Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 274-277). Also available via the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

A variety of optically active macrocyclic crown ethers that serve as "host" systems that are capable of differentiating between enantiomeric "guest" molecules during host-guest complexation have been prepared via incorporation of chiral elements into the crown ring skeleton. The ability of these crown ethers to recognize the enantiomers of guest salts, i.e., (+) a-methyl benzylamine and to transport them enantioselectively in W-tube transport experiments were studied. The ability of these crown ethers to perform as chiral catalysts in an enantioselective Michael addition was studied. The extent of asymmetric induction, expressed in terms of the enantiomeric excess (%ee), was monitored by measuring the optical rotation of the product and comparing to the literature value.

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New phosphine ligands which also contained crown ether groups were synthesized by condensing two main reagents. Reagent A was Ph2P(CH2)3NH2 and it was prepared by reductingPh2P(CH2)2CN with LiALH4 in diethyl ether. Ph2P(CH2)2CN is obtained by reacting Ph2PH and CH2=C(H)CN in a Michael-type reaction. Reagent B, 4-formyl-benzo-15-crown-5, was obtained from the reaction of 3,4 dihydroxybenzaldehyde with 1,11 dichloro-3,6,9 trioxoundecane.By condensing the benzaldehyde crown ether and the phosphine amine, a Schiff-base type crown ether containing both P(III) and N(III) centers was obtained. Spectroscopic studies of the ligand and its Pd(II) derivative have shown PdCl2[Ph2P.(CH2)3N CH-C6H3(OMe)2]2 were characterized by that metal binding occurred exclusively on the P( III) center.A model ligand was synthesized by condensing 3,4-dimethoxybenzaldehyde with Ph2P(CH2)3NH2 to obtain an analogous product. Both ligands, Ph2P(CH2)3N=CH-benzo-15crown-5 and Ph2P(CH2)3N=CH -C6H3(OMe)2 and their palladium derivatives, PdCl2[Ph2P(CH2)3N=CH-benzo-15-crown-5]2 and spectroscopic and elemental analysis. The Pd(II) derivatives were synthesized from the reactions of (Ph2CN)2)PdC12 with the ligands. / Department of Chemistry

The objective of this research was to synthesis dibenzo-dihydroxy-26-crown-8 (1) as an ionophore for variety of chemosensors. Complexation of the ionophore (1) to a cation would cause a change of conformation. The conformational changes could affect fluorescence, UV spectra and/or Carbon-13 NMR of the chemosensor, depending on the fluorophores attached to the hydroxyl groups of crown 1 and/ or the identity of the ion. Several synthetic routes for crown 1 formation are given in the proposed synthetic procedure. Bis-1,2[2-hydroxyethoxy]benzene (17), bis-1,2[2-(3-chloro-2-hydroxypropoxy)ethoxy]benzene (18), bis-1,2[2-(2,3-epoxypropoxy)ethoxy]benzene (19) and bis-1,2[2(3-chloro-2-oxopropoxy)ethoxy]benzene (22) were synthesized. The reaction of 17 and 19 was attempted in the presence of SnC14, basic and acidic conditions, and in several solvents. The reaction of 17 and 22, and the reaction of 17 and 1,3-dichloroacetone were attempted in various reaction conditions. Crown 1 may have formed in the reaction of 17 and 19 in methylene chloride/ toluene in the presence of SnCl4 as the Lewis acid. / Department of Chemistry

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Thesis (Ph. D.)--Carleton University, 1992. / Also available in electronic format on the Internet.