Chelating fluorene dyes as mono- and ditopic 2-(1 H -1,2,3-triazol-4-yl) pyridine ligands and their corresponding ruthenium(II) complexes

Article abstract of DOI:10.1055/s-0031-1289771

2-(1H-1,2,3-Triazol-4-yl)pyridines (trzpy), which can be regarded as analogues to 2,2-bipyridines, were attached to the 2- and 7-position of 9,9-dioctyl-9H-fluorene providing one monotopic and two ditopic ligands. The bidentate N-heterocycles were synthesized by the copper(I)-catalyzed azide-alkyne 1,3-cycloaddition. Moreover, the palladium(0)-catalyzed Sonogashira coupling allowed the introduction of an electron-withdrawing phenylacetylene moiety at 5-position of the pyridine unit. The emission maximum of the ligands could be varied over a range of 100 nm with extinction coefficients up to 95 000 M^-1·cm^-1. Even though the monotopic system revealed a similar absorption behavior compared to its ditopic counterpart, a remarkable fluorescence quantum yield deviation of one order of magnitude was observed (Φ=0.66 for the unsubstituted ditopic and Φ=0.07 for the monotopic ligand). All trzpy systems were coordinated to ruthenium(II) ions in high yields (>90%) using the bis(4,4-dimethyl-2,2-bipyridine)ruthenium(II) precursor. Though 2-(1,2,3-triazol-4-yl)pyridine ligands are known to be potential quenchers for ruthenium(II) ions, all ruthenium complexes revealed room temperature phosphorescence, whereby emission lifetimes proved to be relatively short (<10 ns). Photophysical and electrochemical measurements indicated no electronic interaction of the two ruthenium centers. Georg Thieme Verlag Stuttgart New York.

Full text of DOI:10.1055/s-0031-1289771

PAPER
▌2287
paper
Chelating Fluorene Dyes as Mono- and Ditopic 2-(1H-1,2,3-Triazol-4-yl)pyridine
Ligands and Their Corresponding Ruthenium(II) Complexes
Chelating Fluorene Dyes
Bobby Happ,a,b,c Johann Schäfer,b,d Christian Friebe,a,b Helmar Görls,e Andreas Winter,a,b,c Martin D. Hager,a,b,c
Jürgen Popp,b,d,f Benjamin Dietzek,b,d,f Ulrich S. Schubert*a,b,c
a
Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University of Jena, Humboldtstr. 10, 07743 Jena,
Germany
Fax +49(3641)948202; E-mail: ulrich.schubert@uni-jena.de
b
Jena Center for Soft Matter (JCSM), Friedrich Schiller University of Jena, Humboldtstr. 10, 07743 Jena, Germany
c
Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
d
Institute of Photonic Technology Jena (IPHT), Albert-Einstein-Str. 9, 07745 Jena, Germany
e
Laboratory of Inorganic and Analytical Chemistry, Friedrich Schiller University of Jena, Lessingstr. 8, 07743 Jena, Germany
f
Institute for Physical Chemistry (IPC) and Abbe Center of Photonics (ACP), Friedrich Schiller University of Jena, Helmholtzweg 4,
07743 Jena, Germany
Received: 09.01.2012; Accepted after revision: 28.04.2012
ligand charge transfer (MLCT, d–π*) or intraligand (IL,
Abstract: 2-(1H-1,2,3-Triazol-4-yl)pyridines (trzpy), which can be
π–π*) states exhibiting triplet character because of effi-
regarded as analogues to 2,2′-bipyridines, were attached to the 2-
cient intersystem crossing (ISC) transitions. Very often
the complexes are luminescent and show intense visible
and 7-position of 9,9-dioctyl-9H-fluorene providing one monotopic
and two ditopic ligands. The bidentate N-heterocycles were synthe-
sized by the copper(I)-catalyzed azide-alkyne 1,3-cycloaddition. absorption in solution, which enhances the sensitivity and
variety of excitation sources.1a–e The primary fundamen-
tals for the coordination behavior of mono- and multime-
Moreover, the palladium(0)-catalyzed Sonogashira coupling al-
lowed the introduction of an electron-withdrawing phenylacetylene
moiety at 5-position of the pyridine unit. The emission maximum of
tallic coordination assemblies have been well explored
the ligands could be varied over a range of 100 nm with extinction
and led to an extensive array of architectures.1 Despite this
coefficients up to 95 000 M–1·cm–1. Even though the monotopic sys-
broad range of ligand architectures, which are accessible
to scientists, still a significant number of these require ei-
ther troublesome multi-step syntheses or can only be gen-
erated under highly demanding conditions prohibiting the
incorporation of relevant functional groups. In this re-
spect, the Cu(I)-catalyzed 1,3-cycloaddition of organic
azides with terminal alkynes (the CuAAC reaction) offer
a great potential due to its mild reaction conditions and
wide range of usable substrates.2 The latter features have
directed to numerous applications in the synthesis of func-
tional molecules, for instance, in biological and material
science.3 The development of the CuAAC reaction result-
ed in an increased interest towards the coordination chem-
istry of 1,4-functionalized 1H-1,2,3-triazoles due to their
potential to act as bidentate N-donor ligands. Recently, a
variety of new bi-,4 tri-,4c,5 and polydentate6 1H-1,2,3-tri-
azole-containing ligands have been synthesized and their
coordination properties were examined. The present con-
tribution will discuss the synthesis and characterization of
new fluorene-based 2-(1H-1,2,3-triazol-4-yl)pyridines
(trzpy) as well as their corresponding ruthenium(II) com-
plexes (Figure 1).
tem revealed a similar absorption behavior compared to its ditopic
counterpart, a remarkable fluorescence quantum yield deviation of
one order of magnitude was observed (Φ = 0.66 for the unsubstitut-
ed ditopic and Φ = 0.07 for the monotopic ligand). All trzpy sys-
tems were coordinated to ruthenium(II) ions in high yields (>90%)
using the bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) precur-
sor. Though 2-(1,2,3-triazol-4-yl)pyridine ligands are known to be
potential quenchers for ruthenium(II) ions, all ruthenium complexes
revealed room temperature phosphorescence, whereby emission
lifetimes proved to be relatively short (<10 ns). Photophysical and
electrochemical measurements indicated no electronic interaction
of the two ruthenium centers.
