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1
Sun, Yu. "Cocoon construct around supramolecular domains in supramolecular elastomers." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460410519.
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2
Leech, Michael Andrew. "Supramolecular crystallography." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301231.
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3
Stephenson, Maria Dianne. "Supramolecular arrays of metal complexes and metallo-supramolecular assemblies." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435894.
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4
Saunders, Joshua Daniel. "Novel Supramolecular Polyamides." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-07242005-213223/.
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The objective of this research is to use low DP poly(p-benzamide) (PBA) segments, terminated by units forming supramolecular bonds, able to extend the overall DP of the aromatic polyamide. PBA fibers, and the related industrially produced PPTA (Kevlar), exhibit their most interesting ultra-high strength properties only when a considerably large DP (>100) is attained. Use of cumbersome and expensive syntheses and solvents are required to attain DP in the range (~200-300) of industrial interest. Moreover, the fully covalent polymers thus far produced are highly insoluble in common organic solvents. On the other hand, easier processing becomes feasible if the DP of conventional PBA (prepared by the Yamazaki reaction) is increased by supramolecular bonding through ionic or hydrogen bond interactions. The effects of three different binding methods were first investigated on short rigid monomers with promising results the same binding was then used on rigid segments of PBA. The binding methods used two diamine binders triethylenediame (TED) and bipiperidine (Bipip) to form ionic bonds with the monomer, and polymer segments. The last method utilized a 2(6-iso cyanato hexylamino carbonyl amino)-6-methyl-4[1H]pyrimidinone (Upy) end group covalently bonded to the PBA polymer. This end group has the ability to form 4 hydrogen bonds with itself and thus could be used to increase the overall DP of the polymer starting material. This is believed to be the first recorded hydrogen bonded supramolecular interaction in amide type solvents. The novel and revolutionary idea of using low DP segments of PBA to increase the overall DP of polymer could be an industrially viable way to produce the highly sought after industrial polyamides.
5
Greenaway, Alex. "3D supramolecular architectures." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594870.
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The design, synthesis and crystallisation properties of molecular tectons that are capable of participating in the formation of 3D supramolecular architectures are outlined with two distinct aspects of research presented. A series of molecules which contain both hydrogen bond acceptor and donor sites is synthesised to test the scope of ligands to form porous supramolecular organic frameworks (SOFs). Two analogous tripodal tri carboxylate ligands which are able to form coordination complexes in both a convergent and a divergent mode of coordination are synthesised and their formation of complexes with a variety of metal salts is described.
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Subbaiyan, Navaneetha Krishnan. "Supramolecular Solar Cells." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149672/.
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Supramolecular chemistry - chemistry of non-covalent bonds including different type of intermolecular interactions viz., ion-pairing, ion-dipole, dipole-dipole, hydrogen bonding, cation-p and Van der Waals forces. Applications based on supramolecular concepts for developing catalysts, molecular wires, rectifiers, photochemical sensors have been evolved during recent years. Mimicking natural photosynthesis to build energy harvesting devices has become important for generating energy and solar fuels that could be stored for future use. In this dissertation, supramolecular chemistry is being explored for creating light energy harvesting devices. Photosensitization of semiconductor metal oxide nanoparticles, such as titanium dioxide (TiO2) and tin oxide (SnO2,), via host-guest binding approach has been explored. In the first part, self-assembly of different porphyrin macrocyclic compounds on TiO2 layer using axial coordination approach is explored. Supramolecular dye sensitized solar cells built based on this approach exhibited Incident Photon Conversion Efficiency (IPCE) of 36% for a porphyrin-ferrocene dyad. In the second part, surface modification of SnO2 with water soluble porphyrins and phthalocyanine resulted in successful self-assembly of dimers on SnO2 surface. IPCE more than 50% from 400 - 700 nm is achieved for the supramolecular self-assembled heterodimer photocells is achieved. In summary, the axial ligation and ion-pairing method used as supramolecular tools to build photocells, exhibited highest quantum efficiency of light energy conversion with panchromatic spectral coverage. The reported findings could be applied to create interacting molecular systems for next generation of efficient solar energy harvesting devices.
7
Giansante, Carlo <1978>. "Supramolecular photoactive systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1045/1/Tesi_Giansante_Carlo.pdf.
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Giansante, Carlo <1978>. "Supramolecular photoactive systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1045/.
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Ferrito, Maria Stefania <1986>. "Supramolecular Photoresponsive Systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7549/1/TesiDottoratoFerritoMstefania.pdf.
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This PhD research project deals with the synthesis and characterization of supramolecular photoresponsive systems based on the azobenzene unit.
1)Azobenzene-cyclodextrin inclusion complexes: the aim of this study was to obtain relatively simple, water-soluble derivatives, whose self-assembly could be reversibly controlled by light. On the basis of previous results, this opens the possibility of directly converting light into mechanical energy via osmosis. Several
new azobenzene functionalized cyclodextrins have been synthesized, fully characterized and studied The inclusion
complexes thus formed and their light-driven disassembly were studied by means of several
complementary techniques including NMR, UV, CD, ICT, mass spectroscopy. The most suitable
systems were used in experiments, still in progress, of light-to-mechanical energy conversion.
2)Azobenzene-guanosine hybrids: several novel azobenzene-guanosine hybrids were synthesized for the purpose of investigating the effect of cis-trans photoisomerization on guanosine self-assembly. Lipophilic guanosines in organic solvents can form either ribbon-like supramolecular polymers or, in the presence of alkali metal ions, G-quartet
based supramolecular complexes. These complexes were fully characterized for newly synthesized
azobenzene-guanosine hybrids. In the absence of ions, the ribbon-like supramolecular polymer
gives rise to a gel-like system, which turned out to be a lyotropic liquid
crystalline phase. Photoisomerization to cis form induces the transition to an isotropic solution,
in a reversible fashion. In addition, the G-quartet structure obtained in the presence of alkali metal
ions can be disassembled by light.
3) Oligoazobenzenes’s project. While several examples of electron-rich conjugated polymers are
known and find application e.g. as electron donors in “plastic” photovoltaics, no examples are
reported on the use of electron-poor conjugated polymers as acceptor counterpart. In particular, no
polyazobenzenes having the (-C6H4-N=N-) repeat unit have ever been reported. Although no
polymeric has been obtained yet, we succeeded in synthesizing several homologues up to a
tetramer. The compounds were subjected to photophysical, photochemical and electrochemical
characterization.
10
Ferrito, Maria Stefania <1986>. "Supramolecular Photoresponsive Systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7549/.
Full textAbstract:
This PhD research project deals with the synthesis and characterization of supramolecular photoresponsive systems based on the azobenzene unit.
