Pd-Catalyzed Functionalization of the Thenoyltrifluoroacetone Coligands by Aromatic Dyes in Bis(cyclometallated) IrIII Complexes: From Phosphorescence to Fluorescence?

Article abstract of DOI:10.1002/ejic.201500227

The synthesis, characterization and photophysical properties of a series of neutral Ir(CN-Meppy)₂(OO-tta-Ar) (MeppyH = 4-methyl-2-phenylpyridine; tta = thenoyltrifluoroacetonate) complexes containing new functionalized tta-Ar ligands in which the incorporated Ar group is an aromatic dye such as naphthalene, pyrene, naphthalimide or coumarin, are reported. The arylated proligands ttaH-Ar are readily obtained in two steps through Pd-catalyzed C-H bond activation of 2-acetylthiophene. In contrast to the parent Ir(CN)₂(OO) complexes, which are phosphorescent in solution at room temperature, all of the arylated complexes display fluorescence, and the phosphorescence emission is quenched. Thus, this work shows that the incorporation of such aromatic dyes in the tta ligand has a dramatic influence on the photophysical properties of the resulting Ir complexes.

Full text of DOI:10.1002/ejic.201500227

FULL PAPER
DOI:10.1002/ejic.201500227
Pd-Catalyzed Functionalization of the
Thenoyltrifluoroacetone Coligands by Aromatic Dyes in
Bis(cyclometallated) IrIII Complexes: From
Phosphorescence to Fluorescence?
Tung T. Dang,[a] Mickaële Bonneau,[a,b] J. A. Gareth Williams,[b]
Hubert Le Bozec,[a] Henri Doucet,*[a] and Véronique Guerchais*[a]
Keywords: Iridium / Palladium / Ligand design / C–H activation / Luminescence
∧
∧
The synthesis, characterization and photophysical properties
of a series of neutral Ir(C N-Meppy)2(O O-tta-Ar) (MeppyH
2-acetylthiophene. In contrast to the parent Ir(C N)2(O O)
∧
∧
complexes, which are phosphorescent in solution at room
= 4-methyl-2-phenylpyridine; tta = thenoyltrifluoroaceton- temperature, all of the arylated complexes display fluores-
ate) complexes containing new functionalized tta-Ar ligands
in which the incorporated Ar group is an aromatic dye such
cence, and the phosphorescence emission is quenched. Thus,
this work shows that the incorporation of such aromatic dyes
as naphthalene, pyrene, naphthalimide or coumarin, are re- in the tta ligand has a dramatic influence on the photophysi-
ported. The arylated proligands ttaH-Ar are readily obtained
in two steps through Pd-catalyzed C–H bond activation of
cal properties of the resulting Ir complexes.
∧
is coordinated to the iridium centre, and also with Ir(C N-
Introduction
∧
ppy)2(O O-tta), in which the thiophene ring is located
within the O O-coordinated coligand (thpyH = 2,2Ј-thien-
∧
Neutral and cationic cyclometallated iridium(III) com-
plexes have attracted much interest over the past 15 years,
owing to their applications in electroluminescence,[1] photo-
catalysis,[2] phosphorescent molecular probes[3] and, more
recently, triplet–triplet annihilation (TTA) upconversion.[4]
In this field, the variation of the cyclometallated ligand, the
ancillary ligands or both can profoundly affect the optical
properties of the resulting IrIII complexes. Thus, ligand de-
sign is crucial for the control of excited states and photo-
physical properties, and the preparation of new ligands con-
taining functional groups to modulate such properties re-
mains challenging.
ylpyridine; ppyH = 2-phenylpyridine; acac = acetylace-
tonate; tta = thenoyltrifluoroacetonate; see Scheme 1).[8]
The arylation reaction occurs regiospecifically at the 5-posi-
tion of the thienyl ring and is compatible with a variety of
aryl bromides. The functional-group tolerance of this
method allows the easy modification of the electronic struc-
ture of the resulting complexes. Through changes to the na-
ture of the appended aromatic group or the modification
of the electron-withdrawing or -donating character of the
additional aryl groups, a large panel of emitters becomes
readily accessible.
Recently, we have demonstrated that palladium-catalyzed
arylation through C–H activation[5,6] is a powerful tool to
functionalize luminescent IrIII complexes, especially those
containing electron-rich thiophene rings.[7,8] For example,
this direct arylation can be readily achieved with tris(cyclo-
[7]
∧
metallated) Ir(thpy)3 and bis(cyclometallated) Ir(C N-
∧
thpy)2(O O-acac) complexes, in which the thiophene ring
[a] Institut des Sciences Chimiques de Rennes, UMR CNRS – Uni-
versité de Rennes 1,
Scheme 1. Chemical structures of the arylated tris- and bis(cyclo-
metallated) IrIII complexes.
6226, Campus de Beaulieu, 35042 Rennes Cedex, France
E-mail: henri.doucet@univ-rennes1.fr
veronique.guerchais@univ-rennes1.fr
As an extension of this work, we decided to investigate
http://www.scienceschimiques.univ-rennes1.fr/en/home/teams/
omc/research-groups/organometallics-for-optics/Home/
http://scienceschimiques.univ-rennes1.fr/catalyse/person-
al%20web%20pages/page%20web%20Doucet.pdf
[b] Department of Chemistry, Durham University,
South Road, Durham, DH1 3LE, United Kingdom
∧
∧
access to arylated Ir(C N-Meppy)2(O O-tta-Ar) (MeppyH
= 4-methyl-2-phenylpyridine) complexes, in which the in-
corporated aryl group is an aromatic chromophore such as
naphthalene, pyrene, naphthalimide or coumarin, and to
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study the photophysical properties of the resulting com- 7.24 ppm. It should be mentioned that the purification of
plexes. 3e was very tedious, as several purifications by column
There are several reports on the combination of organic chromatography were needed to obtain the analytically pure
+
∧
∧
dyes with bis(cyclometallated) [Ir(C N)2(N N)] com- compound. Moreover, some degradation occurred owing to
plexes.[9,10] Various designs have been reported in which the the long reaction time at 100 °C. As a consequence, we
connection of a 2,2Ј-bipyridine (bpy) ligand through a decided to investigate route (2), that is, to perform the cata-
CϵC– unit to different dyes such as Bodipy, coumarin or lytic arylation on thiophene derivatives, precursors of the
naphthalenediimide (NDI) leads to intriguing TTA-based proligand ttaH.