Key words: copper(I)-catalyzed azide-alkyne cycloaddition, Cu-
AAC reaction, fluorine, photophysics, ruthenium, phosphorescence
Over the last decades, the field of polypyridine-based
metallosupramolecular chemistry experienced a rapid de-
velopment. In particular, d6-configured N-heterocyclic
complexes of second and third row transition metal ions
have been widely used due to their beneficial low-spin
ground states. This configuration enables kinetic stability
as well as thermal durability by formation of stable coor-
dinative bonds between the metal ion and the ligands. The
thermally equilibrated excited states of these complexes,
which can be usually observed on a nanosecond or micro-
second time scales, are generally assigned to be metal-to-
The trzpy subunit was intended to be directly connected to
the fluorene at the N1-position of the five-membered tri-
azole ring. By using the CuAAC a straightforward and
easy access to the mono- and ditopic architectures was
possible in good to high yields. Furthermore, the rutheni-
um(II) complexes were obtained in high yields by an op-
timized microwave-assisted synthesis route using cis-
dichloro-bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II)
SYNTHESIS 2012, 44, 2287–2294
Advanced online publication: 18.06.2012
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X
DOI: 10.1055/s-0031-1289771; Art ID: SS-2012-T0029-OP
© Georg Thieme Verlag Stuttgart · New York

2288
B. Happ et al.
PAPER
monotopic ligand
[Ru(dmbpy)2Cl2] as precursor. The compounds were
characterized in detail by NMR spectroscopy, elemental
analysis, high-resolution ESI-TOF mass spectrometry as
well as X-ray crystallography and the photophysical prop-
erties were studied by UV/Vis absorption and emission
spectroscopy.
N
N
N
C8H17
C8H17
N
The general synthetic routes for the monotopic ligand 3
and the ditopic ligand 6 are outlined in Schemes 1 and 2,
respectively. The CuAAC reaction facilitated a straight-
forward preparation of the N-heterocycles exploiting a
two-step one-pot procedure. Subsequent to the copper(II)-
catalyzed in situ azidation of the glycol 9,9′-dioctyl-9H-
fluorene boronates 1 and 4, the aimed mono- and ditopic
architectures were obtained utilizing the CuAAC with 2-
ethynylpyridine. Copper(II) sulfate and sodium ascorbate
(NaAsc) were used as catalytic system for the CuAAC.
The purification of the final products was carried out by
column chromatography on silica gel and the purity of the
compounds was confirmed by elemental analysis, mass
spectrometry as well as 1H and 13C NMR spectroscopy.
ditopic ligand
N
N
N
N
N
N
C8H17
C8H17
N
N
R
R
Figure 1 Schematic representation of the molecular structures of the
fluorene-based trzpy ligands
NaN3 (1.5 equiv)
CuSO4 (10 mol%)
25 °C, 24 h
Furthermore, an acceptor-type phenylacetylene moiety
bearing an electron-withdrawing nitro group was intro-
duced in the 5-position of the pyridine ring (Scheme 3).
The in situ generated azide 5 was allowed to react with 4-
(6-ethynylpyridin-3-yl)-2-methylbut-3-yn-2-ol and the
subsequent alkaline cleavage of the protecting group pro-
vided compound 8 in good yield (62%) after column chro-
matography on aluminum oxide. Finally, the acceptor-
type ditopic ligand 9 was obtained via palladium(0)-cata-
lyzed Sonagashira cross-coupling of 8 with 4-nitro-1-io-
dobenzene (72% yield). The purity was confirmed by
abs. MeOH
O
B
N
N
N
>95%
O
C8H17
C8H17
C8H17
C8H17
2
1
N
(1 equiv)
5
NaAsc (0.5 equiv)
25 °C, 24 h
THF–H2O (9:1)
4
6
3
N
7
N
N
5''
2
1
8
3'
elemental analysis, mass spectrometry as well as H and
1
91%
13C NMR spectroscopy.
C8H17
C8H17
4'
N
3
In the case of 6, single crystals suitable for X-ray crystal-
lography were obtained by slow evaporation of acetoni-
trile. The compound crystallized in an orthorhombic space
group of Pca21 symmetry. A summary of the crystal data
and refinement are given in the experimental part. The
N=N (1.31 Å) and C=C (1.37 Å) bond distance of the tri-
azole ring correlated with those published for previous
5'
6'
Scheme 1 Schematic representation of the one-pot synthesis of a
monotopic trzpy-ligand (final structure comprises the NMR number-
ing)
NaN3 (3 equiv)
CuSO4 (20 mol%)
25 °C, 24 h
O
O
abs. MeOH
N
B
N
B
N
N
N
N
O
O
>95%
C8H17
C8H17
C8H17
C8H17
4
5
(2.2 equiv)
N
4
3
NaAsc (1 equiv)
25 °C, 24 h
N
N
N
N
N
N
N
5''
THF–H2O (9:1)
5
1
3'
75%
C8H17
C8H17
4'
N
6
5'
6'
Scheme 2 Schematic representation of the one-pot synthesis of a ditopic trzpy-ligand (final structure comprises the NMR numbering)
Synthesis 2012, 44, 2287–2294
© Georg Thieme Verlag Stuttgart · New York

PAPER
Chelating Fluorene Dyes
2289
i) NaN3 (3 equiv), CuSO4 (20 mol%)
dry MeOH
ii) 7 (2 equiv), NaAsc (50 mol%)
24 h, 55 °C
EtOH–H2O (7:3)
N
N
iii) toluene, NaOH/KOH
reflux
OH
N
N
N
4
+
N
N
N
62%
N
C8H17
C8H17
7
8
O2N
NO2
I
NO2
(2 equiv)
N
N
N
N
Pd(PPh3)4, CuI (cat.)
48 h, 55 °C
Et3N–THF (1:1)
N
N
N
N
C8H17
C8H17
8
72%
9
Scheme 3 Schematic representation of the synthesis of a ditopic acceptor-type ligand
(N6–N5–C4–C3) and 41.20° (C14–N1–C11–C12), re-
spectively. Probably, this effect originates from crystal
packing.5e By contrast, the pyridine rings do not deviate
from planarity with respect to the triazole rings (Figure 2).
Both triazole rings possess an anti-conformation regard-
ing the pyridine rings caused by a repulsive interaction of
the nitrogen atoms of both heterocycles.
The heteroleptic ruthenium(II) complexes 10 to 12 were
synthesized by heating cis-Ru(dmbpy)2Cl2 and the appro-
priate ligands 3, 6 and 9 under microwave irradiation
(Scheme 4). In general, after two hours, the reactions were
completed and a ten-fold excess of solid NH4PF6 was add-
ed to the still hot solution. In most cases, precipitation oc-
curred after 15 minutes and the pure complexes were
isolated after washing with ethanol and diethyl ether in
very good yields (Table 1). The verification of the struc-
tures of 10–12 was carried out by 1H and 13C NMR spec-
troscopy as well as by HR-ESI mass spectrometry.
