Arylethynyl-substituted tristriazolotriazines: Synthesis, optical properties, and thermotropic behavior

Article abstract of DOI:10.1002/ejoc.201400088

The synthesis of C₃-symmetrical tristriazolotriazines with conjugated arms and lateral alkoxy side chains was performed by a threefold condensation of cyanuric chloride with tetrazoles. Conjugated π segments include phenyl, tolane, and its phenylethynyl-elongated homologue. Disclike and a dendritic molecule have been obtained, and two compounds with a 3,4,5-tris(octyloxy) substitution form broad thermotropic mesophases. The linear optical properties, solvatochromism of the fluorescence, acidochromism, and the two-photon absorption efficiency of selected compounds are reported. Copyright

Full text of DOI:10.1002/ejoc.201400088

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FULL PAPER
DOI: 10.1002/ejoc.201400088
Arylethynyl-Substituted Tristriazolotriazines: Synthesis, Optical Properties,
and Thermotropic Behavior
Stefan Glang,[a] Thorsten Rieth,[a] Dorothee Borchmann,[a] Ilaria Fortunati,[b]
Raffaella Signorini,[b] and Heiner Detert*[a]
Dedicated to Professor Helmut Ringsdorf on the occasion of his 85th birthday
Keywords: Liquid crystals / Conjugated oligomers / Chromophores / Fluorescence / Nonlinear optics / Heterocycles
The synthesis of C3-symmetrical tristriazolotriazines with
conjugated arms and lateral alkoxy side chains was per-
formed by a threefold condensation of cyanuric chloride with
tetrazoles. Conjugated π segments include phenyl, tolane,
and its phenylethynyl-elongated homologue. Disclike and a
dendritic molecule have been obtained, and two compounds
with a 3,4,5-tris(octyloxy) substitution form broad thermo-
tropic mesophases. The linear optical properties, solvato-
chromism of the fluorescence, acidochromism, and the two-
photon absorption efficiency of selected compounds are re-
ported.
molecules that form thermotropic mesophases have a flat
structure comprising a rigid core, a ring of four to nine
aliphatic side chains, and a high symmetry. The core is often
a polycyclic hydrocarbon such as triphenylene or hexa-
benzocoronene, but three to six conjugated arms on a small
central ring are also sufficient to meet the steric require-
ments.[13] In the molecular design of new cores for discotic
molecules, nitrogen-containing heterocycles are receiving
increasing attention, for example, phthalocyanine,[14] hexa-
azatriphenylene,[15] and tricycloquinazoline[16,17] are impor-
tant central units. The incorporation of nitrogen atoms into
the π-conjugated core allows tailoring of the frontier orbital
shapes, optical and electrical properties, and intermolecular
interactions such as those between neighboring molecules
in a column.[18] Depending on the nature of the heterocycle,
it is possible to synthesize n- and p-type semiconducting
materials in which the structural features of the parent iso-
cyclic system are retained.[19]
A threefold annulation of 1,2,4-triazoles to a 1,3,5-tri-
azine can result in two C3-symmetric tristriazolotriazines
(TTT), both of which have a disc-shaped geometry (Fig-
ure 1). Whereas the molecular structures of both types have
C3h symmetry, the shape of the threefold substituted deriva-
tives is also C3h for 1 but D3h for 2. A century ago, Hof-
mann reported the first synthesis of a tristriazolotriazine.[20]
The initially proposed structure 2 (R = NH2) was proved
to be 1 (R = NH2) by Kaiser in 1953.[21] Only one further
report of a tristriazolotriazine appeared in the 20th century.
During his investigations on the ring transformations of
tetrazoles,[22] Huisgen succeeded in the formation of a tri-
phenyl-TTT with structure 1 (R = phenyl).[23] Despite their
Introduction
Star-shaped conjugated compounds are of current inter-
est as active materials for several electronic, optical, and
nonlinear optical applications. A variety of stars composed
of different core systems with high symmetry and π-conju-
gated branches have been investigated in recent times.[1] The
two-dimensional π system allows an enhanced electronic in-
teraction,[2] and these molecules are also good candidates
for mesomorphous materials. The discovery by Chandrase-
khar of liquid-crystalline mesophases formed by the self-
assembly of disclike molecules[3] opened a large and contin-
uously expanding area in organic synthesis and materials
science.[4–6] Whereas calamitic liquid crystals (LCs) are
probably the most prominent class of organic molecules for
optoelectronic devices such as liquid-crystal displays
(LCDs), technologies based on discotic LCs are only at
their beginning.[7] These molecules can combine several
advantageous properties such as self-healing of films,[8]
fluorescence, and directed charge transport.[4,9] Possible ap-
plications include xerography, field-effect transistors, photo-
voltaic devices,[10] optical compensation layers for LC dis-
plays,[11] and light-emitting diodes.[12] Commonly, discotic
[a] Institute for Organic Chemistry, Johannes Gutenberg
University,
Duesbergweg 10–14, 55099 Mainz, Germany
E-mail: detert@uni-mainz.de
http://www.blogs.uni-mainz.de/fb09ak-detert/
[b] Department of Chemical Science and INSTM PD UdR,
University of Padova,
Via Marzolo 1, 35131 Padova, Italy
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201400088.
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H. Detert et al.
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intriguing structural features, research interest in TTTs has For the synthesis of tetrazoles 26–30 with a larger conju-
only recently seen a revival. Tartakovsky reported the first gated system, the Sonogashira–Hagihara coupling of
TTTs with structure 2 (R = phenyl)[24] and Gallardo[25] and phenyl acetylenes to iodo- or bromo-substituted phenyl-
we[26] recognized that the Huisgen method offers a general tetrazoles 20 and 21 was chosen (Scheme 2). The donor-
route for the formation of disclike molecules with the ability substituted phenylacetylenes 22–24 were prepared from the
to form thermotropic mesophases. The tristriazolotriazine corresponding aldehydes[28,32–34] by ultrasound-supported
1 represents a new core for discotic liquid crystals. Herein, Corey–Fuchs reactions. For the elongation of the conju-
we describe star-shaped molecules 3–10 based on the gated system of 23 by a further phenylacetylene unit, the
tris[1,2,4]triazolo[1,3,5]triazine core 1 with three π-conju- Pd-catalyzed coupling of 23 to trimethylsilyl-protected
gated branches. The branches are phenyl, tolane, or phenyl- (TMS-protected) bromophenylacetylene 31[35] followed by
ethynyl-extended tolane with flexible alkoxy or dialk- deblocking gave 25 in 46% yield (Scheme 2). A significantly
ylamino chains on the periphery. The syntheses, optical and higher yield (65%) of 25 was obtained when the coupling
thermal properties, and two-photon absorption experiments of 23 to 31 was performed under Negishi conditions. Mod-
are reported.
erate-to-good yields were obtained in the Sonogashira cou-
pling reactions of these alkynes with iodophenyltetrazole 20
(26: 75%, 27: 62%, 28: 73%, 29: 65%), but a yield of only
32% of the branched 26 was obtained in the twofold cou-
pling with the less reactive 21 (Scheme 3). The lower yield
for 27 results from decomposition of this compound during
purification and storage.
Figure 1. Isomeric tris[1,2,4]triazolo[1,3,5]triazines with C3-sym-
metry 1 and 2.
Discussion
Synthesis
The acylation of tetrazoles with cyanuric chloride fol-
lowed by threefold thermal elimination of nitrogen and ring
closure to tristriazolotriazines[23] is the best available
method for the synthesis of TTTs 1. With minor modifica-
tions, this protocol proved to be suitable for the synthesis
of TTTs carrying donor-substituted phenyl rings.[25,26]
The synthesis of TTTs 3–10 starts with typical alkyl-
ations of hydroxy- and amino-substituted benzene deriva-
tives and their transformation to nitriles 11 and 12 or benz-
amides 13 and 14.[27–29] The required phenyltetrazoles 17–
19 can be prepared by the addition of hydrazoic acid or
azides to benzonitriles;[30] for carboxylic acids as starting
materials, their conversion to amides 15 and 16 followed by
reaction with in situ generated triazidochlorosilane
(TACS)[31] proved to be advantageous (Scheme 1). The ad-
dition of triethylammonium azide to nitriles 11 and 12 led
to the tetrazoles 17 and 18 in good yields. The TACS route
gave only a moderate yield of donor-substituted 19 but very
good yields of iodo- and bromo-substituted tetrazoles 20
and 21. The latter were used as synthons for the preparation
of phenylethynyl-elongated tetrazoles 26–30 by Pd-cata-
lyzed coupling with suitable phenylacetylenes.
