π-conjugated 2,2′:6′,2″-Bis(terpyridines): Systematical tuning of the optical Properties by variation of the linkage between the terpyridines and the π-conjugated system

Article abstract of DOI:10.1002/ejoc.200901112

2,2′:6′,2″-Terpyridines bearing well-defined π-conjugated substituents at the 4′-position are known to exhibit interesting electronic and optical properties. The systematic variation of both the spacer unit and the linker in conjugated bis(terpyridines) has resulted in a library of π-conjugated systems, enabling the study of the structure-property relationships of these materials. We have proven the Huisgen 1,3-dipolar cycloaddition reaction to be a versatile tool for connecting conjugated systems, even though the conjugation is hindered by the introduced triazole moiety. All the terpyrid ine derivatives were fully characterized by ¹H and ¹³C NMR spectroscopy, UV/Vis absorption and emission measurements as well as MALDI-TOF MS. Thin films of the materials were produced by spin-coating and subsequently characterized. Because tuning of the band gap of the materials over a wide range is possible, quantum yields of up to 85% and extinction coefficients of around 100000 M^-1Cm^-1 could be observed, the compounds might be promising candidates for the design of new functional supramolecular materials.

Full text of DOI:10.1002/ejoc.200901112

FULL PAPER
DOI: 10.1002/ejoc.200901112
π-Conjugated 2,2Ј:6Ј,2ЈЈ-Bis(terpyridines): Systematical Tuning of the Optical
Properties by Variation of the Linkage between the Terpyridines and the
π-Conjugated System
Andreas Wild,[a,b] Christian Friebe,[a] Andreas Winter,[b,c] Martin D. Hager,[a,b]
Ulrich-Walter Grummt,[d] and Ulrich S. Schubert*[a,b,c]
Keywords: Conjugation / Supramolecular chemistry / UV/Vis spectroscopy / Density functional calculations
1
2,2Ј:6Ј,2ЈЈ-Terpyridines bearing well-defined π-conjugated
substituents at the 4Ј-position are known to exhibit interest-
ing electronic and optical properties. The systematic varia-
tion of both the spacer unit and the linker in conjugated bis-
(terpyridines) has resulted in a library of π-conjugated sys-
tems, enabling the study of the structure–property relation-
ships of these materials. We have proven the Huisgen 1,3-
dipolar cycloaddition reaction to be a versatile tool for con-
necting conjugated systems, even though the conjugation is
hindered by the introduced triazole moiety. All the terpyrid-
ine derivatives were fully characterized by H and 13C NMR
spectroscopy, UV/Vis absorption and emission measure-
ments as well as MALDI-TOF MS. Thin films of the materials
were produced by spin-coating and subsequently charac-
terized. Because tuning of the band gap of the materials over
a wide range is possible, quantum yields of up to 85% and
extinction coefficients of around 100000
M
–1 cm–1 could be
observed, the compounds might be promising candidates for
the design of new functional supramolecular materials.
ine systems have recently been published, but the spacer
and/or connecting units utilized were generally not varied
significantly nor in any systematic way.[6,15,17,26,27] To enable
the preparation of metallo-polymers exhibiting absorption
over a wide range of the visible spectrum, we aimed to tune
the band gap of our systems in an easy and systematic man-
ner. The exchange of a phenyl moiety of the conjugated
substituent by, for example, an anthracene or fluorene, en-
ables the variation of the absorption of the derived terpyr-
idyl system over a range of more than 100 nm. But not only
the type of spacer unit affects the photophysical properties
of these materials, but also the linker connecting the spacer
to the terpyridine units, required for later introduction into
supramolecular assemblies. This allows the synthesis of ma-
terials that show tailor-made optical properties. As a con-
tinuation of previous work in the field of π-conjugated ter-
pyridines and their applications in supramolecular chemis-
try,[27–29] in which we synthesized systems with different
geometries[30,31] and introduced the Huisgen reaction to the
field of conjugated terpyridines,[32] we have studied the ef-
fect of the systematic variation of both the spacer unit and
the linker in conjugated bis(terpyridines). This should allow
the elucidation of selected structure–property relationships
of these materials. Furthermore, the knowledge gained by
this investigation will facilitate the synthesis of materials
that show tailor-made properties for applications in organic
light-emitting diodes (OLEDs) and photovoltaic (PV) de-
vices. This can be achieved by using a defined ratio of
monomers showing complementary absorption spectra in
combination with suitable transition-metal ions.
Introduction
In recent years there has been an enormous growth of
interest in the field of supramolecular architectures con-
sisting of small molecules held together by weak, reversible,
non-covalent interactions.[1,2] Oligopyridyl ligands and their
transition-metal complexes, which have found applications
in several areas of modern research, are examples of such
systems.[3–13] 2,2Ј:6Ј,2ЈЈ-Terpyridines bearing well-defined
π-conjugated substituents at the 4Ј-position are known
to exhibit attractive electronic and optical proper-
ties.[6,8,10,14–25] When two 2,2Ј:6Ј,2ЈЈ-terpyridine units are in-
troduced at either end of a rigid conjugated spacer, the re-
sulting ditopic bis(terpyridine) ligand enables the synthesis
of metallo-supramolecular polymers by coordination with
different metal ions. Several publications dealing with the
synthesis and characterization of such conjugated terpyrid-
[a] Laboratory of Organic and Macromolecular Chemistry, Fried-
rich-Schiller-University Jena,
Humboldtstr. 10, 07743 Jena, Germany
Fax: +49-3641-9482-02
E-mail: ulrich.schubert@uni-jena.de
www.schubert-group.com
[b] Dutch Polymer Institute (DPI),
P. O. Box 902, 5600 AX Eindhoven, The Netherlands
[c] Laboratory of Macromolecular Chemistry and Nanoscience,
Eindhoven University of Technology,
P. O. Box 513, 5600 MB Eindhoven, The Netherlands
[d] Institute of Physical Chemistry, Friedrich-Schiller-University
Jena,
Lessingstr. 10, 07743 Jena, Germany
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.200901112.
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Results and Discussion
Synthesis of Bis(terpyridines)
To investigate the influence of the electron-rich aromatic
systems anthracene (9, 11 and 13) and fluorene (14–16) as
part of the π-conjugated system in bis(terpyridines) and to
determine differences with their phenyl-containing counter-
parts (8, 10 and 12), we initially synthesized the different
conjugated spacer units by the approach shown in
Scheme 1. The use of branched 2-ethylhexyl (EH) alkyl
chains lead to soluble products, despite their linear and stiff
geometry. By choosing different end-group functionalities
we were able to investigate the effect of the connecting unit
between the spacer and the terpyridine moiety. The general
reaction scheme for the synthesis of the bis(terpyridines)
T8–T16 by linking functionalized 4Ј-phenyl-2,2Ј:6Ј,2ЈЈ-ter-
pyridines 17 and 18 to the spacer units 8–16 is shown in
Figure 1.
