Synthesis and properties of mixed chelates of ruthenium containing 1,2-diimine, 1,2-iminoquinone and dioxolene ligands

Abstract

The reaction of RuCl₂(PhNH₂)₂(L¹), <b>1</b> (L¹=N-aryl-1 ,2-areno-quinonediimine)

with 3,5-ditertiarybutylcatechol affords a blue RuCl₂(L¹)(L²)<b>2</b>[L²=N-phenyl-(3,5-ditertiarybutyl) 1,2-benzoquinoneiminej and a violet Ru(L¹)(L³)₂, <b>3</b> (L³=3,5-ditertiarybutyl- 1,2-semiquinone) compounds. These have been isolated in their pure states by column chromatography. The complexes have been fully characterized and their physicochemical data are reported. While the complex <b>2 </b>displays two methyl resonances, the complex <b>3</b> shows four such signals as expected. Solution spectra of the complexes consist of multiple transitions. The most intense visible range transition for 2 appears at 625 nm, which is blue shifted to 520 nm in 3. These transitions involve the orbitals that have both metal and ligand characters. Cyclic voltammetry of these complexes has been studied. Metal redox associated with multiple ligand based responses are observed.