Scheme 2. Synthesis of phenylacetylenes and tolanyltetrazoles R =
4-OC6H13 (26): 75%; R = 4-N(C12H25) (27): 62%; R = 3,4,5-
(OC8H17)3 (23): 92%, (25): 46% (Sonogashira), 65% (Negishi), 28:
73%, 29: 65%.
Scheme 3. Synthesis of branched di(phenylethynyl)phenyltetrazole
30.
Tetrazoles 17–19 and 26–30 were dissolved in an inert
solvent by the aid of a small excess of pyridine before cyan-
uric chloride 32 was added. Heating the mixture to reflux
initiated threefold nucleophilic substitution followed by eli-
mination of nitrogen and ring transformation (Scheme 4).
The yields of the chromatographically purified products are
good for alkoxyphenyl- and dihexylaminophenyl-TTTs 3–5
Scheme 1. Synthesis of phenyltetrazoles; R = 4-OC6H13 (17): 68%
(a), 90% (b); R = 4-N(C6H13) (18): 83% (a); R = 3,4,5-(OC8H17)3
(19): 47% (b); R = 4-I (20): 89% (b); R = 3,5-Br2 (21): 95% (b).
2
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Arylethynyl-Substituted Tristriazolotriazines
(77–92%), moderate for the linear phenylethynyl oligomers Table 2. Linear optical properties of TTTs in different solvents and
in the solid state.
(6–9), and only 37% for the branched di(phenylethynyl)-
phenyl-TTT 10 (Table 1).
Entry Solvent[a,b]
λmax /nm logε λF
/nm[c] ΔνSt /cm–1
˜
max
3
cyclohexane
toluene
dichloromethane
acetonitrile
ethanol
film
cyclohexane
toluene
dichloromethane
acetonitrile
ethanol
film
cyclohexane
toluene
dichloromethane
film
cyclohexane
toluene
dichloromethane
acetonitrile
ethanol
film
cyclohexane
toluene
dichloromethane
cyclohexane
toluene
dichloromethane
film
289
291
288
281
284
280
340
342
348
339
343
335
302
303
298
293
334
334
331
324
326
338
376
381
385
333
337
336
331
347
349
349
343
307
308
307
299
4.72
4.72
4.68
4.71
4.73
–
4.74
4.74
4.71
4.73
4.73
–
4.63
4.66
4.59
–
5.03
5.04
5.05
5.00
5.01
–
5.08
5.04
5.03
5.10
5.06
5.02
–
5.32
5.26
5.28
–
347
355
5784
6195
7474
8190
8964
–
2602
3198
4755
5802
5625
–
7667
7029
9167
–
3058
3694
6515
7500
7310
–
2786
3825
6556
5092
5977
8841
–
3693
4557
8119
–
367
365
381
368
373
384
417
422
425
412
393
385
410
395
372
381
422
428
428
454
420
446
515
401
422
478
437
398
415
487
448
421
419
491
423
4
5
6
Scheme 4. Synthesis of phenyl- and tolanyl-substituted TTTs 3–10.
7
8
Table 1. Synthesis of TTTs.
Entry R1
R2
n
Yield [%] M.p. [°C]
3
4
5
6
7
8
9
10
hexyl-O-
H
H
0
0
0
1
1
1
2
0
71
71
74
45
38
66
38
37
123
168
127
245
135
81
hexyl2N-
octyl-O-
hexyl-O-
dodecyl2N-
octyl-O-
octyl-O-
H
9
cyclohexane
toluene
dichloromethane
film
cyclohexane
toluene
dichloromethane
film
octyl-O-
H
H
octyl-O-
octyl-O-
3,4,5-tris(octyloxy)-
phenylethynyl
10
5.23
5.19
5.22
–
8820
8601
12206
–
159
90
donor-substituted end group and the acceptor TTT: the ab-
Optical Properties
sorption λmax of 9 is 349 nm, only 1020 cm–1 more on the
Owing to the large number of lipophilic side chains on red side than that of the lower homologue 8. The effect of
the periphery, all TTTs are highly soluble in nonpolar sol- the increasing conjugation length is overcompensated by a
vents. Except for 4, 7, and 10, the TTTs are colorless, and decrease in the donor–acceptor interaction.[36] As the meta
all are fluorescent in the solid state as well as in solution. linkages in 10 inhibit the donor–acceptor interaction, the
Their linear optical properties are collected in Table 2.
absorption λmax is 308 nm.
All TTTs show a strong absorption band in the UV and
The fluorescence of the TTTs in toluene is separated by
are intensively fluorescent with emission maxima ranging large Stokes shifts ΔνSt from their absorption. These shifts
˜
from the UV to the blue part of the visible spectrum. In of up to ΔνSt = 7029 cm–1 for the alkoxy-TTTs 3 and 5
˜
solutions of the TTTs in the good solvent toluene, donor decrease with extension of the π system by a phenylethynyl-
substitution and extension of the π-conjugated system cause ene unit to ΔνSt = 3694 (6) and 5977 cm–1 (8) and with a
˜
strong redshifts of the absorption and emission maxima. further phenyleneethynylene unit to ΔνSt = 4557 cm–1 (9).
˜
TTT 3 absorbs with λmax = 291 nm, an additional 3,5-dialk- The smallest Stokes shifts in this series were observed for
oxy substitution (5) slightly shifts the absorption band to the amino-substituted TTTs 4 and 7.
the red (Δν = 1361 cm–1), but the absorption of 4 with the
The UV/Vis absorption of TTTs is only weakly influ-
˜
dihexylamino donor is strongly shifted to lower energy (Δν enced by solvent polarity. A small redshift from cyclohex-
˜
= 5125 cm–1). Like an increased donor strength, an exten- ane to toluene is generally followed by a weak negative sol-
sion of the conjugated system by one phenyleneethynylene vatochromism. Contrary to the absorption, the fluorescence
unit results in significant bathochromic shifts of Δν = of all compounds is strongly positively solvatochromic.
˜
4424 (3Ǟ6), 2993 (4Ǟ7), and 3330 cm–1 (5Ǟ8). This effect Comparing solutions in cyclohexane and in dichlorometh-
decreases if a second phenyleneethynylene unit separates the ane, bathochromic shifts Δν increase with the conjugation
˜
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length (5: 1055 cm–1, 8: 4017 cm–1, 9: 4205 cm–1) as well as
with the electron-donating capability of the substituent (3:
1570 cm–1, 4: 2829 cm–1). These data indicate a strong cou-
pling of the lateral donors through the π bridge with the
central acceptor. The strong solvatochromism of the
fluorescence of these octupolar dyes can result in a localiza-
tion of the excitation on one of the dipolar donor–π-
bridge–triazole branches[37,38] as the electronic coupling be-
tween the arms is only small.
The huge Stokes shifts of Δν = 8601–12206 cm–1 dis-
˜
played by dendritic TTT 10 indicate a strong stabilization
of the excited state, probably by rotation of one of the 3,5-
bis-phenylethynylbenzene dendrons around the TTT–
phenyl bond at the sterically congested periphery of the
dendrimer.
Compared to those of the solution spectra, the absorp-
tion maxima of spin-coated films of 3–10 are shifted to
higher energies, but the emission maxima of the films are
located between the positions of the maxima recorded for
the toluene and dichloromethane solutions.
