UCLA

Luminescent boron cluster-based compounds have gained recent attention for their potential use in optoelectronic applications due to their three-dimensional aromaticity, synthetic tunability, and stability profiles. Functionalization of individual boron cage vertices provides a route toward precise structural modification that ultimately affects the photoluminescent and photophysical properties of the overall molecule. For many boron clusters, however, synthetic modification methods are limited, and the structure-function relationships of luminescence are not well understood. In this dissertation, the syntheses and characterization of new luminescent polyhedral borane cluster compounds are described. Chapter 1 focuses on the development of an SNAr method for C-carborane (C2B10H12) functionalization capable of procuring new molecular architectures containing (hetero)aryl groups. We envision that these carborane-based compounds could serve as sterically bulky, rigid ligands in organometallic complexes, which could lend the molecule properties such as high energy emission and high quantum yield. The remaining chapters focus on the synthetic and photoluminescent investigations of the only inherently fluorescent boron hydride cluster known to date, anti-B18H22. Despite its unique luminescence, only a handful of reports on the synthetic reactivity of anti-B18H22 exist, and little is understood about how structural changes affect its innate fluorescence. Therefore, in Chapters 2-4, anti-B18H22 is derivatized through halogenation with iodine, bromine and chlorine, and the photoluminescence and stability properties of the resulting analogues are benchmarked. Finally, Chapter 5 describes both palladium-catalyzed cross-coupling and metal-free nucleophilic substitution reactions on 7-I-B18H21, which result in boron-iodine bond substitution to forge B-N, B-O, and B-S connectivities with the boron cluster cage. Overall, this work advances the fundamental synthetic knowledge of the fluorescent anti�-B18H22 cluster and provides a foundation for the generation of new luminescent boron-cluster-based molecules.