Dioxygen Activation by Redox-Active Bis(aldimine) Ligand Bridged Diruthenium Complex Possessing Singlet Ground State.

The unexplored 'actor' behavior of redox-active bis(aldimine) congener, p-phenylene-bis(picoline)aldimine (L1), towards dioxygen activation and subsequent functionalization of its backbone was demonstrated on coordination with {Ru(acac) 2 } (acac= acetylacetonate). Reaction under aerobic condition led to the one-pot generation of dinuclear complexes with unperturbed L1, imino-carboxamido (L2 - ), and bis(carboxamido) (L3 2- )-bridged isovalent {Ru II (μ-L1)Ru II }, 1/ {Ru III (μ-L3 2- )Ru III }, 3 and mixed-valent {Ru II (μ-L2 - )Ru III }, 2. Authentication of the complexes along with the redox non-innocence behavior of their bridge have been validated through structure, spectroelectrochemistry and DFT calculations. Kinetic and isotope labelling experiments together with DFT analyzed transition states justified the consideration of redox shuttling at metal/L1 interface for 3 O 2 activation despite of the closed shell configuration of 1 (S=0) to give carboxamido derived 2/3.