Figure 1. Schematic representation of the conversion of the conju-
gated spacer units 8–16 to bis(terpyridines) T8–T16.
boronates 12, 13 and 16.[39] These reactions were performed
in a two-step one-pot procedure by first forming the azide
at room temperature and then performing the Huisgen reac-
tion at 100 °C using microwave heating. It was shown that
both reactions can be carried out at room temperature, but
under these conditions longer reaction times were required.
Finally, the spacer was connected to the terpyridines
through a C=C double bond by Horner–Wadsworth–Em-
mons (HWE) condensation of dialdehydes 8, 9 or 14 with a
phosphonate-functionalized terpyridine (18)[27] to yield the
systems T8, T9 and T14.
All the terpyridine derivatives shown in this contribution
were fully characterized by 1H and 13C NMR spectroscopy,
absorption and emission spectroscopy in dilute solutions
and as thin films as well as by MALDI-TOF mass spec-
Table 1. Synthesis of the bis(terpyridines) T8–T16.[a]
Scheme 1. Schematic representation of the structures and synthesis
of the spacer units 8–16.
By using halogen end-groups, the systems were coupled
to a terpyridine derivative bearing an ethynyl functionality
(17) by Sonogashira reaction to yield the conjugated bis(ter-
pyridines) T10, T11 and T15. The Huisgen 1,3-dipolar cy-
cloaddition reaction[33] under CuI catalysis, one of the so-
called “click” reactions,[34–38] was used to connect the terpy-
ridine and the spacer in the cases of compounds T12, T13
and T16. Again, 17 was used and “clicked” to the diazides
of the aromatic systems synthesized in situ from the glycol [a] Experimental details are given in the Supporting Information.
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Tuning of π-Conjugated 2,2Ј:6Ј,2ЈЈ-Bis(terpyridines)
trometry. Additionally, several spacer and ligand systems
were investigated by temperature-dependent absorption
spectroscopy. Table 1 provides an overview of the synthe-
sized systems, their spacer and linker units and the isolated
yields.
Photophysical Properties
The photophysical properties of the π-conjugated terpyr-
idines were investigated in detail by absorption and emis-
sion spectroscopy in solution (Table 2). In addition, we pre-
pared thin films of the materials by spin-coating to study
the optical properties in the solid state. Figure 2 shows the
absorption and emission spectra of the phenyl-containing
bis(terpyridines) T8, T10 and T12, connected to the spacer Figure 2. Normalized absorption and emission spectra of terpyrid-
ines T8, T10 and T12 and the spacer 10. For all measurements:
units through a double bond, triple bond and 1H-1,2,3-tri-
azole, respectively, and illustrates the effect of the conju-
CHCl3, 10–6 , 25 °C.
gated linker. As also summarized in Table 2, the longest-
wavelength absorption maximum shows a constant ba-
compared with the spacer 10 can be explained by a non-
optimal conjugation through the 1H-1,2,3-triazole moiety.
This assumption was confirmed by calculations and will be
described in the Calculations section of this contribution in
detail (see below). In the cases of T10 and T8, the intensities
of the longest wavelength bands also increase significantly
compared with the one around λabs = 320–350 nm, which
can be confirmed by the extinction coefficients (Table 2).
This trend can also be seen for the fluorene-containing
bis(terpyridine) systems T14–T16 (Figure 3, Table 2). In
these systems no torsion is possible in the spacer unit itself
and, therefore, all changes in the geometry have to occur in
the connecting unit. Compared with the fluorene spacer
unit (15), the longest-wavelength absorption maximum of
the system connected by two triazole units (T16) is shifted
by 13 nm. The introduction of a triple (T15, λabs = 369 nm,
λPL = 404 nm) or a double bond (T14, λabs = 399 nm, λPL
= 444 nm) leads to the expected redshift in the absorption
and emission.
thochromic shift of around 7 nm on going from the conju-
gated spacer unit without terpyridines (10, λabs = 377 nm)
to the triazole-connected system (T12, λabs = 384 nm), the
triple bond linked (T10, λabs = 392 nm) and the system con-
taining the double bond (T8, λabs = 399 nm). The molar
extinction coefficient increases in the same way. It has been
proven by DFT calculations and experiments that a double
bond next to a terpyridine unit leads to a higher degree of
conjugation than in the case of a triple bond.[40–42] This
general trend can be verified by the experimental values re-
ported herein. The fluorescence spectra show a strong
S10ǞS00 transition and a S10ǞS01 transition as a shoulder.
The emission maxima exhibit the same general trends as
the absorption maxima.
Table 2. Selected photophysical properties of compounds 10, 11, 15
and T8–T16 in dilute solution (10–6  in CHCl3, 25 °C).
[a]
Code
λabs [nm]
ε [–1 cm–1]
λPL [nm]
ΦPL
10
377
399
392
384
38000
100700
77400
56400
418
450
438
424
0.70
0.85
0.75
0.77
T8
T10
T12
11
477
478
503
482
44200
99700
45400
51200
500
545
553
510
0.73
0.12
0.25
0.72
T9
T11
T13
15
315
399
369
328
30800
98900
91200
89300
330
444
404
378
0.24
0.88
0.77
0.55
T14
T15
T16
[a] Absolute fluorescence quantum yield.
Within this series, the quantum yield in solution is the
highest for the double-bond-containing bis(terpyridine) T8
(ΦPL = 0.85). Because no other structural parameters have
been changed, the changes in optical properties can be un-
ambiguously explained by the different linker units. The
value of the absorption maximum is an indication of the
conjugation length of the systems studied. Therefore, the
Figure 3. Normalized absorption and emission spectra of the
spacer 15 and the bis(terpyridines) T14–T16. For all measurements:
surprisingly small bathochromic shift observed for T12 CHCl3, 10–6 , 25 °C.
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When comparing the spectra of the anthracene-contain- Figure 5 and Table 3. A comparison of the data for dilute
ing systems with each other, it is obvious that the spacer solutions and the solid state show that the absorption prop-
unit 11 (λabs = 477 nm), the triazole- (T13) (λabs = 482 nm) erties remain in principle the same: only small shifts of 220–
and double-bond- (T9) (λabs = 478 nm) -connected systems 460 cm–1 were observed (Table 3). In contrast, the solid-
exhibit absorption maxima in the same region, but for dif- state emission spectra exhibit large bathochromic shifts of
ferent reasons. The connection of a triazole to the anthra- 3725–5300 cm–1 in comparison with the solution spectra.
cene unit also leads, in addition to the electronic situation Additional shoulders are observed on the short-wavelength
previously discussed for T12 and T16, to decreased conju- side of the luminescence bands, which exhibit energy differ-
gation due to steric hindrance. We have calculated that the ences of 740–830 cm–1 compared with the solution emission
interaction between the hydrogen atoms at the 1- and 8- maxima. Moreover, the photoluminescence quantum yields
positions of the anthracene and the triazole leads to an ΦPL show a notable decrease from 0.88, 0.77 and 0.55 in
energetic minimum at a dihedral angle of around 85°.
