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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Chiral and racemic calix[6]arenes and their self-assembly /

Hayes, Monty, January 2008 (has links)
Thesis (M.S.)--Texas State University--San Marcos, 2008. / Vita. Supplemental material: leaves 72-121. Includes bibliographical references (leaves 122-125). Also available on microfilm.
22

New lower rim calix[4]arene derivatives containing mixed donor atoms, synthesis, characterisation and binding properties

Hutcherson, Robert George January 1997 (has links)
Novel P-tert-butylcalix[4]arene derivatives (L-3-10) containing mixed donor atoms (O, N, S) have been synthesised in a two stage reaction, the first part of which involves the preparation of L-2 using 18-crown-6 as a phase transfer catalyst and K2CO3 as a weak base. These conditions lead to the removal of two distal protons from the lower rim, allowing the 1,3-bis-niethylethylthio ether derivative (L-2) to be synthesised in a reduced reaction time with greater yield and purity than previously published. The final two protons were removed using NaH, sites to which a variety of amine, amide and thiophene moieties were introduced. This thesis reports investigations on these new compounds detailed as follows, i) 1H and 13C NMR characterisation of these derivatives. In two cases, X-ray crystallograpliic structures have been determined, showing distortions from the symmetrical cone conformation of p-tert-butylcalix[4]arene caused by steric interactions of the lower rim substituents. ii) Solubility and derived Gibbs energies of these ligands in various solvents at 298.15 K. Using acetonitrile and methanol as reference solvents, Gibbs energy of transfer are calculated. iii)The acid-base properties of ligands L-3,4,6-8 were investigated by potentiometry. Equilibrium constants for the dissociation processes reveal relative proton affinities in methanol at 298.15 K. Data of individual species present as a function of pH are presented in diagrams. iv) Conductimetric measurements. These data are used to derive the stoichiometry of metal cation complexes of L-4 in methanol. v) 1H NMR studies of the complexation of L-4 with metal cations in CD3OD at 298 K. These reveal conformational change in the macrocycle cyclic structure as the substituents' arrangements are altered to accommodate the guests cations. vi) Determination of Gibbs energy of complexation for ligand L-4 and Ag+, Pb+2, Cd2+ and Cu2+ metal cations in methanol at 298.15 K, using a competitive potentiometric method. Cation selectivities are discussed.
23

Ab initio studies on the diffusion mechanism of vinyl bromide through p-tert-butylcalix[4]arene. / 乙烯溴在異丁基杯(四)芳烴晶體中擴散機理的從頭算研究 / Ab initio studies on the diffusion mechanism of vinyl bromide through p-tert-butylcalix[4]arene. / Yi xi xiu zai yi ding ji bei (si) fang jing jing ti zhong kuo san ji li de cong tou suan yan jiu

January 2005 (has links)
Zhang Liang = 乙烯溴在異丁基杯(四)芳烴晶體中擴散機理的從頭算研究 / 章良. / Thesis submitted in: August 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Zhang Liang = Yi xi xiu zai yi ding ji bei (si) fang jing jing ti zhong kuo san ji li de cong tou suan yan jiu / Zhang Liang. / TITLE PAGE --- p.i / THESIS COMMUTE --- p.ii / ABSTRACT (English) --- p.iii / ABSTRACT (Chinese) --- p.iv / ACKNOWLEDGMENTS --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.ix / Chapter CHAPTER 1 --- Introduction / Chapter 1.1 --- Background Information of Calixarenes --- p.1 / Chapter 1.1.1 --- "History, Synthesis and Applications" --- p.1 / Chapter 1.1.2 --- Physical Properties --- p.2 / Chapter 1.1.3 --- Conformation of Calix[4]arenes --- p.3 / Chapter 1.1.4 --- Inclusion and Host-Guest Interactions --- p.4 / Chapter 1.2 --- Computational Theory --- p.8 / Chapter 1.2.1 --- Framework of Self-Consistent Field (SCF) --- p.8 / Chapter 1.2.2 --- Density function theory (DFT) --- p.9 / Chapter 1.3 --- Constrained Optimization Methods --- p.13 / Chapter 1.3.1 --- Introduction --- p.13 / Chapter 1.3.2 --- Augmented Lagrangian Method --- p.14 / Chapter 1.4 --- References --- p.16 / Chapter CHAPTER 2 --- Transformations of TBC4 Crystals / Chapter 2.1 --- Introduction and Experimental Results --- p.19 / Chapter 2.2 --- "II (""ab/ab"") to I (""ab/cd"") Transformation" --- p.21 / Chapter 2.3 --- "I (""ab/cd"") to III (Capsule) Transformation" --- p.25 / Chapter 2.4 --- Torsion of Capsulation --- p.27 / Chapter 2.5 --- References --- p.31 / Chapter CHAPTER 3 --- Diffusion through TBC4 Crystal / Chapter 3.1 --- Experimental Facts --- p.32 / Chapter 3.1.1 --- Kinds of TBC4 Inclusions --- p.32 / Chapter 3.1.2 --- "Inclusions of O2, vinyl bromide, toluene in TBC4" --- p.36 / Chapter 3.2 --- Diffusion of 02 in “ab/cd´ح TBC4 --- p.40 / Chapter 3.3 --- Diffusion of Vinyl Bromide through TBC4 --- p.44 / Chapter 3.3.1 --- "Vinyl bromide diffuses in ""ab/cd"" TBC4" --- p.45 / Chapter 3.3.2 --- Transformation/migration mechanism --- p.47 / Chapter 3.4 --- References --- p.51
24

