Luminescent ion pairs with tunable emission colors for light-emitting devices and electrochromic switches

Article abstract of DOI:10.1039/c6sc02837c

Most recently, stimuli-responsive luminescent materials have attracted increasing interest because they can exhibit tunable emissive properties which are sensitive to external physical stimuli, such as light, temperature, force, and electric field. Among these stimuli, electric field is an important external stimulus. However, examples of electrochromic luminescent materials that exhibit emission color change induced by an electric field are limited. Herein, we have proposed a new strategy to develop electrochromic luminescent materials based on luminescent ion pairs. Six tunable emissive ion pairs (IP1-IP6) based on iridium(iii) complexes have been designed and synthesized. The emission spectra of ion pairs (IPs) show concentration dependence and the energy transfer process is very efficient between positive and negative ions. Interestingly, IP6 displayed white emission at a certain concentration in solution or solid state. Thus, in this contribution, UV-chip (365 nm) excited light-emitting diodes showing orange, light yellow and white emission colors were successfully fabricated. Furthermore, IPs displayed tunable and reversible electrochromic luminescence. For example, upon applying a voltage of 3 V onto the electrodes, the emission color of the solution of IP1 near the anode or cathode changed from yellow to red or green, respectively. Color tunable electrochromic luminescence has also been realized by using other IPs. Finally, a solid-film electrochromic switch device with a sandwiched structure using IP1 has been fabricated successfully, which exhibited fast and reversible emission color change.

Full text of DOI:10.1039/c6sc02837c

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Luminescent ion pairs with tunable emission colors for light-
emitting devices and electrochromic switches
Received 00th January 20xx,
Accepted 00th January 20xx
Song Guo,‡a Tianci Huang,‡a Shujuan Liu,a Kenneth Yin Zhang,a Huiran Yang,a Jianmei Han,a Qiang
Zhao,*a and Wei Huang*ab
DOI: 10.1039/x0xx00000x
Most recently, stimuli-responsive luminescent materials have attracted increasing interest because they can exhibit
tunable emissive properties which are sensitive to external physical stimuli, such as light, temperature, force, electric field.
Among these stimuli, electric field is an important external stimulus. However, the examples about electrochromic
luminescent materials that exhibit emission color change induced by the electric field are limited. Herein, we have
proposed a new strategy to develop electrochromic luminescent materials based on luminescent ion pairs. Six tunable
emissive ion pairs (IP1 - IP6) based on iridium(III) complexes have been designed and synthesized. The emission spectra of
ion pairs (IPs) show concentration dependence and the energy transfer process is very efficient between positive and
negative ions. Interestingly, IP6 displayed white emission at a certain concentration in solution or solid state. Thus, in this
contribution, UV-chip (365 nm) excited light-emitting diodes showing orange, light yellow and white emission colors were
successfully fabricated. Furthermore, IPs displayed tunable and reversible electrochromic luminescence. For example,
upon applying a voltage of 3 V onto the electrodes, the emission color of the solution of IP1 near the anode or cathode
changes from yellow to red or green, respectively. Color tunable electrochromic luminescence has also been realized by
using other IPs. Finally, a solid-film electrochromic switch device with a sandwiched structure using IP1 has been
fabricated successfully, which exhibited fast and reversible emission color change.
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with the current semiconductor technology in electronic devices.29-
33
Introduction
Recently, electrochromic luminescent materials that exhibited
emission color changing induced by electric field have been
Luminescent materials have attracted considerable attention
because of their wide applications in displays, data recording and
storage, chemical sensing, bioimaging, etc.1-9 Emissive materials
with tunable luminescence colors are of great significance for their
optical applications. Up to now, conventional methods for tuning
photophysical properties of luminescent materials are mainly
limited to the modification of the chemical structures, such as the
change of π-conjugation skeletons or the introduction of functional
groups.10-21 However, this method often requires complicated
synthetic processes and tedious purification procedures. Stimuli-
responsive luminescent materials have attracted increasing interest,
because they can exhibit tunable emissive properties which are
sensitive to external physical stimuli, such as light, temperature,
force, electric field, etc.22-28 Among these stimuli, electric field is an
important external stimulus, which can be conveniently combined
reported (Fig. 1a). For example, Chidichimo and co-workers have
presented the π-conjugated ionic liquid crystals in which the direct
electrochemical reduction leads to reversible electrochromic
luminescence (ECL) response.34 Beneduci and co-workers have
shown an ECL-active polymer gel based on the conversion of the
redox states, in which emission properties of the polymer depend
on the fluorophore contents and the voltages applied.35 We have
also reported a series of phosphorescent iridium(III) complexes
containing a protonating functional group, which exhibited evident
emission color change induced by the electric field.36-38 However,
special functional groups, such as redox active or protonating
groups, in these electrochromic luminescent materials may reduce
their stability, especially toward redox reagents and pH values.
Therefore, it is urgent to explore
a new generation of
electrochromic luminescent materials with controllable emission
color change.
a. Key Laboratory for Organic Electronics and Information Displays and Institute of
Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for
Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications
(NUPT), Nanjing 210023, P. R. China, E-mail: iamqzhao@njupt.edu.cn.
b. Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials
(IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials
(SICAM), Nanjing Tech University (NanjingTech), Nanjing 211816, P. R. China, E-
mail: wei-huang@njtech.edu.cn.
Ion pairs (IPs) consist of an anionic and a cationic components
which are bonded together with electrostatic and Van-der Waals
interactions. Employment of emissive anionic and cationic
components yields luminescent IPs showing a mixed luminescence
color.39-43 Compared to single luminophores, IPs containing two
luminescent chromophores exhibit richer excited states, which
results from potential energy transfer between the two
luminophores. In addition, IPs exhibit “single-component”
†
Electronic Supplementary Information (ESI) available: details of NMR and MS
spectra. See DOI: 10.1039/x0xx00000x
S. Guo and T. Huang contributed equally to this work.
‡
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characteristic and can avoid phase separation in solid state which or solid state. Thus, in this contribution, UV-chip (36V5iewnmAr)ticelexOcintleinde
DOI: 10.1039/C6SC02837C
light-emitting diodes (LEDs) showing orange, light yellow and white
usually occurs in physical mixture of two luminophores.
In this work, we aim to develop luminescent IPs with tunable emission colors were successfully fabricated using IP6 as emitter. In
emissive colors. Owing to the advantageous photophysical addition, interesting and tunable electrochromic luminescence has
properties of phosphorescent iridium(III) complexes, such as high been observed in solution and quasi-solid devices, and the
luminescence quantum yields, long emission lifetimes, large Stokes electrochromic mechanism of these IPs has been investigated.
shifts, high photostability, and sensitive photophysical properties to
the microenvironment, a series of positively- and negatively-
Results and discussion
charged iridium(III) complexes have been chosen as the cationic and
anionic components of luminescent IPs (IP1-IP6, Fig. 1b),
respectively.44-53 Upon photoexcitation, these IPs exhibited a mixed
Synthesis and characterizations
luminescence from both the cation and the anion. The emission
spectra of IP1-IP6 show concentration dependence. In particular,
IP6 displayed white emission at a suitable concentration in solution
Fig. 1 (a) The design principles of electrochromic luminescent materials. (b) The structures of six ion pairs. (c) Luminescence spectra of IP1 at
n
-Bu4NA1 (10-5 M). (e) Stern-Volmer plot of the
different concentrations in acetonitrile. (d) Absorption and luminescence spectra of C1Cl and
quenching study between C1Cl and -Bu4NA1 and the numerical fitting of Kq.
n
2 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C6SC02837C
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The photophysical properties of iridium(III) complexes are closely also measured in various solvents (THF, ethyl acetate, CHCl3, CH2Cl2,
related to their ligands. Hence, to obtain IPs showing different CH3OH), and there is no evident change in different solvents at the
luminescent colors, various cationic and anionic complexes same concentration of IPs as shown in Fig. S2.
((C^N)2Ir(N^N)+Cl- and (C^N)2Ir(CN)2-n-Bu4N+) with different HC^N
ligands (HC^N 2-phenylpyridine, 2-phenylquinoline, 2-(2,4-
disfluorophenyl)pyridine, 2-thiophenylquinoline, N-hexyl-2-(2-
pyridyl)benzimidazole, 2-(4-((tert-butyldiphenylsilyl)oxy)phenyl)-
phenylbenzothiazole; N^N 2,2'-biquinoline, 2,2'-dipyridine,
The energy transfer process between two components of IP1 was
investigated by Stern-Volmer quenching analysis (Fig. 1d,e). The
quenching study was based on a bimolecular quenching model, τ0/τ
= 1 + Kqτ0[Q], where τ and τ0 are the emission lifetimes of n-Bu4NA1
with and without the quencher C1Cl, Kq is the experimental
quenching rate constant and [Q] is the molar concentration of the
quencher. The lifetimes of n-Bu4NA1 in acetonitrile solution with
various amounts of the quencher, C1Cl, were measured. The
concentration of n-Bu4NA1 was kept at 1.0 × 10-5 M, while that of
C1Cl varied from 0 to 4.0 × 10-4 M. The Stern-Volmer plot of the
=
=
cyanide) were selected to prepare the luminescent IPs and the
emission colors of these complexes cover the entire visible region.