Figure 2 ORTEP plot of the ditopic ligand 6 (50% probability level);
hydrogen atoms are omitted for clarity
structures.6b,7 Noteworthy is the large difference of the di-
hedral angles for the two triazole rings relative to the
fluorene plane: the angles were determined to be 1.08°
C8H17
C8H17
N
N
3
N
·2PF6
N
Ru
N
N
i) EtOH, 120 °C, 2 h
MW
ii) NH4PF6
N
N
N
N
10
Ru2+
Cl
N
N
R
R
N
Cl
N
6, 9
=
N
C8H17
C8H17
N
N
N
N
N
N
N
Ru
N
N
N
N
Ru
N
N
N
N
·4PF6
N
N
11: R = H
12: R =
NO2
Scheme 4 Schematic representation of the synthesis of heteroleptic mono- and ditopic ruthenium(II) complexes
© Georg Thieme Verlag Stuttgart · New York
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B. Happ et al.
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Table 1 Isolated Yields of the Heteroleptic Mono- and Ditopic Ru-
thenium(II) Complexes
Compound
Type
Yield (%)
10
11
12
mononuclear
dinuclear
96
91
93
dinuclear
The photophysical properties of the ligands 3, 6 and 9
were investigated in solution by UV/Vis absorption and
emission spectroscopy; Figure 3 displays their absorption
and emission spectra. The nitro-functionalized ditopic li-
gand 9 revealed both the largest bathochromic shift in the
absorption spectrum and in the emission spectrum. Fur-
thermore, 9 exhibited a remarkably large Stokes shift of
5210 cm−1, which was attributed to the charge transfer na-
ture of the electronic transition. The considerable low
quantum yield of 9 (Φ ≤ 0.001) can be explained by a large
geometrical distortion during the excitation process as in-
dicated by the large Stokes shift as well as the activation
of a significant number of radiationless deactivation chan-
nels due to the electron-withdrawing nitro entities. More-
over, the ditopic ligands possessed high molar extinction
coefficients of over 90 000 M−1·cm−1. The absorption and
emission behavior of the monotopic ligand 3 and the di-
topic ligand 6 appeared to be very similar despite a small
red-shift for 6 of 11 nm at the longest-wavelength absorp-
tion and emission maximum (Table 2). This fact can be
explained by an unfavorable conjugation as well as the
electron-withdrawing nature of the ancillary trzpy moiety
of compound 6. However, 3 featured a 60% higher Stokes
shift than 6, which could be explained by the higher prob-
ability of planarization of one triazole ring and, thus, a
larger geometrical reorganization. As a consequence, the
fluorescence quantum yield of 3 (Φ = 0.07) diminished by
approximately one order of magnitude compared to 6
(Φ = 0.66).
Figure 3 UV/Vis absorption (solid) and emission (dashed) spectra of
the organic ligands
chemical density functional theory (DFT) calculations
showed that the lowest unoccupied molecular orbital (LU-
MO) corresponds to a π-antibonding orbital located on the
trzpy ligand and, thus, it is assumed that the MLCT is pre-
dominantly a dπRu(II)→π*trzpy electronic transition.4d The
bands around 320 nm and for compound 12 at 354 nm can
be allocated to IL transitions of the trzpy ligand, since the
absorption maxima of the corresponding ligands 3, 6, and
9 showed similar values in this region (Table 2). The
strong absorption of all complexes at 287 nm was as-
signed to πdmbpy→π*dmbpy transitions for the supplementa-
ry dmbpy ligand as the absorption maximum stays
constant and merely depends on the nature of the trzpy li-
gand. The ruthenium(II) complexes 10–12 revealed room
The photophysical properties of the mono- and dinuclear
ruthenium(II) complexes 10–12 were investigated in di-
chloromethane. All materials showed absorption bands in
the visible region up to 500 nm (Figure 4). The longest-
wavelength absorption maximum at around 450 nm was
assigned to spin-allowed MLCT transitions, typical for ru-
thenium(II) polypyridine complexes.1b,c Former quantum
Figure 4 UV/Vis absorption (solid) and emission (dashed) spectra of
the ruthenium(II) complexes
Table 2 Photophysical Properties of the Ligands
λabs (nm) (ε [103 M−1·cm−1])a,b
λem (nm)c
ΦPL
Stokes shift (cm−1)
a,d
Compound
3
6
9
315 (39.3), 299s (34.8), 255s (16.6)
326 (90.8), 308s (65.6), 258s (39)
350 (95), 277s (30.7)
361
0.07
3970
2510
5210
355, 372
428
0.66
≤0.001
a Measurements in 10−6 M solution (CH2Cl2).
b The letter ‘s’ denotes a shoulder in the absorption band.
c Emission measurements: excitation at longest absorption wavelength (CH2Cl2).
d Photoluminescence quantum yields determined using quinine bisulfate (ΦPL = 0.546) as standard.
Synthesis 2012, 44, 2287–2294
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Chelating Fluorene Dyes
2291
Table 3 Photophysical Properties of the Ruthenium(II) Complexes
Compound λabs (nm) (ε [103 M−1·cm−1])a,b
λem at 298 K (λem at 77 K) (nm)c τ (ns)d
Egopt (eV)e
10
11
12
448s (14), 415 (16), 320 (41), 287 (106), 260 (25), 243 (28)
448 (23), 410 (33), 370 (40), 323s (47), 287 (145), 260 (40), 244 (43) 593 (571, 615)
452 (30), 401s (46), 354 (132), 287 (167), 259 (75), 249 (78) 636 (570, 612)
587 (570, 612)
2.7
2.4
0.3
2.54
2.52
2.45
a Measurements in 10−6 M solution (CH2Cl2).
b The letter ‘s’ denotes a shoulder in the absorption band.
c Excitation occurred at longest absorption wavelength. The emission measurements were carried out in CH2Cl2 for the experiments at 298 K
and in n-butyronitrile for the experiments at 77 K.
d Phosphorescence lifetimes were measured with a streak camera in acetonitrile at 298 K.
e Estimated from the UV/Vis spectra at 10% of the maximum of the longest-wavelength absorption band on the low-energy side.8
temperature luminescence with emission bands at 587, tion process due to decomposition during the
593, and 636 nm, respectively, arising from spin-forbid- measurement.
3
den MLCT excited states. The red-shift of the emission
In summary, the synthesis of mono- and ditopic 2-(1H-
maximum of compound 12 was allocated to the electron-
1,2,3-triazol-4-yl)pyridines based on a 9,9′-dioctylfluo-
withdrawing nature of the trzpy ligand. The emission life-
rene spacer was accomplished by the copper(I)-catalyzed
times of the complexes were determined by time-correlat-
azide-alkyne cycloaddition. An electron-withdrawing 4-
ed single photon counting (see Supporting Information for
nitrophenylacetylene moiety was further introduced using
the emission decay curves). The ruthenium(II) complexes
the palladium(0)-catalyzed Sonogashira cross-coupling.
