includes bibliographical references (p. 172-185). Also available online.
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Ioup, Sarah E. "Water-Soluble Deep-Cavity Cavitands: Synthesis, Molecular Recognition, and Interactions with Phospholipid Membranes." ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1572.
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Water-soluble deep-cavity cavitands provide a rare opportunity to study self-assembly driven by the hydrophobic effect. These molecular hosts dimerize in the presence of certain guest molecules to form water-soluble molecular capsules. These systems have given rise to numerous novel chemical phenomena and have potential use in drug delivery. The host octaacid (OA) has been particularly well-characterized, but studies are limited to basic pH because of limited host solubility.
Herein we report an improved synthesis of OA and the syntheses of three new water-soluble deep-cavity cavitands. The new hosts are soluble at neutral pH, increasing relevance for biological studies. The new syntheses are versatile enough to apply to the synthesis of additional water- soluble cavitands in the future. We also describe preliminary characterization of the molecular recognition properties of the new hosts. Binding of organic guest molecules to form 1:1 host:guest complexes and 2:1 host:guest capsules was qualitatively similar to that of OA. However, binding of anions spanning the Hofmeister series revealed interesting new behavior. The new hosts bound a wider range of anions inside the hydrophobic pocket with much higher association constants. Moreover, external binding of several anions to the cavitand pendant feet was observed.
Looking towards biological applications, we desired to learn how these molecules interact with phospholipid membranes. Six water-soluble cavitands were tested for their ability to permeabilize liposomal POPC membranes. One host showed very high potency in permeabilizing membranes, while three other hosts showed moderate activity. Host binding of POPC was found to be at least one factor in host-induced permeabilization. A requenching assay to determine leakage mechanism strongly supported all-or-none leakage, whereby some vesicles lose all contents while others lose none. These results suggest that these cavitands induce partial transient leakage of vesicles by the formation of transient membrane pores. These findings show potential for the use of these hosts as drug delivery carriers, antimicrobial compounds, and tools in membrane alteration studies.
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Pederson, Adam Micheal-Paul. "Efficient Syntheses of Strong Binding Cryptands and their Derivatives for Supramolecular Polymer Synthesis." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26128.
Full textAbstract:
Production of efficiently synthesizable, strongly associating crown ether-based cryptands is desired for pseudorotaxane complexation of bipyridinium guests to produce suprapolymers and supramolecularly-linked block copolymers.
Cryptands based on bis(meta-phenylene)-32-crown-10 (BMP32C10) were synthesized. The functionality of phenylenemethanol-BMP32C10 cryptand III-3 (Ka = 2.0 x 104 M-1) did not negatively affect binding strength, although the strength of complexation is marginal to achieve the desired suprapolymers. The cryptand dimethylpyridyl-BMP32C10 IV-2 was synthesized in an attempt to improve over the binding ability of the pyridyl-BMP32C10 cryptand IV-1; instead, interesting host design insights were discovered as binding strengths were reduced over 1000-fold. The crystal structure of IV-2 shows acyl-aryl conjugation which limits the hostâ s ability to accept guests.
Synthesis of larger cis-di(carbomethoxybenzo)-3n-crown-n crown ethers was explored using the high concentration, template technique previously reported for cDB24C8 diester. cDB30C10 diester (V-1c) was produced in 93% yield; the desired pyridyl-cDB30C10 cryptand V-12 binds paraquat strongly (Ka = 1-2x105 M-1) and diquat stronger than any other host (Ka = 1.9x106 M-1), both in 1:1 fashions; association constants were measured by ITC. X-ray crystallography of the complexes shows the cryptandâ s para arm is too far away to interact with paraquat and the host has numerous bifurcated interactions with diquat, explaining the difference in binding strengths.
Syntheses of the regioisomers of cDB27C9 diester was also explored; the cyclization yields (cDB27C9S, VI-2: 59% and cDB27C9L, VI-3: 44%) are lower, likely due to poor attack angles due to mismatched arm length in cyclization, than the equivalent length ethyleneoxy-armed cDB24C8 and cDB30C10. Modeling of the cryptand isomers, pyridyl-cDB27C9S and pyridyl-cDB27C9L, showed that the former should improve para arm interaction with paraquat, but should be sterically hindered for diquat and the latter should have a highly flexible, poorly preorganized interaction with either type of guest. ITC, MS, and crystallography data supported the predictions.