The addition of up to 0.1 m of trifluoroacetic acid (TFA)
to solutions of alkoxy-TTTs in dichloromethane does not
significantly change the electronic spectra. However, the
electronic spectra of amino-TTT 4 are sensitive towards
protonation, as illustrated in Figure 2. Small amounts of
TFA in dichloromethane (10–6 to 10–5 m) cause a hyperchro-
mism of the long-wavelength absorption band (λmax = 348
nm). With higher concentrations (10–4 to 10–3 m), the inten-
sity of this band drops to the initial value combined with a
small increase of the band at higher energy (λmax = 268 nm).
In 10–2 m TFA, this band becomes the main absorption, and
the long-wavelength band strongly decreases in intensity
and is slightly shifted to the red (λmax = 358 nm); the long-
wavelength band completely vanishes in 0.1 m TFA. Like
the absorption, the fluorescence efficiency (λFmax = 420 nm)
increases with small amounts of TFA and decreases with
more TFA. In 10–3 m TFA, the band at λF = 420 nm has
only 15% of the original efficiency, but simultaneously a
new shoulder at λF = 518 nm is visible and becomes the
main band in 10–2 m TFA. As the absorption band at λ =
350 nm vanishes in 0.1 m TFA, no emission of 4 could be
observed upon excitation with λexc = 350 nm, but irradia-
tion into the high-energy maximum (λexc = 270 nm) gives a
new emission in the UV at λFmax = 345 nm. The same emis-
sion is observed if 4 in 10–2 m TFA is excited at λexc = 270
nm. The absorption maximum of protonated 4 (λmax = 268
Figure 2. Electronic spectra of 4 in dichloromethane with increas-
ing concentrations of TFA (10–5 to 10–1 m): (a) absorption spectra,
dichloromethane, 10–1 m TFA; (b) fluorescence in dichloromethane
and 10–2 m TFA, excitation at 345 nm; (c) fluorescence in 10–3 to
10–1 m TFA, excitation at 270 nm; (d) fluorescence in 10–4 to 10–2
m
TFA, excitation at 345 nm.
strengthened donor–acceptor substitution. Similar proton-
ations of aniline-substituted “nonbasic” heterocycles have
been observed recently.[40] On the other hand, excitation
with λexc = 250 nm under the same conditions causes exclu-
sively an emission at λF
= 350 nm from a species with a
max
protonated amino group. The emission bands of the two
protonated species of 4 in 10–2 m TFA are separated by ca.
9340 cm–1, without an indication for a proton transfer in
the excited state [excited-state intramolecular proton trans-
fer (ESIPT)].
Two-Photon Absorption
The large π systems of TTTs 8 and 9 together with their
nm) corresponds to that of a tristriazolotriazine with simple solvatochromic fluorescence are good prerequisites for ef-
octyl side chains (λmax = 248 nm),[39] and the emission ficient two-photon absorption properties. The two-photon-
maximum matches that of a TTT with three m-tolyl substit- induced fluorescence measurements (TPIF) were performed
uents (λF
= 346 nm).[39]
with solutions of 8 and 9 in cyclohexane (CH) and dichloro-
max
The changes in the absorption spectra of 4 result from methane (DCM); fluorescein (in H2O, pH = 12) and rhod-
simultaneous protonation of the peripheral amino groups; amine B (in methanol) were used as reference substances
this inverts the donor effect of the amine to a weakly ac- (R). The available two-photon excitation range was 735–
cepting ammonium group. The effect of TFA on the emis- 810 nm. To determine the two-photon cross-section of the
sion is more interesting: in 10–2 m TFA, excitation at λexc
=
sample (S), it is necessary to compare its efficiency with
350 nm gives an emission at λF
= 520 nm, shifted by Δν that of a reference sample (R) by using the following rela-
˜
max
≈ 4579 cm–1 to the red. This emission can be attributed to tionship for a two-photon absorption cross-section [Equa-
a species with a protonated triazole ring and, therefore, a tion (1)]:[41]
4
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Arylethynyl-Substituted Tristriazolotriazines
three different excitation wavelengths (λTPA = 750, 760, and
780 nm) and also very similar to the one-photon emission
spectra recorded with a common spectrofluorometer.
(1)
ϽFϾ is the fluorescence signal collected by the detector, C
is the compound concentration, η is the fluorescence quan-
tum yield, and n is the refractive index of the solution. The
used ϽFϾ value is corrected for the detector response
curve, the filter transmittance, and the reabsorption of the
emission spectrum.
The one- and two-photon absorption (TPA) spectra of 9
in dichloromethane are shown in Figure 3. In the wave-
length range studied, the TPA spectra of both TTTs 8 and
9 show the same trend as the linear absorption spectra, but
the available excitation range was not wide enough to reach
maxima in the TPA spectra. This is more evident for 8 as
its linear absorption peaks deeper in the UV region.
Thermal Properties
The thermal properties of the TTTs were studied by
differential scanning calorimetry (DSC) and polarized op-
tical microscopy (POM). Disclike molecules with a bal-
anced ratio between the size of the rigid core and the flexi-
ble side chains can form thermotropic mesophases. Whereas
a single hexyloxy chain per phenyl group on a TTT (3) is
not sufficient for liquid-crystalline behavior, a threefold 3,4-
didodecyloxy substitution results in the formation of a
broad (92.2–207.6 °C) mesophase with Colh structure.[25a]
Accordingly, the TTTs with hexyl chains (4 and 6) are not
mesomorphous. However, the second DSC heating scan of
TTT 5 reveals a transition into a mesophase at 126 °C (ΔH
= 22.8 kJmol–1) and a second endothermic transition
(184 °C, ΔH = 5.6 kJmol–1) to the isotropic melt. Upon
cooling, the LC–crystalline transition was shifted to 105 °C.
Though this compound carries the same number of sp3 car-
bon atoms in the periphery as the LC with a 3,4-didode-
cyloxy substitution of Gallardo,[25a] the mesophase of 5 is
only half as broad (48 vs. 115 °C). This can be attributed
to the higher symmetry of 5 and the shorter side chains.
Polarized optical microscopy of 5 (Figure 4) showed fan-
shaped textures below the clearing point, and X-ray diffrac-
tion on oriented fibers led to the assignment of the meso-
phase as a disordered hexagonal columnar structure. The
cell parameter a was calculated to be 25.2 Å, significantly
smaller than the van der Waals diameter of the molecule in
the most extended conformation (AM1: 34 Å). This indi-
cates either interdigitation or partial folding of the chains.
The core–core mean distance was found to be d = 3.9 Å,
suitable for π stacking. In addition, the main characteristics
of the X-ray diffractogram of 5 in the mesophase (145 °C)
also appear at room temperature; this indicates that the co-
lumnar structure is retained in the crystalline phase (a =
3.5 Å, d = 27.8 Å).
Contrary to the tris(octyloxy)phenyl TTT 5, its phenyl-
eneethynylene-elongated congener 8 as well as didode-
cylamino-substituted 7 did not give any indication for
mesomorphous behavior by DSC and POM. However, 9,
the next member in this homologous series, showed two
transitions in the DSC curve (159 and 204 °C, ΔH Ͻ 1
kJmol–1) and optical birefringence under crossed polariz-
ers. X-ray scattering in the mesophase (165 °C) of an ori-
ented sample of 9 gives a strong reflection in the small-
angle region (d = 40.2 Å). Three reflections in the wide-
angle region have been found and correspond to d = 14.1,
8.5 (very weak reflection), and 4.5 Å. Like for 5, the calcu-
lated diameter of 9 (AM1: 54 Å) is significantly higher than
the spacing d = 40.2 Å obtained from X-ray scattering.
With minor variation, the last three distances (d = 15.45,
8.96, and 4.4 Å) have also been observed by powder diffrac-
tion at 20 °C. The small transition enthalpy (ΔH Յ 1 kJ/
Figure 3. One- (–) and two-photon (*) absorption spectra of TTT
9; two-photon absorption spectrum with half-wavelength scale.