upconversions.[10] The direct cyclometallation of the fluoro-
phore has also been reported; for example, complexes incor-
porating cyclometallated pyrene units[11] resulted in en-
hanced visible absorption compared to the benchmark
+
∧
∧
∧
complexes [Ir(C N-ppy)2(N N-bpy)] and Ir(C N-ppy)2-
∧
(O O-acac). The synthesis and photophysical properties of
a series of neutral and cationic IrIII complexes comprising
two cyclometallating 3-(2-benzothiazolyl)-7-(diethylamino)-
coumarin ligands and an acac[12] or diimine[13] ancillary li-
gand have also been recently described, and their use as
efficient photosensitizers for visible-light-driven hydrogen
generation has been demonstrated.[14] In addition, the
∧
fluorescent coumarin 343 has been connected to the O O-
ancillary ligand of a phosphorescent bis(cyclometallated) Ir
complex to monitor oxygen levels in living cells and tissues,
and a tetraproline linker was used to separate the phosphor
from the fluorophore.[14]
In contrast, to the best of our knowledge, the molecular
engineering of heteroleptic cyclometallated IrIII complexes
featuring functionalized “acac-type” ligands directly conju-
gated with aromatic dyes has not been investigated. Herein,
we present an original synthesis of such ligands and their
Scheme 2. Synthesis of Ir-NI (3e) by the Pd-catalyzed arylation of
Ir-1.
Our attempts to prepare tta-Ar (2a; Ar = C6H4-CF3)
from thenoyltrifluoroacetone and 1-bromo-3-(trifluoro-
methyl)benzene as the coupling partner in the presence of
a palladium catalyst were not successful, as only the acetyl-
thiophene derivative 1a was obtained from the cleavage of
a C–C bond (Scheme 3).
∧
corresponding iridium(III) complexes Ir(C N-Meppy)2-
∧
(O O-tta-Ar) and show that the incorporation of such dyes
has a dramatic influence on the absorption and emission
properties.
Results and Discussion
Preparation of the Arylated Proligands ttaH-Ar (2a–2f) and
the Corresponding Complexes Ir-Ar (3a–3f)
We have investigated two routes to the naphthalimide-
∧
∧
based complex Ir(C N-Meppy)2(O O-tta-NI) (Ir-NI, 3e):
(1) the Pd-catalyzed direct arylation of the coordinated tta
∧
∧
ligand of Ir(C N-Meppy)2(O O-tta) (Ir-1) and (2) the syn-
thesis of the proligand ttaH-NI (2e) through a Pd-catalyzed
arylation step and its subsequent complexation to the
Scheme 3. Attempted Pd-catalyzed arylation of thenoyltrifluoro-
acetone.
+
∧
[Ir(C N-Meppy)2] unit. The desired complex Ir-NI (3e)
was formed by route (1) from Ir-1 in the presence of 6-
bromonaphthalimide under the Pd-catalyzed direct aryl-
Therefore, we prepared the arylated ttaH-Ar proligands
ation conditions previously operative for aryl bromides 2a–2f in two steps. In the first step, the Pd-catalyzed aryl-
[Pd(OAc)2, KOAc in N,N-dimethylacetamide (DMA)].[8] ation of 2-acetylthiophene afforded th-Ar compounds 1a–
Complex Ir-NI (3e), in which the naphthalimide group is 1f. Then, the condensation of the latter with ethyl tri-
incorporated at the 5-position of the thiophene ring of the fluoroacetate in the presence of a base afforded the ttaH-
coordinated tta ligand, was isolated as a red powder in 16% Ar proligands 2a–2f (Schemes 4 and 5).[15] The chromo-
1
yield (Scheme 2). The H NMR spectrum (CDCl3) of 3e phores were used as their bromo derivatives in the catalytic
exhibits signals in the aromatic region typical of the NI reactions {conditions: Pd(OAc)2 or PdCl(C3H5)(dppb)
group at δ = 8.65, 8.56, 8.50, 7.75 and 7.69 ppm. The pro- [dppb = bis(diphenylphosphino)butane], DMA, KOAc,
ton signals of the thiophene ring appear at δ = 7.73 and 150 °C, 48 h}. The new thiophene derivatives th-Ar [Ar =
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m-C6H4-CF3 (th-PhCF3, 1a), naphthyl (th-Napht, 1b), tion of two sets of signals for the magnetically nonequiva-
pyrene (th-Pyr, 1c), perylene (th-Per, 1d), naphthalimide (th- lent 4-methyl-2-phenylpyridine ligands in the 1H NMR
NI, 1e) and coumarin (th-Coum, 1f)] were obtained in mod- spectra (see Experimental Section).
erate to high yields. In all cases, the reaction was regiospec-
ific in favour of the arylation at the 5-position of the thienyl
ring.
Scheme 4. Pd-catalyzed arylation of 2-acetylthiophene.
Scheme 6. Synthesis of the Ir-Ar complexes 3a–3f.
Scheme 5. Synthesis of the ttaH-Ar proligands 2a–2f.
Photophysical Properties of the Arylated Thiophene
The ttaH-Ar proligands 2a–2f were then obtained ac-
Ketones th-Ar and Their IrIII Complexes
cording to a reported procedure[15] with ethyl trifluoroacet-
ate as the reactant and lithium bis(trimethylsilyl)amide
The electronic absorption spectra of the newly prepared
[LiN(TMS)2] as the base (Scheme 5). All of the target com- arylated thienyl ketones th-Ar (1a–1f) were recorded in
pounds 2a–2f were isolated in high yields after column dichloromethane solution at room temperature (Figure 1,
chromatography. The coumarin derivative was isolated as a Table 1). The thiophene derivatives th-NI (1e) and th-Pyr
deep orange solid in 75% yield. The other derivatives were (1c) exhibited intense absorption bands at λ = 365 (32100)
yellow or brown.
and 367 nm (33700), respectively, whereas the absorption
The arylated complexes Ir-Ar (3a, 3b, 3c, 3e and 3f) were band of th-Napht (1b) appears at higher energy at λ =
synthesized upon treatment of the chlorido-bridged dimer 344 nm. The absorptions of th-Per (1d) and th-Coum (1f)
[16]
∧
[Ir(C N-Meppy)2(μ-Cl)]2
with the appropriate diketone were more in the visible region, and they showed maxima
ttaH-Ar in the presence of Na2CO3 (Scheme 6). All of com- at λ ≈ 450 nm. Note that the absorption band of th-PhCF3
plexes were isolated in low to moderate yields and charac- (1a, λmax = 322 nm) is blueshifted compared with those of
terized by standard techniques. The formation of the tta- the other arylated compounds of the series, owing to the
Ar-based complexes was verified by the appearance of absence of an extended π-conjugated system. All of the
signals for the new arylthiophene protons and the forma- compounds except 1a are fluorescent in CH2Cl2 solution
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Table 1. Photophysical data of th-PhCF3, th-Napht, th-NI, th-Pyr, th-Per and th-Coum (1a–1f).