The luminescent IPs were synthesized in two steps. Firstly, three
cationic (C1Cl − C3Cl) and four anionic complexes (n-Bu4NA1 − n-
Bu4NA4) were synthesized by refluxing biscyclometalated iridium(III)
dichloro-bridged dimers in the presence of an excess of auxiliary
N^N or CN- ligands. In the second step, six IPs without small
counterions, IP1−IP6 (C1A1, C2A2, C3A2, C1A2, C2A3 and C2A4),
were obtained by the metathesis reactions (Scheme 1 and Scheme
S1).43,54-58
mixture of the two complexes in solution revealed a good linear
_
S
S
IrCl3.3H2O, 110 oC
S
S
CN
CN
Cl
Cl
n-Bu4N+CN-
Ir
Ir
Bu4N+
Ir
2
n-
N
N
N
N
2
2
2-ethoxyethanol: H2O = 3 : 1
-Bu NA1
n
4
[(thq)2Ir(μ-Cl)2Ir(thq)2]
N
N
C6H13
+
N
All the complexes and IPs have been fully characterized by 1H
nuclear magnetic resonance (NMR), 13C{1H} NMR, 19F{1H} NMR,
matrix-assisted laser desorption ionization time-of-flight mass
spectrometry (MALDI-TOF MS), electrospray ionization mass
spectrometry (ESI-MS) (see Supplementary Information), UV/Vis
absorption spectrometry and steady-state photoluminescence (PL)
N
N
N
Cl-
Ir
F
F
C6H13
N
_
2
110 oC, IrCl3.3H2
O
N
N
N
Cl
Cl
F
Ir
Ir
F
F
F
C1Cl
2
2
2-ethoxyethanol: H2O = 3 : 1
n-Bu4N+CN-
F
F
F
N
CN
CN
n-Bu4
N
Ir
2
[(2fppy)2Ir(μ-Cl)2Ir(2fppy)2]
F
1
spectrometry. In H NMR spectra, the anionic complexes exhibited
n-Bu4NA4
+
four peaks at 3.06, 1.58, 1.34 and 0.96 ppm in CD3CN, which can be
assigned to the tetrabutylammonium cation. These signals were
absent in the 1H NMR spectra of IPs, indicating the successful
metathesis reaction and the quantitative synthesis of the IPs
starting from equal molar quantity of the two luminescent
components in dichloromethane.
N
N
N
N
N
Ir
Cl
2
110 oC, IrCl3.3H2
O
N
N
N
Cl
Cl
Ir
Ir
2
C2Cl
2-ethoxyethanol: H2O = 3 : 1
_
2
n-Bu4N+CN-
N
CN
n-Bu4N+
Ir
[(ppy)2Ir(μ-Cl)2Ir(ppy)2]
CN
2
n-Bu4NA2
N
N
Photophysical properties
+
.
110 oC, IrCl3 3H2
O
Cl
N
The photoluminescence properties of the complexes were
investigated. The PL spectra of the cationic (C1Cl − C3Cl) and anionic
(n-Bu4NA1 − n-Bu4NA4) complexes in acetonitrile solution are
presented in Fig. S3, peaking at 524, 591, 638, 550, 595, 475 and
523 nm, respectively. For IPs, their emissions are contributed by
both of cations and anions. Interestingly, the PL spectra of IPs
exhibit concentration dependence (Fig. S1). Taking IP1 as an
example (Fig. 1c), at a relatively low concentration of 10-6 M, the
emission peak of IP1 is around 524 nm, which is originated from C1,
because the quantum yield of C1 (21 %) is much higher than that of
A1 (17 %). As the concentration of solution increases, the green
emission from C1 was quenched by the anionic complex A1, due to
energy transfer from C1 to A1. When the concentration of IP1 was
increased to 10-3 M, the PL spectrum is dominated by the emission
from anionic component. The emission spectra of IP1 - IP6 were
Ir
Ir
2
Ir
N
Cl
N
N
Cl
N
N
2
2-ethoxyethanol: H2O = 3 : 1
2
[(pq)2Ir(μ-Cl)2Ir(pq)2]
C3Cl
Si
O
S
N
Si
O
-
Si
O
IrCl3.3H2
O
n-Bu4N+CN-
Ir
Cl
2
2
n-Bu4N+
Cl
Ir
2-ethoxyethanol: H2O = 3 : 1
CN
CN
Ir
2
N
S
N
S
N
O
Si
S
n-Bu4NA3
[(Si)2Ir(μ-Cl)2Ir(Si)2]
CH2Cl2 / H2
O
Ir+ Ir-
n-Bu4N+Cl-
-
+
Ir+ Cl-
+
+
Ir n-Bu4N
Ion Pairs
Scheme 1 The synthetic routes of positive and negative Ir(III) complexes and
ion pairs
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relationship between τ0/τ and [Q]. The calculation yields a Kq value
3 V onto the electrodes, the emission color of the solution near the
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of 1.63 × 10-4 M-1s-1. This quenching effect can be attributed to the
intermolecular triplet–triplet energy transfer.43,46 The results
indicate that the energy transfer quenching process is very efficient
between the two ionic complexes.
DOI: 10.1039/C6SC02837C
anode changes from yellow to red within 30 s, which is in
accordance with its cationic component (C1). In the meanwhile, the
yellow emission near the cathode changes to green, which is same
to that of anionic component (A1). Such a change of emission color
gradually extends to the middle of the two electrodes, appearing a
clear boundary.
White LED devices
Then the voltage was removed, the original yellow emission can
be recovered after stirring the solution and the electrochromic
luminescence reappeared when the stirring was stopped. This
observation indicates that IP1 shows an excellent reversibility for
electrochromic luminescence. To explore the mechanism of this
phenomenon, the emission spectra of IP1 near anode and cathode
after electrical stimuli are measured and shown in Fig. 3b. It was
found that the emission spectra of the solution near the anode and
cathode electrode are almost same to those of the anionic (n-
Bu4NA1) and cationic iridium(III) complex (C1Cl), respectively.
Therefore, we believe that the anionic component directionally
moves to anode and the cationic one shifts to cathode because the
electrostatic interaction was broken under electric field, resulting in
the emission color changes near two electrodes.
For IP6, the two luminescent components peak at 475 nm and 580
nm. At a concentration of 1.0 × 10-3 M, the ion pair shows orange
emission. With the decrease of concentration in CH3CN, the
greenish-blue emission increases gradually (Fig. 2a,c). When the
concentration decreases to be 6.5 × 10-6 M, the solution exhibits
white emission with the Commission Internationale de L’Eclairage
(CIE) of (0.28, 0.30) and the quantum efficiency of 0.22. As the
concentration continues to decrease, the solution shows weak blue
emission.
IP6 was doped into a polyethylene-polypropylene glycol polymer
to investigate the photophysical properties of the solid film. At
different doping concentration, the film showed different emission
colors (Fig. 2b, and Fig. S4). At a concentration of about 1.9 mg IP6
in 800 mg polymer, the solid film exhibited orange emission. With
the decrease of the doping concentration, the solid film showed
light yellow emission gradually. At last, when the concentration
decreases to about 0.7 mg IP6 in 800 mg polymer, the solid film
showed white emission with the quantum efficiency of 0.16. IP6,
therefore, is a potential candidate material for white LED (WLED).
Compared to the widely used inorganic phosphors, organic
emitters have greater advantage in their large absorption
crosssection, which can reduce the phosphor consumption and cut
down the costs.59 Here, to fabricate the near-UV excited LED,
powdered organic emitter IP6 was dispersed in a polyethylene-
polypropylene glycol polymer and then coated onto the surface of
commercially available 365 nm UV LED chips. Bright orange, light
yellow and white emission were obtained when polyethylene-
polypropylene glycol polymers doped with different concentration
(1.9 mg / 800 mg, 0.9 mg / 800 mg and 0.7 mg / 800 mg) of IP6
were coated onto the UV chip as emitters. We can clearly see the
bright orange, light yellow and white emissions from the prepared
devices with CIE coordinate values of (0.51, 0.47), (0.40, 0.41) and
(0.31, 0.36), respectively (Fig. 2d).
