N. Yoshikawa et al.
FULL PAPER
2,2Ј:6Ј,2ЈЈ-terpyridine (Aldrich), tterpy (Aldrich), and potassium
hexafluorophosphate (KPF6, Wako). The complex [IrCl3(terpy)] (1)
Computational Methods: DFT calculations of complexes 1–5 were
performed by using the Gaussian98 program package.[27] The
was synthesized. Tetrabutylammonium perchlorate {TBAP, Becke three parameters hybrid exchange and the Lee–Yang–Parr
[(C4H9)4N]ClO4, Aldrich} as a supporting electrolyte was pur-
chased and used without further purification. CH3CN and N,N-
dimethylformamide (DMF) used in spectroscopic and electrochem-
ical studies were of spectroscopic grade obtained from Dojindo
Laboratory. All other reagents and solvents were of guaranteed
grade.
correlation functionals (B3LYP) were used.[28,29] Geometries in the
ground state were optimized by the RB3LYP/LANL2DZ
method.[30] In the basis set LANL2DZ[6-311 + G(d)], LANL2DZ
was used for the IrIII metal and 6-311+G(d).[31] was used for other
atoms. After the RB3LYP/LANL2DZ[6-311+G(d)] geometry opti-
mizations were completed, single-point calculations of RB3LYP/
LANL2DZ [6-311+G(d)] TD SCRF = PCM were carried out for
complexes 1–5. The solvent effect of CH3CN was included by the
SCRF = PCM method.[32–37]
Synthesis: The complexes [IrCl3(L)] (L = terpyridine derivatives)
were prepared by a sequential procedure with a ligand replacement.
(NH4)3[IrCl6] (0.24 g, 0.50 mmol) and ligand L (0.50 mmol) were
mixed in ethylene glycol (15 mL). The suspended mixture was
heated at reflux for 15 min in a microwave oven with purging of
nitrogen atmosphere. After the mixture was cooled to room tem-
perature, an orange yellow product began to precipitate and was
collected by vacuum filtration. The residue was dissolved in a mini-
mal amount of CH3CN.
Supporting Information (see footnote on the first page of this arti-
cle): Schematic drawing of the orbital energies of the HOMO and
LUMO obtained from B3LYP calculations; calculated bond
lengths and angles for the ground states of complexes 1–5; com-
puted TDDFT vertical excitation energies for the lowest singlet ex-
cited states of complexes.
Measurements: Electronic absorption spectra were recorded at
room temperature in CH3CN solution with a Shimadzu UV-2550
spectrophotometer. Mass spectra (ESI) were obtained by a JEOL
JMS-T100LC AccuTOF spectrometer. All NMR spectra were re-
corded with a JEOL JNM-AL400 FT-NMR spectrometer. 1H
NMR chemical shift values are reported in ppm as reference to
the internal standard TMS. CV were measured with an ALS-610B
electrochemical analyzer fitted with a three-electrode system con-
sisting of a glassy carbon working electrode, a platinum auxiliary
electrode, and a Ag/AgCl reference electrode. CV experiments were
performed for DMF solution of the complexes (5.0ϫ10–4 ) and
0.050 TBAP under a nitrogen atmosphere at 25 °C with a scan
rate of 100 mVs–1. The emission lifetimes were measured in nitro-
gen-equilibrated CH3CN solutions by using a Horiba single-pho-
ton counting system (NAES-500). The emission quantum yields for
the iridium complexes were determined in CH3CN at room tem-
perature relative to those of a solution containing [Ru(bpy)3]Cl2
and having the same absorbance. The emission quantum yields for
the iridium complexes were determined by comparing the inte-
grated emission spectra and by using φ = 0.062 for the standard.[26]
[1] I. M. Dixon, J.-P. Collin, J.-P. Sauvage, L. Flamigni, S. Encinas,
F. Barigelletti, Chem. Soc. Rev. 2000, 29, 385–391.
[2] E. Baranoff, J.-P. Collin, J.-P. Sauvage, L. Flamigni, Chem. Soc.
Rev. 2004, 33, 147–155.
[3] L. Flamigni, B. Ventura, F. Barigelletti, E. Baranoff, J.-P. Col-
lin, J.-P. Sauvage, Eur. J. Inorg. Chem. 2005, 1312–1318.
[4] L. Flamigni, A. Barbieri, C. Sabatini, B. Ventura, F. Barigel-
letti, Top. Curr. Chem. 2007, 281, 143–203.
[5] P. T. Chou, Y. Chi, Chem. Eur. J. 2007, 13, 380–395.
[6] F. M. Hwang, H. Y. Chen, P. S. Chen, C. S. Liu, Y. Chi, C. F.
Shu, F. L. Wu, P. T. Chou, S. M. Peng, G. H. Lee, Inorg. Chem.
2005, 44, 1344–1353.
[7] S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R.
Kwong, I. Tsyba, M. Bortz, B. Mui, R. Bau, M. E. Thompson,
Inorg. Chem. 2001, 40, 1704–1711.
[8] S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, H.-
E. Lee, C. Adachi, P. E. Burrows, S. R. Forrest, M. E. Thomp-
son, J. Am. Chem. Soc. 2001, 123, 4304–4312.
[9] A. J. Wilkinson, A. E. Goeta, C. E. Foster, J. A. G. Williams,
Inorg. Chem. 2004, 43, 6513–6515.
