Synthesis and structural characterization of novel symmetric homodinuclear iridium acetylacetonate complexes

Two novel symmetric homodinuclear iridium acetylacetonate complexes were synthesized via the direct reaction of 2 equivalent [(acac-O,O)(2)(acac-C-3)Ir(III)(H2O)] with 1 equivalent of pyrazine or 4,4'-bipyridine. The structures were fully characterized by elemental analysis, H-1-NMR, and single-crystal X-ray diffraction. The structural data support that they have a highly symmetric dinuclear nature with two motifs containing iridium [(acac-O,O)(2)(acac-C-3) Ir(III)] bridged by two nitrogen atoms of pyrazine or 4,4'-bipyridine in a trans position. Absorption spectra of both compounds were measured and purple-shifted about 78.9 nm of the metal-to-ligand charge transfer transition was observed.