Cp*RuII(Cl)(diphosphine) complexes have been synthesized with 1,5-diaza-3,7-diphosphacyclooctane (PR2NR'2) ligands.  These complexes are being explored as potential O2 reduction catalysts, in which the amines in the second coordination sphere of the metal could serve as proton relays.  Chloride abstraction in aerobic solvent gives stable, cationic species with O2 bound in a side-on fashion, Cp*Ru(PR2NR'2)O2+.  In the presence of acid, a non-coordinating amine is protonated.  For the complex with the ligand R = tert-butyl R' = benzyl, the protonated complex has been characterized by X-ray crystallography, indicating that the added proton forms a hydrogen bond to the O2 ligand.  The effect of varying the basicity of the pendent amine (R' = benzyl, phenyl) and the electron-donating character of the phosphine (R =  tert-butyl, phenyl) has been studied.  Chemical and electrochemical reductions of the Cp*Ru(PR2NR'2)O2+ complexes in the presence of acid will be described.

Synthesis, protonation, and reduction of ruthenium(II) dioxygen complexes with pendent amines

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.