Derivatization of the pyridyl-cDB30C10 cryptand V-12 was explored using chelidamic acid (VII-1). Schemes yielding alcohol, alkyl halide, alkyne, and TEMPO functionality were followed, but failed. Currently, functionalized cryptand derivatives have not been achieved, future directions are proposed.Ph. D.
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Shields, Dylan J. "Photochemistry of Organic Azides, Quinones, and Peroxides in Solution, Crystals, Super Molecular Complexes and Cryogenic Matrices." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin157441745178423.
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Polavarapu, Anjaneya Prasad. "Exploring Molecular Interactions : Synthesis and Studies of Clip-Shaped Molecular Hosts." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8220.
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Flynn, John J. "Optimizing the Discovery and Processability of Biologically Derived Molecular Glass Host Materials for Photonic Applications." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1588192751503223.
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Fox, Jack David. "Infrared vibrational spectra of tert-butyl halides in dehydrated NA-X and low-aluminum H-Y faujasites vibrational excitation exchange and other effects of guest-host interactions /." Diss., Online access via UMI:, 2006.
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Bouchet, Aude. "Étude des propriétés chiroptiques de cryptophanes hydrosolubles lors de l’encapsulation de molécules invitées." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14344/document.
Full textAbstract:
Les cryptophanes constituent une famille de molécules chirales qui comportent une cavité dans laquelle elles peuvent accueillir des espèces invitées de taille et de nature variables (halogénométhanes, xénon, cations). Nous nous sommes intéressés aux propriétés d’encapsulation présentées par trois espèces solubles dans l’eau : le cryptophane-A hexa-hydroxyle, le cryptophane-A penta-hydroxyle et le cryptophane-A hexa-acide carboxylique. La chiralité de ces systèmes a été utilisée pour en étudier les propriétés de complexation au moyen de techniques chiroptiques : la polarimétrie, le dichroïsme circulaire électronique (ECD) et le dichroïsme circulaire vibrationnel (VCD), cette dernière technique étant associée à des calculs de chimie théorique. Les effets de différents paramètres, tels que le pH de la solution et la nature des contre-ions, sur la complexation de molécules invitées ont été analysés. Les modifications conformationnelles induites sur les cryptophanes lors de l'encapsulation ont également été déterminées. De plus, des propriétés d'énantiodiscrimination de ces cryptophanes hydrosolubles énantiopurs vis-à-vis de petites molécules invitées chirales ont été mises en évidence. Enfin, ces cryptophanes ont montré une affinité exceptionnelle pour le cation césium Cs+ en solution aqueuse. Ces deux derniers résultats permettent d’envisager des applications intéressantes de ces systèmes en chromatographie chirale d’une part, et en chimie de l’environnement pour la détection de césium radioactif d’autre partCryptophanes derivatives are a family of chiral molecules containing a cavity which enables them to encapsulate guest species with variable size and nature (halogenomethanes, xenon, cations). We have been interested in the encapsulation properties of three different water soluble cryptophanes: hexa-hydroxyl cryptophane-A, penta-hydroxyl cryptophane-A and hexa-carboxylic acid cryptophane-A. The chirality of these systems have been exploited to study their complexation properties using chiroptical techniques: polarimetry, electronic circular dichroism (ECD) and vibrational circular dichroism (VCD), the latter being associated with theoretical calculations. The effects of different parameters such as the pH of the solution and the nature of the counter-ions on the complexation of guest molecules have been analyzed. The conformational changes induced on the cryptophanes upon encapsulation have been also determined. In addition, enantiodiscrimination properties of these enantiopure water soluble cryptophanes toward small chiral guest molecules have been evidenced. Finally, these cryptophanes have shown an exceptional affinity for the cesium cation Cs+ in aqueous solution. These last two results allow to consider interesting applications of these systems in chiral chromatography and environmental chemistry, in particular for the detection of radioactive cesium, respectively
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Escobar, González Luis. "Molecular containers based on aryl-extended calix[4]Pyrroles." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668442.