Compound
λabs [nm] (ε [103 Lmol–1 cm–1])[a]
λem [nm] at 298 K[b]
λem [nm] at 77 K[c]
th-PhCF3 (1a)
th-Napht (1b)
th-Pyr (1c)
322 (6.1)
344 (32.1)
367 (33.7)
–
374
393, 414
450
490,518
440
349
470
518
445
514
th-Per (1d)
425 (23.4), 450 (28.4)
365 (32.1)
th-NI (1e)
th-Coum (1f)
450 (34.0)
511, 532
[a] In CH2Cl2 solution. [b] In CH2Cl2 solution: th-Napht (1b): λexc = 320 nm; th-Pyr (1c): λexc = 360 nm; th-Per (1d): λexc = 450 nm; th-
NI (1e): λexc = 365 nm; th-Coum (1f): λexc = 460 nm. [c] In diethyl ether/isopentane/ethanol (EPA, 2:2:1 v/v).
under excitation with UV or visible light. The emission In the UV region, the spectra are dominated by an intense
spectra are broad and featureless (Figure 2). Interestingly, absorption band at λ ≈ 270 nm, attributed to ligand-centred
changes to the nature of the appended aryl group allow a transitions (1LC). In the lower-energy region (λ Ͼ 320 nm),
fine modulation of the emission wavelength (from 360 to the absorption spectra are characteristic of IrIII complexes
514 nm). The emissions from the coumarin- and perylene- with a moderately intense and broad band (λ = 320 to
based compounds (λem ≈ 515 nm) are the most redshifted, 450 nm) tailing up to 500 nm for the non-coumarin
which mirrors the trends seen in the absorption spectra.
complexes. This broad band could be assigned as a metal-
to-ligand charge-transfer (1MLCT) transition [dπ(Ir)Ǟπ*-
∧
(C N)]. The spectrum of the coumarin complex is domi-
nated by an intense band centred at λ = 482 nm, which is
presumably associated predominantly with the coumarin
moiety but is redshifted compared with the absorption of
the corresponding proligand.
Figure 1. Absorption spectra of th-PhCF3, th-Napht, th-NI, th-Pyr,
th-Per and th-Coum (1a–1f) in CH2Cl2 solution at 298 K.
Figure 3. Absorption spectra of Ir-PhCF3 (3a), Ir-Napht (3b), Ir-
Pyr (3c), Ir-NI (3e) and Ir-Coum (3f) in CH2Cl2 solution at 298 K.
All of the arylated complexes 3a–3f display fluorescence
in solution at room temperature upon irradiation into the
low-energy absorption bands. There is no detectable phos-
phorescence emission of the type normally found for simple
∧
∧
Ir(C N)2(O O) complexes (Figure 4). The emission lifetime
(τ = 2.2 ns) of Ir-coum (3f), which is the brightest com-
pound, supports this assignment; the excitation spectrum (λ
= 600 nm) nicely matches the absorption spectrum. For the
other complexes, the lifetimes could not be measured, be-
cause they are too weak, too short or both. This feature
was previously observed by us for arylated tta complexes
Figure 2. Emission spectra of th-Napht (1b, λexc = 320 nm), th-Pyr
(1c, λexc = 360 nm), th-Per (1d, λexc = 450 nm), th-NI (1e, λexc
=
365 nm) and th-Coum (1f, λexc = 460 nm) in CH2Cl2 solution at
298 K.
The electronic absorption spectra of the arylated IrIII containing an electron-donating substituent on the aryl
complexes in dichloromethane solution at room tempera- group attached to the thiophene ring (C6H4-p-OMe, C6H4-
ture are displayed in Figure 3, and the accompanying data p-NH2 and 3-Cl-5-NH2-C6H3).[8] All of the emissions are
are listed in Table 2. All of the complexes present similar insensitive to O2, indicative of spin-allowed fluorescence
absorption profiles (although with a significant displace- from the singlet state. These results show the dramatic effect
ment of the lowest-energy band for the coumarin complex). of the incorporation of an aromatic chromophore into the
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Table 2. Photophysical data of Ir-tta-Ar complexes 3a–3f.
Compound
λabs [nm] (ε [103 Lmol–1 cm–1])[a]
λem [nm] at 298 K[b]
φ[c]
Ir-PhCF3 (3a)
Ir-Napht (3b)
Ir-Pyr (3c)
275 (61.4), 359 (42.8), 394 (33.8)
440
473
563
440
600
Յ0.01
Յ0.01
Յ0.01
275 (39.1), 364 (21.4), 400 (27.7)
277 (87.1), 337 (42.0), 408 (52.2)
270 (55.2), 400 (31.2)
Ir-NI (3e)
Յ0.01
Ir-Coum (3f)
260 (31.4), 482 (38.6)
0.49 (τ = 2.2 ns)
[a] In CH2Cl2 solution. [b] In CH2Cl2 solution: Ir-PhCF3 (3a): λexc = 350 nm; Ir-Napht (3b): λexc = 400 nm; Ir-Pyr (3c): λexc = 410 nm;
Ir-NI (3e): λexc = 350 nm; Ir-Coum (3f): λexc = 475 nm. [c] Reference [Ru(bpy)3]Cl2.
ancillary ligand: the extension of the π conjugation of the complexes. Apparently, as the π system remote to the metal
ancillary ligand leads to a decrease of the spin–orbit cou- ion is extended, the spin–orbit coupling effect of the metal
pling influence of the metal ion. As a result, fluorescence atom is attenuated to such an extent that fluorescence can
from the π system can compete successfully with inter- compete with intersystem crossing to the triplet. On the
system crossing (ISC) to the triplet, whereas for most of other hand, the fluorescence of all of the complexes (with
the archetypal IrIII complexes, ISC is too fast to allow the the exception of the coumarin derivative) is weak, which
observation of fluorescence.[17] Similar switches from suggests that nonradiative decay pathways dominate.
phosphorescence to fluorescence upon extension of a re-
mote π system have been observed for other IrIII, PtII, AuIII
and OsII complexes.[18] Compared with those of the free
ttaH-Ar ligands, the emission bands are redshifted (Δ = 86–
124 nm), except for those of the NI-based derivatives, which
are located at the same energy. The quantum yields are very
low in all cases (φ Յ 0.01 and detectable only with difficulty
for the CF3-substituted complex 3a), except for that of Ir-
Coum (3f), which is strongly fluorescent (φ = 0.49; Table 2).
The weakness of the emission from 3a is consistent with the
absence of fluorescence from the corresponding proligand
2a.
