This project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is in the general area of main-group chemistry and in the specific area of boron hydride chemistry. Boron-hydrogen compounds are of considerable practical interest as starting materials for the synthesis of new materials or for improved syntheses of known materials, such as metal borides. The goal of this project is to develop new synthetic strategies to facilitate high yield selective transformations in boron hydride chemistry. Of especial interest is the use of transition metals to catalyze transformations of polyhedral boranes and carboranes. The use of ruthenium carbonyl compounds to catalyze the insertion of alkynes into polyhedral carboranes will be investigated. Metal-catalyzed alkyne and olefin addition and coupling reactions will be used for the synthesis of alkenyl- and alkyl-boranes. Late transition elements will be investigated as catalysts for isomerizations of carborane cages. Transition metals, particularly Pt(II), will be investigated also as catalysts for dehydro-coupling, -condensation, -cyclization and -cage growth reactions of boranes. In a second major sub-project the syntheses and chemical and structural properties of hybrid polyhedral boranes, such as hypho-dithiaborane clusters, will be investigated.