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Aquesta Tesi s'ocupa del disseny i síntesi de receptors còncaus que posseeixen cavitats hidrofíliques: receptors covalents, caixes metàl·liques i càpsules no covalents. Per a la seva construcció, triem la bastida de calix[4]pirrol aril-estès (C[4]P-AE), que proporciona una cavitat aromàtica profunda tancada en un extrem per un lloc d'unió polar i oberta a l'extrem oposat. També investiguem les propietats de reconeixement dels receptors sintetitzats en dissolvents orgànics així com en aigua. Específicament, descrivim un mètode sintètic per l'allargament de la cavitat de C[4]P-AEs que condueix a derivats súper aril-estesos (C[4]P-SAE). Primer, vam preparar un C[4]P-SAE tetra-èster i realitzem estudis d'enllaç amb una sèrie de N-òxids en dissolució de cloroform. Els complexos del C[4]P-SAE tenien una estequiometria 1:1 i eren termodinàmicament i cinèticament altament estables. Els resultats destaquen les propietats d'unió superiors del receptor C[4]P-SAE davant l'inicial aril-estès. A continuació, sintetitzem C[4]P-SAEs amb vuit grups ionitzables (octa-àcid) o carregats (octa-piridini). Els últims C[4]P-SAEs eren solubles en aigua bàsica o neutra. Nosaltres vam determinar l'estabilitat termodinàmica dels seus complexos d'inclusió amb una sèrie de N-òxids de piridina, que tenien diferents residus no polars en la seva posició per. En base a aquests resultats, quantifiquem la magnitud de l'efecte hidrofòbic que opera a aquests complexos de C[4]P-SAE. També reportem l'auto-assamblatge de caixes metàl·liques i càpsules, que presenten cavitats tancades. Referent a això, vam mostrar que un lligant C[4]P-SAE tetra-piridina s'auto-assembla en una caixa mono-metàl·lica de Pd(II)/Pt(II). Estudiem l'encapsulació de substrats polars de mida considerables en la cavitat de la caixa. Els resultats obtinguts en la caracterització cinètica dels complexos de la caixa ens van permetre proposar mecanismes d'inclusió/intercanvi dels substrats. Finalment, descrivim els estudis de dimerització d'una tetra-urea basada en un SAE-C[4]P per donar càpsules no covalents estabilitzades per enllaços d'hidrogen.Esta Tesis se ocupa del diseño y síntesis de receptores cóncavos que poseen cavidades hidrofílicas: receptores covalentes, cajas metálicas y cápsulas no covalentes. Para su construcción, elegimos el andamio de calix[4]pirrol aril-extendido (C[4]P-AE), que proporciona una cavidad aromática profunda cerrada en un extremo por un sitio de unión polar y abierta en el extremo opuesto. Nosotros investigamos las propiedades de reconocimiento molecular de los receptores sintetizados tanto en disolventes orgánicos como en agua. Específicamente, describimos un método sintético para el alargamiento de la cavidad de C[4]P-AEs que conduce a derivados súper aril-extendidos (C[4]P-SAE). Primero, preparamos un C[4]P-SAE tetra-éster y realizamos estudios de enlace con una serie de N-óxidos en disolución de cloroformo. Los complejos del C[4]P-SAE tenían una estequiometría 1:1 y eran termodinámicamente y cinéticamente altamente estables. Los resultados destacan las propiedades de unión superiores del receptor C[4]P-SAE frente al inicial aril-extendido. A continuación, sintetizamos C[4]P-SAEs con ocho grupos ionizables (octa-ácido) o cargados (octa-piridinio). Los últimos C[4]P-SAEs eran solubles en agua básica o neutra. Nosotros determinamos la estabilidad termodinámica de sus complejos de inclusión con una serie de N-óxidos de piridina, que tenían diferentes residuos no polares en su posición para. En base a estos resultados, cuantificamos la magnitud del efecto hidrofóbico que opera en estos complejos de C[4]P-SAE. También reportamos el auto-ensamblaje de cajas metálicas y cápsulas no covalentes, que presentan cavidades cerradas. A este respecto, mostramos que un ligando C[4]P-SAE tetra-piridina se auto-ensambla en una caja mono-metálica de Pd(II)/Pt(II). Estudiamos la encapsulación de substratos polares neutros en la cavidad de la caja. Los resultados obtenidos en la caracterización cinética de los complejos de la caja nos permitieron proponer mecanismos para los procesos de inclusión/intercambio de los sustratos. Finalmente, describimos los estudios de dimerización de un SAE-C[4]P tetra-urea en cápsulas diméricas estabilizadas a través de interacciones de enlaces de hidrógeno.