1)Azobenzene-cyclodextrin inclusion complexes: the aim of this study was to obtain relatively simple, water-soluble derivatives, whose self-assembly could be reversibly controlled by light. On the basis of previous results, this opens the possibility of directly converting light into mechanical energy via osmosis. Several
new azobenzene functionalized cyclodextrins have been synthesized, fully characterized and studied The inclusion
complexes thus formed and their light-driven disassembly were studied by means of several
complementary techniques including NMR, UV, CD, ICT, mass spectroscopy. The most suitable
systems were used in experiments, still in progress, of light-to-mechanical energy conversion.
2)Azobenzene-guanosine hybrids: several novel azobenzene-guanosine hybrids were synthesized for the purpose of investigating the effect of cis-trans photoisomerization on guanosine self-assembly. Lipophilic guanosines in organic solvents can form either ribbon-like supramolecular polymers or, in the presence of alkali metal ions, G-quartet
based supramolecular complexes. These complexes were fully characterized for newly synthesized
azobenzene-guanosine hybrids. In the absence of ions, the ribbon-like supramolecular polymer
gives rise to a gel-like system, which turned out to be a lyotropic liquid
crystalline phase. Photoisomerization to cis form induces the transition to an isotropic solution,
in a reversible fashion. In addition, the G-quartet structure obtained in the presence of alkali metal
ions can be disassembled by light.
3) Oligoazobenzenes’s project. While several examples of electron-rich conjugated polymers are
known and find application e.g. as electron donors in “plastic” photovoltaics, no examples are
reported on the use of electron-poor conjugated polymers as acceptor counterpart. In particular, no
polyazobenzenes having the (-C6H4-N=N-) repeat unit have ever been reported. Although no
polymeric has been obtained yet, we succeeded in synthesizing several homologues up to a
tetramer. The compounds were subjected to photophysical, photochemical and electrochemical
characterization.
11
Gerhardt, Warren William. "Towards Supramolecular Multifunctional Architectures." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14619.
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The synthesis of new biological and polymeric supramolecular synthons and their assembly into unique supramolecular architectures is presented. These new supramolecular synthons are functionalized with ligands that compliment metallated pincer complexes. Through the use of ditopic metallated pincer complexes these supramolecular synthons can be self-assembled into infinite linear chains. The first class of supramolecular synthons synthesized were based on cyclic peptide units, by embedding a pyridyl unit into the side-chain of one of the peptide residues the cyclic structure can be coordinated to a metallated pincer complex. It is proposed that these supramolecular architectures may be further enhanced by incorporating multiple pyridyl units along the cyclic peptide backbone and coordinating them through multitopic pincer complexes to give porous membrane structures. The second class of supramolecular synthons is based on photoluminescent X-shaped cruciform molecules. By terminating one axis with pyridyl moieties these units may be assembled into fluorescent coordination polymers with good solution processable characteristics. This work is concluded with several synthetic routes to overcome the current limitations of our first generation of cruciform coordination polymers and cyclic peptide structures.
12
Cordes, David B., and n/a. "Supramolecular transition metal architectures." University of Otago. Chemistry Department, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060705.144929.
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This thesis describes the investigation of the coordination and supramolecular chemistry of three different types of pyridine-containing ligand with a selection of Ag(I), Cu(I), Cu(II) and Cd(II) salts. The ligand types are flexible and four-armed, rigid and four-armed and bent with two rigid arms. All the ligands also display the ability to form additional supramolecular interactions.
Chapter one introduces supramolecular chemistry and crystal engineering and covers background on several areas of current interest in these fields. Network structures, both coordination polymers and hydrogen-bonded systems, are discussed and topological analysis as a method of describing and comparing network structures is introduced. An outline of the ligand design, choice of transition metals and anions is given.
Chapter two provides a review of flexible four-armed pyridine-containing ligands and their use in coordination chemistry. The synthesis and characterisation of three flexible four-armed ligands 1,2,4,5-tetrakis(2-pyridylmethyl-sulfanylmethyl)benzene (2tet), 1,2,4,5-tetrakis(3-pyridylmethyl-sulfanylmethyl)benzene (3tet) and 1,2,4,5-tetrakis(4-pyridylmethyl-sulfanylmethyl)benzene (4tet) are given. The synthesis and characterisation of the Ag(I), Cu(II) and Cd(II) complexes formed with these three ligands are also given. The complex of [Cd(2tet)(NO₃)₄] was structurally characterised by X-ray diffraction and was found to be a discrete species. The complexes {[Ag₂(3tet)](ClO₄)₂}n̲, {[Ag₂(3tet)](PF₆)₂}n̲, {[Ag₂(3tet)](CF₃CO₂)₂}n̲, {[Ag₂(4tet)]-(ClO₄)₂�2MeCN�2CHCl₃}n̲, {[Ag₂(4tet)](PF₆)₂�6MeCN}n̲ and {[Ag₂(4tet)](ClO₄)₂-�3H₂O}n̲ were likewise structurally characterised by X-ray diffraction. All these complexes were three-dimensional coordination polymers. A comparison of the seven structures is given at the end of the chapter.
Chapter three reviews rigid four-armed pyridine-containing ligands and their use in coordination chemistry. The preparation of the rigid four-armed ligand 2,3,4,5-tetrakis(4-pyridyl)thiophene (pyth) is given. The synthesis and characterisation of the Ag(I), Cu(I) and Cd(II) complexes formed with this ligand are also given. The complexes [Ag(pyth)](BF₄)�3MeCN�CH₂Cl₂}n̲, [Ag(pyth)](PF₆)�MeCN�CH₂Cl₂}n̲, [Ag(pyth)]-(CF₃SO₃)�2MeCN�CH₂Cl₂}n̲, [Cu(pyth)](PF₆)�MeCN�CH₂Cl₂}n̲ and [(Cu₂I₂)(pyth)]-(BF₄)�1/2CH₂Cl₂�H₂O}n̲ were structurally characterised by X-ray diffraction. The complex with CuI was a two-dimensional coordination polymer, and the other four complexes were three-dimensional coordination polymers. A comparison of the five structures is given at the end of the chapter.
Chapter four begins with a review of rigid angular bridging ligands and their use in coordination and supramolecular chemistry. The preparation of the ligand bis(4-pyridyl)amine (bpa) is given. The structural arrangement of bpa in the solid state was determined by X-ray diffraction. Complexes of Ag(I), Cu(I), Cu(II) and Cd(II) formed with this ligand were synthesised and characterised. The complexes {[Ag(bpa)(MeCN)](CF₃SO₃)}n̲, {[Ag(bpa)](PF₆)�MeCN}n̲, {[Ag(bpa)](ClO₄)-�2MeCN}n̲, {[Ag(bpa)](ClO₄)}n̲, {[Ag(bpa)](NO₃)}n̲, [(Cu₂I₂)(bpa)₂]n̲, {[Cu(bpa)₂Cl₂]-�3DMF�3/2H₂O}n̲, {[Cd(bpa)₂(NO₃)(H₂O)](NO₃)}n̲, {[Cd(bpa)₂(SO₄)(H₂O)]�3H₂O}n̲, [Cd(bpaH)₂(SO₄)₂(H₂O)₂]�2MeCN and {[Cd(bpa)(SCN)₂]�1/5iPrOH}n̲ were structurally characterised by X-ray diffraction. All complexes with Ag(I) were one-dimensional coordination polymers, with two of them helical, the other three zigzag. Both complexes with Cu(I) and (II) were two-dimensional coordination polymers. One complex with CdSO₄ was discrete, with the bpa ligands mono-protonated, but all other three other Cd(II) complexes were three-dimensional coordination polymers. Seven of these complexes showed hydrogen-bonding interactions linking them together to form supramolecular structures of higher dimensionalities. A comparison of the twelve structures is given at the end of the chapter.
