Characterization of the mixed-valent intermediate ( n=3) of the complex series {(μ,η 3:η 3-L)[(Ru(terpy)] 2} n+ with the unsaturated bridging ligand N, N′-bis(α-picolinoyl)hydrazido(2−)=L 2−

Abstract

Listen

Translate article

N, N ′-Bis(α-picolinoyl)hydrazine H 2L, a potentially bis-tridentate conjugated ligand in its doubly deprotonated form L 2−, has been used to synthesize the diruthenium(II) complex {(μ-L)[Ru(terpy)] 2}(PF 6) 2. Its electrochemical and spectroelectrochemical (UV–Vis–NIR, EPR) investigation reveals a mixed-valent (Ru IIIRu II) intermediate with electrochemical and spectroscopic characteristics related to those of the {(μ-adc-R)[Ru(bpy) 2] 2} 3+ ions (adc-R 2−=bis-bidentate C-substituted diacylhydrazido(2−) ligands): comproportionation constant K c=10 9.0 (CH 2Cl 2), intervalence charge transfer band at 1000 nm ( ε=3800 M −1 cm −1), EPR signal at g ⊥=2.14, g ∥=1.953. The non-innocent nature of L n− is inferred from comparative analysis of the spectroscopic data.