Electrochemistry and absorption and emission spectroscopy of new orthometalated complexes of rhodium(III) and iridium(III) with the ligands 1,4,5,8-tetraazaphenanthrene and 1,4,5,8,9,12-hexaazatriphenylene

The electrochcnucal and UV-visible absorption and emission properties of new heterolepticortho-metalated complexes of Rh(III) and Ir(III) are reported and compared to those of similar complexes studied previously in the literature. These novel compounds contain two ortho-metalating ligands (ortho-C-deprotonated forms of 2-phenylpyridine, PPY) and a polyazaaromatic ligand such as 1,4,5,8-tetraazaphenanthrene (TAP) or 1,4,5,8,9,12-hexaazatriphenylene (HAT). The electrochemical behavior, studied by cyclic voltammetry, shows the presence of two reversible reductions, both on a TAP or HAT ligand, and of an irreversible oxidation