Uraiwan Changsaluk and Kanidtha Hansongnern

pp. 739 - 749

Abstract

The new azoimine functionalized ligand, 5-methyl-2-(phenylazo)pyridine (5mazpy) was synthesized.
It reacted with RuCl₃.3H₂O in ethanolic solution to give the isomeric [Ru(5mazpy)₂Cl₂] complexes. One of the
isomers was characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, UV-Visible
absorption spectroscopy, and cyclic voltammetry. Results from infrared spectroscopy show that the N=N
stretching mode in the complex appeared at a lower frequency than that in the free ligand. The formulation
of complex was comfirmed by elemental analysis. The ¹H and ¹³C NMR spectra of complex exhibited two
sets of ligand peaks, this indicated that both 5mazpy ligands were in different environments. Therefore, the
[Ru(5mazpy)₂Cl₂] complex has no C₂-symmetry. Results from UV-Visible absorption spectroscopy show
that the complex exhibited the t₂(Ru) → π*(5mazpy) MLCT transitions in the visible region. Redox studies
showed the Ru(III)/Ru(II) couple at +0.62 V and two azo reductions couple at -1.17 V and -1.51 V versus
ferrocene couple.