The similarity of the one- and two-photon spectra con-
firms the prediction for non-centrosymmetric molecules:
the same electronic levels are allowed by one- and two-pho-
ton absorption processes.[38] The extension of the conju-
gated system of 8 with an additional phenyleneethynylene
segment (9) results in a significantly enhanced linear extinc-
tion coefficient εmax, but this is strongly superseded by the
increase of the two-photon absorption cross-sections
(within the available excitation range). The ΦF and σTPA
values of 8 and 9 are summarized in Table 3. Contrary to
the hypochromism of the linear absorption as the solvent
polarity increases, the maximum TPA values for both stars
in cyclohexane are lower than the values measured in the
dipolar solvent dichloromethane. The two-photon excited
fluorescence spectra of these compounds were identical for
Table 3. Average fluorescence quantum yields ΦF and two-photon
absorption cross-sections σTPA at λTPA = 740 nm.
Entry Solvent εmax /Lmol–1 cm–1
ΦF
σTPA /GM
8
8
9
9
CH
DCM 1.05ϫ105 Ϯ6.30ϫ103
CH
2.11ϫ105 Ϯ1.27ϫ103
DCM 1.90ϫ105 Ϯ1.14ϫ104
1.25ϫ105 Ϯ7.50ϫ103
0.5Ϯ0.02
0.77Ϯ0.04
0.50Ϯ0.09
0.59Ϯ0.09
20Ϯ2
58Ϯ6
140Ϯ27
200Ϯ33
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on the basis of DEPT, COSY 45, heteronuclear multiple quantum
coherence (HMQC), and HMBC experiments. Abbreviations used
for assignment of spectra: Ph phenyl, Tet tetrazole, TTT tristriazol-
otriazine, Tin 1,3,5-triazine, Tol 1,2,4-triazole, In ethynyl, sup. su-
perimposed signals, n.d. not detected owing to poor solubility and/
or broad signal, hyphenation of phenyl and ethynyl from the core
(In, Tet, TTT) to the rim. Melting points were determined with a
Büchi HWS SG 200 or Stuart Scientific SMP3 instrument. DSC
was performed with a Perkin–Elmer DSC 7 instrument at a heating
rate of 10 °C/min. IR spectra were recorded with a JASCO 4100
FTIR (ATR) or Perkin–Elmer Paragon 500 (KBr) spectrometer.
FD-MS was performed with a Mat 95 (Finnigan) spectrometer.
HRMS (ESI) was performed with a Q-TOF-ULTIMA 3, Lock
Spray device (Waters-Micromass) with NaI/CsI as reference. UV/
Vis spectra were recorded with Perkin–Elmer Lambda 16 spectro-
photometer. Fluorescence spectra were recorded with a Perkin–El-
mer LS 50B spectrometer. TPIF measurements were conducted
with a Ti-sapphire laser system (Coherent, mod. Mira Optima 900-
F), which delivers pulses with a duration of ca. 150 fs in the wave-
length range 735–810 nm with a 76 MHz repetition rate and ca.
10 nJ pulse energy at 800 nm. The beam is focused through a 40 cm
lens onto a 10 mm cuvette containing the sample solution. Elemen-
tal analyses were conducted with a Vario EL analyzer. Polarized
microscopy was performed with an Olympus BX51 microscope
with a ColorView Olympus camera equipped with a Linkam LTS
350 heating stage. Wide-angle X-ray scattering (WAXS) measure-
ments were performed with a Cu anode (2.2 kW), a pinhole-colli-
mator, an Osmic CMF15-sCu6 mirror, and a Bruker 1024ϫ1024
pixel detector (Highstar). Silver behenate was used as the cali-
bration standard,[42] and the date were analyzed with the Data-
squeeze software (http://www.datasqueezesoftware.com/). Starting
materials were prepared according to the literature: 4-(hexyloxy)-
benzonitrile,[27] 4-(hexyloxy)benzaldehyde,[34] 4-(hexyloxy)benz-
amide[28d] (13), 4-(dihexylamino)benzaldehyde,[43] 4-iodobenz-
amide[44] (15), 3,5-dibromobenzamide[45] (16), [4-(hexyloxy)phenyl]-
acetylene[46] (22), [4-(didodecylamino)phenyl]acetylene[47] (24),
Figure 4. Texture (crossed polarizers) after cooling from the iso-
tropic melt. Top: 5 at 180 °C, bottom: 9 at 165 °C.
mol), the observed schlieren texture, and the diffuse cyclic
X-ray reflections (see Supporting Information) indicate a
lower-order structure of the mesophase of 9.
Conclusions
The convergent synthesis of star-shaped tristriazolotriaz-
ines with three π-conjugated branches is reported. The π
segments are benzene, tolane, and di(phenylethynyl)benzene [3,4,5-tris(octyloxy)phenyl]acetylene[48] (23), 3,4,5-tris(octyloxy)-
with one to three alkoxy or alkylamino chains on the lateral
rings. Owing to the donor–acceptor character of the three
benzaldehyde,[49] and 2-(4-bromophenyl)ethynyltrimethylsilane[35]
(31).
branches, the fluorescence of these dyes is positively solva-
tochromic. Owing to their non-centrosymmetric structures, amides: To a solution of the corresponding hydroxybenzoic acid
General Procedure A for the Synthesis of Alkoxy-Substituted Benz-
ester (1 equiv.) in acetonitrile were added K2CO3 (1.1 equiv./hyd-
roxy group) and the alkyl bromide (1.1 equiv./hydroxy group), and
the solution was heated to reflux and stirred for 2 h. The solution
was filtered, the residue was washed with ethyl acetate, and the
combined organic solutions were concentrated and washed with
NaOH (1 n) and brine. The solvent was evaporated, the product
was dissolved in methanol/2-propanol, and KOH (3 equiv.) was
added. After 45–60 min at reflux, the starting material was con-
sumed and acidified with HCl (2 n). The product was extracted
with chloroform, and the solution was dried (MgSO4) and concen-
trated. The acid was dissolved in toluene, SOCl2 (3 equiv.) and N,N-
dimethylformamide (DMF; 0.5 mL) were added, and the mixture
was heated to reflux for 6 h. The solution was concentrated and
poured into aqueous ammonia (28%, –10 °C). The mixture was
stirred for 10 min, and the product was isolated by suction fil-
tration, washed with water and petroleum ether (PE), and dried in
vacuo.
the two-photon absorption spectra of 8 and 9 are similar to
their linear absorption spectra, and cross-sections of up to
200 GM were found. Tris-tris(octyloxy)phenyl-TTT 5 forms
a hexagonal columnar thermotropic LC phase between 126
and 184 °C; its phenyleneethynylene homologue is not
mesomorphous, but the next homologue 9 forms a meso-
phase of similar width but lower order.
Experimental Section
General Information: All reactions were performed under dry argon
or nitrogen unless otherwise indicated. Commercially available rea-
gents were used without further purification unless otherwise indi-
cated; solvents and gases were dried by standard procedures, yields
refer to chromatographically and spectroscopically pure com-
pounds unless otherwise stated. 1H and 13C NMR spectra were
recorded with Bruker AC 300 (300 MHz), Bruker AV 400
(400 MHz), and Bruker ARX 400 (400 MHz) spectrometers; the
solvents were CDCl3, CD3OD, C6D6, and [D6]dimethyl sulfoxide
([D6]DMSO). Chemical shifts δ are expressed in ppm, and coupling
constants are given in Hz. 1H and 13C NMR signals were assigned
General Procedure B for the Synthesis of Substituted 5-Phenyltetra-
zoles from Benzamides: NaN3 (6.6 equiv.) was suspended in anhy-
drous acetonitrile, SiCl4 (2.2 equiv.) was added, and the mixture
was stirred for 45 min. The benzamide (1 equiv.) was then added,
and the mixture was stirred for 16 h. Further NaN3 (3 equiv.) and
6
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Arylethynyl-Substituted Tristriazolotriazines
SiCl4 (1 equiv.) were added, and the stirred mixture was heated to
50 °C until the starting material had disappeared. Water was added,
and the suspension was extracted with CHCl3. The pooled organic
solutions were washed with brine and dried (MgSO4). Basic alu-
mina was added, the solvent was evaporated, and the residue was
placed at the top of a chromatography column (SiO2, toluene). The
byproducts were eluted with toluene, followed by toluene/ethyl
acetate (1:1), and after the addition of 0.5% glacial acetic acid to
the eluent, the tetrazoles were eluted.