Chapter five is a brief summary of the outcomes of this thesis.
13
Murray, Claire. "Adventures in supramolecular chemistry." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606405.
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The work presented in this thesis is divided into three distinct chapters covering the chemistry high-nuclearity palladium cages, the many structures of Najera's catalyst compounds and the crystal structures of molecular tweezers and their compounds. The o-palladated, chloro-bridged dimers [Pd2-phenylpyridine(-H) -u-Cl]2 and [pdN,N-dimethylbenzylamine(-H)-Cl]2 react with cyanuric acid in the presence of base to afford closed, chiral cage-molecules in which 12 organo-Pd(11) centres, located in pairs at the vertices of an octohedron, are linked by four tetrahedally arranged cyanurator(3-) ligands.
14
Onions, Stuart T. "Functional supramolecular metallo-assemblies." Thesis, Nottingham Trent University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430257.
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Mehrabi, Maryam. "Photophysics of supramolecular conjugates." Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403652.
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Sheehan, Rosemary. "Supramolecular chemistry in silico." Thesis, University of Brighton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426972.
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Painting, C. L. "Metallo-assembled supramolecular architectures." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344047.
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Shannon, Richard J. "Supramolecular approaches to photosynthesis." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245584.
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Dykes, Graham Mark. "Supramolecular dendritic property modification." Thesis, University of York, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411458.
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Ponnuswamy, Nandhini. "Supramolecular chemistry of naphthalenediimides." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610852.
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Shevtsova, Galina. "Química supramolecular (II parte)." Revista de Química, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/100314.
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Shevtsova, Galina. "Química supramolecular. Parte 1." Revista de Química, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/99532.
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Xiang, Yunjie. "Towards multifunctional supramolecular copolymers." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF015/document.
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Le but de cette thèse était de comprendre l'organisation supramoléculaire et le possible réarrangement dynamique de copolymères supramoléculaires multifonctionnels. Ainsi, nous avons synthétisé diverses molécules présentant un coeur urée ou pérylène fonctionalisé par différentes chaines latérales afin de combiner des propriétés de structuration, de fluorescence et de bioreconnaissance dans une même chaine de polymère supramoléculaire. En combinant différentes techniques de spectroscopie, de diffusion du rayonnement et de microscopie, nous avons montré que des molécules avec un même coeur mais des chaines latérales différentes conduisaient à des nanostructures différentes comme des rubans vrillés, des plaques 20 ou encore des fibres branchées. Enfin, plusieurs unités monomériques avec un même coeur mais des chaines latérales différentes ont été mélangées pour former des copolymères supramoléculaires multifonctionnels. La formation préférentielle d'une nanostructure unique dictée par un des monomères a été démontrée selon un mécanisme de tri dit social ( « social self-sorting » )The goal of this thesis was to understand the supramolecular organization and the possible dynamic rearrangement of multifunctional supramolecular copolymers. To this end, we havedeveloped a series of building blocks based on urea or perylene cores with various lateral side chains for combining structuring, fluorescence, and biorecognition properties in a singlesupramolecular polymer chain. Using a combination of spectroscopy, scattering, and microscopy techniques, we have shown that molecules with a same core but different lateral chains can lead to the formation of various nanostructures su ch as twisted ribbons, 20 plates, or branched fibers. Ultimately, by combining monomeric units with different functional side chains, multifunctional supramolecular copolymers have been obtained. Whereas radiation scattering and imaging techniques were used to demonstrate that one of the monomer can dictate the formation of a preferential nanostructure, optical spectroscopies revealed that the polymerization process of our systems indeed occurs via social self-sorting
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Gobius, du Sart Gerrit. "Supramolecular triblock copolymer complexes." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2009. http://irs.ub.rug.nl/ppn/.
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Wehner, Marius [Verfasser], and Frank [Gutachter] Würthner. "Supramolecular Polymorphism in Homo- and Heterochiral Supramolecular Polymerizations / Marius Wehner ; Gutachter: Frank Würthner." Würzburg : Universität Würzburg, 2021. http://d-nb.info/1241045720/34.
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Hernández, Eguía Laura P. "Supramolecular chemistry of bis-porphyrins." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9059.
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(Base de datos de tesis doctorales TESEO) En este trabajo de tesis doctoral se desarrollan básicamente dos aspectos. El primero, es la síntesis de receptores bis-porfirínicos metalados con zinc, tanto acíclicos como cíclicos, y con diferente grado de saturación de las cadenas carbonadas, y el segundo, trata sobre los estudios de complejación llevados a cabo con ligandos de diferente tipo y propiedades: aminas y fullerenos. Los primeros se unen mediante enlaces de coordinación metal-nitrógeno, mientras que los segundos se basan en interacciones entre el anillo aromático de la porfirina y la estructura con un marcado carácter aromático de los fullerenos.
Además, se exponen los resultados obtenidos al derivar uno de los ciclopéptidos del grupo de investigación del Prof. J.R. Granja con una o dos porfirinas de zinc y emplear el ensamblaje supramolecular tipo "sándwich" entre bis-porfirinas y aminas ditópicas para controlar la mezcla regioisomérica que tiene lugar en el proceso de autoensamblaje entre los ciclopéptidos.
(Base de datos de tesis doctorales TESEO) English version
In this doctoral thesis two main aspects are developed. The first is the synthesis of bis-porphyrin receptors metallated with zinc, both acyclic and cyclic, and with different degrees of saturation of the carbon chain, and the second deals with the studies of complexation with ligands of different types and properties: amines and fullerenes. The first ligands are connected by metal-nitrogen coordination between the nitrogen of the ligand and the zinc of the porphyrin ring, while the latter are interactions between the aromatic ring of the porphyrin and the fullerenes.
In addition, we present the results obtained when derive one of the cyclopeptides of the research group of Prof. J.R. Granja with one or two zinc porphyrins, using the motif: "sandwich" complexes between bis-porphyrins and ditopic amines, in order to control the regioisomeric mixture that takes place in the self-assembly of the cyclopeptides.
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Watson, Walter Philip. "Hybrid Macrocycles for Supramolecular Assemblies." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6958.