It has already been shown in the case of PPE/PPV-type
polymers that a double bond connected to an anthracene
unit at the 9- or 10-position leads to a torsion and, thereby,
hindered conjugation in the ground state.[43] This assump-
tion was confirmed by analysing the emission spectra. Sys-
tems 11 (∆νaf = 1000 cm–1) and T13 (∆νaf = 1100 cm–1) ex-
hibit small Stokes shifts, whereas T9 (∆νaf = 2600 cm–1)
shows a clearly larger shift as well as a remarkably low
quantum yield and an unstructured emission band, which
can be explained by the planarization of the conjugated sys-
tem in the excited state and thus a large geometrical re-
arrangement. Consequently, steric effects are absent in the
excited state, but electronic effects still hinder full conjuga-
tion in the case of T13. When the spacer unit is connected
by triple bonds to the terpyridines (T11), the absorption is
shifted to λabs = 503 nm as no steric or electronic effects
hinder the conjugation in this case. As expected, the emis-
sion maximum appears in the same region as for T9 (Fig-
ure 4).
Figure 4. Normalized absorption and emission spectra of the
spacer 11 and the bis(terpyridines) T9, T11 and T13. For all
measurements: CHCl3, 10–6 , 25 °C.
The photophysical properties were also investigated in
the solid state. In particular, the fluorene-containing bis(ter-
pyridines) T14–T16 were chosen because of their good solu-
bility and film-forming properties. Thin films were prepared
by spin-coating onto glass slides from solutions of 10 mg/
mL of the respective compound in chlorobenzene. The ab-
sorption and emission data obtained are summarized in as thin films.
Figure 5. UV/Vis absorption, emission and excitation spectra of a)
T14, b) T15 and c) T16 in solution (10–6  in CHCl3, 25 °C) and
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Tuning of π-Conjugated 2,2Ј:6Ј,2ЈЈ-Bis(terpyridines)
solution to 0.14, 0.26 and 0.07 in the films, respectively.
This behaviour can be explained by the formation of exci-
mers (or larger aggregated excited species), as described in
the literature.[44] In this process an excited species forms a
dimeric system with a non-excited one. Because excimers
mostly possess cofacial sandwich-type configurations, the
planar π-conjugated systems presented in this work are pre-
eminently suited to form such species. Excimer formation
leads to the appearance of an additional emission band that
is both redshifted and unstructured (as can be observed in
Figure 5) as well as to rapidly decreased photoluminescence
quantum yields. The observed short-wavelength shoulders,
which can be attributed to monomer emission, and the fact
that excitation spectra with different emission wavelengths
remain in principle constant support our assumption of ex-
cimer formation. In addition, the formation of excimers
seems to be strongly dependent on film morphology; al-
though different thin-film samples were prepared in the
same way, they show slightly different intensity ratios be-
tween excimer and monomer emissions.
Figure 6. Representation of the LUMO (top) and HOMO (bottom)
of T13.
Table 3. Photophysical properties of compounds T14–T16 in dilute
solution (10–6  in CHCl3, 25 °C) and as thin films.
[a]
λabs [nm]
Solution Film
T14 397
T15 368
T16 327
λPL [nm]
ΦPL
In other words, the chromophores of T12 and T13 can
be identified as the spacer unit consisting of three arylenes
linked by two ethynylene moieties. The same conclusion has
to be drawn from a pairwise comparison of the absorption
and emission spectra of the bis(terpyridine) with the corre-
sponding spacer molecule (i.e., T12/8 and T13/9). With the
vinylene-linked bis(terpyridines) T8 and T9, the HOMO ex-
tends well into the phenylene ring adjacent to the terpyrid-
ine and even the π orbitals of the middle pyridine rings
are involved in the LUMO.[46] This part of the π system is
essentially flat in the case of T8. In T9, steric hindrance
Solution Film[b]
Solution Film
401
371
332
442
404
532, 457s
500, 418s
378, 360 445, 390s, 371s 0.55
0.88
0.77
0.14
0.26
0.07
[a] Absolute fluorescence quantum yield. [b] s: short-wavelength
shoulder.
Calculations
All the bis(terpyridines) described in this paper may be between the vinylene protons and two anthracene protons
regarded as more or less conjugated multichromophoric π causes a tilt of about 70° between the planes of the anthra-
systems. The π conjugation may not extend over the entire cene and the phenylene moieties, as determined by structure
molecule, but may be disturbed by torsional disorder and optimization. Nevertheless, mediated by the vinylene
also by potential sinks within the chain. Standard quantum moiety, conjugation also extends to the middle pyridine
chemical calculations were performed in order to interpret rings. The planes of the central part of the linker and the
the spectroscopic findings, to localize the essential chromo- terpyridine are essentially perpendicular to each other. As
phores and to identify rotational disorder. Density func- a result of the larger size of the LUMO, one might expect
tional theory at the B3LYP/6-31g(d) level of theory was ap- some symmetric charge transfer from the centre of the mo-
plied to all full geometry optimizations using the lecules to the periphery. With the fluorene-containing
GAUSSIAN03 program package.[45] For computational bis(terpyridines) T14 and T15, the frontier orbitals include
ease, the 2-ethylhexyloxy substituents and the octyl substit- the phenylene rings attached to the middle pyridine ring.
uents in the fluorene-containing compounds were replaced The π system is essentially flat and the triazole moieties in
by hydroxy groups and hydrogen atoms, respectively. Elec- T16 do not interrupt the conjugation (Figure 7). The mid-
tronic transitions were calculated with the help of time-de- dle pyridine rings of T14 and T15 contribute significantly
pendent density functional theory implemented in the same more to the LUMOs than to the HOMOs. Again, we can
package. From an inspection of the frontier orbitals we may conclude that some symmetric charge transfer occurs from
draw a series of qualitative conclusions, although the the centre of the molecules to the periphery upon exci-
HOMO/LUMO configuration interaction (CI) coefficients tation.
for the S1 state are only close to 0.66 throughout.
In addition, we recorded absorption spectra at low tem-
The π system of the terminal phenylterpyridine moiety is peratures. The data have been interpreted by exemplarily
only negligibly involved in the frontier orbitals of T10–T13. comparing the calculated and experimental positions of the
The triazole units of T12 and T13 do not contribute to the longest wavelength transitions of T13 and its spacer unit
frontier orbitals either (see also Figure 6).
13. When comparing the theoretical results (λmax = 551 nm;
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U. S. Schubert et al.