Tol), 142.1 (C-4 Ph), 140.5 (C-3 Tol), 119.3 (C-1 Ph), 109.4 (C-2,
C-6 Ph),73.5, 69.4 (OCH2), 32.0, 30.8, 29.7, 29.6, 29.5, 26.4, 26.3,
22.8 (CH ), 14.1 (CH ) ppm. IR (ATR): ν = 2920, 2853, 1583,
˜
2
3
1486, 1466, 1430, 1385, 1339, 1283, 1228, 1112, 1007, 975, 868,
835, 718, 702, 671 cm–1. FD-MS: m/z (%) = 790.8 (23), 791.6 (10)
[M]2+, 1581.2 (97), 1582.2 (100), 1583.2 (55), [M]+. C96H159N9O9
(1583.39): calcd. C 72.82, H 10.12, N 7.96; found C 72.59, H 10.52,
N 8.00.
Tris{4-[2-(4-hexyloxyphenyl)ethynyl]phenyl}tris[1,2,4]triazolo[4,3-
a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (6): According to the general pro-
cedure E, 26 (229 mg, 0.66 mmol) and 32 (37 mg, 0.2 mmol) in xyl-
enes (25 mL) and pyridine (0.5 mL) gave 6 as colorless amorphous
solid (90 mg, 45%); m.p. 245 °C. Rf = 0.33 (toluene/ethyl acetate
20:1). 1H NMR (400 MHz, 25 °C, CDCl3): δ = 8.41 (d, 3J = 8.4 Hz,
General Procedure C for the Synthesis of Substituted Phenyltetra-
zoles from Benzonitriles: A suspension of the nitrile (1 equiv.),
NaN3 (3.5 equiv.), and triethylammonium chloride (3.5 equiv.) in
xylenes was heated to reflux. When the starting material had disap-
peared (1–5 d, TLC), petroleum ether was added, and the solid
was isolated by suction filtration, washed with petroleum ether, and
dissolved in water. Hydrochloric acid (2 n) was added to pH 3, and
the product was collected by filtration, dried, and recrystallized.
3
6 H, 2-H, 6-H Ph), 7.75 (d, J = 8.4 Hz, 6 H, 3-H, 5-H Ph), 7.12
3
3
(d, J = 8.8 Hz, 6 H, 2-H, 6-H PhЈ), 6.73 (d, J = 8.8 Hz, 6 H, 3-
3
H, 5-H PhЈ), 3.53 (t, J = 6.5 Hz, 6 H, OCH2), 1.49–1.61 (m, 6 H,
β-CH2), 1.11–1.35 (m, 18 H, CH2), 0.88 (t, J = 7.2 Hz, 9 H, CH3)
3
General Procedure D for the Sonogashira–Hagihara Coupling with
Iodo- and Bromophenyl-Substituted Tetrazoles: Under nitrogen, aryl
halide, Pd(PPh3)2Cl2, and CuI were added to the deaerated solvent
(three freeze–pump–thaw cycles) in a Schlenk flask. The solution
of the alkyne was added, and the mixture was heated to 70 (piper-
idine as solvent) or 85 °C (DMF/1 m K2CO3) until complete con-
version (TLC). The solvent was evaporated, and the residue was
dissolved in ethyl acetate. The solution was filtered through Celite,
washed twice with HCl (2 n) and brine, and dried (MgSO4). The
solution was then concentrated, and the product was purified by
flash chromatography.
ppm. 13C NMR (75 MHz, 25 °C, CDCl3): δ = 159.5 (C-4 PhЈ),
150.5 (C-5 Tol), 140.5 (C-2 Tin), 132.1, 131.4, 130.0, (C-2, C-3, C-
5, C-6 Ph, C-2, C-6 PhЈ), 127.4 (C-1 Ph), 122.7 (C-4 Ph), 114.5 (C-
3 PhЈ), 114.4 (C-1 PhЈ), 92.5 (C-2 In), 87.4 (C-1 In), 68.1 (OCH2),
31.6, 29.5, 29.1, 25.7, 22.6 (CH2), 14.1 (CH3) ppm. IR (neat, ATR):
ν = 2960, 2924, 2854, 2220, 1584, 1507, 1476, 1417, 1393, 1286,
˜
1246, 1173, 1139, 1088, 1018, 946, 834 cm–1. FD-MS: m/z (%) =
515.5 (41) [M]2+, 1029.8 (100) [M]+. C66H63N9O3 (1030.30): calcd.
C 76.94, H 6.16, N 12.24; found C 76.54, H 6.17, N 12.12.
Tris{4-[2-(4-didodecylaminophenyl)ethynyl]phenyl}tris[1,2,4]-
triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (7): According to the
general procedure E, a solution of 27 (209 mg, 0.9 mmol), 32
(20 mg, 0.11 mmol), and pyridine (0.5 mL) in xylenes (50 mL) gave
7 as a yellow solid (75 mg, 38%); m.p. 135 °C. Rf = 0.35 (toluene/
General Procedure E for the Synthesis of Tristriazolotriazines: The
tetrazole (3.3 equiv.) was suspended in xylenes or CHCl3, pyridine
(6 equiv.) was added, and the mixture was stirred for 30 min. Com-
pound 32 (1 equiv.) was added, and the stirred solution was slowly
heated to reflux and kept at this temperature for 1 h. The cooled
mixture was diluted with ethyl acetate, washed twice with HCl (2 n)
and brine, and dried (Na2SO4). The product was purified by col-
umn chromatography.
1
ethyl acetate 20:1). H NMR (400 MHz, CDCl3, 25 °C): δ = 8.17
3
3
(d, J = 8.4 Hz, 6 H, 2-H, 6-H Ph), 7.62 (d, J = 8.4 Hz, 6 H, 3-
3
3
H, 5-H Ph), 7.30 (d, J = 8.8 Hz, 6 H, 2-H, 6-H PhЈ), 6.49 (d, J
= 8.8 Hz, 6 H, 3-H, 5-H PhЈ), 3.19–3.24 (m, 12 H, NCH2), 1.52–
1.54 (m, 12 H, β-CH2), 1.24–1.29 (m, 108 H, CH2), 0.84–0.89 (m,
18 H, CH3) ppm. 13C NMR (75 MHz, CDCl3, 25 °C): δ = 150.7
(C-4 PhЈ), 148.2 (C-5 Tol), 140.5 (C-2 Tin), 133.0 (C-2, C-6 PhЈ),
131.1, 129.9 (C-2, C-3 Ph), 128.2 (C-1 Ph), 122.2 (C-4 Ph), 111.1
(C-3, C-5 PhЈ), 107.8 (C-Ј1 PhЈ), 94.1 (C-2 In), 86.8 (C-1 In), 50.9
(NCH2), 31.9, 29.7, 29.5, 29.3, 27.1, 22.7 (CH2, sup.), 14.1 (CH3)
Tris(4-hexyloxyphenyl)tris[1,2,4]triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e]-
[1,3,5]triazine (3): According to the general procedure E, 3 was ob-
tained from 17 (212 mg) in xylenes (50 mL) and pyridine (0.5 mL)
and 32 (55 mg, 0.3 mmol) as a colorless amorphous solid (155 mg,
71%); m.p. 123–124 °C (ref. 127 °C).[25a]
ppm. IR (KBr): ν = 2924, 2852, 2362, 2207, 1599, 1518, 1470, 1423,
˜
Tris(4-dihexylaminophenyl)tris[1,2,4]triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e]-
[1,3,5]triazine (4): According to the general procedure E, 4 was ob-
tained from 18 (271 mg) as an amorphous solid (155 mg, 58%);
m.p. 156 °C (DSC).[26c] Rf = 0.25 (toluene/ethyl acetate 10:1). 1H
1403, 1369, 1320, 1302, 1195, 1137, 1013, 949, 838, 814, 728 cm–1.
FD-MS: m/z (%) = 893.4 (77) [M]2+, 1785.9 (100) [M]+. HRMS
(ESI): calcd. for C120H175N12 [M + H]+ 1784.4062; found
1784.4075.