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Hybrid macrocycles, which chimerically integrate multiple chemical compositions and architectures, provide an effective way to impart new properties to polymers that are not found in their linear or homocyclic analogues. This dissertation addresses the incorporation of hydrophilic blocks into hydrophobic polymer, as either a poly(dimethyl siloxane)-block-poly(oxyethylene) (PDMS-POE) tadpole with a hydrophobic head and a hydrophilic tail or as a diblock poly(styrene)-block-diethylene glycol (PS-DEG) hydrophobic-hydrophilic macrocycle. The supramolecular association properties of both kinds of cycles were studied: the PDMS-POE tadpoles in forming micelles, and the PS-DEG macrocycles in threading with linear polymer to form polyrotaxanes.
For the PDMS-POE macrocycle, linear alpha,omega-dihydroxy PDMS was cyclized under dilute conditions with dichloromethylhydrosilane as a linking group to produce hydrosilane-functionalized cyclic PDMS. This was joined to alpha-methoxy,omega-allyl POE via a free radical hydrosilylation reaction to produce the hybrid tadpole macrocycle, which was analyzed by GPC, DSC, and 1H, 13C, and 29Si NMR spectroscopy. Supramolecular aggregation consisting of the formation of micelles under both polar and nonpolar conditions was studied by surface tensiometry and quasielastic light scattering. For the PS-DEG macrocycle, linear alpha,omega-dihydroxy PS was prepared by ATRP polymerization of styrene, followed by reaction with KOH to give hydroxyl endgroups. The linear PS was then cyclized under dilute conditions with diethylene glycol ditosylate, and the product was analyzed by GPC, MALDI-TOF MS, DSC, and 1H, 13C and DOSY NMR spectroscopy. The macrocycle was then statistically threaded with linear PS to give the supramolecular structure poly(styrene)-rotaxa-cyclo[poly(styrene)-block-diethylene glycol]. Characterization was performed with DOSY NMR to verify that the product was threaded, and 1H NMR was collected to determine that the product was 13% macrocycle by weight. DSC showed only one Tg, indicating that the linear and cyclic species were present in the same phase.
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Moon, Ryan N. "Allosteric control of supramolecular systems." Thesis, University of Huddersfield, 2006. http://eprints.hud.ac.uk/id/eprint/5970/.
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Black, Cory A., and n/a. "Supramolecular complexes of multimodal ligands." University of Otago. Department of Chemistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070518.091104.
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This thesis describes the synthesis and X-ray crystallographic analysis of a series of supramolecular architectures prepared using seven flexible multimodal ligands with Ag(I), Cu(I), Cd(II), Co(II), Ni(II) and Pd(II) metal salts.
Chapter one introduces some examples of fundamental supramolecular systems with particular focus on metallo-supramolecular motifs, specifically coordination polymers. Topological analysis is discussed as a method for the simplified description and comparison of network structures.
Chapter two describes the design, synthesis and characterisation of the symmetrical ligands bis(2-pyrazylmethyl)sulfide (psp), bis(4-pyrimidylmethyl)sulfide (msm) and 5,5�-(thiodimethylene)di-pyrazine-2-carboxylic acid methyl ester (csc) as well as the asymmetrical ligands 2-benzylsulfanylmethyl-pyrazine (psb), 2-pyridylsulfanylmethyl-pyrazine (psd), 3-pyridylsulfanylmethyl-pyrazine (psn) and 4-pyridylsulfanylmethyl-pyrazine (psy).
Chapter three presents a literature review of ligands related to psp, msm and csc, followed by the synthesis and characterization of thirteen Ag(I), Cd(II), Co(II), Ni(II) and Pd(II) complexes. The X-ray crystal structures of nine of these complexes are reported and compared. The structures were present as either one- or two-dimensional coordination polymers. The {[Ag(psp)](PF₆)}[infinity] and {[Ag₂(psp)(C₆H₆)(CH₃CN)₂](PF₆)₂�CH₃CN}[infinity] structures demonstrated a solvent dependence by forming a 1-D twisted ladder with a [eta]�-bound benzene and a 2-D undulating sheet with a 4.8� topology respectively. Six of the structures {[Cd₂(psp)(CH₃CN)(H₂O)(NO₃)₄]�H₂O}[infinity], {[Co(psp)(CH₃CN)₂](ClO₄)₂}[infinity], {[Ni(psp)(NO₃)₂]}[infinity] and {[Ag(msm)](X)}[infinity] (X = BF₄⁻, ClO₄⁻, PF₆⁻) displayed anion-[pi] interactions between multi-atomic anions and [pi]-acidic ring centres. A novel N[pz]���cent[pz] T-shaped [pi]-[pi] interaction was also identified in the {[Ni(psp)(NO₃)₂]}[infinity] structure. A 2-D sheet with 6� topology was observed in the X-ray structure of {[Ag₂(csc)](NO₃)₂}[infinity].
Following a review of related ligands, chapter four focuses on seven Ag(I), Cd(II), Co(II) and Cu(I) complexes formed using the asymmetric pyrazine-benzene ligand psb. In total six 1-D coordination polymer chains are reported. Two structurally disparate supramolecular isomers were formed in [Ag(psb)NO₃][infinity] and {[Ag₂(psb)₂NO₃]NO₃�H₂O}[infinity]. The compound {[Ag(psb)](BF₄)}[infinity] was similar to the former isomer [Ag(psb)NO₃][infinity]. The structurally similar coordination polymers {[Cd(psb)(H₂O)(NO₃)₂]}[infinity] and {[Co(psb)(H₂O)₃](ClO₄)₂�H₂O}[infinity] formed structures that showed anion-[pi] interactions using coordinated and non-coordinated anions respectively. The [Cu₂(psb)I₂][infinity] chain consisted of ligands linked together by a Cu₄I₄ stepped cubane tetramer.
