Inorganic Chemistry
Article
molecular level. All experimental and TD-DFT calculations
results proposed that the phase transition resulting from the
destruction of intermolecular stacking modes is not the only
room temperature. After the reaction was over, the mixture was
extracted with dichloromethane and water. The organic phase was
dried over anhydrous sodium sulfate, and dichloromethane was
removed under reduced pressure. The crude product was separated
and purified by column chromatography with dichloromethane/
petroleum ether (2/1 v/v). The product was colorless transparent
crystals in a yield of 17%.
3
reason for the MCL property, and the CT dominant emitting
excited state plays a key role in achieving MCL in iridium(III)
complexes. Isomer 1 with CT characterization and a larger
transition dipole moment is more sensitive to force stimulus
than isomer 2, since force stimulus could lead to larger
intermolecular packing changes. This work might provide
particularly valuable information for the further understanding
of the MCL mechanism and supply new guidelines to the
design and preparation of MCL-active iridium(III) complexes.
1
Spectral data of ligand dptzpy 2 are as follows H NMR (600 MHz,
CDCl , ppm): δ 8.45 (dd, J = 4.9, 2.1 Hz, 1H), 8.30−8.25 (m, 2H),
3
7.83 (ddt, J = 9.6, 7.8, 1.8 Hz, 1H), 7.59 (ddd, J = 8.5, 6.3, 1.5 Hz,
3H), 7.52−7.42 (m, 4H), 7.42−7.35 (m, 2H), 7.32 (ddt, J = 6.3, 4.8,
1
.6 Hz, 1H).
4
.4. Preparation of Iridium(III) Complex Isomer 1. A
suspension of ligand dptzpy 1 (1.192 g, 4 mmol, 2.00 equiv) and
∧
2
2
the dichloro-bridged diiridium(III) complex [Ir(N C-dfppy) Cl]
2
4
. EXPERIMENTAL SECTION
(
2.432 g, 2 mmol, 1.00 equiv) in MeOH (50 mL) and CH Cl (50
2 2
mL) was refluxed under an inert atmosphere of N in the dark for 6 h.
4.1. General Information and Materials. All chemicals were
2
The solution was then cooled to room temperature, and excess solid
potassium hexafluorophosphate was added to the solution. The
mixture was stirred for 30 min at room temperature, and then the
suspension was filtered and the precipitate was purified by column
chromatography with dichloromethane/methanol (40/1 v/v) to
produce isomer 1 in a yield of 63%.
purchased from commercial suppliers without further purification
unless otherwise stated. All syringes, glassware, needles, and magnetic
stirring bars were dried thoroughly in a vacuum oven. Thin-layer
1
chromatography (TLC) was used for monitoring reactions. H NMR
spectra were recorded at 25 °C on a Varian 600 MHz spectrometer,
and TMS was used as the internal standard. The chemical shifts (δ)
are given in parts per million relative to the internal standard TMS (0
ppm for 1H). UV−vis absorption spectra were recorded on a
Shimadzu UV-3100 spectrophotometer. Photoluminescence spectra,
excited-state lifetimes, and photoluminescence quantum yields
1
Spectral data of iridium(III) complex isomer 1 are as follows. H
NMR (600 MHz, DMSO-d , ppm): δ 8.70 (d, J = 5.6 Hz, 1H), 8.33
6
(d, J = 8.5 Hz, 1H), 8.13 (dt, J = 18.8, 8.1 Hz, 2H), 8.06 (d, J = 4.6
Hz, 2H), 7.97 (d, J = 5.8 Hz, 1H), 7.89 (dd, J = 12.3, 6.2 Hz, 3H),
7
7
6
2
6
.85−7.78 (m, 3H), 7.72−7.67 (m, 1H), 7.45 (t, J = 6.7 Hz, 1H),
.40 (d, J = 8.2 Hz, 1H), 7.35−7.27 (m, 2H), 7.15−7.05 (m, 4H),
.99−6.91 (m, 1H), 5.59 (dd, J = 8.4, 2.1 Hz, 1H), 5.36 (dd, J = 8.6,
(PLQYs) were determined using an Edinburgh FLSP920 spectro-
fluorimeter with an integrating sphere. Powder X-ray diffraction
patterns of isomers were collected on a Rigaku Dmax 2000 instrument
on solid powders. Differential scanning calorimetry (DSC) curves
were measured with a PerkinElmer DSC-7 thermal analyzer under
1
3
.1 Hz, 1H). C NMR (125 MHz, DMSO-d , ppm): δ 163.2 (d, J =
6
.25 Hz), 162.7 (d, J = 6.25 Hz), 162.0 (d, J = 12.5 Hz), 161.6, 161.4
−1
(q, J = 46.25 Hz), 161.1 (t, J = 11.25 Hz), 160.0 (t, J = 13.75 Hz),
nitrogen with a heating rate 10 °C min . Transmission electron
1
1
1
56.5, 152.1 (d, J = 6.25 Hz), 151.8, 151.6, 150.6, 144.2, 140.5 (d, J =
3.75 Hz), 136.4, 132.4, 130.9, 130.6, 130.2, 129.4, 128.7, 127.9,
27.2, 126.5, 125.9 (d, J = 6.25 Hz), 125.1, 124.7, 113.8 (q, J = 45.0
microscopy (TEM) was performed using a TECNAI F20 microscope.
4.2. Preparation of Ligand dptzpy 1 (Ligand 1). A suspension
of 3-phenyl-5-(pyridin-2-yl)-1,2,4-triazole (3.38 g, 15.2 mmol),
iodobenzene (4.9 g, 24 mmol), cuprous iodide (0.96 g, 5.0 mmol),
Hz), 99.6 (t, J = 53.75 Hz), 98.8 (t, J = 53.75 Hz). MS (MALDI-
TOF) [m/z]: 1016.19 (M − PF ). Anal. Calcd for C H F IrN P:
C, 48.48; H, 2.58; N, 8.27. Found: C, 48.41; H, 2.59; N, 8.29.
