UC San Diego

The investigation of elusive species is of great interest to chemists – particularly those comprising groups III-V in the periodic table. What gives these compounds their transient nature is their ferocious reactivity – either within themselves or with other molecules. The work herein focuses on a range of attempts to isolate unstable subvalent species. A library of novel secondary amine scaffolds is employed as electronic and steric stabilizers to pursue this goal. Furthermore, it is demonstrated that the elusive diphosphorus molecule can be stabilized by two small monosubstituted (amino)carbene ligands – resulting in a species that can act as a diphosphorus surrogate, both as a triple-bonded diphosphorus source, in addition to a bis-phosphinidene. This species also shows promise as a P- transfer agent. Lastly, transient catalytic intermediates in the palladium-catalyzed C-H activation of free carboxylic acids are characterized, giving insights into the rationale responsible for the enhanced reactivity.