The photophysical properties of the ligands were investi-
gated in solution by UV/Vis absorption and emission
spectroscopy. The nitro-functionalized ditopic ligand 9
10 and 11 possessed relatively short luminescence life-
times in the nanosecond range (Table 3). In the case of 12,
the emission lifetime even decreased one order of magni-
tude to 300 ps, which was most likely caused by the elec-
tron-withdrawing nitro substituents of complex 12
leading to the launch of additional deactivation channels.
revealed both the largest bathochromic shift in the absorp-
tion spectrum and in the emission spectrum. Furthermore,
it exhibited a remarkably large Stokes shift of 5210 cm−1,
The ruthenium complexes were further characterized by which was most likely caused by the charge transfer na-
cyclic voltammetry using acetonitrile as solvent. The ture of the electronic transition. Moreover, the fluores-
complexes 10 and 11 showed reversible oxidation waves cence quantum yield of the monotopic ligand 3 (Φ = 0.07)
at 1.26 V and 1.27 V (vs Fc/Fc+), that could be assigned to diminished by one order of magnitude compared to its di-
a single Ru(II)/Ru(III) oxidation process for compound 10 topic analogue 6 (Φ = 0.66). The appropriate heteroleptic
and a double Ru(II)/Ru(III) oxidation process for com- ruthenium(II) complexes of all obtained chelating agents
pound 11 (Table 4). Due to the appearance of only one ox- were synthesized by using the Ru(dmbpy)2Cl2 precursor.
idation process for the dinuclear complex 11 it can be All ruthenium(II) complexes revealed room temperature
concluded that a concurrent oxidation of the Ru(II/III) oc- phosphorescence, whereas the emission maximum (636
curred and, thus, no electronic interaction between the two nm) of the acceptor-type complex showed a bathochromic
ruthenium(II) centers emerged. By going from the mono- shift of 43 nm. Furthermore, the luminescence lifetime of
nuclear complex 10 to the dinuclear complex 11 a stabili- the acceptor-type ruthenium complex was remarkably
zation of the HOMO energy level was noticed (Table 4). shortened by decreasing one order of magnitude (τ = 300
Unfortunately, no reduction process was observed for the ps) when compared to the other complexes.
complexes 10 and 11 within the solvent window of aceto-
nitrile. Complex 12 did not show an oxidation and reduc-
Unless noted otherwise, all reagents were acquired from commer-
cial sources and used without further purification. Solvents were
Table 4 Electrochemical Properties of the Ruthenium(II) Complex-
dried and distilled according to standard procedures and stored un-
es
der argon. Solvents were degassed by bubbling with argon 1 h be-
fore use, unless otherwise specified. All reactions were performed
Compound
E
1/2,ox [V]a
Eonset, ox [V]
EHOMO [eV]b
in air-dried flasks under an argon atmosphere unless stated other-
wise. Purification of reaction products was carried out by column
chromatography using 40–63 μm silica gel. Analytical TLC was
performed on silica sheets precoated with silica gel 60 F254 and vi-
sualization was accomplished with UV light (254 nm). The hetero-
leptic ruthenium(II) complexes were synthesized by microwave-
assisted reactions using a Biotage Initiator ExpEU (maximum pow-
er: 400 W, working frequency: 2450 MHz) with closed reaction vi-
als. During the experiments the temperature and the pressure
profiles were detected. 1D- (1H and 13C) and 2D- (1H-1H COSY)
NMR spectra were recorded on a Bruker AC 300 (300 MHz) spec-
trometer at 298 K. Chemical shifts are reported in parts per million
10
11
12
1.57 (1e−)
1.60 (2e−)
1.35
1.45
−5.57
−5.65
c
c
c
–
–
–
a Measurements were performed in MeCN containing 0.1 M TBAPF6.
The potentials are given versus ferrocene/ferrocenium (Fc/Fc+) cou-
ple.
b Determined by EHOMO = – [(Eonset,ox – Eonset,Fc/Fc(+)) – 4.8] eV.8
c Decomposed during measurement.
© Georg Thieme Verlag Stuttgart · New York
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2292
B. Happ et al.
PAPER
(ppm, δ scale) relative to the signal of the applied solvent. Coupling
constants are given in hertz. Standard abbreviations are used for de-
noting the signal multiplicity. ESI-Q-TOF-MS measurements were
performed with a micrOTOF (Bruker Daltonics) mass spectrometer
equipped with an automatic syringe pump, which is supplied from
KD Scientific for sample injection. The mass spectrometer operated
in the positive ion mode. The standard electrospray ion (ESI) source
was used to generate the ions. The ESI-Q-TOF-MS instrument was
calibrated in the m/z range 50–3000 using an internal calibration
standard (Tunemix solution), which was supplied from Agilent.
Data were processed via Bruker Data Analysis software version 4.0.
High-resolution mass spectrometry calculations were made by us-
ing this software. Elemental analysis was carried out on a CHN-932
Automat Leco instrument. UV/Vis absorption spectra were record-
ed on a Analytik Jena SPECORD 250 spectrometer. Emission spec-
tra were measured with a Jasco FP-6500 spectrometer.
Anal. Calcd for C31H45BO2 (460.50): C, 80.85; H, 9.85. Found: C,
80.95; H, 9.93.
One-Pot Synthesis of 2-[1-(9,9-Dioctyl-9H-fluoren-2-yl)-1H-
1,2,3-triazol-4-yl]pyridine (3)
NaN3 (169 mg, 2.61 mmol) and anhyd CuSO4 (28 mg, 0.17 mmol)
were dissolved in abs. MeOH (25 mL). Compound 1 (800 mg,
1.74 mmol) was added to the brown solution and the reaction mix-
ture was stirred for 24 h at r.t. The reaction conversion was con-
trolled by TLC on silica gel (CHCl3). The green solution was
concentrated under vacuum and subsequently dissolved in THF (20
mL). Sodium ascorbate (172 mg, 0.87 mmol, dissolved in 1 mL
H2O) and 2-ethynylpyridine (186 mg, 1.8 mmol) as well as H2O (4
mL) were added. The mixture was stirred for another 24 h. After
that, an excess of H2O was added to the mixture and the precipitate
was filtered. The filtrate was further extracted with CHCl3 (3 × 20
mL) and the organic extracts were combined with the precipitate.
The CHCl3 solution was dried (NaSO4), filtered, and subsequent
column chromatography on silica gel (CHCl3–EtOAc, 2:1) provid-
ed the pure product as a white powder (840 mg, 91%); mp 168–
170 °C.
