Azolium Control of the Osmium-Promoted Aromatic C-H Bond Activation in 1,3-Disubstituted Substrates.

The hexahydride complex OsH(PPr) promotes the C-H bond activation of the 1,3-disubstituted phenyl group of the [BF] and [BPh] salts of the cations 1-(3-(isoquinolin-1-yl)phenyl)-3-methylimidazolium and 1-(3-(isoquinolin-1-yl)phenyl)-3-methylbenzimidazolium. The reactions selectively afford neutral and cationic trihydride-osmium(IV) derivatives bearing κ-- or κ--chelating ligands, a cationic dihydride-osmium(IV) complex stabilized by a κ--pincer group, and a bimetallic hexahydride formed by two trihydride-osmium(IV) fragments. The metal centers of the hexahydride are separated by a bridging ligand, composed of κ-- and κ--chelating moieties, which allows electronic communication between the metal centers.

Electronic Communication in Binuclear Osmium- and Iridium-Polyhydrides.

Reactions of polyhydrides OsH(PPr) () and IrH(PPr) () with rollover cyclometalated hydride complexes have been investigated in order to explore the influence of a metal center on the MH unit of the other in mixed valence binuclear polyhydrides. Hexahydride activates an -CH bond of the heterocyclic moiety of the trihydride metal-ligand compounds OsH{κ-,-[CRHN-py]}(PPr) (R = H (, Me (), Ph ()). Reactions of and lead to the hexahydrides (PPr)HOs{μ-[κ-,-[CRHN-CHN]-,-κ]}OsH(PPr) (R = H (), Me ()), whereas gives the pentahydride (PPr)HOs{μ-[κ-,-[CHN-C(CH)HN]-,,-κ]}OsH(PPr) ().