Chapter five presents seventeen Ag(I) and Cu(I) complexes prepared using three asymmetric pyrazine-pyridine ligands psd, psn and psy. A review of asymmetric pyrazine-pyridine ligands is provided. Seventeen X-ray crystal structures are described. Four psd complexes using AgBF₄, AgClO₄, AgNO₃ and AgPF₆ crystallised as discrete dimers with three types of crystal packing and ligand-supported Ag���Ag interactions. The complexes {[Ag₂(psd)₂CF₃SO₃]CF₃SO₃}[infinity] and {Cu₂(psd)I₂}[infinity] were a 1-D X-shaped chain and a 2-D 6� net respectively. The isostructural 2-D sheets in {[Ag(psn)]ClO₄}[infinity] and {[Ag(psn)]PF₆�CH₃CN}[infinity], had 4.8� topologies whereas a thicker sheet was formed in {[Ag₂(psn)₂](BF₄)₂}[infinity] with a complicated (4�.6�.8�)₂(4.6.8)₂ topology. The {[Ag₃(psn)₂](CF₃SO₃)₃�CH₃CN}[infinity] chain polymer displayed three different coordination geometries around the three Ag(I) centres with two ligand-unsupported Ag���Ag interactions. The complex [Cu₂(psn)₂I₂] crystallised as a discrete dimer with a different ligand arrangement than those found in the psd dimers. Six Ag(I) 3-D networks were formed using psy. The complexes {[Ag(psy)]X}[infinity] (X = BF₄, ClO₄, PF₆) formed as isostructural non-interpenetrated (10,3)-d networks. An unprecedented tri-nodal (4.6.8)₂(6.8�)₂(4.6.8�.10)₂ topology was observed in the {[Ag₂(psy)₂](CF₃SO₃)₂}[infinity] structure. The suprarmolecular isomers {[Ag₃(psy)₂(NO₃)₂]NO₃]}[infinity] and {[Ag₃(psy)₂(NO₃)₃]�H₂O}[infinity] formed inclined interpenetrated 6� sheets and a (4�.6)₂(4⁴.6�.8⁸.10) 3-D network respectively. The structures in this chapter showed a general trend of increasing dimensionality when progressing from psd to psn to psy.
Chapter six presents a summary of the more significant results and concluding remarks.
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Kalsani, Venkateshwarlu. "Multi-component metallo supramolecular assemblies." [S.l.] : [s.n.], 2005. http://www.ub.uni-siegen.de/epub/diss/kalsani.htm.
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Bruce, James I. "Supramolecular photochemistry of lanthanide complexes." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308689.
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Roshandel, Sahar. "Supramolecular devices as selective receptors." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1597789.
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We have found that calixarenes are good receptors of choline (trimethylammonium group) and they have strong affinity to form host-guest complexes with a variety of molecules carrying this moiety. Furthermore, the ability of lower rim carboxylic acid calix[n]arenes and upper rim phosphonic acid functionalized calix[4]arene to transport choline-conjugated drugs through a liquid membrane was discovered. The results demonstrate that these systems are highly efficient toward transporting choline-conjugated targets, as well as neurotransmitters that possess ionizable amine termini. The breadth of compounds that are transported is significant, facing limitations only when the payloads become extremely lipophilic. These developments reveal new approaches towards attempting synthetic receptor mediated selective small molecule transport in vesicular and cellular systems.
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Devonport, Wayne. "Oligomeric tetrathiafulvalenes in supramolecular chemistry." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5246/.
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A range of highly ordered dendritic and oligomeric macromolecules, functionalised with tetrathiafulvalene (TTF) derivatives as a redox-active sub-unit were assembled. In particular, the first dendritic macromolecules incorporating TTF were constructed by the reaction of poly-acid chlorides and alcohol functionalities. Electrochemical techniques showed the novel redox-superstructures to be efficient π-electron donors that are able to undergo two reversible, multi-electron-on oxidations. The TTF-units were established to be acting independently, and the extent to which the redox groups could be oxidised was evaluated. UV studies demonstrated the redox- assemblies to be capable of forming charge-transfer complexes m solution and showed potential for the formation of conducting charge-transfer complexes. Preliminary studies showed the precursors to these compounds to be suitable for use as electrochemical detectors for dopamine. Structural variation of the core units increased the air and thermal stability of the dendritic materials, whilst retaining the characteristics of the multi-redox system. These systems formed stable aggregates of the radical cation and afforded conducting charge- transfer complexes with TCNQ. The new precursors to multi-TTF systems were then used in attempts to impart redox characteristics on [2]pseudorotaxanes and rotaxanes. Preliminary attempts were made to assemble multi-TTF systems using a TTF derivative as a core and at the periphery.
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Skabara, Peter John. "Functionalised tetrathiafulvalenes in supramolecular chemistry." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/10491/.
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Using a range of functionalised tetrathiafulvalene (TTF) derivatives, developed at Durham, the first examples of covalently linked TTF-ferrocene systems have been prepared. The redox properties of these molecules, as studied by cyclic voltammetry, provide evidence that these species are efficient π-electron donors. Highly reactive 1,3-dithiole Wittig and Wittig-Homer reagents have been used in the synthesis of complex mixed redox-active systems containing ferrocenyl units. A series of [3]- and [4]-dendralenes has also been developed from this synthetic methodology. Cyclic voltammetry shows that tri- and tetracationic states can be achieved with these systems at relatively low potentials. The potential for vinyl-TTF compounds to undergo [4+2] cycloaddition has been investigated for the first time. The peripheral C=C unit of TTF, together with the adjacent vinylic substituent, is able to act as the diene functionality in Diels-Alder reactions. Remarkably, the π-delocalisation within the TTF moieties is readily disrupted by the addition of strong dienophiles. The reactivity of lithiated TTF towards aldehydes and ketones has established an array of hydroxy-functionalised TTF, bis-TTF and TTF-ferrocene derivatives. The conducting and magnetic properties of the chloranil charge transfer salt of one of these species is also reported.
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Likhitsup, Asawin. "Supramolecular architecture from nucleoside derivatives." Thesis, University of Warwick, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429751.
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Ruiz, Olles Jorge. "Dynamic processes in supramolecular gels." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/20429/.
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Supramolecular gels are self-assembled solid-like materials with a large solvent component making up a liquid-like phase. The 3D scaffold, which is self-assembled from low-molecular-weight building blocks, and is present in form of nanostructured fibres, holds the mobile liquid phase, preventing bulk flow. As a consequence, these gels have interesting dynamic properties, which were the subject of study in this thesis. Chapter One provides an introduction to dynamic processes in gels. Chapter Two focusses on the thermodynamics and kinetics of a two-component gelator system based on a peptide dendron acid combined with an amine. We used rheology, CD spectroscopy and NMR to characterise the gelation process at different length scales (macroscopic, nanoscale and molecular scale respectively). We conclude that thermodynamic stability of the gel network does not correlate with the rate of network formation. Chapter Three reports diffusion across a gel-gel interface, comparing the diffusion of self-assembling small molecules with those which do not form gel fibres. Chapter Four reports the gelation capabilities of certain gelator in deep eutectic solvents. We monitor the ionic conductivity and demonstrate that conductivities for the deep eutectic gels are similar to those of the deep eutectic liquids themselves, indicating that the ionic components do not suffer from immobilisation through interaction with the self-assembled gel nanofibres. Chapter five reports all Experimental details, materials and methods. In summary, this thesis provides insights into a range of different dynamic processes in gels – (i) the formation of gels, (ii) the mobility of the solid-like fibres themselves, and (iii) the mobility/conductivity of ionic species in innovative deep eutectic gels.
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Theogarajan, Luke Satish Kumar. "Supramolecular architectures for neural prostheses." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40514.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (leaves 213-230).