This Thesis deals with the design and synthesis of concave receptors possessing hydrophilic cavities: covalent receptors, metallo-cages and non-covalent capsules. For their construction, we chose the aryl-extended calix[4]pyrrole scaffold (AE-C[4]P), which delivers a deep aromatic cavity closed at one end by a polar binding site and opened at the opposite end. We investigated the binding properties of the synthesized receptors in both organic solvents and water. Specifically, we describe a synthetic approach for the elongation of the cavity of AE-C[4]Ps leading to super aryl-extended derivatives (SAE-C[4]P). First, we prepared a tetra-ester SAE-C[4]P and conducted binding studies with a series of N-oxides in chloroform solution. The SAE-C[4]P complexes had 1:1 stoichiometry and were thermodynamically and kinetically highly stable. The results highlight the superior binding properties of the SAE-C[4]P receptor versus the parent aryl-extended. Next, we synthesized SAE-C[4]Ps bearing eight ionizable (octa-acid) or charged (octa-pyridinium) groups. The later SAE-C[4]Ps were soluble in basic or neutral water. We determined the thermodynamic stability of their inclusion complexes with a series of pyridyl N-oxides, having different non-polar residues at their para-position. Based on these results, we quantified the magnitude of the hydrophobic effect operating in these SAE-C[4]P complexes. We also report the self-assembly of metallo-cages and non-covalent capsules, featuring enclosed cavities. In this regard, we show that a tetra-pyridyl SAE-C[4]P ligand self-assembles into a mono-metallic Pd(II)/Pt(II)-cage. We studied the encapsulation of neutral polar guests in the cage’s cavity. The results obtained in the kinetic characterization of the cage complexes allowed us to propose viable mechanisms for the guest inclusion/exchange processes. Finally, we describe the dimerization studies of a tetra-urea SAE-C[4]P into dimeric capsules stabilized through hydrogen-bonding interactions.
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Joiner, A. "Studies of guest-host chemistry." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384345.
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Lawrence, Amy. "Studies in host-guest chemistry." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/studies-in-hostguest-chemistry(3d13b4e2-f318-446d-b045-4b9f97247bcd).html.
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Previous work in our group has been directed towards the synthesis of crown-ethers for use in the selective complexation of metal ions and as chiral ligands for use in asymmetric catalysis. The development of a modular approach to macrocycle assembly has enabled the synthesis of a library of pyridine-based macrocycles possessing multiple donor sites where chirality was readily introduced from simple amino acids.The nucleophilic ring opening of aziridines 181, 193 or 194, allowed the highly selective synthesis of thioether-based spacers and macrocycles. Extension of this basic approach to the synthesis of seleno-crown ethers was also investigated. The use of chiral-pool starting materials derived from D- or L-alanine, provided access to optically pure macrocycles. The use of the Sharpless-Huisgen 'click' reactions allowed the attachment of a carbohydrate residue directly to a macrocycle via a triazole unit. We hope to attach a macrocycle, carbohydrate residue and azo dye together, to be able to examine further diseases such as Alzheimer's. We have so far succeeded in attaching a macrocycle and sugar to a central scaffold by performing a one-pot double 'click' reaction. The distance between the points of attachment of the chromophore to the macrocycle metal binding site is probably, in this first generation sensor, too great to enable a metal-macrocycle binding event to be reported.
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Gong, Jiachang. "Biomimetics and host-guest chemistry." ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,186.
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Thesis (Ph. D.)--University of New Orleans, 2004.Title from electronic submission form. "A dissertation ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry."--Dissertation t.p. Vita. Includes bibliographical references.
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Faust, Thomas Benjamin. "On the synthesis, measurement and applications of octanuclear heterometallic rings." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/on-the-synthesis-measurement-and-applications-of-octanuclear-heterometallic-rings(a9697906-50e4-4d0a-9eda-bfd09b9e12f8).html.