FULL PAPER
sional motion compare significantly better with the compu-
tational model. An example of the thermochromism is pre-
sented in Figure 8. Furthermore, it is well known that DFT
underestimates the energy difference between the S1 and S0
states for large extended π systems.[47]
Because the temperature-dependent spectra of the spacer
13 and the corresponding bis(terpyridine) T13 are nearly
the same we have to conclude that the torsional disorder is
caused by the ethynylene links. The very different internal
torsional barriers of 9-(triazol-4Ј-yl)anthracene and (tri-
azol-4Ј-yl)benzene, calculated as 54 and 17.5 kJ/mol,
respectively, apparently have only a negligible influence on
the overall spectra. The spectral behaviour, including fluo-
rescence, closely resembles the findings with arylene-ethyn-
ylene/arylene-vinylene copolymers and their low-molecular-
mass model compounds, which have recently been re-
viewed.[48]
Figure 7. Representation of the LUMO (top) and HOMO (bottom)
of T16.
Conclusions
oscillator strength of 1.362) with the experimental ones
(λmax,20 °C = 482 nm, λmax,–200 °C = 502 nm), we have to take
into consideration the fact that theory only predicts transi-
tions for the ideal structure whereas the experiment at room
temperature in solution gives an average ensemble of
strongly torsionally disordered systems. Hence, the low-
temperature spectra of samples with partially frozen tor-
In this contribution we have described the synthesis of a
series of bis(terpyridines) containing phenyl, anthracene
and fluorene systems. To be able to compare the results of
a photophysical study of these compounds in detail we var-
ied both the spacer unit as well as the connecting unit be-
tween the spacer and the terpyridine moiety in a systematic
manner. In this way we found that 1H-1,2,3-triazole is in-
valuable for the connection of conjugated systems under
mild conditions at room temperature. As a result of the
non-optimal conjugation through this connecting unit, the
resulting ligands exhibit the most hypsochromic-shifted ab-
sorption maxima. Through DFT calculations we have
proven this explanation and also shown the fluorene system
to be able to overlap with the p orbital of the tertiary nitro-
gen atom of the triazole and therefore extend the conjuga-
tion, which is also confirmed by the absorption spectra. A
comparison of the absorption spectra of the systems studied
herein with the same conjugated backbone shows the pos-
sibility of tuning the absorption maximum over a range of
about 80 nm by just varying the connecting unit. In ad-
dition, the emission colour could easily be changed, which
is an important consideration when aiming to synthesize
ligands with potential applications as emitting layers in
LED devices. The thin films of the ligands showed a very
high tendency towards excimer formation and thus broad
emission spectra and high Stokes shifts. Thus, this approach
allows the synthesis of materials with tailor-made optical
properties. Moreover, the corresponding metal complexes
may be used for the construction of OLEDs and solar cells
(for the first results of a study in this direction see, for ex-
ample, ref.[49]).
Experimental Section
Materials: All reagents were purchased from commercial sources
and were used without further purification unless specified. Sol-
vents were dried and distilled according to standard procedures.
Figure 8. Temperature-dependent absorption spectra of a) 13 and
b) T13 10–5 to 10–6  in 2-methyltetrahydrofuran.
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Tuning of π-Conjugated 2,2Ј:6Ј,2ЈЈ-Bis(terpyridines)
Unless otherwise specified, solvents or solutions were degassed by
(mc, 4 H), 7.36 (s, 2 H, Cphenyl-H), 4.18 (d, 3J = 5.6 Hz, 4 H,
OCH2), 2.03 (mc, 2 H, CH), 1.80–1.26 (m, 16 H, CH2), 1.02 (t, J
3
bubbling with argon 1 h prior to use. Compounds 2, 7, 14–18, T14
and T15 were prepared following previously published proto- = 7.6 Hz, 6 H, ethyl-CH3), 0.86 (t, 3J = 6.8 Hz, 6 H, hexyl-
cols.[17,27,43] All the terpyridine derivatives were purified by flash
column chromatography (neutral alumina, CH2Cl2/MeOH as elu-
ent) or preparative size-exclusion chromatography (BioBeads® S-
X5, toluene as eluent). The commercially available boronic acids 5
and 6 were converted into the corresponding ethylene glycol bo-
ronate by heating with ethylene glycol at reflux in toluene.
CH3) ppm. 13C NMR (100 MHz, CDCl3): δ = 192.94 (CHO),
154.29 (Cphenyl-OR), 131.92, 131.39, 128.99, 128.08, 126.58, 125.87,
125.25, 123.94, 116.26, 114.31 (Caryl), 101.61, 92.30 (CϵC), 71.97
(OCH2), 39.69 (CH), 30.45, 29.12, 23.86, 23.03 (CH2), 13.99 (ethyl-
CH3), 11.08 (hexyl-CH3) ppm. MS (MALDI-TOF, dithranol): m/z
= 791.43 [M + H]+. C56H54O4 (791.03): calcd. C 85.03, H 6.88;
found C 84.02, H 6.99.
Instrumentation: 1H and 13C NMR spectra were obtained in deuter-
ated chloroform at 25 °C using a Bruker DRX 400 or AC 250 in-
strument. UV/Vis absorption spectra were recorded in dilute
CHCl3 solutions with a Analytik Jena SPECORD 250 spectrome-
ter. Emission spectra were measured with a Jasco FP-6500 spec-
trometer. Absolute quantum yields were determined by using a
Hamamatsu C 10027 Photonic Multi-Channel Analyzer. UV/Vis
absorption spectra of spin-coated films were obtained using a Per-
kin–Elmer UV/Vis/NIR Lambda 19 spectrometer; the emission
data were recorded with a Hitachi F-4500 fluorescence spectrome-
ter. MALDI-TOF mass spectra were obtained with an Ultraflex III
TOF/TOF mass spectrometer with dithranol as matrix in reflector
mode. Elemental analyses were carried out with a CHN-932 Auto-
mat Leco instrument.
4,4Ј-{[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)}bis(1-
iodobenzene) (10): The reaction of 1,4-diiodobenzene (3; 4.95 g,
15 mmol) and 7 (1.15 g, 3 mmol) was carried out according to the
general procedure. The crude product was purified by column
chromatography (silica gel, toluene/heptane, 2:1) and recrystalli-
zation from acetone to yield 10 as a yellow substance (708 mg,
30%). 1H NMR (250 MHz, CDCl3): δ = 7.69 (d, 3J = 8.3 Hz, 4
3
3
H), 7.23 (d, J = 8.5 Hz, 4 H), 6.99 (s, 2 H), 3.90 (d, J = 5.5 Hz,
4 H, OCH2), 1.78 (mc, 2 H, CH), 1.64–1.21 (m, 16 H, CH2), 0.96
3
3
(t, J = 7.3 Hz, 6 H, ethyl-CH3), 0.88 (t, J = 7.4 Hz, 6 H, hexyl-
CH3) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 153.85 (Cphenyl
-
OR), 137.50, 132.95, 123.03, 116.47, 113.79, 94.04, 93.90, 87.47
(Caryl, CϵC), 71.98 (OCH2), 39.61 (CH), 30.66, 29.68, 29.14, 24.01,
23.05 (CH2), 14.06 (ethyl-CH3), 11.26 (hexyl-CH3) ppm. MS
(MALDI-TOF, dithranol): m/z = 786.15 [M]+. C38H44I2O2
(786.56): calcd. C 58.03, H 5.64, I 32.27; found C 59.03, H 5.98, I
31.56.
