Steric Control of the Coordination Mode of the Salicylaldehyde Thiosemicarbazone Ligand. Syntheses, Structures, and Redox Properties of Ruthenium and Osmium Complexes

Reaction of Hsaltsc (1) with [M(PPh3)3X2] (M = Ru, Os; X = Cl, Br) in ethanol affords complexes of the type [M(PPh3)2(saltsc)2] (2), where the saltsc ligand is coordinated, in spite of having the phenolic oxygen as a potential third donor site, as a bidentate N,S-donor ligand forming a four-membered chelate ring.