2-[4-(3,5-Difluorophenyl)-1H-1,2,3-triazol-5-yl]pyridine (L3).
2-[(3,5-Difluorophenyl)ethynyl]pyridine (1.3 g) and trimethylsi-
lylazide (0.77 mL) are dissolved in DMF (25 mL; dried over
molecular sieves). The mixture is heated and stirred at 90 ꢀC, and
is kept under an argon atmosphere (no argon overflow is applied
to keep the trimethylsilylazide in the mixture). The reaction can
be followed 19F NMR, and when necessary more trimethylsily-
lazide is added. When the reaction is complete, typically after
several days, the mixture is poured into water and the product is
extracted from the water layer with ether. The collected organic
layers are dried with Na2SO4 and evaporated to dryness. The
residue is stirred in a mixture of chloroform and pentane, giving
a precipitate that is collected, washed with pentane and dried.
Yield: 0.47 g (30%) of an off-white powder. 1H NMR (200 MHz,
CDCl3 with some CD3OD) d: 8.70 (m, 1H); 7.74 (m, 2H); 7.30
(m, 3H); 6.83 (m, 1H). 19F NMR (188 MHz, CDCl3 with some
CD3OD) d: ꢂ109.9 (s, 2F). LC-MS (MeCN–H2O): m/z 259 ([M +
H+]). MALDI-TOF-MS (CHCl3–MeOH): m/z 259.0 ([M + H+]).
Synthesis of the iridium complexes. This synthetic strategy was
adapted from already published procedures.26,27 To 0.2 mmol (1
eq.) of [(F2ppy)2Ir(m-Cl)]2 and 0.44 mmol (2.2 eq.) of the pyri-
dine-1,2,3-triazole ligand L1, L2 or L3 were stirred in 15 mL of
CH2Cl2 and 5 mL of EtOH and the reaction was kept under
reflux for 16 h under nitrogen atmosphere. Upon completion of
the reaction (TLC), all solvents were removed under reduced
pressure and the resulting yellow solid was chromatographed on
silica gel (CC), with a dichloromethane–acetonitrile mixture
(9 : 1) as eluent. The yellow solid obtained after drying the
product under vacuum is washed with a minimum amount of
ethyl acetate, and dried affording the pure product.
(F2ppy)2Ir(pta) (1): Yield: 50%. 1H NMR (300 MHz, CD2Cl2)
d: 8.17 (t, 2H, J ¼ 9.7 Hz); 8.06 (s, 1H); 7.69 (m, 1H), 7.47 (m,
2H); 6.97 (ddd, 1H, J ¼ 6.4, 5.6, 2.5 Hz); 6.86 (dddd, 2H,
J ¼ 11.9, 7.3, 5.8, 1.4 Hz); 6.43 (m, 2H); 5.78 (dd, 1H, J ¼ 8.5,
2.3 Hz); 5.68 (dd, 1H, J ¼ 8.8, 2.2 Hz). 19F{1H} NMR (282 MHz,
CD2Cl2) d: ꢂ108.03 (dd, J ¼ 10.40 Hz, 1F), ꢂ108.62 (d, J ¼
10.20 Hz, 1F), ꢂ109.98 (dd, J ¼ 10.50 Hz, 1F), ꢂ110.62 (d, J ¼
10.20 Hz, 1F). MS (ESI+, MeOH): m/z 719.11 ([M + H+]), 741.09
([M + Na+]). HRMS calcd for C29H17F4IrN6 719.1154 ([M +
H]+); found 719.1145. Anal. Calcd for C29H17F4IrN6$1/
3CH2Cl2: C, 47.23; H, 2.39; N, 11.27. Found: C, 47.42; H, 2.65;
N, 11.28%.
2H); 7.05 (dddd, 2H, J ¼ 18.19, 5.72 Hz); 6.97 (ddd, 1H, J ¼ 7.35,
1.37 Hz); 6.89 (tt, 1H, J ¼ 9.07, 2.36 Hz); 6.53 (dddd, 2H, J ¼
15.13, 9.26 Hz); 5.87 (dd, 1H, J ¼ 8.44 Hz); 5.78 (dd, 1H, J ¼ 8.78
Hz). 19F{1H} NMR (282 MHz, CD2Cl2) d: ꢂ107.89 (d, J ¼ 10.47
Hz, 1F), ꢂ108.48 (d, J ¼ 10.23 Hz, 1F), ꢂ109.85 (d, J ¼ 10.48
Hz, 1F), ꢂ110.21 (s, 2F), ꢂ110.50 (d, J ¼ 10.24 Hz, 1F). MS
(ESI+, MeOH): m/z 831.3 ([M + H+]), 853.2 ([M + Na+]). HRMS
calcd for C35H19F6IrN6 853.1099 ([M + Na]+); found 853.1104.
Anal. Calcd for C35H19F6IrN6: C, 50.66; H, 2.31; N, 10.13.
Found: C, 50.30; H, 2.22; N, 9.99%.
Acknowledgements
The authors would like to thank Philips Research and SENTER
(TRIPLED RWC-061-JH-04063-jh) for financial support, Bea
Langeveld at Technical University Eindhoven for TGA
measurements and Evonik Degussa for letting us using the
photoelectron spectrometer. RQA would like to acknowledge the
Humboldt Foundation for financial support. Dr Yinghui Sun
is kindly acknowledged for helping in the device preparation.
Dr Asgeir E. Konradsson is gratefully acknowledged for
performing electrochemical measurements.
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(F2ppy)2Ir(pta)F5Ph (2): Yield: 44%. 1H NMR (300 MHz,
CD2Cl2) d: 8.29 (dd, 2H, J ¼ 15.4, 8.4 Hz); 7.78 (m, 4H); 7.59
(ddd, 2H, J ¼ 18.3, 5.8, 0.9 Hz); 7.33 (d, 1H, J ¼ 8.0 Hz); 7.12
(ddd, 1H, J ¼ 7.5, 5.6, 1.3 Hz); 7.0 (dddd, 2H, J ¼ 17.5, 7.3, 5.9,
1.4 Hz); 6.54 (dddd, 2H, J ¼ 12.5, 11.7, 9.3, 2.4 Hz); 5.87 (dd, 1H,
J ¼ 8.4, 2.4 Hz); 5.79 (dd, 1H, J ¼ 8.8, 2.4 Hz). 19F{1H} NMR
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2F), ꢂ154.61 (t, J ¼ 20.88 Hz, 1F), ꢂ162.21 to ꢂ162.54 (m, 2F),
ꢂ107.73 (d, J ¼ 10.51 Hz, 1F), ꢂ108.38 (d, J ¼ 10.22 Hz,
1F), ꢂ109.74 (d, J ¼ 10.52 Hz, 1F), ꢂ110.46 (d, J ¼ 10.23 Hz,
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Na+]). HRMS calcd for C35H16F9IrN6 907.0816 ([M + Na]+);
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1
(F2ppy)2Ir(pta)3,5FPh (3): Yield: 65%. H NMR (400 MHz,
CD2Cl2) d: 8.29 (dd, 2H, J ¼ 18.60 Hz); 7.91–7.84 (m, 1H); 7.84–
7.67 (m, 5H); 7.57 (ddd, 1H, J ¼ 5.83, 0.70 Hz); 7.28–7.17 (m,
This journal is ª The Royal Society of Chemistry 2008
J. Mater. Chem., 2008, 18, 4579–4590 | 4589