Physical Sciences and Mathematics Commons^™

Polymer-Supported 14-Crown-4 And Bifunctional Resins For Selective Metal Ion Complexation: Synthesis And Characterization, Christy L. Stine

Doctoral Dissertations

Polymer-supported 14-crown-4 and bifunctional resins containing amine and phosphonate ester ligands were synthesized and characterized. Complexation studies were performed to evaluate the metal ion selectivity of the resins.

The immobilization of 14-crown-4 onto crosslinked polymer supports for the complexation of Li(l) from aqueous solutions was studied. M any methods were attempted, but etherification of the hydroxymethyl form of 14-crown-4 was found to be the most successful. The polymers examined were poly(vinylbenzyl chloride), poly(vinylbenzyl chloride)-co-acrylamide and poly(glycidyl methacrylate). The amount of Li(l) complexed by the crown ether supported polymers was affected by the polarity (i.e., hydrophilicity) of the polymer matrix. The …

The Use Of Native And Modified Cyclodextrins For Method Development In Capillary Electrophoresis And Chemical Sensor Applications, Mustafa Culha

Doctoral Dissertations

The development and design of novel methods and materials for separation and sensing systems have critical importance for the analysis of complex mixtures. In these systems, molecular recognition is the key element for desired selectivity and it can only be achieved using rationally designed, chemically selective reagents. Cyclodextrins (CDs) are a group of macro-cyclic molecules that can recognize certain analytes depending on their shape and size. In this work, the primary goal was the design and development of CD-based separation and sensing systems. Native and derivatized CDs were utilized to develop methods for separation of a complex mixture containing six …

Studies Towards Anti-Bredt Ring Systems Of Natural Products, Ulf Peters

Masters Theses

Different ways for the synthesis of anti-Bredt ring systems of natural products have been explored.

An intended Favorskii rearrangement-divinylcyclopropane rearrangement to lead to the bicyclo[4.3.1] decadiene ring system was not accomplished. An envisioned tandem cyclopropanation-divinycyclopropane rearrangement of 2,3-divinyhex-2-enol did not furnish the desired bicyclo[4.4.1]undecadiene system, either, because cyclopropane occurred on the exocyclic double bond.

In the course of cyclopropanation studies on various cyclohexenols, an α-silyl-α-diazoethyl acetate was employed as tether. It could be removed by protodesilylation or oxidative cleavage to give a 1-(carboxylic ester)-cyclopropane or a 1-(carboxylic easter)-1-hydroxy cyclopropane derivative, respectively. Cyclopropanation general occurred on the less substituted more …

Group 4 Metallocene And Half-Sandwich Derivatives Of Spherosilicate: Preparation Fromsi8o20(Snme3)8 And Their Olefin Polymerization Activity, Suree Saengkerdsub

Doctoral Dissertations

Three metallocene and half-sandwich Group 4 complexes of cuboctameric

spherosilicate (Si8O20(TiCp2Cl)8, Si8O20(ZrCp2Cl)8, and Si8O20(TiCp*Cl2)8) were successfully prepared by the exchange reaction of Group 4 metal chlorides with the spherosilicate starting material, Si8O20(SnMe3)8. These complexes were found to be catalytically active in olefin polymerization. Their preparative reactions clearly demonstrate a synthetically useful route towards many other derivatives of spherosilicate through the Si8O20(SnMe3)8 starting material. A new synthesis of the key precursor, octa(trimethyltin) cuboctameric spherosilicate Si8O20(SnMe3)8, was developed. It was found that most of the waters of hydration of the initial hydrate ([NMe4][Si8O20] @ n H2O, = 60! 70) could be removed …