Date of Award

7-1-1996

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

The goal of this work was to synthesize the curved polycyclic aromatic hydrocarbon diindeno (1,2,3,4-defg;$1\sp\prime,2\sp\prime,$3$ \sp\prime,4\sp\prime$-mnop) chrysene (56). Three approaches were proposed to prepare chrysene 56 beginning with appropriately substituted fluorene compounds: the Zipper Approach, the Inside-Out Approach, and the Outside-In Approach. These approaches are based on the order in which the positions of the fluorene compounds are coupled. Therefore, much of this work was devoted to determining which type of coupling reaction would allow both aryl-aryl attachment and bending of the aryl rings to form chrysene 56.Unsuccessful attempts were made at preparing 1-substituted-9-fluorenones using ($\eta\sp6$-arene)Cr(CO)$\sb3$ complexes. It has been shown that substituted-($\eta\sp6$-arene)Cr(CO)$\sb3$ can be regioselectively functionalized ortho to an electron donating substituent by using a strong base to deprotonate the arene ring. However, it was found that the base attacked the carbonyl group of ($\eta\sp6$-9-fluorenone)Cr(CO)$\sb3$ instead of removing a ring proton. Protecting the carbonyl group resulted in the preparation of the 3-substituted product instead of the desired 1-substituted product. This result was attributed to steric hindrance of the protecting group. Both 1- and 1,8$\sp\prime$-di-substituted-9-fluorenones were prepared using standard chemistry.Both the Zipper Approach and the Outside-In Approach utilize aryl-aryl coupling. Attempts to homo-couple bromo-fluorenones using Ullmann coupling conditions, a nickel(II) complex, an in situ palladium(0)-catalyzed Suzuki cross-coupling reaction, and a catalyzed Gringard reaction were all unsuccessful.A variety 9,9$\sp\prime$-bifluorenyls and 9,9$\sp\prime$-bifluorenylidenes were prepared for use in the Inside-Out Approach including $1,1\sp\prime,8,$8$ \sp\prime$-tetrabromo-9,9$\sp\prime$-bifluorenyl and tetramethyl 9,9$\sp\prime$-bifluorenyl-$1,1\sp\prime,8,$8$ \sp\prime$-tetracarboxylate. This is the first reported synthesis of these compounds. It was found that 9,9$\sp\prime$-bifluorenyl-1,1$\sp\prime$-dicarbonyl chloride would undergo an intermolecular Friedel-Crafts acylation reaction with benzene to yield 1,1$\sp\prime$-dibenzoyl-9,9$\sp\prime$-bifluorenyl. However, conditions were not found which resulted in 9,9$\sp\prime$-bifluorenyl-1,1$\sp\prime$-dicarbonyl chloride undergoing an intramolecular Friedel-Crafts acylation reaction. Attempts using 1,1$\sp\prime$-disubstituted-$9$,9$\sp\prime$-bifluorenylidenes were also unsuccessful because of the inability to prepare pure starting material. It was found that 1,1$\sp\prime$-disubstituted-9,9$\sp\prime$-bifluorenylidenes were very susceptible to reduction at the 9,9$\sp\prime$-position. Several intramolecular coupling reactions were unsuccessfully attempted using the $1,1\sp\prime,8,8\sp\prime$-tetrasubstituted-9,$9$ $\sp\prime$-bifluorenyls.

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