heteroleptic iridium complex from this ligand was synthesized
and characterized. By using the new heteroleptic iridium
complex as a guest and polyfluorene as a host, high-efficiency
red phosphorescent polymer light-emitting devices were
obtained. In comparison, we also synthesized a homoleptic
iridium complex Ir(1-piq)3. The devices doped with the
homoleptic iridium complex are also demonstrated.
as an elute formed a pale yellow oil (17.11g, 82.4%). 1H NMR
(CDCl3, 400 MHz): dH(ppm) 7.60–7.58 (dd, 2 H), 7.41–7.40
(m, 4 H), 7.26–7.21 (m, 3 H), 3.86–3.82 (t, 2 H), 2.80–2.77 (t,
2 H). GC-MS: m/z 207 (M+).
l-Phenylisoquinoline (3). 17.01 g (0.082 mol) of 2 were
dissolved in 50 mL 1,2,4-trimethylbenzene, and 1.75 g of 10%
Pd/C (2% mol) were added, and the mixture refluxed for 3 h
at 190 uC in N2. The black power was filtered and washed with
dichloromethane several times. Volatiles were removed to
leave a yellow liquid, which was stored at 4 uC for 1 h, with a
yellow solid being separated out. The product was purified by
recrystallization from petroleum ether to form white crystals
Experimental
Measurement and characterization
The 1H NMR and 13C NMR spectra were collected on a
Bruker DRX 400 spectrometer in deuterated chloroform
solution operating respectively at 400 or 100 MHz, with
tetramethylsilane as reference. Elemental analyses were per-
1
(12.30 g, 73%). H NMR (CDCl3, 400 MHz): dH(ppm) 8.60–
8.59 (d, 1 H), 8.10–8.08 (d, 1 H), 7.87–7.85 (d, 1 H), 7.70–7.67
(m, 3 H), 7.65–7.62 (t, 1 H), 7.54–7.46 (m, 4 H). GC-MS: m/z
205 (M+).
formed on
a Vario EL elemental analysis instrument
(Elementar Co.). EI-MS were recorded on a LCQ DECA XP
Liquid Chromatograph–Mass Spectrometer (Thremo Group)
and UV-visible absorption spectra were recorded on a HP
8453 UV-Vis spectrophotometer. Cyclic voltammetry was
carried out on a CHI660A electrochemical workstation in
3-(Pyridin-2-yl)-1H-1,2,4-triazole (4). 5.00 g of 2-cyanopyr-
idine were added to 20 ml of methanol and then added to 10 ml
of a methanol solution of sodium methoxide (25 wt%), and the
resulting solution was stirred at a room temperature for 1 hour.
5 ml of acetic acid were added to the solution dropwise, and
10 g of formylhydrazide were added and stirred at room
temperature for 1 hour to precipitate a white crystal. The
crystal was separated via filtration, 50 ml of toluene was added
into it, and the resulting mixture was stirred under reflux for
3 hours. The mixture was then cooled to room temperature
and the solvent was removed to obtain a white solid (4.01 g,
a
solution of tetrabutylammonium hexafluorophosphate
(Bu4NPF6) (0.1 M) in dichloromethane at a scan rate of
10 mV s21 at room temperature under argon protection. A
platinum electrode was used as the working electrode. A Pt
wire was used as the counter electrode, and a saturated calomel
electrode was used as the reference electrode.
Syntheses
1
57.0%). H NMR (CDCl3, 400 MHz): dH(ppm) 15–14 (br s,
1 H), 8.70–8.68 (d, 1 H), 8.27 (s, 1 H), 8.10–8.08 (d, 1 H), 7.98–
7.94 (m, 1 H), 7.50–7.47 (m, 1 H).
Reagents. All reagents and solvents were obtained from
Aldrich, Acros, and TCI Chemical Co. and used as received.
Tetrakis(triphenylphosphine)palladium was stored in an
atmosphere of dry argon. The ligands 1-phenylisoquinoline
(1-piq)26 and 3-(pyridin-29-yl)-1H-1,2,4-triazole (pt)27 were
synthesized according to the literature.
[Ir(1-piq)2Cl]2, tetrakis(l-phenylisoquinoline-C2,N9)(m-chloro-
bridged)diiridium(III). Iridium trichloride hydrate (1.318 g,
3.8 mmol) was combined with 1.915 g (9.4 mmol) of 3, dissolved
in a mixture of 20 mL 2-ethoxyethanol and water (3 : 1), and
refluxed for 24 h in N2. The solution was cooled to room
temperature, and the deep-red precipitate was collected on a
glass filter frit. The precipitate was washed with 95% ethanol
and ethyl ether to form a dark-red power (2.134 g, 90%), which
was used directly for the next step without purification.20
N-Phenethyl benzamide (1). Benzoyl chloride(28.10 g,
0.20 mol) was dropped into a mixture of phenethylamine
(24.20 g, 0.20 mol) and triethylamine (20.20 g, 0.2 mol) in
300 mL dichloromethane. The mixture was stirred at room
temperature for 4 hours. After being washed with water, 5%
hydrochloric acid and water, the organic layer was dried with
anhydrous magnesium sulfate. The product obtained was
purified by recrystallization from ethyl acetate to form white
crystals of 3 (37.3 g, 83.3%). GC-MS (225, M+).
Ir(1-piq)3, tris(l-phenylisoquinoline-C2,N9)iridium(III). [Ir(1-
piq)2Cl]2 (0.508 g, 0.4 mmol), 3 (0.328 g, 1.6 mmol), acetyl
acetone (0.081 g, 0.8 mmol) and triethylamine ((0.080 g,
0.8 mmol) were dissolved in 50 mL of glycol. The solution was
refluxed under nitrogen for 48 h. After cooling the reaction
mixture to room temperature, 10 mL of 1 M aqueous hydro-
chloric acid was added to the solution, resulting in precipita-
tion of the product. Then the product was filtered, washed
with water and ethyl ether, and dried at 100 uC in vacuum. The
purification of the product was carried out by silica gel column
chromatography with CH2Cl2 as an eluent to obtain a red
powder (0.193 g, 30%). 1H NMR (CDCl3, 400 MHz): dH(ppm)
8.94 (m, 3 H), 8.18 (d, 3 H), 7.71 (m, 3 H), 7.62 (m, 6 H), 7.33
(d, 3 H), 7.09 (d, 3 H), 6.94–6.99 (m, 6 H), 6.84 (t, 3 H). Anal.
Calcd for C45H30IrN3: C, 67.14, H, 3.76, N, 5.22. Found: C,
67.24, H, 3.59, N, 5.18%. EIMS: m/z 805 (M + 1)+.
l-Phenyl-3,4-dihydroisoquinoline (2). 22.51 g (0.1 mol) of 1
were dissolved in 40 mL of xylene. P2O5 (28.60 g, 0.1 mol) and
POCl3 (80 mL) were added via stirring, and the mixture was
heated to reflux and held at that temperature for 3 hours. Then
the solution was allowed to cool to room temperature. The
solvent was decanted, and the residual solid was carefully
triturated to neutrality with 10% sodium hydroxide solution.
The resultant aqueous mixture was extracted with dichloro-
methane. The organic layer was dried with anhydrous
magnesium sulfate. Evaporating the solvent formed
a
brown–yellow oily crude product. Further purification by
silica gel column using ethyl acetate–dichloromethane (1 : 10)
1282 | J. Mater. Chem., 2006, 16, 1281–1286
This journal is ß The Royal Society of Chemistry 2006