Synthesis of the π-Conjugated Spacer Units by Sonogashira Reac-
tion: The aryl halide 1, 2, 5 or 6 (6.3 mmol) was dissolved in a
mixture of THF (20 mL) and diisopropylamine (10 mL). CuI
(23 mg, 0.12 mmol) and [Pd(PPh3)4] (139 mg, 0.12 mmol) were
added and the mixture was heated to 45 °C. A degassed solution
of 7 (1.15 g, 3 mmol) in THF (10 mL) was added dropwise. The
reaction mixture was stirred at 45 °C for 2–48 h. After cooling, the
precipitate was removed by filtration. The solvent was then re-
moved and the residue was redissolved in CHCl3, washed with a
sat. NH4Cl solution and water, dried with MgSO4 and the solution
concentrated. In the case of aryl halides 4 and 5 a larger excess
(15 mmol) was used to avoid polycondensation. Owing to their in-
stability towards water, the spacer units 12 and 13 were not washed
with water.
10,10Ј-{[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)}bis-
(9-bromoanthracene) (11): The reaction of 9,10-dibromoanthracene
(4; 5.04 g, 15 mmol) and 7 (1.15 g, 3 mmol) was carried out accord-
ing to the general procedure. The crude product was purified by
column chromatography (silica gel, CH2Cl2) to yield 11 as a red
1
substance (616 mg, 23%). H NMR (400 MHz, CDCl3): δ = 8.87
(mc, 4 H), 8.62 (mc, 4 H), 7.70–7.64 (m, 8 H), 7.34 (s, 2 H), 4.17–
4.13 (m, 4 H, OCH2), 2.00 (mc, 2 H, CH), 1.78–1.28 (m, 16 H,
CH2), 1.01 (t, 3J = 7.6 Hz, 6 H, ethyl-CH3), 0.85 (t, 3J = 7.2 Hz,
6 H, hexyl-CH3) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 153.97
(Cphenyl-OR), 132.98, 130.34, 128.20, 127.62, 127.45, 126.71,
124.16, 118.66, 116.05, 114.14 (Caryl), 98.84, 91.84 (CϵC), 71.83
(OCH2), 39.67 (CH), 30.42, 29.68, 29.11, 23.82, 23.04 (CH2), 14.02
(ethyl-CH3), 11.07 (hexyl-CH3) ppm. MS (MALDI-TOF,
dithranol): m/z = 890.24 [M]+. C54H52Br2O2 (892.80): calcd. C
72.65, H 5.87, Br 17.90; found C 72.87, H 6.06, Br 17.54.
4,4Ј-{[2,5-Bis(2-Ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)}-
dibenzaldehyde (8): The reaction of 4-bromobenzaldehyde (1;
1.17 g, 6.3 mmol) and 1,4-bis(2-ethylhexyloxy)-2,5-diethynylbenz-
ene (7; 1.15 g, 3 mmol) was carried out according to the general
procedure. The crude product was purified by column chromatog-
raphy (silica gel, toluene/heptane, 5:1) and recrystallization from
1
acetone to yield 8 as a yellow substance (1.31 g, 74%). H NMR
2,2Ј-{4,4Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)-
bis(4,1-phenylene)}di-1,3,2-dioxaborolane (12): The reaction of 2-(4-
iodophenyl)-1,3,2-dioxaborolane (5; 1.73 g, 6.3 mmol) and 7
(1.15 g, 3 mmol) was carried out according to the general pro-
cedure. The crude product was purified by recrystallization from
THF to yield 12 as a yellow substance (1.62 g, 79%). 1H NMR
(250 MHz, CDCl3): δ = 10.02 (s, 2 H, CHO), 7.87 (AAЈ, 4 H), 7.66
(XXЈ, 4 H), 7.04 (s, 2 H, Cphenyl-H), 3.94 (d, 3J = 5.5 Hz, 2 H,
OCH2), 1.80 (mc, 3J = 6.1 Hz, 2 H, CH), 1.67–1.23 (m, 16 H, CH2),
0.99 (t, 3J = 7.4 Hz, 6 H, ethyl-CH3), 0.90 (t, 3J = 6.9 Hz, 6 H,
hexyl-CH3) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 191.32
(CHO), 154.06 (Cphenyl-OR), 135.41, 131.96, 129.72, 129.57,
116.52, 113.84 (Cphenyl), 94.18, 90.12 (CϵC), 71.97 (OCH2), 39.62
(CH), 30.87, 30.68, 29.14, 24.02, 23.05 (CH2), 14.05 (ethyl-CH3),
11.27 (hexyl-CH3) ppm. MS (MALDI-TOF, dithranol): m/z =
591.36 [M + H]+. C40H46O4 (590.79): calcd. C 81.32, H 7.85; found
C 81.38, H 7.80.
3
3
(250 MHz, CDCl3): δ = 7.80 (d, J = 8.0 Hz, 4 H), 7.54 (d, J =
3
7.5 Hz, 4 H), 7.02 (s, 2 H), 4.39 [s, 8 H, B(OCH2)2], 3.92 (d, J =
5.8 Hz, 4 H, OCH2), 1.80 (mc, 2 H, CH), 1.67–1.26 (m, 16 H, CH2),
0.97 (t, 3J = 7.5 Hz, 6 H, ethyl-CH3), 0.88 (t, 3J = 7.3 Hz, 6 H,
hexyl-CH3) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 153.90
(Cphenyl-OR), 134.64, 130.81, 126.48, 116.60, 113.91 (Caryl), 94.86,
87.63 (CϵC), 72.05 (OCH2), 66.12 [(OCH2)2], 39.65 (CH), 30.68,
29.17, 24.01, 23.08 (CH2), 14.09 (ethyl-CH3), 11.29 (hexyl-
CH3) ppm. C42H52B2O6 (674.48): calcd. C 74.79, H 7.77; found C
75.12, H 7.97.
10,10Ј-{[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)}-
dianthracene-9-carbaldehyde (9): The reaction of 9-bromoanthrac-
ene-10-carbaldehyde (2; 1.80 g, 6.3 mmol) and 7 (1.15 g, 3 mmol)
was carried out according to the general procedure. The crude
product was purified by column chromatography (silica gel, 2,2Ј-{10,10Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethynediyl)-
CHCl3) to yield 9 a red substance (759 mg, 32 %). 1H NMR bis(anthracene-10,9-diyl)}di-1,3,2-dioxaborolane (13): The reaction
(400 MHz, CDCl3): δ = 11.56 (s, 2 H, CHO), 8.97 (dd, 4 H), 7.73
of 2-(10-bromoanthracen-9-yl)-1,3,2-dioxaborolane (6; 2.06 g,
1865
Eur. J. Org. Chem. 2010, 1859–1868
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org

U. S. Schubert et al.
FULL PAPER
6.3 mmol) and 7 (1.15 g, 3 mmol) was carried out according to the
general procedure. The crude product was purified by recrystalli-
zation from toluene to yield 13 as a red substance (2.13 g, 81%).
