摘要:
                                The syntheses of greenish-blue light emitting [Ir(ppy)(2)(dppel)] (2), [Ir(ppy)(2)(dppp)] (3) and [Ir(ppy)(2) (dppe)] (4) [ppy, 2-phenylpyridine; dppel, 1,2-bis(diphenylphosphino)ethylene; dppp, 1,3-bis(diphenylphosphino)propane; dppe, 1,2-bis(diphenylphosphino)ethane] complexes were carried out using [(ppy)(2)Ir(mu-Cl)(2)Ir(ppy)(2)] (1) as a starting material. These complexes were characterized by elemental analyses and NMR (H-1, C-13 and P-31) spectral studies. A single-crystal X-ray diffraction study confirmed a distorted octahedral geometry for 3. Complexes 2-4 were found to exhibit blue-shifted emission as compared to [Ir(ppy)(2)(acac)] (acacH = acetylacetone) and [Ir(ppy)(2)pic] (pic = 2-picolinic acid) because of the presence of strongly pi-accepting, (Ph2PPPh2)-P-boolean AND units. The solution quantum efficiency for 2-4 was measured and 2 showed the highest quantum efficiency. Ground state geometry optimizations for 2-4 were performed using density functional theory (DFT) with the B3LYP hybrid functional and excitation energies for low lying singlet and triplet excited states were obtained via time-dependent DFT (TDDFT) calculations. Further, complexes 1-4 were synthesized by a Microwave Irradiation technique (MW) in a reasonably shorter time. This facile and expeditive synthetic route has been extended and successfully verified for other heteroleptic complexes of Ir(III) with varying different bidentate [((NN)-N-boolean AND) (5), ((OO)-O-boolean AND) (6), ((NO)-O-boolean AND) (7)] and monodentate [PPh3 (8)] ancillary ligands. (C) 2013 Elsevier Ltd. All rights reserved.