Philip Keehn
Professor of Chemistry Emeritus
Degrees
Yale University, PhD
Profile
The relationships between structure, properties and reactivities of molecules are important for the fundamental understanding of chemical systems and processes. These relationships are the general focus of our research efforts. We synthesize and study molecules with unusual architecture or unique physical and/or chemical properties in order to better understand the novel structures, the causes for their unique characteristics and the general limitations of carbonaceous materials. Ultimately, we hope to obtain a better comprehension of the properties of atoms and molecules in order to have a better understanding of chemical substances and in order to make more useful materials.
We are interested in the extraordinary host properties of tri-o-thymotide (1, TOT, R=i-pr) in TOT clathrates. While TOT forms a large variety of complexes with many different guests, similar tri-salicylide structures with only slight modifications do not form clathrates whatsoever. We are presently involved in a study which will help define the role that substituents and conformation play in the process of clathrate formation. The synthetic aspects of this project have been defined and a variety of analogues are being synthesized. Conformational and crystallographic studies are in progress. The results of these studies will help us engineer better hosts for complexation with specific guests. Ultimately, controlled chemical reactions will be carried out in the solid phase by taking advantage of the unique directional and enzyme mimicking characteristics of the solid phase.
Other recent work on the use of trifluoroacetic acid to cyclooligomerize various substituted benzyl alcohols led us to consider the potential of using an analogue of cyclooligomer 2 as a precursor for "Buckyball" C60. We continue our quest for a rational, high yield synthesis of 2 and ultimately for C60, a new form of carbon.
Selected Publications
"Tri-3-(2-butyl)-6-methylsalicylide. A Novel, Versatile Tri-o-thymotide Based Clathrate Host Having Chiral Centers," J. Am. Chem. Soc. 1992, 114, 1915; with J.M. Gnaim, B.S. Green, R. Arad-Yellin, K. Vyas, J. Levy and F. Frolow.
"Analogues of Tri-o-thymotide (TOT) and Tri-o-carvacrotide (TOC) by Direct Bromination of TOT and TOC," J. Org.
Chem. 1992, 57, 3208; with L. Xu, J.M. Gnaim and B.S. Green.
"Cyclo-oligomerization of Veratryl Alcohol with Trifluoroacetic Acid," Tetrahedron Lett. 1992, 33, 3591; with E. Al-Farhan and R. Stevenson.
"A Simple Synthesis of Cyclotribromoveratrylene (CTBV) . An Extractive of the Red Algae Halopytis pinastroides," Tetrahedron Lett. 1992, 33, 5885; with E. Al-Farhan, O.M. Falana and R. Stevenson.