H]+. C100H84N6O2 (1401.78): calcd. C 85.68, H 6.04, N 6.00; found
C 85.92, H 6.32, N 5.82.
Synthesis of Bis(terpyridines) by Sonogashira Reaction: CuI (6 mg,
0.032 mmol) and [Pd(PPh3)4] (18 mg, 0.016 mmol) were added to a
solution of the dihalide derivative 10, 11 or 15 (0.2 mmol) and 17
(133 mg, 0.4 mmol) in a mixture of THF (5 mL) and diisopropyl-
amine (2 mL) and the mixture was stirred at 45 °C for 24 h. After
cooling, the precipitate was removed by filtration. The solvent was
removed and the residue was redissolved in CHCl3, washed with a
sat. NH4Cl solution and water, dried with MgSO4 and concen-
trated. The crude product was purified as described above.
3
1H NMR (250 MHz, CDCl3): δ = 8.80 (d, J = 7.8 Hz, 4 H), 8.33
3
(d, J = 7.3 Hz, 4 H), 7.66–7.54 (m, 8 H), 7.34 (s, 2 H), 4.68 [s, 8
3
H, B(OCH2)2], 4.15 (d, J = 5.38 Hz, 4 H, OCH2), 2.02 (mc, 2 H,
CH), 1.80–1.22 (m, 16 H, CH2), 1.00 (t, 3J = 7.5 Hz, 6 H, ethyl-
CH3), 0.85 (t, 3J = 7.0 Hz, 6 H, hexyl-CH3) ppm. 13C NMR
(62.9 MHz, CDCl3): δ = 153.98 (Cphenyl-OR), 135.32, 131.87,
129.01, 127.66, 126.10, 126.03, 120.66, 116.16, 114.20 (Caryl), 98.86,
92.36 (CϵC), 71.84 (OCH2), 66.27 [(OCH2)2], 39.66 (CH), 30.42,
29.11, 23.82, 23.05 (CH2), 14.04 (ethyl-CH3), 11.08 (hexyl-
CH3) ppm. C58H60B2O6 (874.72): calcd. C 79.64, H 6.91; found C
79.92, H 7.12.
4,4Ј-(4,4Ј-{4,4Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(ethyne-
dil)bis(4,1-phenylene)}bis(ethynediyl)bis(4,1-phenylene))bis-
(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl) (T10): The reaction of 10 (157 mg,
0.2 mmol) and 4Ј-(4-ethynylphenyl)-2,2Ј:6Ј,2ЈЈ-terpyridine (17;
133 mg, 0.4 mmol) was carried out according to the general pro-
cedure for the Sonogashira reaction. After purification T10 was
obtained as an orange substance (180 mg, 77 %). 1H NMR
(400 MHz, CDCl3): δ = 8.69 (s, 4 H, tpy-H3Ј,5Ј), 8.67 (d, 3J =
Synthesis of Bis(terpyridines) by Horner–Wadsworth–Emmons
(HWE) Reaction: KOtBu (34 mg, 0.3 mmol) was added to a solu-
tion of a dialdehyde 8, 9 or 14 (0.2 mmol) and 18 (184 mg,
0.4 mmol) in toluene (20 mL). The reaction mixture was heated at
reflux for 3 h and subsequently quenched with an aq. 10% HCl
solution (10 mL). The organic phase was separated and washed
with distilled water. The organic phase was dried with MgSO4 and
then evaporated. The crude product was purified as described
above.
3
4.8 Hz, 4 H, tpy-H3,3ЈЈ), 8.60 (d, J = 8.0 Hz, 4 H, tpy-H6,6ЈЈ), 7.85
3
(AAЈ, 4 H), 7.81 (t, J = 7.6 Hz, 4 H, tpy-H4,4ЈЈ), 7.60 (XXЈ, 4 H),
3
7.46 (AAЈXXЈ, 8 H), 7.29 (t, J = 6.0 Hz, 4 H, tpy-H5,5ЈЈ) 7.00 (s,
3
2 H, Cphenyl-H), 3.87 (d, J = 5.6 Hz, 4 H, OCH2), 1.75 (mc, 2 H,
CH), 1.60–1.21 (m, 16 H, CH2), 0.92 (t, 3J = 7.6 Hz, 6 H, ethyl-
CH3), 0.84 (t, 3J = 7.2 Hz, 6 H, hexyl-CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ = 156.18, 156.11, 153.96, 149.35, 149.16,
138.40, 136.87, 132.18, 131.59, 131.48, 127.31, 123.88, 123.86,
123.58, 122.90, 121.37, 118.68, 116.62, 113.97 (Cphenyl), 94.65,
91.03, 90.67, 88.18 (CϵC), 72.12 (OCH2), 39.69 (CH), 30.72, 29.20,
24.06, 23.09 (CH2), 14.08 (ethyl-CH3), 11.30 (hexyl-CH3) ppm. MS
(MALDI-TOF, dithranol): m/z = 1198.59 [M + H]+. C84H72N6O2
(1197.51): calcd. C 84.25, H 6.06, N 7.02; found C 84.42, H 6.29,
N 6.69.
