Two unusual cyclometalated dimeric Ir(III) complexes: Synthesis, crystal structure and phosphorescent properties

Two cyclometalated dimeric Ir(III) complexes, [{Ir(μ-Cl)(μ-ppa)(dmppa)}2] (dimer 1) and (dmppa)Ir(μ-Cl)(μ-ppa)Ir(ppa) (dimer 2) (dmppa = 1-(2,6-dimethylphenoxy)-4-phenylphthalazine, ppa = 1-hydroxyl-4-phenylphthalazine), containing the bridging phthalazine ligands and bridging chlorides have been synthesized and fully characterized. Dimer 1 can form a noncovalently linked crystalline porous frameworks. The emission wavelength of dimer 1 in CH2Cl2 solution was 596 nm and the further hydrolysis of phenolic groups red shift the emission of dimer 2 to 634 nm. Two dimers have relatively high quantum efficiency, i.e., ca. 0.21 for dimer 1 and 0.3 for dimer 2 in CH2Cl2 solution.