Binuclear platinum(II) complexes based on a new bis-bidentate 3,6-di(thien-2-yl)pyridazine skeleton, a novel type of deep-red phosphorescent emitters: Synthesis and nonempirical calculations

Abstract

Three novel template bis-bidentate ligands based on {3,6-di(thien-2-yl)pyridazine} skeleton and four binuclear Pt(II) complexes containing these metalating templates were synthesized and characterized including photophysical study of two emissive compounds. These complexes display phosphorescence from triplet excited state localized primarily at the thienyl-pyridazine aromatic system, the emission bands being unusually strong shifted (ca. 100 nm/4380 cm−1) to the NIR region compared to analogous phenyl-pyridazine complexes. The absorption and emission characteristics of the complexes were analyzed by using DFT and TD DFT calculations. The results of calculations confirm that emission originates from a mixture of 3LC, 3MLCT, 3LLCT with major contribution of the former excited state and show reasonable agreement with the experimental data.