4,4Ј-(4,4Ј-(1E,1ЈE)-2,2Ј-{4,4Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenyl-
ene]bis(ethynediyl)bis(4,1-phenylene)}bis(ethene-2,1-diyl)bis(4,1-
phenylene))bis(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl) (T8): The reaction of 8
(118 mg, 0.2 mmol) and diethyl 4-(2,2Ј:6Ј,2ЈЈ-terpyridin-4Ј-yl)benz-
ylphosphonate (18; 184 mg, 0.4 mmol) was carried out according
to the general procedure for the HWE reaction. After purification
1
T8 was obtained as a yellow substance (192 mg, 79%). H NMR
(400 MHz, CDCl3): δ = 8.78 (s, 4 H, tpy-H3Ј,5Ј), 8.75 (d, 3J =
3
5.0 Hz, 4 H, tpy-H3,3ЈЈ), 8.69 (d, J = 8.0 Hz, 4 H, tpy-H6,6ЈЈ), 7.95
3
(AAЈ, 4 H), 7.90 (t, J = 7.8 Hz, 4 H, tpy-H4,4ЈЈ), 7.66 (XXЈ, 4 H),
3
7.54 (AAЈXXЈ, 4 H), 7.38 (t, J = 5.2 Hz, 4 H, tpy-H5,5ЈЈ), 7.21 (s,
3
4,4Ј-(4,4Ј-{10,10Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis(eth-
ynediyl)bis(anthracene-10,9-diyl)}bis(ethynediyl)bis(4,1-phenylene))-
bis(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl) (T11): The reaction of 11 (179 mg,
0.2 mmol) and 17 (133 mg, 0.4 mmol) was carried out according to
the general procedure for the Sonogashira reaction. After purifica-
tion T11 was obtained as a red substance (196 mg, 72%). 1H NMR
(400 MHz, CDCl3): δ = 8.90–8.69 (m, 20 H), 7.97 (AAЈXXЈ, 8 H),
4 H), 7.04 (s, 2 H, Cphenyl-H), 3.95 (d, J = 5.5 Hz, 4 H, OCH2),
1.84 (mc, 2 H, CH), 1.73–1.22 (m, 16 H, CH2), 1.01 (t, 3J = 7.3 Hz,
6 H, ethyl-CH3), 0.92 (t, 3J = 6.8 Hz, 6 H, hexyl-CH3) ppm. 13C
NMR (100 MHz, CDCl3): δ = 154.30, 156.00, 153.92, 149.63,
149.13, 137.95, 137.70, 137.07, 136.87, 131.89, 128.88, 128.84,
127.65, 127.14, 126.54, 123.82, 122.84, 121.40, 118.57, 116.63,
114.03 (Cphenyl), 95.07, 87.32 (CϵC), 72.12 (OCH2), 39.71 (CH),
30.72, 29.21, 24.07, 23.09 (CH2), 14.09 (ethyl-CH3), 11.31 (hexyl-
CH3) ppm. MS (MALDI-TOF, dithranol): m/z = 1201.62 [M +
H]+. C84H76N6O2 (1201.54): calcd. C 83.97, H 6.38, N 6.99; found
C 84.21, H 6.52, N 6.73.
3
3
7.91 (t, J = 7.5 Hz, 4 H, tpy-H4,4ЈЈ) 7.76–7.65 (m, 8 H), 7.39 (t, J
= 5.9 Hz, 4 H, tpy-H5,5ЈЈ) 7.32 (s, 2 H, Cphenyl-H), 4.16 (d, 3J =
5.3 Hz, 4 H, OCH2), 2.04 (mc, 2 H, CH), 1.84–1.22 (m, 16 H, CH2),
1.03 (t, 3J = 7.5 Hz, 6 H, ethyl-CH3), 0.87 (t, 3J = 7.0 Hz, 6 H,
hexyl-CH3) ppm. The 13C NMR spectrum could not be measured
due to the low solubility of T11. MS (MALDI-TOF, dithranol):
m/z = 1398.68 [M + H]+. C100H80N6O2 (1397.74): calcd. C 85.93,
H 5.77, N 6.01; found C 86.21, H 6.02, N 5.82.
4,4Ј-(4,4Ј-(1E,1ЈE)-2,2Ј-{10,10Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phen-
ylene]bis(ethynediyl)bis(anthracene-10,9-diyl)}bis(ethene-2,1-diyl)-
bis(4,1-phenylene))bis(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl) (T9): The reaction
of 9 (158 mg, 0.2 mmol) and 18 (184 mg, 0.4 mmol) was carried out
according to the general procedure for the HWE reaction. After
purification T9 was obtained as an orange substance (238 mg,
Synthesis of Bis(terpyridines) by “Click” Reaction: NaN3 (32 mg,
0.5 mmol) and anhydrous CuSO4 (16 mg, 0.1 mmol) were sus-
pended in MeOH (2 mL). Subsequently, the aromatic glycol bo-
ronate 12, 13 or 16 (0.2 mmol) was added. The mixture was stirred
1
87%). H NMR (300 MHz, CDCl3): δ = 8.92 (d, 3J = 8.6 Hz, 4 H,
3
Canth-H), 8.84 (s, 4 H, tpy-H3Ј,5Ј), 8.78 (d, J = 5.4 Hz, 4 H, tpy-
H3,3ЈЈ), 8.72 (d, 3J = 8.1 Hz, 4 H, H6,6ЈЈ), 8.46 (m, 4 H, Canth-H), vigorously at room temperature until full conversion of the boronic
3
8.10–8.01 (m, AAЈ, CH=CH, 6 H), 7.92 (t, J = 7.6 Hz, 4 H, tpy-
acid ester (TLC monitoring). Subsequently, H2O (0.1 mL), ethanol
(2 mL), sodium ascorbate (4 mg, 0.02 mmol), CuI (38 mg,
3
H4,4ЈЈ), 7.83 (XXЈ, 4 H), 7.70–7.52 (m, Canth-H, 8 H), 7.40 (t, J =
5.42 Hz, 4 H, tpy-H5,5ЈЈ), 7.33 (s, 2 H, Cphenyl-H), 7.07 (d, 3J = 0.2 mmol) and 18 (133 mg, 0.4 mmol) were added. The resulting
16.5 Hz, 2 H), 4.16 (d, 3J = 5.6 Hz, 4 H, OCH2), 2.05 (mc, 3J =
mixture was heated under microwave irradiation at 100 °C for 1 h.
3
6.2 Hz, 2 H, CH), 1.83–1.26 (m, 16 H, CH2), 1.03 (t, J = 7.2 Hz, After cooling, H2O (15 mL) was added and the precipitate was col-
3
6 H, ethyl-CH3), 0.87 (t, J = 6.9 Hz, 6 H, hexyl-CH3) ppm. The
13C NMR spectrum could not be measured due to the low solubil-
ity of T9. MS (MALDI-TOF, dithranol): m/z = 1402.75 [M +
lected by filtration. The precipitate was washed with N-(2-hydroxy-
ethyl)ethylenediamine-N,NЈ,NЈ-triacetic acid (HEDTA) solution
(10 mL) and water. The residue was extracted with toluene and the
1866
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 1859–1868

Tuning of π-Conjugated 2,2Ј:6Ј,2ЈЈ-Bis(terpyridines)
solution was dried with MgSO4 and then evaporated. The crude
product was purified as mentioned above.
dithranol): m/z = 1139.55 [M + H]+. C75H70N12 (1139.44): calcd.
C 79.06, H 6.19, N 14.75; found C 79.08, H 6.18, N 14.70.
Supporting Information (see also the footnote on the first page of
this article): 1H NMR and MALDI-TOF MS spectra of the bis(ter-
pyridines) T8–T16.
4,4Ј-[4,4Ј-(1,1Ј-{4,4Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis-
(ethynediyl)bis(4,1-phenylene)}bis[1H-[1,2,3]-triazole-4,1-diyl])-
bis(4,1-phenylene)]bis(2,2Ј:6Ј,2ЈЈ-terpyridine) (T12): The reaction of
12 (135 mg, 0.2 mmol) and 17 (133 mg, 0.4 mmol) was carried out
according to the general procedure for the “click” reaction. After
purification T12 was obtained as a white substance (139 mg, 54%).
