Synthesis, Structural Characterization, and Electrophosphorescent Properties of Rhenium(I) Complexes Containing Carrier-Transporting Groups

Abstract

Two novel diimine rhenium(I) carbonyl complexes with the formula [Re(CO)(3)(L)Br], where L = 1-(4-5'-phenyl-1,3,4-oxadiazolylbenzyl)-2-pyridinylbenzoimidazole (1) and 1-(4-carbazolylbutyl)-2-pyridinylbenzoimidazole (2), have been successfully synthesized and characterized by elemental analysis, (1)H NMR, and IR spectra. Their electrochemical, photophysical, and electroluminescent behaviors, along with the X-ray crystal structure analysis of 2, are also described. White electrophosphorescent devices were fabricated using 1 and 2 as emitters. The devices based on carbazole-containing (hole-transporting group) 2 with the structure ITO/m-MTDATA (30 nm)/NPB (20 nm)/2:CBP (8%, 30 nm)/Bphen (20 nm)/Alq(3) (20 nm)/LiF (0.8 nm)/Al (200 nm) exhibit Commission Internationale de L'Eclairage coordinates of x = 0.34, y = 0.33 with a maximum brightness of 2300 cd/m(2) at 580 mA/cm(2). When a brightness of 1500 cd/m(2) appears at 230 mA/cm(2), the devices based on 10 wt % 2 still possess 56% of the maximum efficiency which appeared at 2.7 mA/cm(2). These performances are among the best reported for devices using Re(I) complexes as emitters. By comparison of the electroluminescent properties of the devices based on 1 and 2, we conclude that the introduction of the carbazole group into the ligand improves the performance of 1-doped devices.

Synthesis, Characterization, Fluorescence and Antibacterial Activity of the Re(VII) Complex [ReO3(phen)(H2PO4)]・H2O

“…These assignments are confirmed by the absorption spectra of free phen (Fig. 4a) and the results for related systems [24,25]. The energy gap (Fig.…”

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

“…[ 156 ] However, few Re (I) complexes were reported to be used in PhOLEDs owing to the disadvantage of the saturation of emission states resulting from triplet-triplet annihilation which leads to low effi ciency at high current density. [157][158][159] The electrophosphorescent performances of Re (I) complexes can be improved through modifi cation of the ligands. For example, the π -conjugation Ir(ppy-NPh 2 ) 2 (acac) 528 10.3 [120] Ir(ppy) 2 (CBDK) 525 [121] Ir(ppi) 2 (acac) 513 13.4 [122] N N Pt C 6 F 5 space of ligands can be extended via the incorporation of a 2-(4-octadecyloxylphenyl)vinyl group into 2,2 ′ -bipyridine to adjust the molecular orbital energy levels to give red emission.…”

Synthesis, crystal structure and electroluminescent properties of fac-bromotricarbonyl ([1,2,5]oxadiazolo[3',4':5,6]pyrazino- [2,3-f][1,10]phenanthroline) rhenium (I)

“…We have found that the treatment of 1,2,5-oxadiazole-3,4-diamine 7a with 1,10-phenanthroline-5,6-dione 6 in refluxing acetic acid for 2 h gave the target product in 92% yield and high purity (Scheme 1). The same procedure has been used for the preparation of [1,2,5]thiadiazolo [3',4':5,6]pyrazino[2,3-f] [1,10]phenanthroline 5b. The solubility of compounds 5 has decreased dramatically from 5a to 5b.…”