Experimental Section
General: All of the catalytic reactions were performed in Schlenk
tubes under argon with analytical-grade DMA and potassium acet-
ate (Ͼ99%). Commercial bromoaryl reagents and 2-acetylthio-
phene were used without purification. The cyclometallated IrIII μ-
∧
chlorido-bridged dimer complex [Ir(C N-Meppy)2(μ-Cl)]2 was pre-
pared according to a reported procedure.[16] Flash chromatography
was performed with silica gel (230–400 mesh). 1H (500, 400 or
300 MHz) and 13C (125, 100 or 75 MHz) NMR spectra were re-
corded with samples in CDCl3 solution at 298 K. Chemical shifts
are reported in ppm and were referenced to CDCl3 (1H: δ =
7.29 ppm; 13C: δ = 77.0 ppm).
UV/Vis and Emission Spectroscopy: The UV/Vis absorption spectra
were recorded with an Analytik Jena SPECORD 205 spectro-
photometer by using quartz cuvettes of 1 cm pathlength. The
steady-state luminescence spectra were measured with a Jobin Yvon
FluoroMax-2 spectrometer fitted with a red-sensitive Hamamatsu
R928 photomultiplier tube or an Edinburgh Instruments FLSP920
steady-state spectrometer. The spectra were corrected for the wave-
length dependence of the detector, and the quoted emission max-
ima refer to the values after correction.
HRMS: The mass spectra were recorded at the Centre de mesures
physiques de l’Ouest (CRMPO) of the University of Rennes 1 by
Philippe Jéhan with a Thermo Fisher Scientific Q-Exactive instru-
ment with an ESI+ source.
Figure 4. Normalized fluorescence spectra in CH2Cl2 at 298 K: Ir-
General Procedures for the Synthesis of 5-Arylated 2-Acetylthio-
phenes 1a–1f. Method A: In a typical experiment, the reaction of
the aryl bromide (1 equiv.), 2-acetylthiophene (3 equiv.), Pd(OAc)2
(3 mol-%) and KOAc (5 equiv.) in DMA (5–15mL) under argon
in a Schlenk tube at 150 °C for 48 h afforded the 5-arylated 2-
acetylthiophene. The products were purified by silica gel column
chromatography. Method B: In a typical experiment, the reaction
of the aryl bromide (1 equiv.), 2-acetylthiophene (3 equiv.),
PdCl(C3H5)dppb (3 mol-%)[19] and KOAc (5 equiv.) in DMA (5–
15mL) under argon in a Schlenk tube at 150 °C for 24 h afforded
the 5-arylated 2-acetylthiophene. The products were purified by sil-
ica gel column chromatography.
Napht (3b): λexc = 400 nm (blue); Ir-Pyr (3c): λexc = 410 nm
(orange); Ir-NI (3e): λexc = 350 nm (green); Ir-Coum (3f): λexc
=
475 nm (red).
Conclusions
We have prepared a series of neutral bis(cyclometallated)
iridium complexes with aromatic chromophores incorpo-
∧
rated in the ancillary, O O-coordinated ligand. The combi-
nation of these two organic and organometallic chromo-
phores leads to ligand-based fluorescence at room tempera-
1-{5-[3-(Trifluoromethyl)phenyl]thiophen-2-yl}ethanone (th-PhCF3,
3
1a):[20] Method B. From 1-bromo-3-(trifluoromethyl)benzene
ture rather than the MLCT phosphorescence typically ob-
served in the simpler, parent cyclometallated iridium(III) (1.35 g, 6 mmol) and 2-acetylthiophene (2.27 g, 18 mmol), the
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product was obtained in 55% yield (0.891 g). 1H NMR (400 MHz,
138.8, 132.7, 129.5, 125.4, 113.3, 109.6, 108.5, 97.0, 45.0, 26.8,
CDCl3): δ = 7.83 (s, 1 H), 7.76 (d, J = 7.6 Hz, 1 H), 7.63 (d, J = 12.5 ppm. C19H19NO3S (341.42): calcd. C 66.84, H 5.61; found C
3.9 Hz, 1 H), 7.57 (d, J = 7.6 Hz, 1 H), 7.50 (t, J = 7.6 Hz, 1 H),
7.33 (d, J = 3.9 Hz, 1 H), 2.54 (s, 3 H) ppm.
66.98, H 5.40. MS: m/z = 341 [M]+.
Procedures for Synthesis of Butane-1,3-diones 2a–2f. Method A: In
1-[5-(Naphthalen-2-yl)thiophen-2-yl]ethanone
(th-Napht,
1b): a Schlenk tube, to a solution of dry tetrahydrofuran (THF, 15 mL)
Method B. From 2-bromonaphthalene (1.04 g, 5 mmol) and 2-acet-
ylthiophene (1.89 g, 15 mmol), the product was obtained in 65%
yield as a yellow solid (0.819 g). H NMR (400 MHz, CDCl3): δ =
was added the 2-acetyl-5-arylthiophene (1 equiv.) and lithium bi-
s(trimethylsilyl)amide (1.5 equiv.), and then the mixture was stirred
vigorously at room temperature under argon for 1 h. Ethyl trifluo-
1
8.10 (s, 1 H), 7.88–7.80 (m, 3 H), 7.73 (dd, J = 8.5, 1.9 Hz, 1 H), roacetate (1.2 equiv.) was added, and the mixture was stirred at
7.68 (d, J = 3.9 Hz, 1 H), 7.52–7.47 (m, 2 H), 7.42 (d, J = 3.9 Hz, room temperature overnight. EtOH (2 mL) was then added to
1 H), 2.56 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 190.5, quench the reaction. The crude product was obtained after evapo-
152.7, 143.2, 133.5, 133.4, 130.6, 128.9, 128.3, 127.7, 126.8, 126.7,
125.3, 124.2, 124.0, 26.6 ppm. C16H12OS (252.33): calcd. C 76.16,
H 4.79; found C 76.25, H 4.99. MS: m/z = 252 [M]+.
ration of the organic solvent. The product was purified by column
chromatography with acetone and pentane. Method B: Same as
Method A, but the final product was purified by centrifugation to
afford a solid product, which was washed three times with an acet-
one/pentane mixture (1:2.5) and three times with dichloromethane.
1-[5-(Pyren-1-yl)thiophen-2-yl]ethanone (th-Pyr, 1c): Method A.
