Date of Award

10-1-1995

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

The formation and properties of a variety of polycyclic aromatic hydrocarbons (PAH) and arene chromiumtricarbonyl complexes (Cr(CO)$\sb3$) have been researched, with the main emphasis on cata- and peri-condensed PAH Bis(Cr(CO)$\sb3$) complexes and their chemistry. $\eta\sp6$:$\eta\sp6$-Pyrene bis(Cr(CO)$\sb3$) and $\eta\sp6$:$\eta\sp6$-phenanthrene bis(Cr(CO)$\sb3$) complexes were formed from the reaction of the PAH, $\rm (NH\sb3)\sb3Cr(CO)\sb3$, and BF$\sb3$. X-ray analysis showed both complexes to have the anti orientation of the Cr(CO)$\sb3$ moieties. In the phenanthrene complex, the rotomer conformations for the two Cr(CO)$\sb3$ moieties are different, while the pyrene complex has a center of inversion. Preparation of C$\sb{60}$-Cr(CO)$\sb3$ was also attempted but the desired results were not achieved.In situ deprotonation/substitution reactions were then carried out on both of the complexes. Silylation, hydroxylation and carbethoxylation were accomplished simultaneously at the 2 and 7 positions of pyrene while silylation on the phenanthrene complex resulted in three main products being formed; 2,7-disilyl-;2,6-disilyl-; and 1,3,7-trisilyl-phenanthrene being formed. Dianion formation and subsequent reduction of pyrene Bis (Cr(CO)$\sb3$) with lithium naphthalide and methyliodide yielded 4,5-dihydro-4,5-dimethylpyrene.Mono Cr(CO)$\sb3$ complexes or deutero-, trimenthylsilyl- and carbethoxy-pyrene and -naphthalene were prepared in both the substituted ring as well as in the nonsubstituted ring in attempts to perform haptotropic shift and then substitution reactions. Although the desired results were not achieved in this set of reactions, many not previously isolated complexes were made and their chemistry and analytical data developed.A theoretical study to parallel the above topics was developed with specific interests in ab initio calculations of benzene-, toluene-, and silylbenzene-Cr(CO)$\sb3$ complexes. A small basis set by Huzinaga was modified and determined to be adequate (by comparison to a larger basis set) for these calculations. The results showed optimized structures with very close structural parameters to the known molecules. Also, the correct rotomer isomers were predicted for all three complexes based on the energies of 5 rotational isomers (0-60$\sp\circ$ in 15$\sp\circ$ increments). Most notable was the correct prediction of the rotational isomer and proposed explanation for the silylbenzene complex which has been shown to have a unique staggered structure.

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