The lifetimes of the complexes were obtained by time-correlated
single photon counting (TCSPC) after excitation with a frequency-
doubled Ti-sapphire laser (Tsunami, Newport Spectra-Physics
GmbH), λex = 430 nm. The absorbance at the excitation wavelength
in a 1 cm cuvette was below 0.1. The repetition rate of the laser was
adjusted to 0.8 MHz by a pulse selector (Model 3980, Newport
Spectra-Physics GmbH). The emission was detected using a streak-
camera in TCSPC mode.
2,2′-(9,9-Dioctylfluorene-2,7-diyl)bis(1,3,2-dioxaborolane) (4),9 4-
(6-ethynylpyridin-3-yl)-2-methylbut-3-yn-2-ol (7)4d and cis-dichlo-
ro-bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II)4d were synthe-
sized according to literature reported procedures. 2,2′-(9,9-
Dioctylfluorene-2,7-diyl)-2,7-diboronic acid was converted into the
corresponding ethylene glycol boronate by heating with ethylene
glycol at reflux in toluene.
1H NMR (CDCl3, 300 MHz): δ = 8.68 (s, 1 H, H-5′′), 8.64 (d,
3J = 4.4 Hz, 1 H, H-6′), 8.29 (d, 3J = 7.9 Hz, 1 H, H-3′), 7.86–7.73
(m, 5 H, H-4, fluorene-H), 7.37 (m, 3 H, fluorene-H), 7.29 (m, 1 H,
H-5′), 1.98 (m, 4 H), 1.27–1.02 (m, 20 H), 0.80 (t, 3J = 6.8 Hz, 6 H),
0.64 (m, 4 H).
13C NMR (CDCl3, 62.9 MHz): δ = 152.70, 151.01, 150.17, 149.52,
148.92, 141.95, 139.72, 137.0, 135.93, 127.82, 127.08, 123.04,
123.01, 120.65, 120.48, 120.10, 120.09, 119.28, 115.14, 55.64,
40.35, 31.73, 29.97, 29.20, 29.17, 23.81, 22.56, 14.01.
Anal. Calcd for C36H46N4 (534.78): C, 80.85; H, 8.67; N, 10.48.
Found: C, 80.81; H, 8.73; N, 10.25.
Crystal Structure Determination10
The intensity data for the compounds were collected on a Nonius
KappaCCD diffractometer using graphite-monochromated Mo-Kα
radiation. Data were corrected for Lorentz and polarization effects
but not for absorption effects.11 The structure was solved by direct
methods (SHELXS12) and refined by full-matrix least squares tech-
niques against Fo2 (SHELXL-9712). All hydrogen atoms were in-
cluded at calculated positions with fixed thermal parameters. All
non-hydrogen atoms were refined anisotropically.12 XP (Siemens
Analytical X-ray Instruments, Inc.) was used for structure represen-
tations.
One-Pot Synthesis of 2,2′-[1,1′-(9,9-Dioctyl-9H-fluorene-2,7-di-
yl)bis(1H-1,2,3-triazole-4,1-diyl)]dipyridine (6)
NaN3 (294 mg, 4.53 mmol) and anhyd CuSO4 (52 mg, 0.32 mmol)
were dissolved in abs. MeOH (20 mL). 2,2′-(9,9-Dioctyl-9H-fluo-
rene-2,7-diyl)bis(1,3,2-dioxaborolane) (4; 800 mg, 1.51 mmol) was
added to the brown solution and the reaction mixture was stirred for
24 h at r.t. The reaction conversion was controlled by TLC on silica
gel (CHCl3). The green solution was concentrated under vacuum
and subsequently dissolved in THF (15 mL). Sodium ascorbate
(300 mg, 1.5 mmol, dissolved in 2 mL H2O) and 2-ethynylpyridine
(330 mg, 3.2 mmol) as well as H2O (5 mL) were added and then the
mixture was stirred for another 24 h. After that, an excess of H2O
was added to the mixture and the precipitate was filtered. The fil-
trate was extracted with CHCl3 (3 × 20 mL) and the organic extract
was combined with the precipitate. The CHCl3 solution was dried
over NaSO4, filtered, and subsequent column chromatography on
silica gel (CHCl3–EtOAc, 1:3) provided the pure product as a white
powder (762 mg, 75%); mp 189–190 °C.
2-(9,9-Dioctylfluorene-2-yl)-1,3,2-dioxaborolane (1)
In a three-necked round-bottomed flask, 2-bromo-9,9-dioctyl-9H-
fluorene (7.51 g, 16 mmol) was dissolved in anhyd THF (110 mL)
under argon flow. After cooling to –78 °C, a 2.5 M n-BuLi solution
(7.1 mL, 17.6 mmol) was added slowly using a syringe so that the
temperature did not exceed –65 °C. The solution was stirred for 1 h
and then triisopropyl borate (5.5 mL, 24 mmol) was added very
quickly. After stirring for another 30 min, the solution was allowed
to warm to r.t. The colorless suspension was hydrolyzed after 3 h
with 0.5 M HCl (200 mL)/ice mixture. The product was extracted
with Et2O (3 × 50 mL) and the combined organic layers were dried
(MgSO4), filtered, and evaporated to dryness. The residue was dis-
solved in toluene (150 mL) and treated with ethylene glycol (5 mL).
The suspension was heated to reflux for 5 h on a water separator and
dried (MgSO4). Subsequent column chromatography on silica gel
(CHCl3) provided the pure product as a slightly yellowish oil (5.3 g,
72%); mp 48–50 °C.
1H NMR (CDCl3, 300 MHz): δ = 8.71 (s, 2 H, H-5′′), 8.66 (ddd,
4
5
3
3J = 4.7 Hz, J = 1.7 Hz, J = 0.9 Hz, 2 H, H-6′), 8.31 (d, J = 7.9
Hz, 2 H, H-3′), 7.92–7.83 (m, 8 H, H-4′, fluorene-H), 7.3 (ddd,
3J = 7.6 Hz, 4J = 4.9 Hz, 5J = 1.2 Hz, 2 H, H-5′), 2.1 (m, 4 H), 1.19–
1.07 (m, 20 H), 0.79 (t, 3J = 7 Hz, 6 H), 0.7 (m, 4 H).
13C NMR (CDCl3, 62.9 MHz): δ = 153.03, 150.04, 149.56, 149.07,
140.43, 137.04, 136.55, 123.14, 121.24, 120.51, 120.04, 119.57,
115.17, 56.24, 40.36, 31.70, 29.92, 29.21, 29.17, 23.91, 22.54,
13.99.
1H NMR (CDCl3, 300 MHz): δ = 7.82–7.71 (m, 4 H), 7.34 (m, 3 H),
4.43 (s, 4 H), 1.98 (m, 4 H), 1.27–1.02 (m, 20 H), 0.82 (t, 3J = 6.9
Hz, 6 H), 0.57 (m, 4 H).
