This award in the Inorganic, Bioinorganic, and Organometallic Program provides continued support for research on carboranes and metallocarboranes by Dr. M. Frederick Hawthorne of the Chemistry Department, University of California at Los Angeles. Diverse structural atomic arrangements such as "carboracycles" and "carborods" will be linked into large "supramolecular" structures. By controlling the size and shape of these clusters, cages of many different sizes, shapes, and electronic properties which can be used for capturing small ions and molecules will be constructed. Some of the most challenging target molecules will have "holes" of the appropriate size to contain three transition metal ions. In addition, the reactivity and acidity of carboranes of lanthanide metals will be investigated. The binding capabilities of electrophilic mercuracarborand hosts will be studied in a variety of new compounds in order to obtain selective anion carriers. Supramolecular structures with specific chirality and binding power will be prepared. Large new molecules of regular geometry which contain boron, carbon, and metal atoms will be synthesized. The structures are sufficiently large that they can "capture" other atoms or small molecules. Because these structures are attractive to negatively charged ions and because the size, shape, and strength of the traps can be controlled, they have great potential as "ion channels" which can transport ions in living systems. They also could be effective as analytical probes or as acid catalysts. This basic reseach is relevant to molecular recognition, homogeneous catalysis, chemic al sensor fabrication and biomolecule modification. # # ! ! ! F # # ( Times New Roman Symbol & Arial " h 1 = Margaret A. Cavanaugh Margaret A. Cavanaugh