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Inorganic macrocycles have stimulated interest in recent years for their magnetic properties, their associated host-guest chemistry and their aesthetically appealing structures. These characteristics have led to suggestions that they could be exploited for the purposes of ion recognition, catalysis, as single molecule magnets, MRI agents, antibacterial agents and as part of larger architectures in a molecular machine. This thesis explores the properties of a group of chromium(III) macrocycles, with functionality tailored towards different pursuits. Firstly the magnetic properties of a newly synthesised family of ring dimers are investigated. The nature of magnetic exchange within each ring leads to a net electronic spin which, it has been proposed, could represent a quantum binary digit within a quantum information processing system. By linking together pairs of rings, the degree of inter ring communication can be determined. Such interactions are important for the correlation of spin as initiation of quantum entanglement, a pre-requisite for quantum computing. The rings can also act as fluoro-metallocrowns, hosting the molecule which templated their formation. A range of rings with different guests are synthesised and their solid and solution state structures are explored. On templating about bulky dialkyl amines hybrid organic-inorganic rotaxanes are formed where the guest is fixed. In contrast when using small amines and alkali metals, exchange of guests is possible. The dynamics of all of these systems are investigated with proton NMR, quite remarkable for such highly paramagnetic complexes.
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Roche, Cécile. "Porphyrin-based [3]- and [4]rotaxanes : towards an adaptable molecular receptor." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00763533.
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Rotaxanes and porphyrins are two particularly active fields of research in chemistry. However,molecules that combine the interesting properties of these types of structures are not so common. In this thesis we describe new porphyrin-based multi-rotaxanes, whose syntheses constitute interesting challenges.Porphyrins linked to two or four coordinating macrocycles were synthesised. The "gathering-andthreading" effect of copper(I) was used to thread molecular rods through the rings; the subsequent introduction of stoppers led to the formation of rotaxanes. In the case of the porphyrinic bis-macrocycle a [4]rotaxane was obtained. Host/guest complexation studies with rigid nitrogen ligands showed that the rotaxane behaves as a distensible molecular receptor that can adopt an "inflated" or "deflated" conformation and adjust its shape to the size of the guest. In the case of the porphyrinic tetra-macrocycle the formation of a [3]rotaxane of novel architecture was observed.The synthesis of a new, more rigid bis-macrocycle is in progress. This compound will be used for the construction of a [4]rotaxane that could act as a molecular press able to change the conformation of a guest substrate by compression.
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Espelt, Ripoll Mónica. "Reversible molecular encapsulation in self-assembled and mechanically locked containers with polar interior." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/275961.
Full textAbstract:
The present thesis work dealt with the study of the polar interiors of self-assembled homocapsules based on aryl-extended calix[4]pyrrole scaffolds, as well as the anisotropic polar interior of a mechanically locked calix[4]arene-calix[4]pyrrole heterocapsule. The properties of the internal cavities of the receptors were probed through the inclusion of different molecules known as guests. Homologous series of aliphatic N-oxides were used in encapsulation experiments to evaluate the size modification and adaptability exhibited by the aromatic cavity enclosed in both systems.
Moreover, new super aryl-extended calix[4]pyrroles were synthesized by the elongation of the aromatic walls of aryl-extended calix[4]pyrroles yielding a substantial increased volume of the internal cavity.
Additionally, the preparation of an unprecedented calix[4]pyrrole – calix[4]pyrrole molecular container having the two hemispheres mechanically linked was achieved. This capsule features a sizeable increase of its internal volume when compared to the previous calix[4]arene-calix[4]pyrrole molecular container. Both mechanically locked capsules displayed a bis-[2]-catenane topology. Furthermore, the new mechanically locked homo-dimer possesses polar functionalization at the closed ends of both hemispheres.En la presente tesis se han estudiado las cavidades polares de cápsulas autoensambladas basadas en estructuras de calix[4]pirrolesaril-extendidos, así como también las cavidades de cápsulas formadas por dos hemisferios distintos, uno de calix[4]areno y otro de calix[4]pirrol que se encuentran mecánicamente entrelazados, mediante la encapsulación de distintos tipos de moléculas a las cuales llamamos huéspedes. Series homólogas de N-óxidos alifáticos se utilizaron en los experimentos de encapsulación para evaluar la modificación del tamaño de cavidad y la adaptabilidad exhibida por la cavidad aromática en los dos sistemas capsulares. Además, se ha sintetizado nuevoscalix[4]pirroles super extendidos mediante la elongación de las paredes aromáticas de los anteriormente conocidoscalix[4]pirroles aril-extendidos, lo que ha repercutido en un considerable incremento del volumen de interno de la cavidad. Asimismo, se ha logrado sintetizar un contenedor molecular basado en dos moléculas de calix[4]pirroles en el cual los dos hemisferios están mecánicamente unidos, del mismo modo que lo estaban en la anterior cápsula formada por un calix[4]areno y un calix[4]pirrol. La obtención de esta nueva cápsula molecular ha supuesto un aumento de volumen con respecto a la anterior cápsula también enlazada mecánicamente. Los dos contenedores moleculares descritos presentan una topología de bis-[2]-catenano. La nueva cápsula molecular posee una funcionalización polar interior en los dos hemisferios, una diferencia con respecto a la anterior.