To have
a better understanding of these observations, a
schematic model was proposed in Fig. 4e. Before applying a voltage,
the IPs were disorderly and uniformly distributed in the solution,
and the interaction between cationic and anionic components is
mainly through electrostatic force, which can be broken upon
applying a voltage, leading to migration of cationic and anionic
components to the cathode and anode, respectively. After
removing the voltage and stirring the solution, two components
held together again. This mechanism was confirmed by the NMR
experiments. Because of the asymmetry of the ancillary ligand in
C1Cl, the two C^N ligands are non-chemically equivalent. There are
two peaks attributed to the proton in the b-position with each
integral of 1 (Fig. S5). For n-Bu4NA1, the two C^N ligands are
chemically equivalent owing to the symmetry of the ancillary
ligands CN- in structure. Eight peaks from C^N ligand could be
observed in the NMR spectrum. The integral of the proton in the a-
position is 2. In the original NMR spectrum of IP1, the integral ratio
of protons at a-position to b-position is 2 : 1, indicating that the
anion and cation are equal. After applying a voltage, the integral
ratio in the NMR spectrum of solution near the cathode changed to
0.56 : 1.00, while that near the anode changed to 2.00 : 0.82. These
results demonstrated the migration of anions and cations to anode
and cathode, respectively, under the electric field.
Electrochromic Switches
Considering that IPs consist of luminescent ions with opposite
charges, the electric field is anticipated to regulate the luminescent
behavior. In order to demonstrate this behavior, IP1 was used to
perform the electrochromic luminescence experiment as illustrated
in Fig. 3a. A concentration of 10-4 M of the ion pair was chosen,
because the emission intensity of the two peaks of IP1 was almost
equal at this concentration. Two platinum electrodes were
immersed in a CH3CN solution of IP1 with a distance of 20 mm
between each other. Before applying a voltage, the solution of IP1
exhibited yellow emission. Subsequently, upon applying a voltage of
To prove that the formation of IPs is necessary for realizing this
electrochromism phenomenon, a control experiment using a mixed
solution of n-Bu4NA1 and C1Cl (molar ratio 1 : 1) was carried out.
Upon applying a voltage of 3 V on electrodes for about 2 minutes,
no emission color changing was observed (Fig. S6), which may be
because the small counterions Cl- and n-Bu4N+ moved to the anode
and cathode preferentially compared to the bulky ionic iridium(III)
complexes. Hence, our design strategy based on luminescent IPs is
effective to realize the electrochromic luminescence.
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Fig. 2 (a) The luminescence spectra of IP6 at different concentrations in acetonitrile. (b) The solid state luminescence spectra of IP6 doped into a
polyethylene-polypropylene glycol polymer with different weight ratios. (c) Photographs of IP6 at different concentrations (left, 1.0 × 10-3 M; middle, 1.0 ×
10-4 M; right, 6.5 × 10-6 M) in acetonitrile under excitation at 365 nm. (d) The pictures of the orange (left, 1.7 mg in 800 mg), light-yellow (middle, 0.9 mg in
800 mg) and white (right, 0.7 mg in 800 mg) LEDs operated at 3.5 V. (e) CIE 1931 chromaticity diagram of the obtained orange, light-yellow and white light
from the fabricated LED devices.
the phosphorescence properties of IPs would not be affected by the
Furthermore, color-tunable electrochromic luminescence has presence of SiO2 particles. Under a voltage of 3 V, the luminescent
been realized by using other IPs (IP2 - IP6, Fig. 3). For example, the color near the anode was changed from yellow to red and that near
emission color of IP2 can be changed from yellow to blue at anode the cathode was altered to green, which is consistent with the
and orange at cathode. For IP3, the emission color at anode was electrochromic luminescence observed in solution. When reversing
changed from red to blue, while that near the cathode remained the direction of the electric field, the emission colors near the two
red because of efficient energy transfer. For IP4, the emission color electrodes exchanged within 20 minutes (Fig. S7).
was changed from green to blue at anode, and remained green
Next, we carried out another experiment to further confirm that
near the cathode. For IP5, the emission color at cathode was the mechanism of electrochromic luminescence is due to the
changed from yellow to orange, and that near the anode remained migrations of the ions under electric field, as shown in Fig. 4a,b. At
yellow. For IP6, the emission color at cathode was changed from first, a quasi-solid gel was prepared from adding several drops of
orange to blue-green, and that near the anode remained orange.
DMSO into SiO2 particles and coated between two Pt electrodes.
Based on the above results, we further realized the IP1 was doped into the middle of the gel, which showed yellow
electrochromic luminescence in quasi-solid state. A device with a emission. Upon applying a voltage of 3 V for 10 minutes, the green
simple sandwiched structure, in which a quasi-solid film was coated emission color appeared and gradually spread to the cathode.
between two Pt electrodes, has been fabricated. The yellow- Meanwhile, the red emission color spread to the anode gradually.
emitting quasi-solid film was prepared by mixing ion pair IP1 with Next, the direction of the electric field was exchanged, and the
DMSO and SiO2 particles (300 - 400 mesh). The IPs are able to freely emission colors near the two edges were switched. This
migrate within the inorganic network channels of SiO2 skeleton and phenomenon can be repeated. The above results demonstrated.
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Fig. 3. (a) Photographs of ion pairs (10 M) in acetonitrile before (left) and after (right) applying a voltage of 3 V, followed by stirring and reversing the
voltage under excitation at 365 nm. (b) Luminescence spectra of ion pairs (10-4 M) in acetonitrile before and after applying a voltage at the cathode and
anode, respectively.
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Fig. 4. (a, c) The schematic diagram of the setup for electrochromic luminescence experiments. (b, d) Photographs of electrochromic
luminescence experiments using quasi-solid film doped with IP1. (e) Schematic illustration of ion migration under electric stimuli.
that the electrochromic luminescence is induced by the migration In summary, we have developed a class of tunable emissive
of the ions
materials based on luminescent ion-paired iridium(III) complexes.
Finally, a simple sandwiched structure device, in which quasi- The photophysical properties of the IPs have been studied in detail.
solid film (about 2 mm in thickness) doped with IP1 was coated Orange, light yellow and white light-emitting devices were
between two ITO electrodes, has been fabricated as shown in Fig. successfully fabricated by coating the polymer films doped with IP6
4c,d. At first, a letter pattern of “IAI” was coated onto the ITO on commercially available ultraviolet LEDs. Furthermore, a new
electrodes. The color of the pattern is orange. Then a voltage of 3 V strategy for the design of electric-responsive materials which
was applied on the ITO electrodes for about 3 – 4 seconds. The displayed tunable and reversible electrochromic luminescence was
emission color of film near anode was changed to red immediately. presented. Changing cationic or anionic iridium(III) complexes
Meanwhile, green color appeared near the cathode. This moiety can be used to tune the electrochromic luminescence colors
phenomenon can be repeated very well.
of these ion pairs. To demonstrate potential practical applications, a
solid-film electrochromic switch device using IPs, which showed fast
and reversible emission color change, has been fabricated
successfully. These results showed that electrochromic luminescent
Conclusions
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materials based on ion pairs will be promising candidates for 31.47; 30.13; 26.62; 22.64; 14.12. ESI-MS (m/z): Calcd. for C18H21N3,
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DOI: 10.1039/C6SC02837C
applications in optoelectronic fields.
279.17; found, 279.28.
Synthesis of 3. A mixture of 2-aminothiophenol (4.0 g) and 4-
hydroxybenzaldehyde (4.12 mL) in DMF (10 mL) was heated to
reflux under nitrogen atmosphere at 110 oC for 72 h. Next, the
reaction mixture was cooled down to room temperature, and then
the mixture was extracted with H2O and ethyl acetate. The solvent
was removed under reduced pressure and the product was
recrystallizated by ethanol.
Experimental
General. Unless otherwise stated, all starting materials and
reagents were purchased from commercial suppliers and were used
without further purification. Silica particles (Aesoil 200, 12 nm)
were purchased from Degussa Company (Evonik Industries AG,
Rellinghauser Strabe 1-11, 45128 Essen, Germany). CH2Cl2, CH3CN
and CH3OH were dried under reflux over CaH2 or sodium for several
Synthesis of 4. A mixture of 3, imidazole (200 mg), tert-
butylchlorodiphenylsilane (2 mL) and DMF (4.6 mL) in a two necked
o
o
flask was heated to reflux under nitrogen atmosphere at 40 C for
hours at 70 – 75 C, distilled at these conditions and used freshly.
24 h. Next, the reaction mixture was cooled down to room
temperature, and then the mixture was extracted with H2O and
ethyl acetate. The solvent was removed under reduced pressure
and the product was recrystallizated by ethanol.
1H NMR (400 MHz, CDCl3): δ = 7.99 (d, J = 8.0 Hz, 1H); 7.86-7.82
(m, 3H); 7.74 - 7.72 (m, 4H); 7.47 -7.31 (m, 8H); 6.85 (d, J = 8.4 Hz,
2H); 1.12 (s, 9H). ESI-MS (m/z): Calcd. for C29H27NOSSi, 465.17;
found, 464.97.
