Date of Award

1995

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Andrew W. Maverick

Abstract

We have been synthesizing cofacial binuclear copper(II) and zinc(II) complexes using bis($\beta$-diketone) ligands in order to design a host complex which selectively binds guest molecules and demonstrates catalytic activity. The metal atoms are held by the chelating acetylacetonate groups, of the bis($\beta$-diketone) ligands, in adjacent parallel planes separated by a cavity into which the guest molecule fits. The host-guest interactions are described. The synthesis of these complexes are discussed beginning with the synthesis of the substituted naphthalenes which bridge the meta-acetylacetonate planes. We needed 2,7-dimethylnaphthalene-1-carbonitrile for the synthesis of the bis($\beta$-diketone) ligand, NBAH$\sb2$-1-CN. After the first recrystallization of 2,7-dimethylnaphthalene-1-carbonitrile, it was found to exhibit unusual luminescence properties. The intense luminescence was found to be due to trace amounts of impurities which could be removed via column chromatography. Concentrated solutions of 2,7-dimethylnaphthalene-1-carbonitrile were found to emit excimer fluorescence. The fluorescence of solid samples and dilute solutions of 2,7-dimethylnaphthalene-1-carbonitrile was similar. The methyl groups of 2,7-dimethylnaphthalene-1-carbonitrile derivatives were each brominated once in a free radical bromination to make 2,7-bis(bromomethyl)naphthalene-1-carbonitrile. Pure bis(bromomethyl)naphthalene-1-carbonitrile was needed to make the desired ligand, but the reaction often produced di- and tribrominated side products. The optimization of this reaction and the characterization of the side products are discussed. The side chain Br groups in 2,7-bis(bromomethyl)naphthalene-1-carbonitrile were replaced by acetylacetonate (acac$\sp{-})$ groups in order to achieve the desired bridging/chelating bis($\beta$-diketone) ligand (NBAH$\sb2$-1-CN, 3,3$\sp\prime A$A-(1-cyanonaphthalene-2,7-diylbis(methylene)) bis(2,4-pentanedione). NBAH$\sb2$-1-Br, 3,3$\sp\prime$-(1-bromonaphthalene-2,7-diylbis(methylene)) bis(2,4-pentanedione) was also synthesized in a similar manner from the corresponding bis(bromomethyl)naphthalene compound. The ligands were treated with copper(II) to form the green cofacial bimetallic complexes (Cu$\sb2$(NBA-1-X)$\sb2,$ X = CN or Br). Small nitrogenous bases (Dabco (1,4-diazabicyclo(2.2.2) octane), pyrazine, aminopyrazine, and piperazine) were used as guest molecules, binding to the host complexes via the metal atoms. UV-Vis spectroscopy was used to monitor the host-guest interactions. These interactions are reported in the form of binding constants. Cofacial bimetallic zinc(II) complexes were made using the NBAH$\sb2$ (3,3$\sp\prime$-2,7-naphthalenediylbis(methylene))bis(2,4-pentanedione) ligand and Dabco, pyrazine, and piperazine as guests. These colorless complexes were found to luminesce at wavelengths similar to the NBAH$\sb2$ ligand. Luminescence, lifetime, and NMR spectroscopy data on these complexes are presented.

Pages

106

DOI

10.31390/gradschool_disstheses.6083

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