Novel sulfonated extended arm calixarenes

Makha, Mohamed, 1965- January 2001 (has links)
Abstract not available
25

Organized assemblies of calix[4]arenes in the solid state

Elisabeth, Eric, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 472-488). Also available on the Internet.
26

The study of molecular assemblies formed via non-covalent interactions between calixarenes /

Lee, Eun-ju, January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 84-86). Also available on the Internet.
27

The study of molecular assemblies formed via non-covalent interactions between calixarenes

Lee, Eun-ju, January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 84-86). Also available on the Internet.
28

Organized assemblies of calix[4]arenes in the solid state /

Elisabeth, Eric, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 472-488). Also available on the Internet.
29

Calixarene chemistry en route to nano-fabrication of phosphonated analogues

Clark, Thomas Edward January 2008 (has links)
[Truncated abstract] An efficient synthesis of the p-phosphonic acid calix[n]arenes, (n = 4, 5, 6 and 8) in five steps and excellent yield has been developed. This includes the key use of an acetyl protecting group, which is straightforward to introduce and remove using acetic anhydride and potassium hydroxide respectively. The synthesized p-phosphonic acid calixarenes are water-soluble and the hydrogen bonding prowess of the acidic groups dominates its selfassembly processes. For p-phosphonic acid calix[4]arene these include the formation of nano-rafts in the gas phase (≤ 20 molecules) and nano-particles (3.0(3) and 20.0(2) nm) of the calixarene in water using spinning disc processing stabilized by acetonitrile. The larger p-phosphonic acid calix[5,6,8]arenes also show nano-raft formation in both solution and the gas phase. An extensive study of the supramolecular chemistry of calix[5]arene has also been undertaken to better understand its rich structural diversity. This includes the formation of chloromethane inclusion complexes of p-tert-butyl-calix[5]arene and p-H-calix[5]arene with dichloromethane, p-phenyl-calix[5]arene with chloroform and their potential application as gas storage materials. Along with these three investigated inclusion complexes are two sublimates of p-H-calix[5]arene (α and β) with only the β-polymorph active for sorption of carbon dioxide at room temperature and 1 atm. The α-polymorph adopts an inverted cone conformation and forms helical stacks in the extended structure whereas the β-polymorph adopts the usual cone conformation and packs in both 'self included' and 'back-to-back' helical arrangements. ... Complementary to this study involved the p-H-calix[5]arene inclusion complexes with fluoro-, chloro-, bromo- and iodobenzene. All but the iodobenzene complexes are isostructural forming columnar arrays in the extended packing comprised of 'tri-calix[5]arene' segments. Iodobenzene is too large to form the respective 'tri-calix[5]arene' segments and instead forms sheets in the extended packing. To better understand the type and nature of the intermolecular interactions present within the supermolecules and extended structures a detailed Hirshfeld surface analysis was performed. A detailed Hirshfeld surface analysis was also performed on O-octadecyl-calix[6]arene, which crystallizes in the inverted double cone conformation. Three alkyl chains on either side interplay to form one side of hexagon in an hexagonal close packed array of interdigitated alkyl chains. This was the first Hirshfeld surface analysis performed at variable temperatures and enhanced the description of such a large supramolecular system. The related compound O-octadecyl-calix[4]arene was found to crystallize from toluene or benzene as supramolecular bilayers, 32.2(4) and 32.7(2) Å thick respectively. The calixarenes adopt the cone conformation and the alkyl chains interplay to form a continuous hexagonal motif similar to that seen for O-octadecyl-calix[6]arene. The formation of stable bilayers using octadecyl chains leads to the possibility of inserting long chain calixarenes with suitable functionalization into biological membranes. Such functionalization could include upper rim phosphorylation as seen for the p-phosphonic acid calixarenes to produce phospholipid mimics.
30

Functionalization dependance of calix[6]arene contrast and sensitivity to electron beam exposure /

Ralls, Daniel M. January 1900 (has links)
Thesis (M.S.)--Texas State University--San Marcos, 2008. / Vita. Includes bibliographical references (leaves 50-51). Also available on microfilm.

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