NMR spectra were recorded on a Bruker Ultra Shield Plus 400 MHz
NMR instrument (1H: 400 MHz, 13C{1H}: 100 MHz, 19F{1H}: 377 MHz).
Chemical shifts (ppm) were reported relative to tetramethylsilane
(TMS). Mass spectra were obtained on a Bruker autoflex MALDI-
TOF/TOF mass spectrometer and a ESI-MS (LCQ Fleet, Thermo
Fisher Scientific). UV-Vis absorption spectra were recorded on a UV-
1700 Shimadzu UV-Vis spectrophotometer. The photoluminescence
spectra and emission lifetimes were recorded on an Edinburgh
FL920 spectrofluorometer system.
Synthesis of 5. Water (56.0 mL), anhydrous ethanol (112.0 mL)
and acetic acid (112.0 mL) were added into the bottle. Then, the
iron powder (13.15 g, 0.235 mol) was added and the temperature
Synthesis of 1. A mixture of 2-bromopyridine (1.03 g, 6.52 mmol),
2,4-difluorophenylboronic acid (0.94 g, 5.95 mmol), Pd(PPh3)4 (0.21
g, 0.18 mmol) and potassium carbonate (1.0 g) in toluene (30.0 mL),
H2O (10.0 mL) and EtOH (10.0 mL) was stirred for 24 h at 85 oC
under nitrogen. The reaction mixture was cooled down to room
temperature, and then 50.0 mL H2O was added, the solution was
extracted with dichloromethane. The organic layer was dried over
Na2SO4, and the solvents were removed in vaccuo. The crude
material was purified by column chromatography over silica gel (PE
→ PE / EA, 75 : 1), yielding the yellow oil. Yields: 1.08 g (95.0%).
1H NMR (400 MHz, DMSO-d6): δ = 8.70 (ddd, J1 = 0.8 Hz, J2 = 1.6
Hz, J3 = 4.8 Hz, 1H); 7.98 (dt, J1 = 6.8 Hz, J2 = 9.2 Hz, 1H); 7.88 (dt,
J1 = 1.6 Hz, J2 = 7.6 Hz, 1H); 7.74 (m, 1H); 7.38 (ddd, J1 = 1.2 Hz, J2 =
4.8 Hz, J3 = 7.6 Hz, 1H); 7.35 (ddd, J1 = 2.4 Hz, J2 = 9.2 Hz, J3 = 11.6
Hz, 1H); 7.20 (ddt, J1 = 0.8 Hz, J2 = 2.4 Hz, J3 = 8.8 Hz, 1H). 13C{1H}
NMR (100 MHz, DMSO): δ = 162.57 (dd, 3JC-F = 12.3 Hz, 1JC-F = 247.1
Hz); 159.90 (dd, 3JC-F = 12.3 Hz, 1JC-F = 249.6 Hz); 151.64 (d, 3JC-F = 2.5
Hz), 149.81; 136.94; 132.23 (dd, 3JC-F = 4.5 Hz, 3JC-F = 9.8 Hz); 123.93
o
was adjusted to 75 C. At last, the benzaldehyde (5.0 g, 0.033 mol)
was poured into the bottle slowly and stirred for 15 min. Then the
reaction mixture was cooled down to room temperature, the crude
product was filtered and the filtrate was collected, which was then
extracted with CH2Cl2 and water. Next, the organic phase was
washed with saturated sodium bicarbonate solution (300 × 3 times)
and deionized water (300 × 3 times), and then dried over anhydrous
magnesium sulfate. The solvent was removed under reduced
pressure to afford yellow oily liquid. Yields: 3.25 g (81.0%)
1H NMR (400 MHz, CDCl3): δ = 9.81 (d, J = 0.8 Hz, 1H); 7.53 (dd, J1
= 1.6 Hz, J2 = 7.6 Hz, 1H); 7.29 (ddd, J1 = 1.6 Hz, J2 = 7.2 Hz, J3 = 8.4
Hz; 1H); 7.10 (brs, 2H); 6.70 - 6.85 (m, 1H); 6.63 (ddd, J1 = 1.2 Hz, J2
= 7.2 Hz, J3 = 8.0 Hz, 1H). ESI-MS (m/z): Calcd. for C7H7NO, 121.06;
found, 120.98.
Synthesis of 6. Sodium hydroxide (1.0 g) was dissolved in
anhydrous ethanol (15.0 mL). To this solution was added o-amino-
benzaldehyde (600.0 mg, 4.96 mmol) and 2-acetylthiophene (688.0
mg, 5.46 mmol). The reaction mixture was refluxed at 80 oC with
stirring for 12 h. The reaction mixture was cooled down to room
temperature and the mixture was extracted with CH2Cl2, and then
the solvent was removed under reduced pressure. Purifying the
residue using silica gel column chromatography (CH2Cl2 / PE, 1 : 10)
to give a white solid. Yields: 835.4 mg (80.0%).
1H NMR (CDCl3): δ = 8.14 (d, J = 8.8 Hz, 1H); 8.09 (d, J = 8.8 Hz,
1H); 7.79 (d, J = 8.8 Hz, 1H); 7.76 (dd, J1 = 1.6 Hz, J2 = 8.4 Hz, 1H);
7.74 (dd, J1 = 0.8 Hz, J2 = 4.0 Hz, 1H); 7.69 (ddd, J1 = 1.6 Hz, J2 = 7.2
Hz, J3 = 8.4 Hz; 1H); 7.49 (ddd, J1 = 1.2 Hz, J2 = 6.8 Hz, J3 = 8.0 Hz;
1H); 7.47 (dd, J1 = 1.2 Hz, J2 = 5.2 Hz, 1H). ESI-MS (m/z): Calcd. for
C13H9NS, 211.05; found, 211.16.
(d, 3JC-F = 8.6 Hz); 123.70 (d, 2JC-F = 11.8 Hz); 122.90; 112.05 (d, 2JC-F
=
21.1 Hz); 104.56 (t, 2JC-F = 27.0 Hz). 19F{1H} NMR (376.5 MHz, DMSO)
δ = -109.35 (d, J = 8.28 Hz); -112.826 (d, J = 8.28 Hz). ESI-MS (m/z):
Calcd. for C11H7F2N, 191.05; found, 191.12.
Synthesis of 2. A mixture of 2-(2-pyridyl)benzimidazole (200.0 mg,
2.5 mmol), n-hexane (175.0 mg, 2.6 mmol) and potassium
hydroxide (60.0 mg, 2.5 mmol) in DMF (5.0 mL) was heated at room
temperature under nitrogen atmosphere for
4 h, and then
extracted with CH2Cl2 and water. The crude product was purified
through column chromatography on silica gel (PE → PE / EA, 30 : 1)
to yield pure product as colorless oil. Yields: 0.46 mg (61.0%).
1H NMR (400 MHz, CDCl3): δ = 8.67 (d, J = 4.0 Hz, 1H); 8.38 (d, J =
8.0 Hz, 1H); 7.85 -7.81 (m, 2H); 7.44 (dd, J1 = 6.7 Hz, J2 = 2.0 Hz, 1H);
7.35 - 7.27 (m, 3H); 4.81 (t, J = 8.0 Hz, 3H); 1.86 (dt, J = 15.0 Hz, 7.6
Hz, 2H); 1.36 - 1.24 (m, 6H); 0.85 (t, J = 7.1 Hz, 3H). 13C{1H} NMR
(100 MHz, CDCl3, 298 K): δ = 150.92; 150.08; 148.76; 142.81; 136.89;
136.77; 124.82; 123.80; 123.31; 122.60; 120.21; 110.37; 45.58;
Synthesis of 7. Sodium hydroxide (1.0 g) was dissolved in
anhydrous ethanol (15.0 mL). To this solution was added o-amino
benzaldehyde (600.0 mg, 4.96 mmol) and acetophenone (0.6 mL,
4.28 mmol). The reaction mixture was refluxed at 80 oC with stirring
for 12 h. The reaction mixture was cooled down to room
8 | J. Name., 2012, 00, 1-3
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Page 9 of 13
Chemical Science
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Journal Name
temperature and extracted with CH2Cl2, the solvent was removed
ARTICLE
Synthesis of C2Cl. A mixture of yellow powder of [(ppy)2Ir(µ-
View Article Online
under reduced pressure. The crude product was purified through Cl)2Ir(ppy)2] (100.0 mg, 0.093 mmol) anDdOaI:u1x0i.l1i0a3ry9/Cli6gSaCn0d2823,72C-
column chromatography on silica gel (CH2Cl2 / PE, 1 : 10) to yield dipyridyl (dpy) (29.0 mg, 0.186 mmol) in MeOH (3.0 mL) and CH2Cl2
(9.0 mL) was stirred for 4 h at 40 oC. The reaction mixture was then
pure product as a white solid. Yields: 686.5 mg (81.0%).
