Syntheses and structures of cationic osmium bis(σ-B–H) borane complexes

Abstract

Transition metal (TM) σ-B–H borane/borate complexes are fundamentally intriguing due to their connections with TM-mediated B–H bond activation and catalytic application. Most of the reported examples are neutral σ-B–H complexes. However, to date, examples of cationic σ-B–H species remain exceedingly scarce. Herein, we report an efficient salt elimination/hydride removal approach for the construction of rare cationic osmium bis(σ-B–H) borane complexes. These novel cationic species feature the cationic fragment OsH(CO)(PCy₃)₂⁺ coordinated with monoaryl borane ligands through two geminal σ-B–H bonds. Atoms in molecules (AIM) analyses of 1a and 2a show remarkable differences in their Os–H–H–B regions. Our results enrich the diversity of osmium σ-B–H complexes.