Ruthenium-Chelated Non-Innocent Bis(heterocyclo)methanides: A Mimickedβ‑Diketiminate

The unexplored substrate-based reactivity profile of newly designed bis(heterocyclo)methanide (BHM, L1–L3), a structural mimic of ubiquitous β-diketiminate, was demonstrated on an electronically rich {Ru(acac)2} platform (acac = σ-donating acetylacetonate). In this regard, this work deals with structurally characterized [Ru(L)(acac)2] complexes 1A–3A incorporating electronically varying heterocycles {1A, L1 = bis(imidazo[1,5-a]pyridin-3-yl)methanide; 2A, L2 = (Z)-4-[(6,7-dihydrothieno[3,2-c]pyridin-4-yl)methylene]-6,7-dihydro-4H-thieno[3,2-c]pyridin-5-ide; 3A, L3 = (Z)-6-chloro-1-[(6-chloro-3,4-dihydroisoquinolin-1-yl)methylene]-3,4-dihydro-1H-isoquinolin-2-ide}. The significant impact of electronic modification at the BHM backbone (L1–L3) on its redox tunability at the metal–ligand interface in 1A–3A and its subsequent oxygenation profile to yield bis(heterocyclo)methanone (BMO, analogue of α-ketodiimine) in the corresponding [Ru(BMO)(acac)2] (1B–3B) via a radical pathway were rationalized. In addition, ...