13C NMR (CDCl3, 62.9 MHz): δ = 149.95, 144.39, 140.77, 133.65,
129.02, 128.21, 127.61, 126.70, 125.29, 122.91, 120.13, 119.16,
66.03, 55.03, 40.31, 31.77, 30.01, 29.20, 23.71, 22.58, 14.05.
MS (MALDI-TOF, dithranol): m/z = 679.43 [M + H]+.
Anal. Calcd for C43H50N8 (678.91): C, 76.07; H, 7.42; N, 16.50.
Found: C, 75.97; H, 7.38; N, 16.23.
Crystal Data10
C43H50N8, Mr = 678.91 g·mol–1, colorless prism, size 0.04 × 0.04 ×
0.04 mm3, orthorhombic, space group Pca21, a = 10.6712(3),
Synthesis 2012, 44, 2287–2294
© Georg Thieme Verlag Stuttgart · New York

PAPER
Chelating Fluorene Dyes
2293
b = 10.0493(3), c = 35.0278(9) Å, V = 3756.31(18) Å3, T =
–140 °C, Z = 4, ρcalcd = 1.200 g·cm–3, μ (Mo-Kα) = 0.73 cm–1,
F(000) = 1456, 22649 reflections in h(–13/13), k(–13/13), l(–42/45),
measured in the range 2.78° ≤ Θ ≤ 27.50°, completeness
Complexing the (1H-1,2,3-Triazole)pyridine Ligand to
Ru(dmbpy)2Cl2; General Procedure
cis-Dichloro-bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) (43
mg, 0.08 mmol) and the respective 1H-1,2,3-triazole ligand (0.08
mmol) were suspended in degassed EtOH (8 mL). After heating un-
der microwave irradiation at 120 °C for 2 h, the red solution was
treated with a 10-fold excess of NH4PF6 and subsequently stirred
until precipitation occurred (usually after 10 min). The colored pre-
cipitate was collected by filtration and purified by washing twice
with EtOH and Et2O providing the pure product. In the case where
the 1H NMR spectrum indicated any impurities, the compound was
further purified by recrystallization from EtOH.
Θmax = 99.5%, 8259 independent reflections, Rint = 0.0347, 7779 re-
flections with Fo > 4σ(Fo), 462 parameters, 1 restraints,
R1obs = 0.0411, wR2obs = 0.0960, R1all = 0.0453, wR2all = 0.1001,
GOOF = 1.034, Flack parameter 0.9(14), largest difference peak
and hole: 0.266/–0.178 e Å–3.
6,6′-[1,1′-(9,9-Dioctyl-9H-fluorene-2,7-diyl)bis(1H-1,2,3-tri-
azole-4,1-diyl)]bis(3-ethynylpyridine) (8)
NaN3 (200 mg, 3.06 mmol) and anhyd CuSO4 (33 mg, 0.204 mmol)
were dissolved in abs. MeOH (20 mL). Compound 4 (540 mg, 1.02
mmol) was added to the brown solution and the reaction mixture
was stirred for 24 h at r.t. The reaction progress was controlled by
TLC on silica gel (CHCl3). After consumption of the starting mate-
rial, 4-(6-ethynylpyridin-3-yl)-2-methylbut-3-yn-2-ol (7; 377 mg,
2.03 mmol) was added to the green solution as well as sodium
ascorbate (214 mg, 1.02 mmol, dissolved in 2 mL H2O). The reac-
tion turned violet after 10 min and the mixture was stirred for anoth-
er 24 h at 55 °C. After that, an excess of H2O was added to the
reaction mixture and the precipitate was filtered. The precipitate
was slurried in CHCl3 (50 mL), and the suspension was filtered and
dried (NaSO4). After concentration under vacuum, the crude prod-
uct was dissolved in anhyd toluene (20 mL) and stirred under reflux
with solid KOH (150 mg, 2.6 mmol) for 5 h. The suspension was
evaporated to dryness and partitioned between CH2Cl2 (80
mL)/H2O (20 mL) (pH 3). The organic layer was concentrated in
vacuo and subsequent column chromatography on Al2O3 (CHCl3)
provided the pure product as an off-white powder (460 mg, 62%),
mp >195 °C (dec.).
Bis(4,4′-dimethyl-2,2′-bipyridine)-{2-[1-(9,9-dioctyl-9H-fluo-
ren-2-yl)-1H-1,2,3-triazol-4-yl]pyridine}ruthenium(II)
Bis(hexafluorophosphate) (10)
According to the above described general procedure cis-dichloro-
bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) (43 mg, 0.08
mmol) and 3 (39 mg, 0.08 mmol) were reacted to yield the pure
product after washing with EtOH (2 × 30 mL) and Et2O (2 × 30
mL); yield: 91 mg (96%); orange powder; mp >235 °C (dec.).
1H NMR (CD3CN, 300 MHz): δ = 9.27 (s, 1 H), 8.40 (s, 2 H), 8.36
(s, 1 H), 8.33 (s, 1 H), 8.20 (d, 3J = 7.9 Hz, 1 H), 8.06 (dt, 3J = 7.9
Hz, 4J = 1.3 Hz, 1 H), 7.92 (d, 3J = 8.2 Hz, 1 H), 7.86–7.82 (m, 2 H),
7.74–7.64 (m, 6 H), 7.47 (m, 1 H), 7.40 (m, 2 H), 7.36 (m, 1 H), 7.30
(m, 3 H), 7.22 (m, 1 H), 2.58–2.55 (s, 12 H), 2.05 (m, 4 H), 1.18–
1.03 (m, 20 H), 0.78 (m, 6 H), 0.55 (m, 4 H).
13C NMR (CD3CN, 62.9 MHz): δ = 157.25, 156.94, 156.91, 156.61,
152.73, 151.76, 151.33, 151.21, 151.08, 151.05, 150.88, 150.35,
150.30, 149.97, 148.45, 143.05, 139.41, 138.10, 135.10, 128.32,
128.27, 128.22, 127.49, 127.37, 126.10, 124.90, 124.83, 124.64,
124.20, 123.53, 123.25, 122.56, 120.79, 120.41, 120.0, 115.57,
55.70, 39.56, 31.38, 31.37, 29.38, 28.76, 28.71, 28.69, 23.51, 22.28,
22.25, 20.30, 20.27, 13.30.
1H NMR (CDCl3, 300 MHz): δ = 8.7 (m, 4 H), 8.26 (d, 3J = 8.1 Hz,
2 H), 7.89 (m, 8 H), 3.29 (s, 2 H), 2.1 (m, 4 H), 1.07 (m, 20 H), 0.77
(m, 10 H).