From 4-bromopyrene (0.562 g, 2 mmol) and 2-acetylthiophene
(0.756 g, 6 mmol), the product was obtained in 75% yield as a
4,4,4-Trifluoro-1-{5-[3-(trifluoromethyl)phenyl]thiophen-2-yl}but-
brown solid (0.489 g) after additional recrystallization from tolu-
ane-1,3-dione (ttaH-PhCF3, 2a): Method A. From 1-{5-[3-(trifluor-
1
ene. H NMR (400 MHz, CDCl3): δ = 8.41 (d, J = 9.3 Hz, 1 H), omethyl)phenyl]thiophen-2-yl}ethanone (0.675 g, 2.5 mmol),
8.22–7.98 (m, 8 H), 7.79 (d, J = 3.9 Hz, 1 H), 7.36 (d, J = 3.9 Hz, LiN(TMS)2 (4.2 mL, 0.9 m, 3.75 mmol) and ethyl trifluoroacetate
1 H), 2.64 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 190.8, (0.426 g, 3 mmol), the product was obtained in 83% yield as a yel-
1
151.6, 144.7, 132.9, 131.8, 131.5, 130.9, 129.1, 129.0, 128.7, 128.6,
128.5, 128.2, 127.4, 126.5, 125.9, 125.5, 125.1, 124.8, 124.7, 124.4,
26.9 ppm. C22H14OS (326.41): calcd. C 80.95, H 4.32; found C
80.71, H 4.20. MS: m/z = 326 [M]+.
low solid (0.759 g). H NMR (400 MHz, [D6]acetone): δ = 7.90 (s,
1 H), 7.88 (d, J = 8.0 Hz, 1 H), 7.76 (d, J = 3.8 Hz, 1 H), 7.60–
7.55 (m, 2 H), 7.54 (d, J = 3.8 Hz, 1 H), 6.18 (s, 1 H) ppm. 13C
NMR (100 MHz, [D6]acetone): δ = 181.5, 172.4 (q, J = 30.4 Hz),
149.1, 147.2, 136.0, 131.9 (q, J = 31.9 Hz), 131.1, 130.4, 130.1,
126.4, 125.6, 125.2 (q, J = 271.9 Hz), 123.0, 120.1 (q, J = 286.7 Hz),
89.3 ppm. MS: m/z = 366 [M]+.
1-[5-(Perylen-3-yl)thiophen-2-yl]ethanone (th-Per, 1d): Method A.
From 3-bromoperylene (0.662 g, 2 mmol) and 2-acetylthiophene
(0.756 g, 6 mmol), the product was obtained in 70% yield as a
brown solid (0.526 g) after additional recrystallization from tolu-
ene. 1H NMR (400 MHz, CDCl3): δ = 8.23–8.12 (m, 4 H), 8.02 (d,
4,4,4-Trifluoro-1-[5-(naphthalen-2-yl)thiophen-2-yl]butane-1,3-dione
(ttaH-Napht, 2b): Method A. From 1-[5-(naphthalen-2-yl)thio-
J = 8.3 Hz, 1 H), 7.74 (d, J = 3.8 Hz, 1 H), 7.70 (d, J = 7.8 Hz, 1 phen-2-yl]ethanone (0.504 g, 2 mmol), LiN(TMS)2 (3.33 mL, 0.9 m,
H), 7.68 (d, J = 7.8 Hz, 1 H), 7.54 (d, J = 3.8 Hz, 1 H), 7.51–7.44 3 mmol) and ethyl trifluoroacetate (0.341 g, 2.4 mmol), the product
(m, 3 H), 7.28 (d, J = 3.8 Hz, 1 H), 2.61 (s, 3 H) ppm. 13C NMR was obtained in 86% yield as a yellow solid (0.599 g). 1H NMR
(100 MHz, CDCl3): δ = 190.7, 151.1, 144.3, 134.8, 133.0, 132.9, (400 MHz, [D6]acetone): δ = 8.28 (s, 1 H), 7.99–7.85 (m, 5 H), 7.65
132.6, 131.9, 131.3, 131.1, 130.9, 129.4, 129.2, 128.8, 128.7, 128.6,
128.3, 127.5, 127.0, 126.9, 125.4, 121.1, 121.0, 120.9, 119.8, NMR (100 MHz, [D6]acetone): δ = 183.0, 172.3 (q, J = 31.1 Hz),
(d, J = 3.9 Hz, 1 H), 7.56–7.48 (m, 2 H), 6.33 (s, 1 H) ppm. 13C
27.0 ppm. C26H16OS (376.47): calcd. C 82.95, H 4.28; found C
83.13, H 4.22.
151.0, 145.9, 134.5, 134.2, 132.0, 131.7, 129.5, 128.8, 128.3, 127.4,
127.2, 125.4, 125.2, 124.4, 120.0 (q, J = 286.3 Hz), 90.4 ppm.
6-(5-Acetylthiophen-2-yl)-2-n-butylbenzo[de]isoquinoline-1,3(2H)-di-
one (th-NI, 1e): Method A. From 6-bromo-2-n-butylbenzo[de]iso-
quinoline-1,3(2H)-dione (0.996 g, 3 mmol) and 2-acetylthiophene
4,4,4-Trifluoro-1-[5-(pyren-1-yl)thiophen-2-yl]butane-1,3-dione
(ttaH-Pyr, 2c): Method B. From 1-[5-(pyren-1-yl)thiophen-2-yl]eth-
anone (0.528 g, 1.62 mmol), LiN(TMS)2 (2.71 mL, 0.9 m,
(1.14 g, 9 mmol), the product was obtained in 71% yield as a yellow 2.44 mmol) and ethyl trifluoroacetate (0.267 g, 1.88 mmol), the
solid (0.803 g). 1H NMR (400 MHz, CDCl3): δ = 8.50 (d, J =
product was obtained in 85% yield as a brown solid (0.581 g). After
7.3 Hz, 1 H), 8.47 (d, J = 7.5 Hz, 1 H), 8.43 (d, J = 8.5 Hz, 1 H), the addition of ethyl trifluoroacetate, the reaction mixture was
1
7.74 (d, J = 3.8 Hz, 1 H), 7.72 (d, J = 7.5 Hz, 1 H), 7.67 (t, J =
7.8 Hz, 1 H), 7.29 (d, J = 3.8 Hz, 1 H), 4.09 (t, J = 7.6 Hz, 2 H),
1.62 (quint, J = 7.6 Hz, 2 H), 1.38 (sext, J = 7.6 Hz, 2 H), 2.58 (s,
3 H), 0.91 (t, J = 7.6 Hz, 3 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 190.4, 163.9, 163.6, 147.8, 145.8, 137.6, 132.5, 131.5, 131.4,
130.4, 129.6, 129.5, 128.7, 128.6, 127.6, 123.1, 123.0, 40.3, 30.2,
26.8, 20.3, 13.8 ppm. C22H19NO3S (377.46): calcd. C 70.00, H 5.07;
found C 70.10, H 5.23.
heated at 60 °C overnight. H NMR (400 MHz, [D6]acetone): δ =
8.47 (d, J = 9.3 Hz, 1 H), 8.35–7.98 (m, 9 H), 7.47 (d, J = 3.9 Hz,
1 H), 6.41 (s, 1 H) ppm. 13C NMR (100 MHz, [D6]acetone): δ =
183.3, 172.3 (q, J = 31.1 Hz), 149.5, 147.6, 132.6, 132.5, 131.9,
131.2, 130.2, 130.0, 129.7, 129.4, 129.2, 129.1, 128.3, 127.5, 126.8,
126.4, 125.8, 125.7, 125.4, 125.3, 120.3 (q, J = 287.3 Hz), 90.8 ppm.