.5. Preparation of Iridium(III) Complex Isomer 2. The
1,10-phenanthroline (1.92 g, 9.6 mmol), and cesium carbonate (7.44
6
41 26 10
6
g, 22 mmol) in a 200 mL round flask with 80 mL of dry DMF, under
nitrogen protection reflux for 24 h. After the mixture was cooled to
room temperature, DMF was concentrated under reduced pressure,
and the residue was extracted with ethyl acetate and water. The
organic phase was dried over anhydrous sodium sulfate, and ethyl
acetate was removed under reduced pressure. The crude product was
separated and purified by column chromatography with dichloro-
methane/petroleum ether (3/1 v/v) to give a white solid in a yield of
4
synthesis of iridium(III) complex isomer 2 was similar to that of
iridium complex isomer 1 except that the ligand dptzpy 1 was
replaced by dptzpy 2. The yield of as-synthesized isomer 2 was 57%.
1
Spectral data of iridium(III) complex isomer 2 are as follows. H
NMR (400 MHz, DMSO-d , ppm): δ 8.84 (d, J = 5.6 Hz, 1H), 8.40
6
(
8
dd, J = 19.8, 7.1 Hz, 2H), 8.15 (t, J = 7.0 Hz, 2H), 8.03 (dt, J = 17.2,
.1 Hz, 2H), 7.89 (d, J = 7.4 Hz, 2H), 7.75 (ddd, J = 27.1, 15.0, 7.5
5
8%.
1
Hz, 4H), 7.60−7.51 (m, 1H), 7.48−7.38 (m, 2H), 7.32 (q, J = 6.2, 5.4
Hz, 2H), 7.22 (d, J = 7.4 Hz, 2H), 7.10 (t, J = 7.7 Hz, 2H), 7.00 (t, J =
Spectral data of ligand dptzpy 1 are as follows. H NMR (600
MHz, CDCl , ppm): δ 8.51 (dt, J = 4.8, 1.3 Hz, 1H), 8.29−8.24 (m,
3
1
1
6
1
1
1
0.2 Hz, 1H), 5.64 (dd, J = 8.3, 2.2 Hz, 1H), 5.41 (dd, J = 8.6, 2.1 Hz,
2
7
H), 7.95 (dt, J = 7.9, 1.1 Hz, 1H), 7.78 (td, J = 7.7, 1.8 Hz, 1H),
.50−7.40 (m, 8H), 7.30 (ddd, J = 7.6, 4.8, 1.2 Hz, 1H).
1
3
H). C NMR (125 MHz, DMSO-d , ppm): δ 165.5, 163.2 (d, J =
6
.25 Hz), 162.4 (d, J = 7.5 Hz), 161.9 (d, J = 12.5 Hz), 161.6 (d, J =
2.5 Hz), 160.0 (d, J = 13.75 Hz), 158.7, 152.0 (d, J = 7.5 Hz), 151.7,
50.8, 149.8 (d, J = 7.5 Hz), 149.4, 147.8, 142.1, 140.9, 133.1, 131.3,
30.0 (d, J = 17.5 Hz), 128.6, 128.0 (q, J = 52.5 Hz), 127.3, 126.4 (d,
4
.3. Preparation of Ligand dptzpy 2 (Ligand 2). Benzonitrile
(
10.3 g, 100 mmol) and 70 mL of ethanol were placed in a 250 mL
single-neck flask. The mixture was cooled to 0 °C and acetyl chloride
62.8 g, 800 mmol) added dropwise. After the addition, the mixture
(
J = 11.25 Hz), 125.2, 124.6, 124.1 (d, J = 18.75 Hz), 123.3 (d, J =
0.0 Hz), 117.9, 114.1 (q, J = 67.5 Hz), 99.9 (t, J = 52.5 Hz), 99.0 (t,
was warmed to room temperature and allowed to react for 8 h. Then,
the reaction solution was concentrated under reduced pressure to
remove excess acetyl chloride and ethanol. 100 mL of water was
added to the residue, and the solution was neutralized with saturated
2
J = 53.75 Hz). MS (MALDI-TOF) [m/z]: 1016.78 (MPF ). Anal.
6
Calcd for C H F IrN P: C, 48.48; H, 2.58; N 8.27. Found: C,
41 26 10
6
48.72; H, 2.55; N, 8.05.
NaHCO solution and extracted with ether. The organic phase was
3
dried with anhydrous magnesium sulfate, and the ether was removed
under reduced pressure to give the intermediate product ethyl
benzimidate. Ethyl benzimidate (5.96 g, 40 mmol) was dissolved in
ASSOCIATED CONTENT
sı Supporting Information
■
*
150 mL of dichloromethane. This solution was cooled to 0 °C, and
benzoyl chloride (5.62 g, 40 mmol), triethylamine (4.44 g, 44 mmol),
and acylation catalyst 4-dimethylaminopyridine (DMAP, 0.49 g, 40
mmol) were added dropwise. After the addition, the temperature was
raised to 30 °C and the mixture allowed to react for 6 h.
Subsequently, 2-hydrazine pyridine (4.37 g, 40 mmol) was added
dropwise to the reaction solution and stirring was continued for 6 h at
Additional photophysical properties, TEM and ED
experiments, TGA and DSC curves, X-ray crystallo-
graphic data, and TD-DFT calculations (PDF)
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Inorg. Chem. 2021, 60, 3741−3748