Acknowledgments
1H NMR (400 MHz, CDCl3): δ = 8.76 (s, 4 H, tpy-H3Ј,5Ј), 8.70 (d, Financial support of this work by the Dutch Polymer Institute, the
3J = 5.4 Hz, 4 H, tpy-H3,3ЈЈ), 8.62 (d, J = 8.2 Hz, 4 H, tpy-H6,6ЈЈ), Nederlandse Organisatie voor Wetenschappelijk Onderzoek (VICI
3
3
8.20 (s, 2 H), 7.99 (AAЈXXЈ, 8 H), 7.82 (t, J = 7.5 Hz, 4 H, tpy-
award to U. S. S.), the Fonds der Chemischen Industrie and the
Deutsche Forschungsgemeinschaft (DFG) is kindly acknowledged.
H4,4ЈЈ), 7.77 (AAЈ, 4 H), 7.65 (XXЈ, 4 H), 7.29 (t, 3J = 4.8 Hz, 4 H,
tpy-H5,5ЈЈ), 7.01 (s, 2 H, Cphenyl-H), 3.93 (mc, 4 H, OCH2), 1.79 (mc, Furthermore, the authors want to thank Anja Baumgärtel for
2 H CH), 1.65–1.27 (m, 16 H, CH2), 0.97 (t, 3J = 7.8 Hz, 6 H,
MALDI-TOF MS measurements, Alfred Jacobi for the low-tem-
perature absorption measurements and Beate Lentvogt for the ele-
mental analyses.
3
ethyl-CH3), 0.88 (t, J = 7.2 Hz, 6 H, hexyl-CH3) ppm. 13C NMR
(100 MHz, CDCl3): δ = 156.46, 156.22, 154.24, 149.60, 149.12,
148.12, 138.75, 136.63, 136.45, 132.85, 130.90, 127.87, 126.42,
124.41, 123.63, 121.31, 120.29, 118.73, 117.46, 117.09, 114.23
(Caryl), 93.60, 88.31, (CϵC), 72.54 (OCH2), 39.89 (CH), 30.79,
29.20, 24.18, 22.97 (CH2), 13.85 (ethyl-CH3), 11.19 (hexyl-
CH3) ppm. MS (MALDI-TOF, dithranol): m/z = 1283.67 [M +
H]+. C84H74N12O2 (1283.57): calcd. C 78.60, H 5.81, N 13.09;
found C 78.84, H 6.09, N 13.01.
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4,4Ј-[4,4Ј-(1,1Ј-{10,10Ј-[2,5-Bis(2-ethylhexyloxy)-1,4-phenylene]bis-
(ethynediyl)bis(anthracene-10,9-diyl)}bis[1H-[1,2,3]triazole-4,1-diyl])-
bis(4,1-phenylene)]bis(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl) (T13): The reaction
of 13 (175 mg, 0.2 mmol) and 17 (133 mg, 0.4 mmol) was carried
out according to the general procedure for the “click” reaction.
After purification T13 was obtained as an off-white substance
(131 mg, 44%). 1H NMR (400 MHz, CDCl3): δ = 8.92 (d, 3J =
8.8 Hz, 4 H) 8.81 (s, 4 H, tpy-H3Ј,5Ј), 8.74 (d, 3J = 4.4 Hz, 4 H, tpy-
H3,3ЈЈ), 8.67 (d, 3J = 8.0 Hz, 4 H, tpy-H6,6ЈЈ), 8.30 (s, 2 H), 8.07
[5] A. A. Stefopoulos, E. K. Pefkianakis, K. Papagelis, A. K. And-
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3
3
(AAЈXXЈ, 8 H), 7.87 (t, J = 7.5 Hz, 4 H, tpy-H4,4ЈЈ), 7.68 (t, J =
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3
8.0 Hz, 4 H), 7.59 (t, J = 6.4 Hz, 4 H), 7.47–7.44 (m, 4 H), 7.34
(t, J = 6.2 Hz, 4 H, tpy-H5,5ЈЈ) 7.28 (s, 2 H, Cphenyl-H), 4.12 (d, J
3
3
= 5.8 Hz, 4 H, OCH2), 2.00 (mc, 2 H, CH), 1.81–1.22 (m, 16 H,
3
3
CH2), 1.01 (t, J = 7.8 Hz, 6 H, ethyl-CH3), 0.85 (t, J = 7.2 Hz, 6
H, hexyl-CH3) ppm. 13C NMR (100 MHz, CDCl3): δ = 156.29,
156.13, 154.15, 149.54, 149.16, 147.40, 138.44, 136.86, 132.18,
130.94, 128.67, 128.29, 128.18, 127.91, 127.51, 126.99, 126.44,
124.56, 123.85, 122.64, 121.68, 121.41, 118.67, 116.22, 114.20
(Caryl), 99.97, 91.56 (CϵC), 72.04 (OCH2), 39.78 (CH), 30.51,
29.18, 23.93, 23.09 (CH2), 14.05 (ethyl-CH3), 11.13 (hexyl-
CH3) ppm. MS (MALDI-TOF, dithranol): m/z = 1483.74 [M +
H]+. C100H82N12O2 (1483.80): calcd. C 80.95, H 5.57, N 11.33;
found C 81.18, H 5.64, N 10.89.
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4,4Ј-(4,4Ј-(1,1Ј-(9,9-Dioctyl-9H-fluorene-2,7-diyl)bis(1H-[1,2,3]-tri-
azole-4,1-diyl))bis(4,1-phenylene))bis(2,2Ј:6Ј,2ЈЈ-terpyridin-4-yl)
(T16): The reaction of 2,2Ј-(9,9-dioctyl-9H-fluorene-2,7-diyl)di-
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the “click” reaction. After purification T16 was obtained as a white
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1
substance (169 mg, 74%). H NMR (400 MHz, CDCl3): δ = 8.82
3
(s, 4 H, tpy-H3Ј,5Ј), 8.77 (d, J = 3.6 Hz, 4 H, tpy-H3,3ЈЈ), 8.70 (d,
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3J = 8.0 Hz, 4 H, tpy-H6,6ЈЈ), 8.38 (s, 2 H), 8.08 (AAЈXXЈ, 8 H),
7.92–7.80 (m, 10 H), 7.38 (t, 3J = 6.0 Hz, 4 H, tpy-H5,5ЈЈ) 2.15 (mc,
4 H, CH2), 1.20–0.99 (m, 20 H, CH2), 0.80 (t, 3J = 7.2 Hz, 6 H,
CH3), 0.77–0.69 (m, 4 H, CH2) ppm. 13C NMR (100 MHz,
CDCl3): δ = 156.22, 156.06, 153.06, 149.58, 149.18, 147.96, 140.39,
138.40, 136.94, 136.57, 130.95, 127.92, 126.38, 123.94, 121.43,
121.20, 119.57, 118.66, 118.06, 115.31 (Caryl), 56.33, 40.36, 31.77,
29.96, 29.30, 29.24, 23.94, 22.60, 14.09 ppm. MS (MALDI-TOF,
22, 1358–1363.
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Received: September 30, 2009
Published Online: February 23, 2010
1868
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 1859–1868