[10] K. Dedeian, J. Shi, N. Shepherd, E. Forsythe, D. C. Morton,
Inorg. Chem. 2005, 44, 4445–4447.
[IrCl3(Clterpy)](2): Yield: 40% (113 mg). C15H10Cl4IrN3 (566.30):
calcd. C 31.81, H 1.77, N 7.42; found C 31.31, H 2.02, N 7.49. MS
[11] S.-B. Zhao, T. McCormick, S. Wang, Inorg. Chem. 2007, 46,
10965–10967.
= 571.09 [IrCl2(Clterpy) +
CH3CN]+, 530.05
[12] Y. You, S. Y. Park, J. Am. Chem. Soc. 2005, 127, 12438–12439.
[13] J. Li, P. I. Djurovich, B. D. Alleyne, M. Yousufuddin, N. N. Ho,
J. C. Thomas, J. Peters, R. Bau, M. E. Thompson, Inorg. Chem.
2005, 44, 1713–1727.
[14] S.-Y. Takizawa, J.-I. Nishida, T. Tsuzuki, S. Tokito, Y. Yamash-
ita, Inorg. Chem. 2007, 46, 4308–4319.
[15] Y.-Y. Lyu, Y. Byun, O. Kwon, E. Han, W. S. Jeon, R. R. Das,
K. Char, J. Phys. Chem. B 2006, 110, 10303–10314.
[16] J.-P. Collin, I. M. Dixon, J.-P. Sauvage, J. A. G. Williams, F.
Barigelletti, L. Flamigni, J. Am. Chem. Soc. 1999, 121, 5009–
5016.
(ESI): m/z
[IrCl2(Clterpy)]+. 1H NMR (400 MHz, CD3CN): δ = 8.82 (dd, J =
5.6 Hz, 2 H), 9.12 (dd, J = 8.0 Hz, 2 H), 9.32 (d, J = 8.0 Hz, 2 H),
9.46 (s, 2 H), 10.28 (d, J = 5.6 Hz, 2 H) ppm.
[IrCl3(Bterpy)](3): Yield: 30% (105 mg). C27H35Cl3IrN3 (700.18):
calcd. C 46.32, H 5.00, N 6.00; found C 45.81, H 4.88, N 5.88. MS
(ESI): m/z = 705.33 [IrCl2(Bterpy) + CH3CN]+, 664.30 [IrCl2-
1
(Bterpy)]+. H NMR (400 MHz, CD3CN): δ = 1.55 (s, 27 H), 7.79
(d, J = 6.0 Hz, 2 H), 8.36 (s, 2 H), 8.37 (s, 2 H), 9.13 (d, J = 6.0 Hz,
2 H) ppm.
[17] N. Yoshikawa, T. Matsumura-Inoue, Anal. Sci. 2003, 19, 761–
765.
[IrCl3(Brterpy)](4): Yield: 25% (86.2 mg). C16H12Br2Cl3IrN3O
(689.66): calcd. C 26.67, H 1.99, N 5.83; found C 26.37, H 2.05, N
6.20. MS (ESI): m/z = 699.92 [IrCl(Brterpy) + 2CH3CN]+, 617.86
[IrCl(Brterpy)]+.
[18] N. Yoshikawa, J. Sakamoto, N. Kanehisa, Y. Kai, T. Matsu-
mura-Inoue, H. Takashima, K. Tsukahara, Acta Crystallogr.,
Sect. E 2003, 59, m830–m832.
[19] N. Yoshikawa, S. Yamabe, N. Kanehisa, Y. Kai, H. Takashima,
K. Tsukahara, Eur. J. Inorg. Chem. 2007, 1911–1919.
[20] T. Yutaka, S. Obara, S. Ogawa, K. Nozaki, N. Ikeda, T. Ohno,
Y. Ishii, K. Sakai, M. Haga, Inorg. Chem. 2005, 44, 4737–4746.
[21] P. J. Hay, J. Phys. Chem. A 2002, 106, 1634–1641.
[22] C. Yang, S. Li, Y. Chi, Y. Cheng, Y. Yeh, P. Chou, G. Lee, C.
Wang, C. Shu, Inorg. Chem. 2005, 44, 7770–7780.
[23] N. Yoshikawa, S. Yamabe, N. Kanehisa, Y. Kai, H. Takashima,
K. Tsukahara, Inorg. Chim. Acta 2006, 359, 4585–4593.
[IrCl3(tterpy)](5): Yield: 15% (46.6 mg). C22H17Cl3IrN3 (621.98):
calcd. C 42.48, H 2.75, N 6.76; found C 42.79, H 3.00, N 6.98. MS
(ESI): m/z
=
627.18 [IrCl2(tterpy)
+
CH3CN]+, 586.15
[IrCl2(tterpy)]+. H NMR (400 MHz, CD3CN): δ = 2.57 (s, 3 H),
7.56 (d, J = 8.0 Hz, 2 H), 7.90 (dd, J = 6.0 Hz, 2 H), 7.98 (d, J =
8.4 Hz, 2 H), 8.22 (dd, J = 7.2 Hz, 2 H), 8.56 (d, J = 8.8 Hz, 2 H)
8.68 (s, 2 H), 9.40 (d, J = 6.0 Hz, 2 H) ppm.
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