1H NMR (CDCl3): δ = 8.23 (d, J = 8.4 Hz, 1H); 8.19 - 8.16 (m, 3H); cooled to room temperature and evaporated to dryness. The crude
7.89 (d, J = 8.4 Hz, 1H); 7.84 (dd, J1 = 1.2 Hz, J2 = 8.0 Hz, 1H); 7.74 material was purified by column chromatography over silica gel
(ddd, J1 = 1.2 Hz, J2 = 6.8 Hz, J3 = 8.4 Hz, 1H); 7.56 - 7.52 (m, 3H); (CH2Cl2 → CH2Cl2 / MeOH, 45 : 1), yielding the orange-red solid.
7.47 (tt, J1 = 2.4 Hz, J2 = 7.2 Hz, 1H). ESI-MS (m/z): Calcd. for Yields: 41.9 mg (65.4%).
C15H11N, 205.09; found, 205.18.
1H NMR (400 MHz, DMSO-d6): δ = 8.90 (d, J = 8.4 Hz, 2H); 8.29 -
.
Synthesis of [(2fppy)2Ir(µ-Cl)2Ir(2fppy)2]. A mixture of IrCl3 3H2O 8.25 (m, 4H); 7.96 - 7.91 (m, 4H); 7.87 (dd, J1 = 0.8 Hz, J2 = 5.2 Hz,
(200.0 mg, 0.56 mmol) and 2-(2,4-difluorophenyl)pyridine (2fppy) 2H); 7.69 (ddd, J1 = 0.8 Hz, J2 = 5.2 Hz, J3 = 6.4 Hz, 2H); 7.61 (d, J =
(235.8 mg, 0.91 mmol) in 2-ethoxyethanol / water (8.0 mL, 3 : 1 v / 5.2 Hz, 2H); 7.16 (ddd, J1 = 1.2 Hz, J2 = 5.6 Hz, J3 = 7.2 Hz, 2H); 7.02
v) was heated to reflux under nitrogen atmosphere for 24 h. Next, (dt, J1 = 1.2 Hz, J2 = 8.0 Hz, 2H); 6.90 (dt, J1 = 1.2 Hz, J2 = 7.6 Hz,
the reaction mixture was cooled down to room temperature, a 2H); 6.19 (dd, J1 = 0.8 Hz, J2 = 7.6 Hz, 2H). 13C{1H} NMR (100 MHz,
large amounts of water was added into the mixture, which was DMSO-d6): δ = 166.86; 155.392; 150.49; 149.87; 148.91; 143.84;
filtered. Then the residue was dried to give the desired yellow- 139.75; 138.85; 131.12; 130.31; 128.73; 125.14; 125.07; 123.99;
green powder.
122.36; 120.11. MALDI-TOF-MS (m/z): Calcd. for C32H24IrN4Cl,
Synthesis of C1Cl. A mixture of yellow powder of [(2fppy)2Ir(µ- 692.13; found, 656.99 (M-PF6)+. Anal. Calcd., C 55.52, H 3.49, N
Cl)2Ir(2fppy)2] (100.0 mg, 0.093 mmol) and auxiliary ligand N-hexyl- 8.09; found, C 55.07, H 3.90, N 7.98.
2-(2-pyridyl)benzimidazole (2) (52.0 mg, 0.186 mmol) in MeOH (3.0
Synthesis of n-Bu4NA2. The complex [Ir(ppy)2(CN)2]TBA, where
o
mL) and CH2Cl2 (9.0 mL) was stirred for 4 h at 40 C. The reaction TBA is the tetrabutylammonium ion, was prepared according to the
mixture was cooled down to room temperature and evaporated to literature procedure, with some modifications. The dimeric
dryness. The crude material was purified by column iridium(III) complex (ppy)2Ir(µ-Cl)2Ir(ppy)2 (200.0 mg) was dissolved
chromatography over silica gel (CH2Cl2 → CH2Cl2 / MeOH, 45 : 1), in 30.0 mL of dichloromethane solvent under nitrogen. To this
yielding the orange-red solid. Yields: 99.6 mg (60.4%).
solution was added tetrabutylammonium cyanide (100.0 mg) ligand.
1H NMR (400 MHz, DMSO-d6): δ = 8.68 (d, J = 8.4 Hz, 2H); 8.38 (dt, The reaction mixture was refluxed with stirring for 8 h. The reaction
J1 = 1.2 Hz, J2 = 8.0 Hz, 1H); 8.31 (d, J = 8.4 Hz, 1H); 8.21 (d, J = 8.8 mixture was cooled down to room temperature, and then the
Hz, 1H); 8.05 - 7.94 (m, 4H); 7.83 (dd, J1 = 0.8 Hz, J2 = 5.6 Hz, 1H); solution was washed three times with distilled H2O, and extracted
7.76 - 7.73 (m, 2H); 7.47 (ddd, J1 = 0.6 Hz, J2 = 6.4 Hz, J3 = 7.6 Hz, with dichloromethane. The organic layer was dried over Na2SO4,
1H); 7.22 - 7.16 (m, 3H); 7.04 (ddd, J1 = 2.4 Hz, J2 = 9.6 Hz, J3 = 12.4 and the solvents were removed in vaccuo. The crude material was
Hz, 1H); 6.99 (ddd, J1 = 2.4 Hz, J2 = 9.6 Hz, J3 = 12.4 Hz, 1H); 6.25 (d, purified by column chromatography over silica gel (CH2Cl2 → CH2Cl2
J = 8.0 Hz, 1H); 5.72 (dd, J1 = 2.4 Hz, J2 = 8.8 Hz, 1H); 5.62 (dd, J1 = / MeOH, 50 : 1), yielding the green solid. Yields: 114.9 mg (77.5%).
2.4 Hz, J2 = 8.8 Hz, 1H); 5.02 - 4.86 (m, 2H); 1.96 - 1.86 (m, 2H); 1.28
1H NMR (400 MHz, DMSO-d6): δ = 9.52 (dd, J1 = 0.8 Hz, J2 = 6.0
- 1.16 (m, 6H); 0.77 (t, J = 7.2 Hz, 3H). 13C{1H} NMR (100 MHz, Hz, 2H); 8.07 (d, J = 8.4 Hz, 2H); 7.89 (dt, J1 = 1.6 Hz, J2 = 7.6 Hz,
DMSO): δ = 162.97 (dd, 3JC-F = 12.5 Hz, 1JC-F = 254.0 Hz); 162.39 (dd, 2H); 7.66 (d, J = 7.6 Hz, 2H); 7.31 (dt, J1 = 5.6 Hz, J2 = 7.2 Hz, 2H);
3JC-F = 12.5 Hz, 1JC-F = 253.6 Hz); 162.81 (d, 3JC-F = 6.6 Hz); 160.85 (dd, 6.73 (dt, J1 = 1.2 Hz, J2 = 6.8 Hz, 2H); 6.61 (dt, J1 = 1.2 Hz, J2 = 7.2
1
3
1
3JC-F = 13.7 Hz, JC-F = 259.0 Hz); 160.51 (dd, JC-F = 12.4 Hz, JC-F
=
Hz, 2H); 6.08 (dd, J1 = 1.2 Hz, J2 = 7.6 Hz, 2H); 3.17 - 3.13 (m, 8H);
257.0 Hz); 155.56 (d, 3JC-F = 6.2 Hz); 152.01; 151.93; 151.92; 151.68; 1.60 - 1.52 (m, 8H); 1.34 - 1.25 (m, 8H); 0.93 (t, J = 7.6 Hz, 12H).
150.23; 149.81; 146.16; 140.63; 139.92; 139.73; 138.39; 136.37; 13C{1H} NMR (100 MHz, DMSO-d6): δ = 168.02; 163.78; 153.48;
129.10; 128.27 (dd, J1 = 2.4 Hz, J2 = 4.1 Hz); 127.86; 126.18; 126.13; 144.55; 136.42; 131.48; 130.88; 128.50; 123.81; 122.74; 120.24;
125.92; 125.35; 124.42 (d, J = 11.1 Hz); 123.35 (d, J = 18.3 Hz); 119.14; 57.71; 23.21; 19.36; 13.64. MALDI-TOF-MS, ESI-MS (m/z):
122.96 (d, J = 19.6 Hz); 116.17; 113.73 (d, J = 16.7 Hz); 113.10; Calcd. for C40H52IrN5, 795.38; found, 553.17 (M-n-Bu4N)-, 242.42(n-
113.16 (d, J = 15.8 Hz); 99.06 (t, 2JC-F = 27.1 Hz); 98.84 (t, 2JC-F = 27.1 Bu4N)+. Anal. Calcd., C 60.57, H 6.49, N 8.56; found, C 60.42, H 6.59,
Hz); 45.49; 30.78; 29.14; 25.49; 21.94; 13.79. 19F{1H} NMR (376.5 N 8.81.
