DESIGNED SYNTHESIS OF MULTIFUNCTIONAL CARBORANES AND ORGANOTRANSITION METAL CARBORANE COMPLEXES

General synthetic routes to functionalized C- and B-substituted derivatives of nido-C//2B//4H//8, C//4B//8H//1//2, and C//2B//3H//7**2** minus are described together with their use as building-block units in the planned construction of multidecker transition-metal sandwich complexes and related systems. Specifically discussed are (1) synthesis of C//2B//4 nido-carboranes containing sterically demanding and/or electronically active groups; (2) transition-metal pi -complexation of the C//2B//4 derivatives at carboranyl and aryl sites; (3) controlled stepwise oxidative fusion of C//2B//4-metal complexes to form asymmetrically substituted C//4B//8 clusters; and (4) current efforts in the author's laboratory directed toward the preparation of electron-delocalized polymers incorporating carboranes or metallacarboranes.