The research of Dr. John E. McMurry, Cornell University, will be supported by the Synthetic Organic Chemistry Program. Dr. McMurry will continue his highly innovative studies of novel molecules with unusual bond types. The studies of the chemistry of these atypical molecules will increase the chemist's ability to design materials with unique properties. A detailed study has been completed of the in-bicyclo?4.4.4!- tetradecyl cation, the first stable organic substance with a three-center, two-electron (3c-2e) C-H-C bond. It is concluded that there is nothing inherently unfavorable about three-center C-H-C bonding in organic chemistry; the only requirement is for a rigid molecule that enforces the proper geometry and prevents rearrangements. The study will now be extended in several directions. Several other rigid bicycloalkyl cations will be prepared to probe the effect of changing the C-H-C bond angle. In principle, a bent 3c-2e bond should be more highly favored than a linear bond owing to the enhanced orbital overlap that results from a decrease in C-C distance. Never before, though, has it been possible to test this hypothesis directly. Second, work recently has begun on the study of three-center, three-electron C-H-C bonds. Such bonding is presently unknown in organic chemistry. Third, McMurry will prepare and study the first examples of organic substances with other kinds of unusual three-center bonds. It is believed that the in-fluorobicyclo?5.5.5!heptadecyl cation should contain a three-center, two-electron C-F-C bond and that a new tetracyclic caged substance should contain an open three-center, two-electron C-C-C bond. Substances with these unusual kinds of bonds are not known at present.