.
MHz, DMSO): δ = -106.49 (d, J = 10.17 Hz); -106.91 (d, J = 10.54 Hz);
Synthesis of [(thq)2Ir(µ-Cl)2Ir(thq)2]. A mixture of IrCl3 3H2O
-108.61 (d, J = 10.54 Hz); -109.12 (d, J = 10.17 Hz). MALDI-TOF-MS (385.0 mg, 1.10 mmol) and 2-(thiophenyl)quinoline (500.2 mg, 2.37
(m/z): Calcd. for C40H33IrF4N5Cl, 887.20; found, 852.06 (M-PF6)+. mmol) in 2-ethoxyethanol / water (8.0 mL, 3 : 1 v / v) was heated to
Anal. Calcd., C 54.14, H 3.75, N 7.89; found, C 54.19, H 3.81, N 7.92.
reflux under nitrogen atmosphere for 24 h. Next, the reaction
.
Synthesis of [(ppy)2Ir(µ-Cl)2Ir(ppy)2]. A mixture of IrCl3 3H2O mixture was cooled down to room temperature and a large
(200.0 mg, 0.56 mmol) and 2-phenylpyridine (ppy) (173.8 mg, 0.16 amounts of water was added into the mixture. The mixture was
mmol) in 2-ethoxyethanol / water (8.0 mL, 3 : 1 v / v) was heated to filtered. Then the residue was dried to give the desired red powder.
reflux under nitrogen atmosphere for 24 h. Next, the reaction Yields: 650.8 mg (85.0%).
mixture was cooled down to room temperature, a large amounts of
water was added into the mixture, which was filtered. Then the [(thq)2Ir(µ-Cl)2Ir(thq)2]
residue was dried to give the desired yellow powder. Yields: 353.8 tetrabutylammonium cyanide (495.7 mg, 1.85 mmol) ligand were
Synthesis of n-Bu4NA1. The dimeric iridium(III) complex
(200.0 mg, 0.15 mmol) and
mg (59.0%).
dissolved in 30.0 mL of dichloromethane solvent under nitrogen.
The reaction mixture was refluxed with stirring for 8 h. Then the
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J. Name., 2013, 00, 1-3 | 9
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Chemical Science
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ARTICLE
Journal Name
mixture was cooled to room temperature and extracted with CH2Cl2 removed in vaccuo. The crude material was purified by column
View Article Online
DOI: 10.1039/C6SC02837C
and water. The crude product was purified through column chromatography over silica gel (CH2Cl2 → CH2Cl2 / MeOH, 50 : 1) to
chromatography on silica gel (CH2Cl2 → CH2Cl2 / MeOH, 50 : 1) to give a green solid. Yields: 115.4 mg (77.5 %).
give pure product as a red solid. Yields: 85.6 mg (61.0%).
1H NMR (400 MHz, DMSO-d6): δ = 9.26 (dd, J1 = 2.4 Hz, J2 = 7.2
1H NMR (400 MHz, CDCl3): δ = 9.99 (d, J = 9.2 Hz, 2H); 7.97 (d, J = Hz, 2H); 8.00 (dd, J1 = 2.4 Hz, J2 = 7.2 Hz, 2H); 7.50 - 7.30 (m, 18H);
8.4 Hz, 2H); 7.68-7.65 (m, 4H); 7.60 (d, J = 8.4 Hz, 2H); 7.42 (t, J = 7.2 7.23 - 7.19 (m, 8H); 6.32 (dd, J1 = 2.4 Hz, J2 = 8.4 Hz, 2H); 5.79 (d, J =
Hz, 2H); 7.03 (d, J = 4.4 Hz, 2H); 6.09 (d, J = 4.4 Hz, 2H); 3.11 - 3.07 2.4 Hz, 2H); 3.18 - 3.14 (m, 8H); 1.61 - 1.52 (m, 8H); 1.35 - 1.26 (m,
(m, 8H); 1.47 - 1.39 (m, 8H); 1.11 - 1.06 (m, 8H); 0.77 (t, J = 7.6 Hz, 8H); 0.93 (t, J = 7.2 Hz, 12H); 0.75 (s, 18H). 13C{1H} NMR (100 MHz,
12H). 13C{1H} NMR (100 MHz, CDCl3): δ = 170.56; 167.67; 150.11; CDCl3): δ = 179.17; 166.57; 156.95; 151.727 135.12; 135.08; 134.67;
141.51; 137.76; 133.34; 131.12; 130.42; 128.95; 127.68; 125.76; 133.29; 133.13; 130.65; 129.41; 129.38; 127.44; 126.67; 126.58;
124.71; 117.47; 58.48; 23.80; 19.47; 13.59. MALDI-TOF-MS, ESI-MS 124.11; 121.43; 113.44; 58.59; 26.53; 23.77; 19.51; 13.59. MALDI-
(m/z): Calcd. for C44H52IrN5S2, 907.33; found, 665.17 (M-n-Bu4N)-, TOF-MS, ESI-MS (m/z): Calcd. for C76H88IrN5S2O2Si2, 1415.55; found,
242.42(n-Bu4N)+. Anal. Calcd., C 58.25, H 5.78, N 7.72; found, C 1173.67 (M-n-Bu4N)-, 242.42(n-Bu4N)+. Anal. Calcd., C 64.46, H 6.26,
58.36, H 5.89, N 7.61.
Synthesis of [(phq)2Ir(µ-Cl)2Ir(phq)2]. A mixture of IrCl3 3H2O
N 4.95; found, C 64.21, H 6.39, N 5.11.
.
Synthesis of IP1. C1Cl (38.1 mg, 0.043 mmol) and n-Bu4NA1 (39.0
(385.0 mg, 1.10 mmol) and 2-phenylquinoline (phq) (500.5 mg, 2.37 mg, 0.043 mmol) were added to water (15.0 mL) and CH2Cl2 (15.0
mmol) in 2-ethoxyethanol / water (8.0 mL, 3 : 1 v / v) was heated to mL). The reaction mixture was stirred for 1 h at room temperature
reflux under nitrogen atmosphere for 24 h. Next, the reaction and then extracted with deionized water. The combined organic
mixture was cooled down to room temperature and a large extracts were concentrated by rotary evaporation. The resulting
amounts of water was added into the mixture. The mixture was solid was washed with n-hexane to afford IP1 as a red solid. Yields:
filtered. Then the residue was dried to give the desired red powder. 39.6 mg (60.7%).
Yields: 600.5 mg (77.1%).
1H NMR (400 MHz, DMSO-d6): δ = 9.90 (d, J = 8.8 Hz, 2H); 8.64 (d,
Synthesis of C3Cl. A mixture of yellow powder of [(phq)2Ir(µ- J = 8.4 Hz, 2H); 8.34 - 8.29 (m, 3H); 8.21 (d, J = 8.8 Hz, 1H); 8.03 -
Cl)2Ir(phq)2] (100.0 mg, 0.093 mmol) and auxiliaryligand 2,2'- 7.91 (m, 6H); 7.81 (d, J = 5.2 Hz, 1H); 7.72 - 7.67 (m, 6H); 7.56 (t, J =
biquinoline (bql) (52.0 mg, 0.20 mmol) in MeOH (3 mL) and CH2Cl2 6.8 Hz, 1H); 7.46 (t, J = 8.0 Hz, 1H); 7.39 - 7.35 (m, 1H); 7.23 - 7.15
(9 mL) was stirred for 4 h at 40 oC. The reaction mixture was cooled (m, 5H); 7.02 (ddd, J1 = 2.0 Hz, J2 = 9.2 Hz, J3 = 12.0 Hz, 1H); 6.96
down to room temperature and then evaporated to dryness. The (ddd, J1 = 2.4 Hz, J2 = 9.6 Hz, J3 = 12.4 Hz, 1H); 6.24 (d, J = 8.4 Hz,
crude material was purified by column chromatography over silica 1H); 5.71 (d, J = 4.8 Hz, 2H); 5.61 (dd, J1 = 2.4 Hz, J2 = 8.4 Hz, 1H);
gel (CH2Cl2 → CH2Cl2 / MeOH, 45 : 1), yielding the orange-red solid. 4.97 - 4.84 (m, 2H); 1.94 - 1.86 (m, 2H); 1.25 - 1.21 (m, 6H); 0.75 (t, J
Yields: 41.0 mg (44.8%).