Neural prosthetic devices offer a means of restoring function that have been lost due to neural damage. The first part of this thesis investigates the design of a 15-channel, low-power, fully implantable stimulator chip. The chip is powered wirelessly and receives wireless commands. The chip features a CMOS only ASK detector, a single-differential converter based on a novel feedback loop, a low-power adaptive bandwidth DLL and 15 programmable current sources that can be controlled via four commands. Though it is feasible to build an implantable stimulator chip, the amount of power required to stimulate more than 16 channels is prohibitively large. Clearly, there is a need for a fundamentally different approach. The ultimate challenge is to design a self-sufficient neural interface. The ideal device will lend itself to seamless integration with the existing neural architecture. This necessitates that communication with the neural tissue should be performed via chemical rather than electrical messages. However, catastrophic destruction of neural tissue due to the release of large quantities of a neuroactive species, like neurotransmitters, precludes the storage of quantities large enough to suffice for the lifetime of the device. The ideal device then should actively sequester the chemical species from the body and release it upon receiving appropriate triggers in a power efficient manner. This thesis proposes the use of ionic gradients, specifically K+ ions as an alternative chemical stimulation method. The required ions can readily be sequestered from the background extracellular fluid. The parameters of using such a stimulation technique are first established by performing in-vitro experiments on rabbit retinas. The results show that modest increases (~~10mM) of K+ ions are sufficient to elicit a neural response.
(cont.) The first building block of making such a stimulation technique possible is the development of a potassium selective membrane. To achieve low-power the membranes must be ultrathin to allow for efficient operation in the diffusive transport limited regime. One method of achieving this is to use lyotropic self-assembly; unfortunately, conventional lipid bilayers cannot be used since they are not robust enough. Furthermore, the membrane cannot be made potassium selective by simply incorporating ion carriers since they would eventually leach away from the membrane. A single solution that solves all the above issues was then investigated in this thesis. A novel facile synthesis of self-assembling receptor functionalized polymers was achieved. By combining the properties of hydrophobic and hydrophilic interactions of two polymers a triblock co-polymer was synthesized. The middle hydrophobic block was composed of biocompatible polysiloxanes and further derivatized to posses ion recognition capabilities via pendant crown ether chains. The hydrophilic blocks were composed of biocompatible polyoxazolines. The self-assembling properties of the membrane were then studied by electroforming them into vesicular structures. The ion responsive properties of these polymers were then examined. These polymers show emergent behavior such as, spontaneous fusion and shape transformation to ionic stimuli due to the synergy between form and function. The results from the thesis show that it is feasible to build a renewable chemically based neural prosthesis based on supramolecular architectures. However, there remains a lot of fundamental work that needs to be pursued in the future to bring the idea to complete fruition.
by Luke Satish Kumar Theogarajan.
Ph.D.
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Zhang, Jing. "Microfluidic droplet-enabled supramolecular microcapsules." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607842.
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Alemán-García, Miguel Angel. "Porphyrin-based multicomponent supramolecular assemblies." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610305.
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Tong, Lok Hang. "New supramolecular chemistry of porphyrins." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614360.
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Di, Stasio F. "Supramolecular architectures : properties and applications." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1350099/.
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Supramolecular architectures represent an increasingly interesting playground both in the chemistry and physics field. In fact, they give us the possibility to tailor the physical and chemical properties of conjugated systems, opening the doors to new applications. In this dissertation I will present my findings regarding different types of supramolecular structures. The first part is dedicated to the study of the optical properties of conjugated polyrotaxanes: conjugated polymers such as poly(4,4’-diphenylene vinylene) threaded through cyclodextrin macrocycles rings, that sterically impose increased intermolecular distances, leading to preserved single-molecule excitonic photophysics even in high concentration regimes, due to reduced pi-pi stacking of the chromophores. In particular, I will show how it is possible to tune their photoluminescence properties for different applications like polarized emission and optically pumped lasers. The incorporation of polyrotaxanes and their unthreaded analogue in a stretch-oriented polyvinyl alcohol matrix gives rise to a strongly polarized photoluminescence parallel to the stretching direction which I studied using steady-state and time-resolved optical techniques. Furthermore, by exploiting the water-solubility of polyrotaxanes is possible to embed them in three-dimensional photonic crystal and tune their radiative rate to achieve low-threshold optically pumped lasers. In the second part, I will present the application of supramolecular structures in light-emitting diodes. In fact, self-assembled monolayers represent an interesting system to tune the work function of commonly used electrodes in the plastic electronics field, therefore changing the injection barriers for holes at the interface between the organic semiconductor and the metallic electrode. Furthermore, I will show how supramolecular architectures are used to obtain efficient near-infrared photoluminescence and electroluminescence introducing a three-dimensional pi conjugation. Moreover, by adding a pyridine derivative it is possible to suppress the efficient self-quenching in this class of porphyrin based molecular assembly increasing further their applicability in light-emitting diodes.
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Chopade, Prashant D. "From supramolecular selectivity to nanocapsules." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/13529.
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Doctor of PhilosophyDepartment of Chemistry
Christer B. Aakeroy
A family of three 2-aminopyrazine derivatives were prepared and co-crystallized with thirty carboxylic acids. Our theoretical charge calculations and experimental results from 90 reactions demonstrated that decreasing the charge on the hydrogen-bond acceptor sites results in a decrease of the supramolecular yield (the frequency of occurrence of the desired outcome). However, synthon crossover (undesired connectivity) was observed 7/12 times and was unavoidable due to competitive binding sites present in the N-heterocyclic bases chosen. To avoid synthon crossover, we used a strategy based on geometric bias. We utilized hydrogen-bonding two-point contacts and halogen-bonding single-point contacts for supramolecular reactions with the 2-aminopyrazine family of compounds. The desired two-point contact and single-point contact (N•••I or N•••Br) appeared in 9/9 times even in the presence of other potentially interfering intermolecular interactions. In addition, the role of charge in controlling the presence/absence of proton transfer was also highlighted. To establish a hierarchy in halogen-bonding interactions we designed and synthesized a library of eight molecules equipped with two different halogen bond donors and combined with variety of halogen-bond acceptors. 11 Halogen-bonded co-crystals were obtained; however, positional disorder of I/Br atoms obscures a complete analysis. This problem was solved by introducing asymmetry in the halogen-bond donor molecules. Finally, successfully demonstrated an unprecedented hierarchy in halogen-bond interactions based on electrostatics. We developed high-yielding Suzuki-Miyaura coupling reactions of tetraboronic pinacolyl ester cavitand to iodoarenes with a range of functional groups (electron withdrawing/donating group and a heterocycle) that show robustness and versatility, making it a ‘launch pad’ for the synthesis of many new cavitands in a facile manner. We have also successfully demonstrated cavitand functionalization from tetraaldehyde to tetraoximes using ‘solvent assisted grinding’, irrespective of the position of the aldehyde. Finally, we prepared tetra-substituted pyridyl and carboxylic acid cavitands having an ellipsoidal cavity capable of encapsulating asymmetric guest molecules and was subsequently obtained the first of its kind, C[subscript]2v symmetric molecular capsule with encapsulated asymmetric guest molecule.
