Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

摘要

Nine new phosphorus-coordinated iridium(III) complexes of the form [Ir(C~(∧)N)_(2)(P~(∧)P)]PF_(6), [Ir(F-piq)_(2)(xantphos)]PF_(6) ( 1 ), [Ir(F-piq)_(2)(binap)]PF_(6) ( 2 ), [Ir(F-piq)_(2)(dppp)]PF_(6) ( 3 ), [Ir(Me-piq)_(2)(xantphos)]PF_(6) ( 4 ), [Ir(Me-piq)_(2)(binap)]PF_(6) ( 5 ), [Ir(Me-piq)_(2)(dppp)]PF_(6) ( 6 ), [Ir(CF_(3)O-piq)_(2)(xantphos)]PF_(6) ( 7 ), [Ir(CF_(3)O-piq)_(2)(binap)]PF_(6) ( 8 ), and [Ir(CF_(3)O-piq)_(2)(dppp)]PF_(6) ( 9 ) (F-piq = 1-(4-fluorophenyl)isoquinoline, Me-piq = 1-( p -tolyl)isoquinoline, CF_(3)O-piq = 1-(4-(trifluoromethoxy)phenyl)isoquinoline, xantphos = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, binap = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, dppp = 1,3-bis(diphenylphosphanyl)propane), have been synthesized and fully characterized. The crystal structures of 1 , 7 , and 9 have been determined by X-ray analysis. The most representative molecular orbital energy-level diagrams and the lowest energy electronic transitions of 1 – 9 have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT). All of the complexes are orange-red emissive with quantum efficiencies of 3.2–24.4% and lifetimes of 1.77–3.19 μs in degassed CH_(2)Cl_(2) solution at room temperature. These research results reveal that the Me-piq C~(∧)N ligand and xantphos P~(∧)P ligand are beneficial for a red shift of absorption and emission wavelength. Complex 4 has better charge transfer ability, which probably promises its use as a red-phosphorescent material.