Synthesis of pyridine-fused 5,6,11,12-tetraazanaphthacene as a bis-bidentate ligand and electrochemistry of a ruthenium(II) dinuclear complex

Abstract

A type of electron-accepting N-heteroacene which can be used as a bis-bidentate ligand, tetrapyrido[3,2-a:2¤,3¤-c:3¤¤,2¤¤j:2¤¤¤,3¤¤¤-l][5,6,11,12]tetraazanaphthacene (TPy-TANC), was synthesized. TPy-TANC is a pyridine-fused tetraazanaphthacene which has the potential to behave as an n-type semiconductor. TPy-TANC was determined to have a monoclinic P21/n space group by single-crystal X-ray diffraction analysis. The cyclic voltammogram of [(bpy)2RuII(TPy-TANC)RuII(bpy)2](PF6)4 (bpy = 2,2¤-bipyridine) showed a reversible four-step/ six-electron transfer in the reduction at 10.553 (1e1, TPy-TANC), 11.15 (1e1, TPy-TANC), 11.81 (2e1, bpy), and 12.02 V (2e1, bpy) (vs. Fc/Fc+).