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Cornut, Damien. "Synthèse et étude des propriétés hôte-invité de récepteurs hétéroditopiques de type calix[6]crypt-(thio)urée." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209159.
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La chimie supramoléculaire est un domaine qui porte sur l’étude des interactionsfaibles entre molécules. Ces interactions sont très répandues dans les systèmes naturels et de
nombreux récepteurs moléculaires synthétiques ont été développés, soit pour un apport
théorique à la compréhension de ces processus de reconnaissance, soit pour d’éventuelles
applications en biologie ou en chimie analytique par exemple.
Les calix[6]arènes sont des composés intéressants pour la reconnaissance moléculaire.
Ils possèdent une cavité idéale pour l’inclusion de petites molécules et peuvent être modifiés
par l’ajout de divers motifs de reconnaissance. Le premier calix[6]crypturée préalablement
étudié au sein du Laboratoire de Chimie Organique est un récepteur dont la cavité aromatique
est juxtaposée à un motif de reconnaissance pour anions. Ce dernier est composé d’un
chapeau à base de tren (tris(2-aminoéthyl)amine) portant trois groupes urée. Ce récepteur
possède notamment une forte sélectivité pour le chlorure et une forte affinité pour les paires
d’ions organiques de type chlorure d’ammonium, dans un solvant apolaire (CDCl3).
Cependant, ces propriétés de reconnaissance sont beaucoup plus limitées dans un solvant
protique (CD3OD), ce qui restreint les éventuelles applications. L’objectif de ces travaux a été
de synthétiser de nouveaux dérivés avec une modification autour du site tris-urée pour
renforcer les propriétés de reconnaissance, notamment en milieu protique.
La première stratégie a consisté à agrandir le chapeau cryptant reliant les trois groupes
urée. Trois modes différents de complexation d’ammonium intra-cavitaire ont été mis en
évidence dans un solvant apolaire, dont deux sont remarquables. Avec un anion peu
coordinant (le picrate), le récepteur protoné inclut l’ammonium selon un processus
allostérique pour donner un complexe dicationique. Avec la protonation du récepteur et un
anion dichargé (SO4
2-), l’inclusion de l’ammonium constitue un complexe cascade, stable en
milieu protique.
La deuxième stratégie a consisté à supprimer les groupes méthyle du petit col
calixarénique via une réaction de déméthylation sélective pour obtenir le calix[6]crypturée
1,3,5-trishydroxyle. Dans un solvant apolaire, ce récepteur a montré une plus forte sélectivité
pour la complexation de paires d’ions par rapport à la complexation d’anions, permettant par
exemple de complexer le chlorhydrate de O,O-diméthyldopamine.
La troisième stratégie a été de synthétiser le calix[6]cryptothiourée, un récepteur dont
le chapeau comporte trois groupes thiourée. Cette modification structurale a fortement
renforcé la complexation d’anions mais n’a pas favorisé la complexation de paires d’ions dans
un solvant protique.
Enfin, la complexation de zwittérions a été testée sur l’ensemble de ces récepteurs et le
calix[6]cryptothiourée s’est avéré être un remarquable complexant de la B-alanine bétaïne.
Dans un mélange protique (CD3OD/CDCl3 1:1) la constante d’association est élevée (K ≈ 104
M-1) et supérieure d’au moins trois ordres de grandeur par rapport aux autres zwittérions
testés. C’est à notre connaissance un des rares récepteurs de bétaïnes et le premier à être
sélectif pour la B-alanine bétaïne. Enfin, le biomimétisme du mode de reconnaissance a été
montré par comparaison avec une protéine transporteur de bétaïne (Corynebacterium
glutamicum).
Doctorat en sciences, Spécialisation chimie
info:eu-repo/semantics/nonPublished