3
NMR (400 MHz, 25 °C, CDCl3): δ = 8.08 (d, J = 8.9 Hz, 6 H, 2-
3
3
H, 6-H Ph), 6.74 (d, J = 8.9 Hz, 6 H, 3-H, 5-H Ph), 3.34 (t, J =
8.5 Hz, 12 H, NCH2), 1.60 (m, 12 H, β-CH2), 1.29 (m, 36 H, CH2),
0.92 (t, 3J = 7.0 Hz, 18 H, CH3) ppm. 13C NMR (75 MHz, CDCl3,
25 °C): δ = 151.5, 150.3, 140.3, 131.5, 110.6, 109.3, 51.1 (NCH2),
31.6, 27.1, 26.7, 22.7 (CH2), 14.0 (CH3) ppm. FD-MS: m/z (%) =
498.8 (5) [M]2+, 979.5 (100) [M]+.
Tris{4-[2-[3,4,5-tris(octyloxy)phenyl]ethynyl]phenyl}tris[1,2,4]-
triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (8): According to the
general procedure E, a solution of 28 (631 mg, 1 mmol), 32 (55 mg,
0.3 mmol), and pyridine (0.5 mL) in xylenes (35 mL) gave 8 as a
colorless solid (371 mg, 66%); m.p. 81 °C. Rf = 0.36 (toluene/ethyl
1
3
acetate 16:1). H NMR (400 MHz, 25 °C, C6D6): δ = 8.63 (d, J =
Tris[3,4,5-tris(octyloxy)phenyl]tris[1,2,4]triazolo[4,3-a:4Ј,3Ј-
c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (5): According to the general procedure E,
5 was obtained from 19 (212 mg) as a colorless solid in 74% yield
(140 mg); m.p. 127 °C (DSC). 1H NMR (400 MHz, C6D6): δ = 8.15
8.4 Hz, 6 H, 2-H, 6-H Ph), 7.89 (d, 3J = 8.4 Hz, 6 H, 3-H, 5-H
3
Ph), 6.92 (s, 6 H, 2-H, 6-H PhЈ), 4.07 (t, J = 6.5 Hz, 6 H, OCH2),
3.67 (t, 3J = 6.4 Hz, 12 H, OCH2), 1.77–1.83 (m, 6 H, β-CH2),
1.52–1.64 (m, 18 H, β-CH2), 1.27–1.32 (m, 84 H, CH2), 0.91–0.95
(m, 27 H, CH3) ppm. 13C NMR (75 MHz, C6D6, 25 °C): δ = 153.0
3
(s, 6 H, 2-H, 6 Ph), 4.33 (br t, J = 6.4 Hz, 6 H, OCH2), 4.18 (br
3
t, J = 6.4 Hz, 12 H, OCH2), 1.91–2.01 (m, 6 H, CH2), 1.73–1.85 (C-3, C-5 PhЈ), 150.5 (C-5 Tol), 140.7 (C-2 Tin), 139.1 (C-4 PhЈ),
(m, 12 H, CH2), 1.57–1.68 (m, 6 H, CH2), 1.43–1.52 (m, 12 H,
CH2), 1.17–1.42 (m, 72 H, CH2), 0.83–0.98 (m, 27 H, CH3) ppm.
131.5 (C-3, C-5 Ph), 130.1 (C-2, C-6 Ph), 127.1, 123.2 (C-1, C-4
Ph), 117.2 (C-1 PhЈ), 110.1 (C-2, C-6 PhЈ), 92.8, 87.5 (C-1, C-2 In),
13C NMR (75 MHz, C6D6): δ = 153.6 (C-3, C-5 Ph), 150.7 (C-5 73.6, 69.1 (OCH2), 32.0, 31.9, 30.3, 29.6, 29.4, 26.1, 22.7 (CH2,
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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7

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H. Detert et al.
FULL PAPER
sup.), 14.1 (CH , sup.) ppm. IR (neat): ν = 2926, 2855, 2208, 1590,
CDCl3): δ = 7.95 (d, 3J = 8.3 Hz, 2 H, 2-H, 6-H), 7.14 (d, 3J =
˜
3
1499, 1469, 1421, 1354, 1256, 1232, 1115, 1014, 837, 728, 563 cm–1. 8.3 Hz, 2 H, 3-H, 5-H), 4.05 (t, 3J = 6.2 Hz, 2 H, OCH2), 1.76–
FD-MS: m/z (%) = 942.0 (11) [M]2 +, 1885.7 (100) [M]+. 1.67 (m. 2 H, CH2), 1.44–1.30 (m, 6 H, CH2),0.88 (t, J = 6.6 Hz,
C120H171N9O9 (1883.76): calcd. C 76.51, H 9.15, N 6.69; found C
76.46, H 9.14, N 6.73.
3
3 H, CH3) ppm. 13C NMR (75 MHz, 25 °C, CDCl3): δ = 160.0 (C-
1, Tet), 154.7 (C-4 Ph), 127.9 (C-2, C-6 Ph), 116.4 (C-1 Ph), 114.6
(C-3, C-5 Ph), 67.1 (OCH2), 30.4, 27.9, 24.6, 21.5 (CH2), 13.5
Tris[4-(2-{4-[2-[3,4,5-tris(octyloxy)phenyl]ethynyl]phenyl}ethynyl)-
phenyl]tris[1,2,4]triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (9):
According to the general procedure E, a solution of 29 (117mg,
0.16 mmol), 32 (9 mg, 0.05 mmol), and pyridine (0.5 mL) in xylenes
(25 mL) gave 9 as a colorless wax (41 mg, 38%); m.p. 159 °C. Rf =
0.29, (toluene/ethyl acetate 50:1). 1H NMR (400 MHz, C6D6,
(CH ) ppm. IR (ATR): ν = 3077, 2924, 2853, 1611, 1582, 1499,
˜
3
1256, 840 cm–1. FD-MS: m/z (%) = 246.2 (100) [M]+, 493.6 (5) [M2
+ H]+. HRMS (ESI): calcd. for C13H18ON4Na [M + Na]+ 2691378;
found 2691383.
5-(4-Dihexylaminophenyl)-2H-tetrazole (18): According to the gene-
1
3
ral procedure C, nitrile 12 gave 18 in 74% yield; m.p. 73–75 °C. H
25 °C): δ = 8.29 (d, 6 H, 2-H, 6-H Ph), 7.69 (d, J = 8.3 Hz, 6 H,
3
NMR (300 MHz, CDCl3): δ = 8.03 (d, J = 8.5 Hz, 2 H, 2-H, 6-
3-H, 5-H Ph), 7.50 (s, 12 H, 2-H, 3-H, 5-H, 6-H PhЈ), 6.61 (s, 6 H,
2-H, 6-H PhЈЈ), 3.85 (br t, 18 H, OCH2), 1.64–1.70 (m, 18 H, β-
CH2), 1.29–1.41 (m, 90 H, CH2), 0.87–0.90 (m, 27 H, CH3) ppm.
13C NMR (100 MHz, CDCl3, 25 °C): δ = 152.7 (C-3, C-5 PhЈЈ),
150.1 (C-5 Tol), 140.7 (C2 Tin), 138.4 (C-4 PhЈЈ), 131.5, 131.6,
131.7 (C-2 Ph, C-3 PhЈ, C-4 PhЈ), 130.3 (C-3 Ph), 126.4 (C-4 Ph),
123.8 (C 2 Ph), 122.4, 123.5 (C-1 PhЈ, C-4 PhЈ), 117.5 (C-1 PhЈЈ),
109.6 (C-2, C-6 PhЈЈ), 91.9 (C-2 InЈ), 91.7 (C-1 InЈ), 90.6, 88.0 (C-
1, C-2 In), 68.9, 73.6 (OCH2), 32.0, 31.9, 30.2, 29.5, 29.3, 29.1,
3
H), 6.63 (d, J = 8.5 Hz, 2 H, 3-H, 5-H), 3.26 (t, 4 H, NCH2), 1.58
(m, 4 H, β-CH2), 1.29 (m, 12 H, CH2), 0.92 (t, 6 H, CH3) ppm.
