Crystal Structure and Photophysical Properties of an Iridium(III) Pyrazine Complex

An iridium(III) complex of (MDPPF)(2)Ir(acac) (MDPPF=4,4'-difluoro-5-methyl-2,3-diphenylpyrazine, acac=acetylacetone) has been prepared and characterized by X-ray single crystal diffraction. The photophysical properties of (MDPPF)(2)Ir(acac) were investigated using UV-Vis spectroscopy and photoluminescence (PL) techniques. X-ray diffraction (XRD) studies revealed that the complex belongs to a triclinic system of the P (1) over bar space group with cell dimensions a=1.13984(3) nm, b=1.26718(3) nm, c=1.29541(3) nm, alpha=93.7181(19)degrees, beta=101.638(2)degrees, gamma=110.853(3)degrees and V=1.69336(7) nm(3). A solution of the (MDPPF)(2)Ir(acac) complex in dichloromethane was found to emit yellow light with a maximum peak at 555 nm at room temperature. Furthermore, (MDPPF)(2)Ir(acac) was used as a phosphorescence dopant in organic light-emitting diodes (OLEDs) with the structures of ITO/NPB (40 nm)/CBP:(MDPPF)(2)Ir(acac) (20 nm)/TPBi (10 nm)/Alq(3) (30 nm)/LiF (1 nm)/Al (100 nm). These devices showed yellow emission at 558 nm, a maximum brightness of 32700 cd.m(-2), current efficiency of 44.7 cd.A(-1) and power efficiency of 20.7 lm.W-1.