4,4,4-Trifluoro-1-[5-(perylen-3-yl)thiophen-2-yl]butane-1,3-dione
(ttaH-Per, 2d): Method B. From 1-[5-(perylen-3-yl)thiophen-2-yl]-
3-(5-Acetylthiophen-2-yl)-7-(diethylamino)chromen-2-one (th-Coum, ethanone (0.398 g, 1.06 mmol), LiN(TMS)2 (1.76 mL, 0.9 m,
1f): Method B. From 3-bromo-7-(diethylamino)chromen-2-one 1.5 mmol) and ethyl trifluoroacetate (0.180 g, 1.27 mmol), the
(0.740 g, 2.5 mmol) and 2-acetylthiophene (0.945 g, 7.5 mmol), the
product was obtained in 60% yield as an orange solid (0.512 g)
product was obtained in 85% yield as a brown solid (0.425 g). After
the addition of ethyl trifluoroacetate, the reaction mixture was
1
after additional recrystallization from acetonitrile. 1H NMR heated at 60 °C overnight. H NMR (400 MHz, [D6]acetone): δ =
(400 MHz, CDCl3): δ = 7.96 (s, 1 H), 7.67 (d, J = 4.1 Hz, 1 H), 8.45–8.35 (m, 4 H), 8.13 (d, J = 8.6 Hz, 1 H), 7.83 (d, J = 3.8 Hz,
7.64 (d, J = 4.1 Hz, 1 H), 7.32 (d, J = 8.9 Hz, 1 H), 6.61 (dd, J =
8.9, 2.4 Hz, 1 H), 6.50 (d, J = 2.4 Hz, 1 H), 3.42 (q, J = 7.6 Hz, 4 3 H), 7.35 (d, J = 3.8 Hz, 1 H), 6.19 (s, 1 H) ppm. 13C NMR
H), 2.55 (s, 3 H), 1.22 (t, J = 7.6 Hz, 6 H) ppm. 13C NMR
(100 MHz, [D6]acetone): δ = 181.9, 172.1 (q, J = 30.0 Hz), 148.8,
(100 MHz, CDCl3): δ = 190.6, 160.0, 156.1, 151.3, 145.9, 142.5, 147.4, 135.8, 133.7, 132.7, 132.5, 131.9, 131.6, 130.0, 129.9, 129.5,
1 H), 7.82–7.77 (m, 2 H), 7.64 (d, J = 7.9 Hz, 1 H), 7.62–7.52 (m,
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129.4, 129.3, 129.1, 128.4, 127.9, 127.8, 126.3, 122.0, 121.9, 121.0,
117.6 (q, J = 296.8 Hz), 89.3 ppm.
(0.150 g, 0.430 mmol) and Na2CO3 (0.182 g, 1.72 mmol) in 2-
ethoxyethanol (15 mL), the product was isolated in 26% yield as a
red powder (0.078 g). Eluent: diethyl ether/pentane (1:1). 1H NMR
(400 MHz, CDCl3): δ = 8.35 (d, J = 6.0 Hz, 1 H), 8.33 (d, J =
6.0 Hz, 1 H), 8.04 (s, 1 H), 7.83–7.75 (m, 3 H), 7.70–7.65 (m, 3 H),
7.64 (d, J = 4.0 Hz, 1 H), 7.57 (d, J = 7.1 Hz, 1 H), 7.54 (d, J =
7.1 Hz, 1 H), 7.50–7.45 (m, 2 H), 7.33 (d, J = 4.0 Hz, 1 H), 7.00
(d, J = 6.0 Hz, 1 H), 6.95 (d, J = 6.0 Hz, 1 H), 6.87 (t, J = 7.5 Hz,
1 H), 6.82 (t, J = 7.5 Hz, 1 H), 6.75 (t, J = 7.5 Hz, 1 H), 6.69 (t, J
= 7.5 Hz, 1 H), 6.32 (d, J = 7.7 Hz, 1 H), 6.25 (d, J = 7.7 Hz, 1
H), 6.17 (s, 1 H), 2.57 (s, 3 H), 2.58 (s, 3 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 175.2, 167.7, 167.6, 150.0, 148.9, 148.8,
147.3, 147.2, 145.3, 145.0, 144.9, 144.8, 144.6, 133.5, 133.3, 133.2,
133.1, 131.1, 129.6, 128.7, 128.6, 128.3, 128.1, 127.7, 126.8, 126.4,
124.6, 124.4, 123.8, 123.5, 123.4, 122.9, 122.8, 92.2, 21.4, 21.3 ppm.
C42H30F3IrN2O2S (876.00): calcd. C 57.59, H 3.45, N 3.20, S 3.66;
found C 57.44, H 3.30, N 3.00, S 3.23. HRMS: calcd. for
C42H30F3IrN2O2S [M]+ 876.1604; found 876.1603.
2-n-Butyl-6-[5-(4,4,4-trifluoro-3-oxobutanoyl)thiophen-2-yl]benzo-
[de]isoquinoline-1,3(2H)-dione (ttaH-NI, 2e): Method B. From 6-(5-
acetylthiophen-2-yl)-2-n-butylbenzo[de]isoquinoline-1,3(2H)-dione
(0.464 g, 1.23 mmol), LiN(TMS)2 (2.1 mL, 0.9 m, 1.85 mmol) and
ethyl trifluoroacetate (0.210 g, 1.48 mmol), the product was ob-
tained in 81 % yield as a brown solid (0.471 g). 1H NMR
(400 MHz, [D6]DMSO): δ = 8.50–8.30 (m, 3 H), 8.02 (d, J =
3.4 Hz, 1 H), 7.88–7.70 (m, 2 H), 7.46 (d, J = 3.4 Hz, 1 H), 6.33
(s, 1 H), 3.96 (t, J = 7.6 Hz, 2 H), 1.62 (quint, J = 7.6 Hz, 2 H),
1.35 (sext, J = 7.6 Hz, 2 H), 0.91 (t, J = 7.6 Hz, 3 H) ppm. 13C
NMR (100 MHz, [D6]DMSO): δ = 181.0, 170.5 (q, J = 30.7 Hz),
163.0, 162.7, 147.4, 144.7, 137.2, 131.4, 130.8, 130.5, 129.9, 128.6,
128.5, 127.8, 127.7, 122.3, 121.8, 119.0 (q, J = 286.8 Hz), 89.4, 29.5,
19.8, 13.7 ppm.
