Date of Award

1983

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

Pyridyllithium reagents were employed in the synthesis of 6-substituted bis(2-pyridyl) ketones and 6,6'-disubstituted 2,2'-dipyridines. The resulting compounds were used in the attempted preparation of pyridine analogues of simple corrins. Coronands were generated from 2,2-bis(6'-bromo-2'-pyridyl)-1,3-dioxolane. Hydrolysis of the protecting dioxolane gave the corresponding ketone coronands, which could be reduced to macrocyclic carbinols with sodium borohydride. Although these compounds would not complex transition metal ions, several were observed to sequester neutral molecules. In particular, the hexaethylene glycol ketone coronand was proven by X-ray diffraction methods to encircle a molecule of water. Electron-poor aromatic ketones were discovered to decarbonylate under mild, basic conditions. The mechanism of this reaction was proposed to be analogous to that of the benzilic acid rearrangement. Coronands of 2,2'-dipyridine could be formed by the decarbonylation of the corresponding ketone macrocycles. Attempts to prepare pyridyl ketone and ketal coronands that possess a methylene unit between the heteroaromatic ring and the glycol bridge were thwarted by the photosensitivity of the parent bis(6-methyl-2-pyridyl) ketone. Efforts to functionalize the methyl groups of the dioxolane-protected ketone by free radical halogenation produced a plethora of virtually inseparable haloketones and ketals. 2,2-Bis(2'-pyridyl)- and 2,2-bis(6'-methyl-2-pyridyl)-1,3-dioxolane were observed to be excellent ligands for transition metal ions. X-ray analysis showed the chelation of the metal to occur primarily through the pyridine nitrogens, with a moderate interaction to one of the dioxolane oxygens. In the octahedral Ni(II) complex of the methylpyridyl ketal, the ligand was bound to the metal in a tridentate fashion. Coronands were formed from 6,6'-bis{2''-6''-bromo-2''-pyridyl)-1'',3''-dioxolan-2''-yl}-2,2'-dipyridine and subsequently hydrolyzed to the diketone coronands. The diketal coronand of bis(2-mercaptoethyl) ether formed complexes with transition metals.

Pages

262

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