13C NMR (CDCl3, 62.9 MHz): δ = 153.01, 52.55, 149.26, 148.40,
140.45, 140.08, 136.39, 121.25, 120.48, 119.65, 119.57, 118.45,
115.13, 81.12, 80.46, 56.23, 40.32, 31.67, 29.87, 29.18, 29.14,
23.86, 22.51, 13.98.
HRMS (ESI-TOF): m/z calcd for C60H70N8Ru [M – 2 PF6]2+:
502.2386; found: 502.2391.
[Ru(dmbpy)2]2{μ-2,2′-[1,1′-(9,9-dioctyl-9H-fluorene-2,7-di-
yl)bis(1H-1,2,3-triazole-4,1-diyl)](dipyridine)} (PF6)4 (11)
According to the above described general procedure cis-dichloro-
bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) (43 mg, 0.08 mmol)
and 6 (23 mg, 0.035 mmol) were suspended in degassed EtOH
(10 mL). After an irradiation time of 2 h at 120 °C in the micro-
wave, the red solution was treated with a 10-fold excess of NH4PF6
and was subsequently stirred until precipitation occurred (~2 h).
The precipitate was purified by washing twice with EtOH (2 × 30
mL) and Et2O (2 × 30 mL) providing the pure product; yield: 72 mg
(91%); orange solid; mp >220 °C (dec.).
Anal. Calcd for C47H50N8 (726.95): C, 77.65; H, 6.93; N, 15.41.
Found: C, 77.87; H, 7.22; N, 15.29.
6,6′-[1,1′-(9,9-Dioctyl-9H-fluorene-2,7-diyl)bis(1H-1,2,3-tri-
azole-4,1-diyl)]bis{3-[(4-nitrophenyl)ethynyl]pyridine} (9)
Compound 8 (200 mg, 0.275 mmol), 1-iodo-4-nitrobenzene (144
mg, 0.58 mmol), Pd(PPh3)4 (32 mg, 0.028 mmol), and CuI (8 mg,
0.028 mmol) were dissolved in a degassed Et3N–THF mixture (1:1,
15 mL) and the solution was stirred for 48 h at 55 °C. The salts
formed were filtered off, and the solution was evaporated under re-
duced pressure. The crude product was passed through a short pad
of silica gel (CHCl3–EtOAc, 1:1) and then concentrated in vacuo.
The yellow powder was placed on a glass filter and washed with
acetone (30 mL), EtOH (30 mL), and n-pentane (30 mL) yielding
the pure product as a yellow powder (192 mg, 72%); mp >205 °C
(dec.).
1H NMR (CDCl3, 300 MHz): δ = 8.81 (m, 4 H), 8.28 (m, 6 H), 7.87
(m, 12 H), 2.11 (m, 4 H), 1.08 (m, 20 H), 0.78 (m, 10 H).
13C NMR (CDCl3, 62.9 MHz): δ = 153.07, 152.21, 149.57, 148.36,
147.38, 140.51, 139.69, 136.40, 132.42, 129.38, 123.75, 121.31,
120.62, 119.86, 119.60, 118.49, 115.17, 91.19, 91.16, 56.28, 40.35,
31.70, 29.90, 29.21, 29.17, 23.90, 22.53, 14.0.
1H NMR (CD3CN, 300 MHz): δ = 9.28 (s, 2 H), 8.40 (s, 4 H), 8.36
(s, 2 H), 8.33 (s, 2 H), 8.20 (d, 3J = 7.8 Hz, 2 H), 8.06 (dt, 3J = 7.8
4
3
3
Hz, J = 1.3 Hz, 2 H), 7.98 (d, J = 8.2 Hz, 2 H), 7.95 (d, J = 5.8
Hz, 2 H), 7.76–7.64 (m, 12 H), 7.36 (m, 2 H), 7.29 (m, 6 H), 7.21
(m, 2 H), 2.58–2.55 (s, 24 H), 2.14 (m, 4 H), 1.14–1.01 (m, 20 H),
0.74 (m, 6 H), 0.55 (m, 4 H).
13C NMR (CD3CN, 62.9 MHz): δ = 158.23, 157.93, 157.88, 157.60,
154.09, 152.77, 152.30, 152.21, 152.09, 151.86, 151.80, 151.38,
151.33, 150.98, 149.54, 142.21, 139.12, 136.87, 129.27, 129.22,
128.50, 127.14, 125.91, 125.84, 125.63, 125.21, 124.57, 123.59,
122.73, 121.38, 116.69, 57.38, 40.30, 32.29, 30.24, 29.64, 29.61,
24.40, 23.25, 21.29, 14.27.
MS (ESI-TOF): m/z = 1320.39 [2 M – 3 PF6]3+, 954.27 [M – 2
PF6]2+, 587.87 [M – 3 PF6]3+, 404.67 [M – 4 PF6]4+.
MS (MALDI-TOF, dithranol): m/z = 969.43 [M + H]+.
HRMS (ESI-TOF): m/z calcd for C91H98F12N16P2Ru2 [M – 2 PF6]2+:
954.2782; found. 954.2817.
Anal. Calcd for C59H56N10O4·1.5 H2O (969.14): C, 71.14; H, 5.97;
N, 14.06. Found: C, 71.05; H, 5.62; N, 13.63.
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 2287–2294

2294
B. Happ et al.
PAPER
[Ru(dmbpy)2]2(μ-6,6′-[1,1′-(9,9-dioctyl-9H-fluorene-2,7-di-
yl)bis(1H-1,2,3-triazole-4,1-diyl]{bis[3-(4-nitrophenyl)ethy-
nyl]pyridine}) (PF6)4 (12)
According to the above mentioned general procedure cis-dichloro-
bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) (35 mg, 0.07
mmol) and 9 (29 mg, 0.03 mmol) were reacted to yield the pure
product after washing with EtOH (2 × 30 mL) and Et2O (2 × 30
mL); yield: 68 mg (93%); orange solid; mp 230–231 °C (dec.).
1H NMR (300 MHz, acetone-d6): δ = 9.89 (s, 2 H), 8.71 (s, 4 H),
8.64 (s, 4 H), 8.52 (m, 2 H), 8.36 (m, 2 H), 8.29 (m, 4 H), 8.20–8.16
(m, 6 H), 8.06 (m, 4 H), 7.98 (m, 2 H), 7.86 (m, 4 H), 7.74 (m, 4 H),
7.46 (m, 4 H), 7.39 (m, 4 H), 2.60 (m, 24 H), 2.17 (m, 4 H), 1.05 (m,
20 H), 0.73 (m, 6 H), 0.56 (m, 4 H).
(2) (a) Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem.