1-{5-[7-(Diethylamino)-2-oxochromen-3-yl]thiophen-2-yl}-4,4,4-tri-
fluorobutane-1,3-dione (ttaH-Coum, 2f): Method B. From 3-(5-acet-
ylthiophen-2-yl)-7-(diethylamino)chromen-2-one (0.716 g, 2.1 mmol),
LiN(TMS)2 (3.5 mL, 0.9 m, 3.1 mmol) and ethyl trifluoroacetate
(0.358 g, 2.52 mmol), the product was obtained in 75% yield as an
orange solid (0.688 g). After the addition of ethyl trifluoroacetate,
the reaction mixture was heated at 60 °C overnight. 1H NMR
(400 MHz, [D6]acetone): δ = 8.26 (s, 1 H), 7.61 (s, 2 H), 7.46 (d, J
= 9.0 Hz, 1 H), 6.71 (dd, J = 9.0, 2.2 Hz, 1 H), 6.49 (d, J = 2.2 Hz,
1 H), 6.10 (s, 1 H), 3.48 (q, J = 7.6 Hz, 4 H), 1.17 (t, J = 7.6 Hz,
6 H) ppm. 13C NMR (100 MHz, [D6]acetone): δ = 182.3, 171.6 (q,
J = 30.1 Hz), 160.5, 157.0, 152.3, 147.6, 143.3, 138.9, 130.7, 129.1,
125.6, 120.6 (q, J = 288.5 Hz), 114.5, 110.6, 109.5, 97.5, 89.5, 45.5,
12.9 ppm.
∧
Complex Ir-Pyr (3c): From [Ir(C N-Meppy)2(μ-Cl)]2 (0.193 g,
0.172 mmol), 4,4,4-trifluoro-1-[5-(pyren-1-yl)thiophen-2-yl]butane-
1,3-dione (0.182 g, 0.430 mmol) and Na2CO3 (0.182 g, 1.72 mmol)
in 2-ethoxyethanol (15 mL), the product was isolated in 17% yield
as a red powder (0.057 g). Eluent: diethyl ether/pentane (1:1). 1H
NMR (400 MHz, CDCl3): δ = 8.42–8.35 (m, 3 H), 8.20 (d, J =
7.6 Hz, 1 H), 8.18 (d, J = 7.6 Hz, 1 H), 8.14–7.96 (m, 6 H), 7.76
(d, J = 3.9 Hz, 1 H), 7.69 (s, 1 H), 7.66 (s, 1 H), 7.57–7.50 (m, 2
H), 7.27 (d, J = 3.9 Hz, 1 H), 7.01 (d, J = 6.0 Hz, 1 H), 6.99 (d, J
= 6.0 Hz, 1 H), 6.82 (t, J = 7.5 Hz, 2 H), 6.70 (t, J = 7.5 Hz, 2 H),
6.32 (d, J = 7.7 Hz, 1 H), 6.27 (d, J = 7.7 Hz, 1 H), 6.24 (s, 1 H),
2.59 (s, 3 H), 2.57 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ
= 175.4, 167.8, 167.7, 166.4, 166.1, 148.9, 148.8, 148.5, 147.3, 147.2,
146.3, 145.2, 144.9, 144.8, 144.6, 133.3, 133.2, 131.4, 130.8, 129.2,
129.1, 129.0, 128.7, 128.6, 128.3, 128.1, 128.0, 127.3, 126.3, 125.6,
125.2, 125.0, 124.7, 124.6, 124.5, 123.5, 123.4, 122.9, 122.8, 121.0,
120.9, 120.2, 119.3, 119.2, 92.4, 21.5, 21.4 ppm. C48H32F3IrN2O2S
(950.07): calcd. C 60.68, H 3.40, N 2.95, S 3.37; found C 60.54, H
3.98, N 2.67, S 3.09. HRMS: calcd. for C48H32F3IrN2O2S [M]+
950.17605; found 950.1764.
∧
Synthesis of the Iridium Complexes 3a–3f: The dimer [Ir(C N-
Meppy)2(μ-Cl)]2 was converted into the corresponding tta-Ar com-
∧
∧
∧
plexes of general formula Ir(C N-Meppy)2(O O-tta-Ar) according
to a reported procedure.[16] The dimer [Ir(C N-Meppy)2(μ-Cl)]2
(1 equiv.), the corresponding thenoyltrifluoroacetone (2.5 equiv.)
and Na2CO3 (10 equiv.) were suspended in 2-ethoxyethanol and
heated at 80 °C for 24 h. Then, water was added, and the precipi-
tate was collected by centrifugation. The residue was purified by
chromatography (silica), and the product was recrystallized from a
mixture of dichloromethane/pentane.
∧
Complex Ir-NI (3e). Route (2): From [Ir(C N-Meppy)2(μ-Cl)]2
(0.193 g, 0.172 mmol), 2-n-butyl-6-[5-(4,4,4-trifluoro-3-oxobut-
anoyl)thiophen-2-yl]benzo[de]isoquinoline-1,3(2H)-dione (0.204 g,
0.430 mmol) and Na2CO3 (0.182 g, 1.72 mmol) in 2-ethoxyethanol
(15 mL), the product was isolated in 9% yield as a red powder
∧
Complex Ir-PhCF3 (3a): From [Ir(C N-Meppy)2(μ-Cl)]2 (0.193 g,
0.172 mmol),
4,4,4-trifluoro-1-{5-[3-(trifluoromethyl)phenyl]-
1
(0.030 g). Eluent: diethyl ether/pentane (1:1). H NMR (400 MHz,
thiophen-2-yl}butane-1,3-dione (0.157 g, 0.430 mmol) and Na2CO3
(0.182 g, 1.72 mmol) in 2-ethoxyethanol (15 mL), the product was
isolated in 17% yield as a red powder (0.053 g). Eluent: diethyl
CDCl3): δ = 8.63 (d, J = 7.6 Hz, 1 H), 8.54 (d, J = 7.6 Hz, 1 H),
8.47 (d, J = 8.5 Hz, 1 H), 8.35 (d, J = 6.0 Hz, 1 H), 8.33 (d, J =
6.0 Hz, 1 H), 7.76–7.74 (m, 2 H), 7.73 (d, J = 3.9 Hz, 1 H), 7.69
(s, 1 H), 7.66 (s, 1 H), 7.56–7.50 (m, 2 H), 7.20 (d, J = 3.9 Hz, 1
H), 7.01 (d, J = 6.0 Hz, 1 H), 6.97 (d, J = 6.0 Hz, 1 H), 6.82 (t, J
= 7.5 Hz, 2 H), 6.70 (t, J = 7.5 Hz, 2 H), 6.30 (d, J = 7.7 Hz, 1 H),
6.24 (d, J = 7.7 Hz, 1 H), 6.20 (s, 1 H), 4.19 (t, J = 7.6 Hz, 2 H),
2.59 (s, 3 H), 2.57 (s, 3 H), 1.72 (quint, J = 7.6 Hz, 2 H), 1.46 (sext,
J = 7.6 Hz, 2 H), 0.98 (t, J = 7.6 Hz, 3 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 174.7, 167.7, 164.0, 163.8, 149.0, 147.9,
147.3, 147.1, 145.0, 144.9, 144.8, 144.7, 144.2, 138.3, 133.3, 133.2,
131.4, 130.4, 129.8, 129.5, 128.8, 128.7 (m), 128.6, 128.5, 128.4,
127.4, 123.5, 123.4, 123.0, 122.9, 122.8, 122.6, 121.1, 121.0, 119.4,
119.3, 92.3, 40.3, 30.2, 29.5, 21.4, 20.4, 13.8 ppm.