= 6.8 Hz, 3H). 19F{1H} NMR (376.5 MHz, DMSO): δ = -106.49 (d, J =
1H NMR (400 MHz, DMSO-d6): δ = 8.71 (d, J = 8.8 Hz, 2H); 8.49 (d, 10.17 Hz); -106.91 (d, J = 10.54 Hz); -108.61 (d, J = 10.54 Hz); -109 (d,
J = 8.8 Hz, 2H); 8.31 (d, J = 8.8 Hz, 2H); 8.20 (d, J = 8.8 Hz, 2H); 8.06 J = 10.17 Hz). Because of the asymmetry of the ancillary ligand in C1,
(d, J = 8.8 Hz, 2H); 7.96 (d, J = 8.0 Hz, 2H); 7.91 (d, J = 8.0 Hz, 2H); the two C^N ligands are non-chemically equivalent. In addition,
7.56 (t, J = 7.6 Hz, 2H); 7.51 (d, J = 8.8 Hz, 2H); 7.43-7.37 (m, 4H); coupling process exists between fluorine nucleus and carbon
7.09 (t, J = 8.0 Hz, 2H); 7.01 (t, J = 7.2 Hz, 2H); 6.86 - 6.81 (m, 4H); nucleus, and we did not obtain the 13C{1H} NMR of IP1. MALDI-TOF-
6.31 (d, J = 7.2 Hz, 2H). 13C{1H} NMR (100 MHz, DMSO): δ = 169.88; MS, ESI-MS (m/z): Calcd. for C68H49Ir2F4N9S2, 1517.27; found, 665.08
159.57; 149.09; 146.72; 145.44; 140.99; 140.59; 137.55; 131.01; (A1-), 852.11 (C1+). Anal. Calcd., C 53.85, H 3.26, N 8.31; found, C
130.96; 130.43; 129.55; 129.43; 129.02; 128.99; 128.34; 128.24; 53.63, H 3.09, N 8.07.
127.60; 127.05; 126.46; 124.47; 123.00; 121.37; 117.65. MALDI-
Synthesis of IP2. C2Cl (29.7 mg, 0.043 mmol) and n-Bu4NA2 (34.1
TOF-MS (m/z): Calcd. for C48H32IrN4Cl, 892.20; found, 857.03 (M- mg, 0.043 mmol) were added to water (15.0 mL) and CH2Cl2 (15.0
PF6)+. Anal. Calcd., C 64.60, H 3.61, N 6.28; found, C 64.50, H 3.52, N mL). The reaction mixture was stirred for 1 h at room temperature
6.54.
and then extracted with deionized water. The combined organic
.
Synthesis of [(Si)2Ir(µ-Cl)2Ir(Si)2]. A mixture of IrCl3 3H2O (200.0 extracts were concentrated by rotary evaporation. The resulting
mg, 0.56 mmol) and 7 (173.8 mg, 0.16 mL, 1.12 mmol) in 2- solid was washed with n-hexane to afford IP2 as a yellow solid.
ethoxyethanol / water (8.0 mL, 3 : 1 v / v) was heated to reflux Yields: 32.3 mg (62.3%).
under nitrogen atmosphere for 24 h. Next, the reaction mixture was
1H NMR (400 MHz, DMSO-d6): δ = 9.53 (d, J = 5.6 Hz, 2H); 8.86 (d,
cooled down to room temperature, a large amounts of water was J = 8.4 Hz, 2H); 8.27 - 8.24 (m, 4H); 8.06 (d, J = 8.0 Hz, 2H); 7.95 -
added into the mixture, which was filtered. Then the residue was 7.86 (m, 8H); 7.70 - 7.61 (m, 6H); 7.30 (t, J = 6.0 Hz, 2H); 7.15 (t, J =
dried to give the desired yellow powder. Yields: 147.1 mg (68.0 %).
6.8 Hz, 2H); 7.02 (t, J = 7.6 Hz, 2H); 6.90 (t, J = 7.2 Hz, 2H); 6.72 (t, J =
Synthesis of n-Bu4NA3. The dimeric iridium(III) complex [(Si)2Ir(µ- 7.2 Hz, 2H); 6.61 (t, J = 7.2 Hz, 2H); 6.19 (d, J = 7.6 Hz, 2H); 6.08 (d, J
Cl)2Ir(Si)2] (200.0 mg) was dissolved in 30.0 mL of dichloromethane = 7.2 Hz, 2H). 13C{1H} NMR (100 MHz, DMSO): δ = 167.93; 166.83;
solvent under nitrogen. To this solution was added 163.83; 155.36; 153.32; 150.48; 149.83; 148.88; 144.42; 143.82;
tetrabutylammonium cyanide (100.0 mg) ligand. The reaction 139.69; 138.82; 136.13; 131.08; 130.76; 130.28; 128.69; 128.29;
mixture was refluxed with stirring for 8 h. The mixture was cooled 125.12; 125.06; 123.97; 123.63; 122.53; 122.32; 120.08; 119.95;
down to room temperature, and then the solution was washed 118.93. MALDI-TOF-MS, ESI-MS (m/z): Calcd. for C56H40Ir2F4N8,
three times with distilled H2O, and extracted with dichloromethane. 1210.26; found, 657.25 (A2-), 553.25 (C2+). Anal. Calcd., C 55.61, H
The organic layer was dried over Na2SO4, and the solvents were 3.33, N 9.27; found, C 55.20, H 3.39, N 8.91.
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
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Synthesis of IP3. C3Cl (40.1 mg, 0.045 mmol) and n-Bu4NA2 (35.7
ARTICLE
1H NMR (400 MHz, DMSO-d6): δ = 9.25 (dd, J1 = 1.2 Hz, J2 = 8.0
View Article Online
mg, 0.045 mmol) were added to water (15.0 mL) and CH2Cl2 (15.0 Hz; 2H); 8.87 (d, J = 8.4 Hz; 2H); 8.28 - 8.24D(mOI;: 410H.1);0389.0/C16-SC7.092983(m7C;
mL). The reaction mixture was stirred for 1 h at room temperature 2H); 7.95 - 7.91 (m; 4H); 7.86 (dd, J1 = 1.2 Hz, J2 = 5.6 Hz; 2H); 7.68
and then extracted with deionized water. The combined organic (ddd, J1 = 0.8 Hz, J2 = 5.6 Hz, J3 = 6.8 Hz; 2H); 7.61 (dd, J1 = 0.8 Hz,
extracts were concentrated by rotary evaporation. The resulting J2 = 5.6 Hz; 2H); 7.50 - 7.42 (m; 6H); 7.39 - 7.30 (m; 12H); 7.25-7.19
solid was washed with n-hexane to afford IP3 as a red solid. Yields: (m; 8H); 7.15 (ddd, J1 = 1.6 Hz, J2 = 6.0 Hz, J3 = 7.6 Hz; 2H); 7.02 (dt,
35.6 mg (56.2%).
J1 = 1.2 Hz, J2 = 7.6 Hz; 2H); 6.90 (dt, J1 = 1.2 Hz, J2 = 7.6 Hz; 2H);
1H NMR (400 MHz, DMSO-d6): δ = 9.51 (d, J = 5.2 Hz, 2H); 8.70 (d, 6.32 (dd, J1 = 2.4 Hz, J2 = 8.0 Hz; 2H); 6.19 (dd, J1 = 1.2 Hz, J2 = 7.6
J = 8.8 Hz, 2H); 8.47 (d, J = 8.8 Hz, 2H); 8.30 (d, J = 8.8 Hz, 2H); 8.19 Hz; 2H); 5.78 (d, J = 2.4 Hz; 2H); 0.75 (s; 18H). 13C{1H} NMR (100
(d, J = 8.8 Hz, 2H); 8.08-8.04 (m, 4H); 7.95 (dd, J1 = 0.8 Hz, J2 = 8.0 MHz, DMSO): δ = 178.51; 166.94; 156.32; 155.46; 151.23; 150.57;
Hz, 2H); 7.91 (d, J = 7.2 Hz, 2H); 7.85 (ddd, J1 = 1.6 Hz, J2 = 6.8 Hz, J3 149.93; 148.96; 143.92; 139.82; 138.95; 134.72; 134.68; 132.54;
= 8.4 Hz, 2H); 7.66 (d, J = 7.6 Hz, 2H); 7.56 (ddd, J1 = 0.8 Hz, J2 = 6.8 132.51; 131.20; 130.41; 130.32; 129.96; 129.36; 128.78; 127.81;
Hz, J3 = 8.0 Hz; 2H); 7.51 (d, J1 = 8.8 Hz, 2H); 7.43 - 7.36 (m, 4H); 126.80; 126.72; 125.21; 125.11; 124.93; 124.06; 123.15; 122.85;
7.30 (t, J = 7.2 Hz, 2H); 7.09 (ddd, J1 = 1.6 Hz, J2 = 6.8 Hz, J3 = 8.8 122.68; 122.48; 120.19; 113.15; 26.67; 19.14. MALDI-TOF-MS, ESI-
Hz; 2H); 7.01 (dt, J1 = 1.2 Hz, J2 = 7.2 Hz, 2H); 6.86 - 6.81 (m, 4H); MS (m/z): Calcd. for C92H76Ir2O2N8S2Si2, 1830.43; found, 1173.67
6.73(dt, J1 = 1.2 Hz, J2 = 7.6 Hz, 2H); 6.61(dt, J1 = 0.8 Hz, J2 = 7.2 Hz, (A3-), 657.01 (C2+). Anal. Calcd., C 60.37, H 4.19, N 6.12; found, C
2H); 6.30 (dd, J1 = 0.8 Hz, J2 = 8.0 Hz, 2H); 6.07(dd, J1 = 0.8 Hz, J2 = 60.11, H 4.36, N 6.30.