13C NMR (100 MHz, CDCl3, 25 °C): δ = 156.0 (C-5 tet), 150.4 (C-
4 Ph), 129.1 (CH), 111.5 (CH), 108.6 (C-1 Ph), 51.0 (NCH2), 31.7,
27.1, 26.8, 22.7 (CH2), 14.0 (CH3) ppm. FD-MS: m/z (%) = 329.4
(100) [M]+, 659.8 (24) [M2 + H]+.
5-[3,4,5-Tris(octyloxy]phenyl-2H-tetrazole (19): According to the
general procedure B, a suspension of 3,4,5-tris(octyloxy)benz-
amide[28] (14) (2.53 g, 5 mmol), NaN3 (2.05 g, 31.5 mmol), and
SiCl4 (1.20 mL, 10.5 mmol) was heated to afford 19 (1.24 g, 47%)
as colorless solid; m.p. 94 °C. 1H NMR (400 MHz, 25 °C, CDCl3):
26.0, 22.7 (CH , sup.), 14.1 (CH , sup.) ppm. IR (Nujol): ν = 2207,
˜
2
3
1591, 1509, 1257, 1234, 1115, 1016, 973, 837, 722 cm–1. FD-MS:
m/z (%) = 728.5 (13) [M]3+, 1093.1 (100) [M]2+, 2187.6 (23) [M+].
C144H183N9O9 (2184.12): calcd. C 79.19, H 8.45, N 5.77; found C
78.98, H 8.28, N 5.96.
3
δ = 7.82 (s, 2 H, 2-H, 6-H Ph), 4.22 (t, J = 6.4 Hz, 2 H, OCH2),
3
3.92 (t, J = 6.3 Hz, 4 H, OCH2), 1.89 (m, 2 H, β-CH2), 1.68 (m,
4 H, β-CH2), 1.59 (m, 2 H, CH2), 1.20–1.41 (m, 34 H, CH2), 0.86–
0.94 (m, 9 H, CH3) ppm. 13C NMR (75 MHz, 25 °C, CDCl3): δ =
157.8 (C-5, Tet), 154.1 (C-3, C-5 Ph), 140.6 (C-4 Ph), 120.9 (C-1
Ph), 105.9 (C-2, C-6 Ph), 69.4, 73.5 (OCH2), 31.9, 29.7, 29.5, 26.3,
Tris{3,5-bis[2-[3,4,5-tris(octyloxy)phenyl]ethynyl]phenyl}tris[1,2,4]-
triazolo[4,3-a:4Ј,3Ј-c:4ЈЈ,3ЈЈ-e][1,3,5]triazine (10): According to the
general procedure E, a solution of 30 (167mg, 0.15 mmol), 32
(8 mg, 0.043 mmol), and pyridine (0.5 mL) in xylenes (35 mL) gave
10 as a slightly brown solid (55 mg, 37%); m.p. 88–91 °C. Rf = 0.39
26.2, 22.8 (CH , sup.), 14.1 (CH , sup.) ppm. IR (ATR): ν = 2952,
˜
2
3
1
2919, 2850, 1584, 1502, 1464, 1443, 1382, 1307, 1247, 1115, 1081,
1051, 991, 948, 871, 844, 824 cm–1. FD-MS: m/z (%) = 502.1 (4)
[M – N2]+, 530.1 (100) [M]+, 1062.3 (7) [M2]+. HRMS (ESI): calcd.
For C31H54O3N4Na [M + Na]+ 553.4094; found 553.4111.
(toluene/ethyl acetate 40:1). H NMR (400 MHz, C6D6, 25 °C): δ
= 8.98 (s, 6 H, 2-H, 6-H Ph), 8.25 (3 H, C-4 Ph), 6.94 (s, 12 H, 2-
3
H, 6-H PhЈ), 4.11 (t, J = 6.4 Hz, 12 H, OCH2), 3.67–3.70 (m, 24
H, OCH2), 1.86–1.88 (m, 12 H, β-CH2), 1.28–1.66 (m, 204 H,
CH2), 0.90–0.94 (m, 54 H, CH3) ppm. 13C NMR (75 MHz, C6D6,
25 °C): δ = 153.4 (C-3, C-5 PhЈЈ), 148.9 (C-5 Tol), 140.8 (C-2 Tin),
139.8 (C-4 PhЈЈ), 137.4 (C-1 Ph), 132.6 (C-3, C-5 Ph), 125.0, 126.4
(C-2, C-6 Ph), 117.4 (C-1 PhЈ), 110.5 (C-2, C-6 PhЈ), 92.3 (C-2 In),
87.1 (C-1 In), 73.4, 68.8 (OCH2), 32.1, 32.0, 30.7, 29.9, 29.8, 29.6,
29.5, 26.4, 26.2, 22.8 (CH2 sup.), 14.1 (CH3 sup.) ppm. IR (neat):
5-[4-Iodo(phenyl)-2H-tetrazole] (20): Following the general pro-
cedure B, p-iodobenzamide[44] 15 (6.67 g, 27 mmol), NaN3 (7.15 g,
110 mmol), and SiCl4 (4.24 mL, 37 mmol) gave 20 (6.56 g, 89%) as
a colorless solid; m.p. 275–278 °C (ref. 271 °C).[51] 1H NMR
(400 MHz, 25 °C, [D6]DMSO): δ = 7.98 (d, 3J = 8.6 Hz, 2 H), 7.80
(d, 3J = 8.6 Hz, 2 H) ppm. 13C NMR δ = (100 MHz, CDCl3,
25 °C): δ = 155.2 (C-5 tet), 138.3 (CH), 128.7 (CH), 123.3 (C-1),
ν = 2924, 2855, 2725, 2214, 1574, 1499, 1458, 1377, 1235, 1115,
˜
1038, 882, 831, 722 cm–1. FD-MS: m/z (%) = 3340.3 (100) [M]+,
5011.8 (49) [M3]2+, 6681.5 (25) [M2]+. C216H327N9O18 (3338.06):
calcd. C 77.72, H 9.87, N 3.78; found C 77.50, H 10.02, N 3.96.
98.5 (C-4) ppm. IR (ATR): ν = 2447, 1909, 1604, 1556, 1477, 1431,
˜
1271, 1165, 1058, 1006, 984, 826, 743 cm–1.
3,5-Dibromophenyl-2H-tetrazole (21): Following the general pro-
cedure B, 3,5-dibromobenzamide[45] 16 (3.5 g, 12 mmol), NaN3
(3.12 g, 48 mmol), and SiCl4 (1.9 mL, 16 mmol) gave 21 (3.43 g,
4-(Dihexylamino)benzonitrile (12):[29] Aqueous ammonia (30 mL,
28%) was added to a vigorously stirred solution of (dihexylamino)
benzaldehyde[34] (1.40 g, 4.84 mmol) in THF (25 mL), and iodine
was added in small portions until the starting material had disap-
peared. Diethyl ether (50 mL) was added, and the mixture was
washed with aqueous NaHSO3 (50 mL, 5%) and brine (3ϫ50 mL)
and dried (Na2SO4). Purification by column chromatography gave
12 (1.16 g, 83%) as a yellowish, fluorescent oil. Rf = 0.65 (toluene).
13C NMR (100 MHz, CDCl3, 25 °C): δ = 150.5 (C-4 Ph), 133.5 (C-
2, C-6 Ph), 120.9 (Cq), 111.0 (C-3, C-5), 96.1 (Cq), 51.0, (N-CH2)
31.9, 27.1, 26.8, 22.6, (CH2), 14.0 (CH3) ppm.