C48H37F3IrN3O4S·C5H12 (1073.30): calcd. C 59.31, H 4.60, N 3.92,
S 2.99; found C 59.36, H 4.67, N 3.66, S 2.96. HRMS: calcd. for
C48H37F3IrN3O4S [M]+ 1001.20808; found 1001.2079. Route (1):
1
ether/pentane (1:1). H NMR (400 MHz, CDCl3): δ = 8.37 (d, J =
6.0 Hz, 1 H), 8.33 (d, J = 6.0 Hz, 1 H), 7.85–7.45 (m, 9 H), 7.23
(d, J = 3.9 Hz, 1 H), 6.98 (d, J = 6.0 Hz, 1 H), 6.94 (d, J = 6.0 Hz,
1 H), 6.86 (t, J = 7.5 Hz, 1 H), 6.82 (t, J = 7.5 Hz, 1 H), 6.73 (t, J
= 7.5 Hz, 1 H), 6.69 (t, J = 7.5 Hz, 1 H), 6.31 (d, J = 7.7 Hz, 1 H),
6.25 (d, J = 7.7 Hz, 1 H), 6.16 (s, 1 H), 2.57 (s, 3 H), 2.56 (s, 3 H)
ppm. 13C NMR (100 MHz, CDCl3): δ = 175.0, 167.7, 149.0, 148.9,
147.7, 147.2, 147.1, 146.1, 145.0, 144.9, 144.8, 144.3, 134.6, 133.3,
133.2, 131.7, 131.4, 129.6, 129.3, 129.1, 128.9, 128.8, 128.7, 125.1,
124.8, 123.5, 123.4, 122.9, 122.8, 122.4 (m), 121.0, 120.9, 119.4,
119.2, 21.4, 21.3 ppm. C39H27F6IrN2O2S·1/3C5H12 (917.96): calcd.
C 53.21, H 3.40, N 3.05, S 3.49; found C 53.03, H 3.21, N 2.71, S
3.80. HRMS: calcd. for C39H27F6IrN2O2S [M]+ 894.13214; found
894.1321.
∧
Complex Ir-Napht (3b): From [Ir(C N-Meppy)2(μ-Cl)]2, 4,4,4-tri- DMA (4 mL) was added to a Schlenk tube charged with 4-bromo-
∧
fluoro-1-[5-(naphthalen-2-yl)thiophen-2-yl]butane-1,3-dione
N-butylnaphthalimide (0.026 g, 0.080 mmol), Ir(C N-Meppy)2-
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∧
[4]
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2, 1712–1728; e) F. N. Castellano, Dalton Trans. 2012, 41,
8493–8501.
(O O-tta-Ar) (Ir-1; 0.050 g, 0.067 mmol), KOAc (0.010 g,
0.1 mmol) and Pd(OAc)2 (0.2 mg, 0.0066 mmol). Then, the mixture
was heated under argon at 100 °C for 72 h. After the mixture had
cooled to room temperature, water (10 mL) was added, and the
resulting precipitate was washed several times with ethanol and di-
ethyl ether. The resulting mixture was purified by silica gel column
chromatography (eluent: hexane/diethyl ether, 9:1 and then 7:3).
The solvent was removed under reduced pressure to afford red solid
3e (0.011 g, 16.5%). The NMR spectroscopic data are similar to
those of the compound obtained by Route (2).
[5]
For reviews on Pd-catalyzed C–H bond functionalization, see:
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∧
Complex Ir-coum (3f): From [Ir(C N-Meppy)2(μ-Cl)]2 (0.193 g,
0.172 mmol), 1-{5-[7-(diethylamino)-2-oxochromen-3-yl]thiophen-
2-yl}-4,4,4-trifluorobutane-1,3-dione (0.193 g, 0.443 mmol) and
Na2CO3 (0.187 g, 1.77 mmol) in 2-ethoxyethanol (15 mL), the
product was isolated in 16% yield as a red powder (0.053 g). Elu-
ent: diethyl ether. 1H NMR (400 MHz, CDCl3): δ = 8.35 (d, J =
6.0 Hz, 1 H), 8.32 (d, J = 6.0 Hz, 1 H), 7.86 (s, 1 H), 7.65 (s, 1 H),
7.64 (s, 1 H), 7.57 (d, J = 4.1 Hz, 1 H), 7.55–7.50 (m, 3 H), 7.26
(d, J = 8.2 Hz, 1 H), 6.98 (d, J = 6.0 Hz, 1 H), 6.93 (d, J = 6.0 Hz,
1 H), 6.84 (t, J = 7.5 Hz, 1 H), 6.80 (t, J = 7.5 Hz, 1 H), 6.72 (t, J
= 7.5 Hz, 1 H), 6.69 (t, J = 7.5 Hz, 1 H), 6.57 (dd, J = 9.0, 2.3 Hz,
1 H), 6.48 (d, J = 2.3 Hz, 1 H), 6.30 (d, J = 7.7 Hz, 1 H), 6.24 (d,
J = 7.7 Hz, 1 H), 6.17 (s, 1 H), 3.40 (q, J = 7.6 Hz, 4 H), 2.56 (s, [6]
3 H), 2.54 (s, 3 H), 1.20 (t, J = 7.6 Hz, 6 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 175.4, 167.7, 167.6, 159.9, 155.8, 151.0,
148.8, 148.7, 147.2 (m), 145.4, 144.9, 144.8, 144.7, 144.5, 143.3,
137.9, 133.3, 133.2, 129.3, 129.2, 128.7, 128.6, 125.9, 123.4, 123.3,
122.9, 122.8, 120.9, 120.7, 119.9, 119.3, 119.2, 117.6, 113.8, 109.5,
108.6, 97.0, 92.6, 44.9, 21.4, 31.3, 12.4 ppm. C45H37F3IrN3O4S·1/
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www.eurjic.org
FULL PAPER
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Published Online: June 2, 2015
Eur. J. Inorg. Chem. 2015, 2956–2964
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