physical organic chemistry
Andrzej Sygula
Our research has been focused on synthesis and structural studies of a novel class of curved-surface polynuclear aromatic hydrocarbons (PAHs) having carbon frameworks structurally related to fullerenes, known as “buckybowls” or “fullerene fragments”. The smallest buckybowl, corannulene, is a C20H10 hydrocarbon representing the polar cap of buckminsterfullerene C60. We have prepared several buckybowls, most notably cyclopentacorannulene (C22H10) and two isomeric semibuckminsterfullerenes C30H12, representing one-half of buckminsterfullerene surface.
The development of practical synthetic methodologies allows for preparation of corannulene on a multi-gram scale. With larger amounts of buckybowls in hand, we have turned our attention to the design and preparation of the molecular receptors with multiple corannulene pincers. Some of the “buckycatchers” exhibit exceptionally high affinity toward fullerenes in the solid state and in solution, strongly binding the carbon cages by the size/shape specific concave-convex pie-pie stacking of the carbon networks.
While the main part of our research is the “hard-core” organic synthesis, the researchers in our laboratory are also exposed to the physical organic chemistry methodologies involving thermodynamic studies of the supramolecular association processes as well as the kinetic studies of the bowl-to-bowl inversions. In addition, we extensively use the computational chemistry tools for the design of the efficient molecular receptors for a given molecular guest (e.g. fullerenes of different sizes and shapes).