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Dovidauskas, Sergio. "Química supramolecular de porfirino-clusters." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/46/46134/tde-30112018-111457/.
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Três novas supermoléculas, aqui designadas por ZnTCP4+, MnTCP5+ e CoTCP5+, foram obtidas pela coordenação de quatro acetatos trinucleares assimétricos de rutênio, [Ru3O(CH3CO2)6(py)2(CH3OH)]+, aos resíduos piridínicos de meso-tetra(4-piridil)porfirinato de ZnII, MnIII e CoIII, respectivamente (ZnTPyP, MnTPyP e CoTPyP). A caracterização destas supermoléculas foi efetuada por espectroscopia de ressonância magnética nuclear e espectroscopia eletrônica. O comportamento eletroquímico foi investigado por voltametria cíclica e espectroeletroquímica. Os efeitos dos acetatos trinucleares periféricos sobre a reatividade do núcleo porfirínico foram analisados: (i) para ZnTCP4+, além da supressão da luminescência, verificou-se que as constantes de coordenação axial determinadas em diclorometano para piridina e imidazol, quando comparadas às respectivas constantes de ZnTPyP e de meso-tetra(fenil)porfirinato de zinco, indicaram um aumento significativo da acidez de Lewis do íon Zn2+; (ii) MnTCP5+ revelou-se um catalisador mais seletivo que MnTPyP na oxidação de ciclohexano em fase homogênea, utilizando-se iodosilbenzeno como doador de oxigênio; (iii) os eletrodos modificados por filmes de CoTCP5+ apresentaram uma eficiente atividade catalítica na redução tetra-eletrônica de dioxigênio a água, comportamento que contrasta com o descrito na literatura para filmes de CoTPyP. A redução tetra-eletrônica de dioxigênio catalisada pelos filmes de CoTCP5+ foi confirmada por voltametria cíclica, voltametria de eletrodo disco rotatório e voltametria de eletrodo de anel e disco rotatórios.Three novel supermolecules designated as ZnTCP4+, MnTCP5+, and CoTCP5+ were obtained by coordination of four assymetric trinuclear ruthenium acetate species, [Ru3O(CH3CO2)6(py)2(CH3OH)]+ to pyridine residues of ZnII -, MnIII -, and CoIIITPyP, respectively (TPyP = meso-tetra(4-pyridil)porphyrinate). These new compounds were characterized by nuclear magnetic resonance spectroscopy and electronic spectroscopy. The electrochemical behavior was investigated by cyclic voltammetry, and spectroelectrochemistry. The influence of the peripheral trinuclear acetate on the porphyrin core reactivity was assayed: (i) for ZnTCP4+, besides the luminescence quenching, the calculated equilibrium constants for axial coordination of pyridine and imidazole in dichloromethane demonstrated a significant increase in the Zn2+ Lewis acidity in comparison with the respective constants from ZnTPyP and zinc meso-tetra(phenyl)porphyrinate; (ii) MnTCP5+ exhibited improved selectivity as catalyst for ciclohexane oxidation (homogeneous phase) in comparison with MnTPyP using iodosylbenzene as oxygen donor; (iii) modified electrodes by CoTCP5+ films showed an outstanding catalytic activity in the tetraelectronic reduction of dioxygen to water, in contrast with CoTPyP films described in the literature; the dioxygen tetraelectronic reduction was confirmed by cyclic voltammetry, rotating disk electrode voltammetry, and rotating ring and disk electrode voltammetry.
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Croce, Mago Vania Cristina. "Supramolecular studies on wormlike micelles." Thesis, University of Bristol, 2004. http://hdl.handle.net/1983/a0bf1b38-2889-4c04-b6a6-aa3c58d8a084.
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Jouvelet, Benjamin. "Kinetic studies of supramolecular polymer." Paris 6, 2013. http://www.theses.fr/2013PA066102.
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Appropriately designed bis-urea monomers dissolved in apolar solvent self-assembled through intermolecular hydrogen bonds into two distinct aggregates. Simple filaments with one monomer in the cross-section are formed at high temperature, although tubes with three bis-ureas in the cross section are formed at low temperature. These two aggregates self-assembled in a highly cooperative fashion and are in dynamic equilibrium with free monomers in solution. Kinetic studies were conducted on this system to determine different mechanistic purposes. By using chiral bis-urea monomers, supramolecular chirality was used to assess the exchange mechanism of material between the self-assembled tubes. The thermal transition between filaments and tubes is a reversible and very sharp process. A monomer with a precise moiety exhibits a strong hysteresis: the transition from tube-to-filament is fast, on the contrary the inverse transition is a very slow process. This particularly property was analysed towards differential scanning calorimetry and infrared spectroscopy. The chiral versions of this monomer induces a kinetic chiral self-sorting during the filament-to-tube transition. By mixing two competing chiral monomers, the resulting supramolecular chirality was a counter-intuitive combination of the homopolymers: a small amount of the "dominant" monomer is sufficient to "inverse" the orientation of the major (but "recessive") monomer in the mixed tubesDissous dans un solvant apolaire, des monomères de type bis-urées s'autoassemblent par liaisons hydrogènes en deux aggrégats distincts. De simples filaments présentant un unique monomère dans la section se forment à température élevée, à l'inverse des tubes avec trois bis-urées par section se forment à plus basse température. Ces deux structures supramoléculaires s'auto-assemblent de manière coopérative et sont en équilibre dynamique avec les monomères libres en solution. Des études cinétiques ont été menées sur ce système pour en déduire plusieurs mécanismes. En utilisant des monomères chiraux, la chiralité supramoléculaire induite a été exploitée pour accéder au mécanisme d'échange des monomères entre les tubes. La transition thermique entre les filaments et les tubes est un processus réversible et véloce. Un monomère présentant une architecture particulière induit un phénomène d'hystérésis important: la transition du tube vers le filament est rapide, à l'inverse la transition du filament vers le tube est un processus très lent. Cette propriété a été étudiée par analyse enthalpique différentielle et par spectroscopie infrarouge. La version chirale de ce monomère induit un phénomène d'auto-ségrégation métastable durant la transition du filament vers le tube. Il a été montré qu'en mélangeant deux monomères chiraux compétiteurs, la chiralité supramoléculaire résultante est une combinaison paradoxale de la chiralité des homopolymères: une faible quantité du monomère "dominant" est suffisante pour "inverser" l'orientation du monomère majoritaire (mais récessif) dans les tubes mélangés
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Eryazici, Ibrahim. "SUPRAMOLECULAR CHEMISTRY OF FUNCTIONALIZED TERPYRIDINES." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195677178.
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Kumar, Nishant C. "Anionically Polymerized Supramolecular Thermoplastic Elastomers." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414.
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Jerga, Agoston. "Current themes in supramolecular chemistry /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115558.
