Ruthenium complexes containing pyridine-2-carbaldehyde azine as a synthon in the synthesis of bi-/trimetallic complexes

Abstract

Ruthenium complexes [(η⁵-C₅H₅)Ru(PPh₃)(κ²-paa)]PF₆ (paa = pyridine-2-carbaldehyde azine) and [(η⁵-C₅H₅)Ru(κ¹-dppm)(κ²-paa)]BF₄ [dppm = bis(diphenylphosphanyl)methane] have been employed as a synthon in the synthesis of homo/hetero bi-/trimetallic complexes. It is the uncoordinated N,N-donor site on paa in complex [(η⁵-C₅H₅)Ru(PPh₃)(κ²-paa)]PF₆, and N,N-donor site on paa and pendant phosphorus in [(η⁵-C₅H₅)Ru(κ¹-dppm)(κ²-paa)]BF₄ that allows for their incorporation into bi-/trimetallic systems. The resulting complexes have been characterized by analytical, spectral and electrochemical studies. Molecular structures of homo-bimetallic complex [(PPh₃)(η⁵-C₅H₅)Ru(μ-paa)Ru(η⁶-C₁₀H₁₄)Cl](PF₆)₂ and hetero-bimetallic complex [(PPh₃)(η⁵-C₅H₅)Ru(μ-paa)Rh(η⁵-C₅Me₅)Cl](PF₆)₂ have been authenticated crystallographically. Complexes exhibit absorptions throughout the visible region and complicated electrochemical behaviour. Metal-based Ru^II/Ru^III oxidations in the bimetallic complexes do not vary as in the trimetallic complexes.