Int. Ed. 2001, 40, 2004. (b) Rostovtsev, V. V.; Green, L. G.;
Fokin, V. V.; Sharpless, K. B. Angew. Chem. Int. Ed. 2002,
41, 2596. (c) Tornøe, C. W.; Christensen, C.; Meldal, M.
J. Org. Chem. 2002, 67, 3057.
(3) (a) Bock, V. D.; Hiemstra, H.; van Maarseveen, J. H. Eur. J.
Org. Chem. 2006, 51. (b) Meldal, M.; Tornøe, C. W. Chem.
Rev. 2008, 108, 2952. (c) Becer, C. R.; Hoogenboom, R.;
Schubert, U. S. Angew. Chem. Int. Ed. 2009, 48, 4900.
(d) Kolb, H. C.; Sharpless, K. B. Drug Discovery Today
2003, 8, 1128. (e) Bratsos, I.; Urankar, D.; Zangrando, E.;
Genova-Kalou, P.; Kosmrlj, J.; Alessio, E.; Turel, I. Dalton
Trans. 2011, 40, 5188.
13C NMR (62.9 MHz, acetone-d6): δ = 157.42, 157.14, 157.09,
156.79, 153.79, 153.25, 151.70, 151.66, 151.38, 151.17, 150.93,
150.52, 150.46, 150.14, 148.34, 148.02, 141.31, 140.66, 136.01,
132.77, 128.61, 128.52, 128.04, 127.78, 125.13, 124.82, 124.44,
124.41, 123.86, 122.47, 121.82, 121.37, 120.31, 114.96, 92.91,
88.39, 56.55, 39.47, 31.48, 31.43, 31.37, 23.66, 22.34, 22.28, 22.23,
20.31, 20.24, 13.39, 13.34, 13.30.
(4) (a) Mourtzis, N.; Carballada, P. C.; Felici, M.; Nolte, R. J.
M.; Williams, R. M.; de Cola, L.; Feiters, M. C. Phys. Chem.
Chem. Phys. 2011, 13, 7903. (b) Stengel, I.; Mishra, A.;
Pootrakulchote, N.; Moon, S.-J.; Zakeeruddin, S. M.;
Graetzel, M.; Bauerle, P. J. Mater. Chem. 2011, 21, 3726.
(c) Struthers, H.; Mindt, T. L.; Schibli, R. Dalton Trans.
2010, 39, 675. (d) Happ, B.; Escudero, D.; Hager, M. D.;
Friebe, C.; Winter, A.; Goerls, H.; Altunaş, E.; González, L.;
Schubert, U. S. J. Org. Chem. 2010, 75, 4025. (e) Happ, B.;
Friebe, C.; Winter, A.; Hager, M. D.; Hoogenboom, R.;
Schubert, U. S. Chem.–Asian J. 2009, 4, 154. (f) Kilpin, K.
J.; Gavey, E. L.; McAdam, C. J.; Anderson, C. B.; Lind, S.
J.; Keep, C. C.; Gordon, K. C.; Crowley, J. D. Inorg. Chem.
2011, 50, 6334. (g) Schweinfurth, D.; Strobel, S.; Sarkar, B.
Inorg. Chim. Acta 2011, 374, 253.
MS (ESI-TOF): m/z = 1514.07 [2 M – 3 PF6]3+, 1099.30 [M – 2 PF6]2+,
684.55 [M – 3 PF6]3+, 477.16 [M – 4 PF6]4+.
HRMS (ESI-TOF): m/z calcd for C107H104F12N18O4P2Ru2 [M – 2 PF6]2+:
1099.2944; found: 1099.2956.
Acknowledgment
(5) (a) Li, Y.; Huffman, J. C.; Flood, A. H. Chem. Commun.
2007, 2692. (b) Schulze, B.; Escudero, D.; Friebe, C.;
Siebert, R.; Goerls, H.; Kohn, U.; Altuntas, E.; Baumgaertel,
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Gonzalez, L.; Schubert, U. S. Chem.–Eur. J. 2011, 17, 5494.
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Kohn, U.; Jahn, B. O.; Goerls, H.; Schubert, U. S. Org. Lett.
2010, 12, 2710. (d) Meudtner, R. M.; Ostermeier, M.;
Goddard, R.; Limberg, C.; Hecht, S. Chem.–Eur. J. 2007,
13, 9834. (e) Zornik, D.; Meudtner, R. M.; Malah, T. E.;
Thiele, C. M.; Hecht, S. Chem.–Eur. J. 2011, 17, 1473.
(f) Ostermeier, M.; Berlin, M.-A.; Meudtner, R. M.;
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(6) (a) Rodionov, V. O.; Fokin, V. V.; Finn, M. G. Angew.
Chem. Int. Ed. 2005, 44, 2210. (b) Happ, B.; Pavlov, G. M.;
Altuntas, E.; Friebe, C.; Hager, M. D.; Winter, A.; Goerls,
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873. (c) Donnelly, P. S.; Zanatta, S. D.; Zammit, S. C.;
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(d) Li, Y.; Flood, A. H. J. Am. Chem. Soc. 2008, 130, 12111.
(e) Hua, Y.; Flood, A. H. Chem. Soc. Rev. 2010, 39, 1262.
(7) Happ, B.; Hoogenboom, R.; Winter, A.; Hager, M. D.;
Baumann, S. O.; Kickelbick, G.; Schubert, U. S. Acta
Crystallogr., Sect. E 2009, 65, o1146.
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Klemm, E. Macromolecules 2003, 36, 5459.
(9) Liu, S.-J.; Zhao, Q.; Chen, R.-F.; Deng, Y.; Fan, Q.-L.; Li,
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J. 2006, 12, 4351.
(10) Crystallographic data (excluding structure factors) have
been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication CCDC-831782 for 6.
Copies of the data can be obtained free of charge on
application to CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK [E-mail: deposit@ccdc.cam.ac.uk].
(11) (a) COLLECT, Data Collection Software; Nonius B. V:
Delft, The Netherlands, 1998. (b) Otwinowsky, Z.; Minor,
W. Methods Enzymol. 1997, 276, 307.
Financial support of this work by the Dutch Polymer Institute (DPI,
technology area HTE), the Fonds der Chemischen Industrie, and the
Thuringian Ministry for Education, Science and Culture [grant
#B514-09049, Photonische Mizellen (PhotoMIC)] is kindly
acknowledged.
Supporting Information for this article is available online at
http://www.thieme-connect.com/ejournals/toc/synthesis. Included
are 1H NMR and 13C NMR spectra for 3, 6, 9–12, cyclic voltammo-
grams of 10 and 11, lifetime measurements and photoluminescence
spectra at 77 K for 10–12.SnuIpgfori
m
p
nirtSantIuofprmoitgriaot
n
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