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Pappas, Charalampos. "Supramolecular systems chemistry using peptides." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26621.
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Living systems possess overwhelming molecular complexity that largely results from combinations of just twenty amino acids that are found across all life forms (the building blocks of life). Complexity of proteins arises from combinations of hundreds amino acid building blocks, where self-assembly dictates structure and functionality. Apart from their vital role on building living processes, short peptide sequences (minimalistic version of more complex biological machinery, consisted of 2-6 amino acids), appear to be ideal structural candidates for the fabrication of soft nanomaterials, with potential applications in food, cosmetics and nanomedicine. Supramolecular systems can be classified into three distinct types of self-assembly, based on the way that precursors and self-assembling building blocks relate in the free energy diagram. Thermodynamically driven supramolecular systems, resulting in the formation of permanent supramolecular assemblies, where the self-assembly pathway and the final supramolecular state is irrelevant. The self-assembly pathway becomes a crucial factor for kinetically controlled supramolecular systems, with the structures formed, representing local minima in the free energy landscapes. Finally, away-from-equilibrium chemical systems, systems that transiently exist only under the influence of constant chemical energy (fuel) and when the energy runs out, the system relaxes back to the initial unassembled state. In the first part of the thesis, we demonstrate the use of mechanical energy (high oscillating pressure waves-ultrasonic frequencies of 80.000 Hz) to trigger anisotropy and the formation of highly ordered supramolecular architectures. This is achieved by using tripeptide sequences with D-stereoisomer in the N-terminus of the sequence, where the use of ultrasound gives rise to the formation of gels with enhanced supramolecular properties, as evidenced using spectroscopic (FT-IR, CD, LD) and microscopic techniques (TEM, SEM). Subsequently, ultrasound was used to transiently affect supramolecular systems. In this case, the mechanical energy was used to trigger temporary supramolecular reconfiguration of aromatic dipeptide amphiphiles. The supramolecular transitions observed were due to an alter balance of hydrophobic and H-bonding type interactions that drive the assembly of aromatic peptide amphiphiles. Notably, a direct comparison between thermal heating and mechanical energy is also demonstrated, which relates the directional and oscillating characteristics of ultrasound, when it is used to locally deliver heat into a system. Responsiveness, functionality and adaptability are further demonstrated using different stimuli. Biocatalytic self-assembly has been utilised to direct supramolecular systems. Thermodynamically driven biocatalytic self-assembly is used to achieve morphological control (fibres, sheets and tubes) on aromatic dipeptide amphiphiles, via minimal stereo-electronic substitution on the para position of the phenylalaline amino acid residue. The control of the resultant supramolecular nanostructures and properties arises from the relative importance of stacking interactions among the aromatics and H-bonding between the dipeptide backbones. The concept of thermodynamically driven biocatalytic self-assembly is further utilised to direct the formation of Dynamic Peptide Libraries (DPLs). The amino acids within a dipeptide sequence are exchanged dynamically using in situ catalytic synthesis and hydrolysis of amide bonds, where the free energy involved in selfassembly of the nanostructure provides the driving force for its formation. The use of searchable dynamic peptide libraries gives rise to the ability to explore the structural sequences space of short peptides. Selective catalytic amplification is achieved through an interplay with environmental triggers. Differential formation of peptide subunits (library members), accompanied with structural reconfiguration is favored in the presence of different environment, such as solvents and salts. Additionally, a direct comparison between biocatalytically driven formation of different molecular species and chemically synthesized assemblies is used to show that shape control may be achieved. Biocatalytic self-assembly is also used to trigger the formation of non-equilibrium transient supramolecular systems. In this case, structural adaption is achieved based on biocatalytic formation and hydrolysis of self-assembling tripeptides, which catalyzed by chymotrypsin, starting from a simple dipeptide methyl ester, the wellknown sweetener, aspartame. The chemical design dictates the kinetics and the consequent lifetime of the nanostructures formed, which can be refueled several times by the addition of the fuel (aspartame), where the fibres are continuously forming and shortening, indicating a dynamically unstable system. This thesis ends with a small chapter, where we demonstrate the use of audible sound frequencies (<1000 Hz) to direct supramolecular reorganization on an aromatic dipeptide amphiphile. We sought to achieve the formation of larger aggregates as a result of aqueous vibrations, using a variety of spectroscopic (FT-IR, fluorescence, DLS, DOSY NMR) and microscopic techniques (AFM, TEM), investigating the effect of pressure waves on molecular self-assembly.
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Lee, Youn-Sik. "Supramolecular assemblies of polymerizable phospholipids." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185929.
Full textAbstract:
Novel polymerizable ether lipids, 1,2-O-bis[10-(2',4'-hexadienoyloxy)decyl]-rac, 1,2-O-bis(10,12-tricosadiynyl)-rac, and (S)-2,3-O-bis(10,12-tricosadiynyl)-sn-glycero-1-phosphocholine (PC), were successfully synthesized. Differential scanning calorimetry (DSC) showed that the gel to liquid crystalline phase transition of the ether lipid bilayers occurs at 11.4, 27.6, and 30.0°C (T(m)), respectively. The T(m) of the saturated analogs of the sorbyl ether and ester lipids, which were synthesized for the study of lipid phase behavior, were -15.4 and -7.5°C, respectively. The sorbyl and diacetylenic ether lipids in bilayers were readily polymerized with 254 nm light. The stability of sorbyl either lipid vesicles toward a detergent, Triton X-100, was somewhat enhanced by photopolymerization. The optically active diacetylenic ether lipid formed microtubules and helices which were observed by transmission electron and optical microscopy. Polymerizable ester lipids, 1-palmitoyl-2-(2-methylene)palmitoyl, 1,2-bis(2-methylenepalmitoyl), and 1-oleoyl-2-(2-methylene)palmitoyl PC were synthesized. The T(m) of these lipids were estimated to be 33.6, 25.3, and ∼-10°C, respectively, via DSC and X-ray diffraction. Thermal reaction of the mono-substituted lipid suspensions with a water-soluble initiator, azobis(2-amidinopropane) dihydrochloride (AAPD), yielded oligomers which were soluble in organic solvents. However, reaction of the bis-substituted ester lipid in bilayers produced cross-linked polymers which are not soluble in organic solvents. The ceiling temperature for the radical polymerization of these lipid systems appears to be near 70°C since the polymerization conversion at 60°C was greater than at 70°C. Finally, a polymerizable ester lipid, 1-oleoyl-2-(2-methylene)palmitoyl-sn-glycerol-3-phosphoethanolamine (PE) was synthesized. According to DSC and X-ray diffraction, this hydrated PE suspension undergoes the transition from the lamellar liquid crystalline to the nonlamellar inverted hexagonal (H(II)) phase at 45-50°C. This compound (T(m) = 11.6°C) is a promising candidate for future studies of the stabilization of the H(II) phase.