7.6 Hz, 2H). 13C{1H} NMR (100 MHz, DMSO): δ = 169.88; 168.05;
IP6 and n-Bu4NA4 were synthesized according to the literature.39
1
159.57; 153.46; 149.09; 146.72; 145.44; 144.59; 140.99; 140.59;
Synthesis of n-Bu4NA4. H NMR (400 MHz, DMSO-d6): δ = 9.54
137.55; 136.51; 131.82; 131.01; 130.96; 130.91; 130.43; 129.55; (dd, J1 = 1.2 Hz, J2 = 6.0 Hz; 2H); 8.22 (d, J = 8.4 Hz; 2H); 8.04 (dt, J1
129.43; 129.02; 128.99; 128.58; 128.34; 128.24; 127.60; 127.05; = 1.2 Hz, J2 = 7.6 Hz; 2H); 7.45 (ddd, J1 = 1.2 Hz, J2 = 6.0 Hz, J3 = 7.0
126.46; 124.47; 123.89; 123.00; 122.83; 121.37; 120.34; 119.22; Hz; 2H); 6.61 (ddd, J1 = 2.4 Hz, J2 = 9.2 Hz, J3 = 12.0 Hz; 2H); 5.54
119.08; 117.65. MALDI-TOF-MS, ESI-MS (m/z): Calcd. for C72H48Ir2N8, (dd, J1 = 2.4 Hz, J2 = 8.0 Hz; 2H); 3.17 - 3.13 (m; 8H); 1.59 - 1.51 (m;
1410.33; found, 553.17 (A2-), 857.11 (C3+). Anal. Calcd., C 61.35, H 8H); 1.32 - 1.24 (m; 8H); 0.92 (t; 12H). 13C{1H} NMR (100 MHz,
3
3.43, N 7.95; found, C 60.97, H 3.79, N 7.86.
DMSO): δ = 169.79 - 169.66 (m); 164.36 (d, JC-F = 7.3 Hz); 162.82
Synthesis of IP4. C1Cl (39.9 mg, 0.045 mmol) and n-Bu4NA2 (35.7 (dd, 3JC-F = 11.1 Hz, 1JC-F = 252.6 Hz); 161.12 (dd, 3JC-F = 11.9 Hz, 1JC-F
=
mg, 0.045 mmol) were added to water (15.0 mL) and CH2Cl2 (15.0 258.2 Hz); 154.19; 138.044; 128.51; 128.29 (t, 4JC-F = 2.2 Hz); 123.86;
2
4
2
mL). The reaction mixture was stirred for 1 h at room temperature 122.92 (d, JC-F = 20.3 Hz); 112.36 (dd, JC-F = 2.5 Hz, JC-F = 15.2 Hz);
2
and then extracted with deionized water. The combined organic 97.02 (t, JC-F = 26.2 Hz); 57.98; 23.51; 19.65; 13.95. 19F{1H} NMR
extracts were concentrated by rotary evaporation. The resulting (376.5 MHz, DMSO): δ = -109.91 (d, J = 9.05 Hz); -110.96 (d, J = 9.42
solid was washed with n-hexane to afford IP4 as a yellow solid. Hz). MALDI-TOF-MS, ESI-MS (m/z): Calcd. for C40H48IrN5F4, 795.38;
Yields: 29.2 mg (46.2%).
found, 624.41 (M-n-Bu4N)-, 242.42 (n-Bu4N)+. Anal. Calcd., C 55.41,
1H NMR (400 MHz, DMSO-d6): δ = 9.52 (d, J = 6.0 Hz, 2H); 8.66 (d, H 5.58, N 8.08; found, C 55.72, H 5.70, N 8.21.
1
J = 8.4 Hz, 2H); 8.37-8.34 (m, 1H); 8.30 (d, J = 7.6 Hz, 1H); 8.21 (d, J =
Synthesis of IP6. H NMR (400 MHz, CDCl3): δ = 9.74 (d, J = 5.6
8.4 Hz, 1H); 8.07 - 7.86 (m, 8H); 7.83 (d, J = 5.6 Hz, 1H); 7.73 - 7.71 Hz; 2H); 8.95 (d, J = 8.4 Hz; 2H); 8.06 - 8.17 (m; 4H); 7.86 - 7.91 (m;
(m, 2H); 7.65 (d, J = 7.6 Hz, 2H); 7.47 (t, J = 7.2 Hz, 1H); 7.31 - 7.15 4H); 7.73 (t, J = 8.0 Hz; 2H); 7.67 (d, J = 8.4 Hz; 2H); 7.62 (t, J = 8.0
(m, 5H); 7.06 - 6.96 (m, 2H); 6.71 (dt, J1 = 1.2 Hz, J2 = 6.8 Hz, 2H); Hz; 2H); 7.47 (d, J = 5.6 Hz; 2H); 7.34 (t, J = 6.4 Hz; 2H); 7.03 (t, J =
6.60 (dt, J1 = 0.8 Hz, J2 = 7.2 Hz, 2H); 6.25 (d, J = 8.0 Hz, 1H); 6.08 7.6 Hz; 2H); 6.99 – 6.90 (m; 6H); 6.28 (d, J = 7.6 Hz; 2H); 6.18 (ddd,
(dd, J1 = 1.2 Hz, J2 = 7.6 Hz, 2H); 5.75 (m, 1H); 5.62 (dd, J1 = 1.6 Hz, J1 = 2.0 Hz, J2 = 9.2 Hz, J3 = 12.4 Hz; 2H); 5.72 (dd, J1 = 2.4 Hz, J2 =
J2 = 8.4 Hz, 1H); 5.02 - 4.84 (m, 2H); 1.98 - 1.84 (m, 2H); 1.28 - 1.19 8.4 Hz; 2H). 19F{1H} NMR (376.5 MHz, CDCl3): δ = -106.57 (d, J =
(m, 6H); 0.77 (t, J = 7.2 Hz, 3H). 19F{1H} NMR (376.5 MHz, DMSO): δ 10.56 Hz); -108.8 (d, J = 10.56 Hz). MALDI-TOF-MS (m/z): Calcd. for
= -106.49 (d, J = 10.17 Hz); -106.91 (d, J = 10.54 Hz); -108.61 (d, J = C56H36Ir2F4N8, 1282.23; found, 624.44 (A4-), 656.99 (C2+). Anal.
10.54 Hz); -109.12 (d, J = 10.17 Hz). Because of the asymmetry of Calcd., C 52.49, H 2.83, N 8.74; found, C 52.09, H 2.66, N 6.49.
the ancillary ligand in C1, the two C^N ligands are non-chemically
equivalent. In addition, coupling process exists between fluorine
Acknowledgements
nucleus and carbon nucleus, there is low signal to noise ratio in the
spectrum of 13C{1H} NMR. MALDI-TOF-MS, ESI-MS (m/z): Calcd. for
We acknowledge financial support from the National Natural
C64H49Ir2F4N9, 1405.32; found, 553.08 (A2-), 852.11 (C1+). Anal.
Science Foundation of China (61274018), National Program for
Calcd., C 54.73, H 3.52, N 8.98; found, C 54.27, H 3.64, N 8.56.
Support of Top-Notch Young Professionals, Scientific and
Synthesis of IP5. C2Cl (29.7 mg, 0.043 mmol) and n-Bu4NA3 (60.8
Technological Innovation Teams of Colleges and Universities in
mg, 0.043 mmol) were added to water (15.0 mL) and CH2Cl2 (15.0
Jiangsu Province (TJ215006), Natural Science Foundation of
mL). The reaction mixture was stirred for 1 h at room temperature
Jiangsu Province of China (BK20130038), and Priority Academic
and then extracted with deionized water. The combined organic
Program Development of Jiangsu Higher Education Institutions
extracts were concentrated by rotary evaporation. The resulting
(YX03001).
solid was washed with n-hexane to afford IP5 as a yellow solid.
Yields: 46.5 mg (59.2%).
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 11
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Journal Name
29 Z. Chen, P. C. Hsu, J. Lopez, Y. Z. Li, J. W. F. To, N. Liu, C.
Wang, S. C. Andrews, J. Liu, Y. Cui andDZO. IN: 1.0B.1a0o39, /NCa6tS.CE0n28e3rg7C.,
Notes and references
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