1
95%) as a colorless solid; m.p. 242 °C (dec). H NMR (400 MHz,
4
25 °C, [D6]DMSO): δ = 8.21 (d, J = 2.1 Hz, 2 H, 2-H, 6-H), 8.08
4
(t, J = 2.1 Hz, 1 H, 4-H) ppm. IR (KBr): ν = 3446, 3079, 2736,
˜
1654, 1553, 1382, 1244, 1103, 1025, 863, 666 cm–1. FD-MS: m/z
(%) = 302.1 (100) [M].+
5-[4-(2-p-Hexyloxy)phenylethynyl]phenyl-2H-tetrazole (26): Accord-
ing to the general procedure, heating a suspension of tetrazole 20
(272 mg, 1 mmol), alkyne[46] 22 (202 mg, 1 mmol), Pd(PPh3)2Cl2
(7 mg), CuI (4 mg), and 1 drop of trihexylamine in DMF (20 mL)
5-(4-Hexyloxyphenyl)-2H-tetrazole (17):[50] According to the gene- and aqueous K2CO3 (1 m, 20 mL) gave 26 (262 mg, 75%) as a col-
ral procedure C, a suspension of 4-(hexyloxy)benzonitrile[27] (11)
(4.07 g, 20 mmol), NaN3 (2.72 g, 40 mmol) and Et3NHCl (5.51 g,
40 mmol) for 5 d gave 17 (3.36 g, 68%) as a colorless solid; m.p.
163 °C. The same product was obtained in 90% yield from benz-
amide[42] 13 and TACS (procedure B). 1H NMR (400 MHz, 25 °C,
orless solid after chromatography (SiO2, toluene/ethyl acetate 20:1,
1
Rf = 0.33); m.p. 199 °C. H NMR (400 MHz, 25 °C, CDCl3): δ =
3
3
7.96 (d, J = 8.4 Hz, 2-H, 6-H, Ph), 7.50 (d, J = 8.6 Hz, 3-H, 5-
3
3
H, Ph), 7.35 (d, J = 8.8 Hz, 2-H, 6-H, PhЈ), 6.77 (d, J = 8.8 Hz,
3-H. 5-H PhЈ), 3.85 (t, J = 6.6 Hz, 6 H,OCH2), 1.65 (m, 2 H, β-
3
8
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Job/Unit: O40088
/KAP1
Date: 09-04-14 17:41:45
Pages: 12
Arylethynyl-Substituted Tristriazolotriazines
CH2), 1.33 (m, 2 H, CH2), 1.11–1.25 (m, 4 H, CH2), 0.77–0.80 (m,
1421, 1382, 1354, 1255, 1115, 838 cm–1. FD-MS: m/z (%) = 731.2
3 H, CH3) ppm. 13C NMR (75 MHz, 25 °C, CDCl3): δ = 159.5 (C- (100) [M]+, 1464.6 (6) [M2]+. C47H62N4O3 (731.04): calcd. C 77.22,
4 PhЈ), 133.0, 131.9, 127.1 (C-2, C-3, C-5, C-6 Ph, C-2, C-6 PhЈ),
126.3 (C-1 Ph), 123.6 (C-4 Ph), 114.5 (C-3, C-5 PhЈ), 114.4 (C-1
PhЈ), 91.3 (C-2 In), 87.3 (C-1 In), 68.0 (OCH2), 31.6, 29.0, 25.6,
H 8.55, N 7.66; found C 76.97, H 8.34, N 7.47.
3,5-Bis[2-[3,4,5-tris(octyloxy)phenyl]ethynyl]phenyltetrazole (30):
According to procedure D, tetrazole 21 (152 mg, 0.5 mmol), alkyne
23 (535 mg, 1.1 mmol), Pd(PPh3)2Cl2 (7 mg), CuI (4 mg), and one
drop of trihexylamine in DMF/aq. K2CO3 (9:1, 50 mL) gave 30
(181 mg, 32%) as a colorless wax; m.p. 111 °C. Rf = 0.19 (toluene/
22.5 (CH ), 13.9 (CH ) ppm (C-5 Tet n.d.). IR (ATR): ν = 2920,
˜
2
3
2857.0 2210, 1603, 1513, 1470, 1431, 1385, 1353, 1294, 1250, 1162,
1110, 1061, 1035, 989, 836, 759 cm–1. FD-MS: m/z (%) = 346.3
(100) [M+]. C21H22N4O (364.41): calcd. C 72.81, H 6.40, N 16.17;
found C 72.46, H 6.68, N 15.76.
1
ethyl acetate 25:1). H NMR (400 MHz, 25 °C, CDCl3): δ = 7.91
(br s, 2 H, 2-H, 6-H Ph), 7.69 (m, 1 H, 4-H Ph), 6.68 (s, 4 H, 2-H,
3
3
5-{4-[2-(4-Didodecylaminophenyl)ethynyl]phenyl}-2H-tetrazole (27):
According to the general procedure D, tetrazole 20 (462 mg,
6-H PhЈ), 4.06 (t, J = 6.1 Hz, 4 H, OCH2), 3.92 (t, J = 6.1 Hz, 8
H, OCH2), 1.69–1.82 (m, 12 H, β-CH2), 1.20–1.49 (m, 60 H, CH2),
1.7 mmol), alkyne[47] 24 (817 mg, 1.8 mmol), Pd(PPh3)2Cl2 (28 mg), 0.83–0.87 (m, 18 H, CH3) ppm. 13C NMR (75 MHz, 25 °C,
CuI (15 mg), PPh3 (21 mg), and one drop of trihexylamine in piper-
idine (50 mL) gave 27 (625 mg, 62%) as a yellow solid. Rf = 0.28
(toluene/ethyl acetate 15:1). Compound 27 turned green within 1
CDCl3): δ = 155.3 (br, C-5 tet), 152.8 (C-3, C-5 PhЈ), 138.4 (C-4
PhЈ), 136.3 (C-3, C-5, Ph), 129.5 (C-1 Ph), 125.1 (C-2 Ph), 124.7
(C-4 Ph), 117.6 (C-1 PhЈ), 110.0 (C-2, PhЈ), 91.5, 86.3 (C-1, C-2
1
3
h. H NMR (400 MHz, CDCl3): δ = 8.04 (d, J = 8.3 Hz, 2 H, 2- In), 69.1, 74.2 (OCH2), 31.8, 30.1, 29.5, 29.3, 26.0, 22.0 (CH2 sup.),
3
3
H, 6-H Ph), 7.59 (d, J = 8.3 Hz, 2 H, 3-H, 5-H Ph), 7.35 (d, J =
14.1 (CH3 sup.) ppm. FD-MS: m/z (%) = 1116.9 (100) [M]+.
8.8 Hz, 2 H, 2-H, 6-H PhЈ), 6.56 (d, 3J = 8.8 Hz, 2 H, 3-H, 5-H
HRMS: calcd. for C71H111N4O6 [M + H]+ 1115.8504; found
PhЈ), 3.26 (m, 4 H, NCH2), 1.56 (m,4 H, β-CH2), 1.24–1.29 (m, 36 1115.8472.
H, CH ), 0.86 (m, 6 H, CH ) ppm. IR (KBr): ν = 2924, 2853, 2207,
˜
2
3
3,4,5-Tris(octyloxy)-ω,ω-dibromostyrene (23a): Zinc powder
(2.87 g, 44 mmol) and PPh3 (9.96 g, 44 mmol) were added to a solu-
tion of CBr4 (14.59 g, 44 mmol) in CH2Cl2 (150 mL), which was
degassed by purging with N2. At 0 °C, the mixture was sonicated
for 1 h (sonotrode, external cooling) and 3,4,5-tris(octyloxy)benz-
1603, 1560, 1521, 1466, 1400, 1369, 1197, 1133, 845, 812, 721 cm–1.
FD-MS: m/z (%) = 597.5 (100) [M]+.
5-{4-[2-[3,4,5-Tris(octyloxy)phenyl]ethynyl]phenyl}-2H-tetrazole
(24): According to procedure D, 20 (544 mg, 2 mmol), alkyne 23
(1.07 g, 2.2 mmol), Pd(PPh3)2Cl2 (14 mg), CuI (8 mg), PPh3 aldehyde[33] (5.40 g, 11 mmol) in anhydrous CH2Cl2 (50 mL) was
(10 mg), and one drop of trihexylamine in DMF/aq. K2CO3 (9:1,
added dropwise to the stirred suspension. Stirring was continued
70 mL) gave 24 (960 mg, 73%) as a colorless solid; m.p. 79 °C. Rf = for 15 min at 0 °C and 1.5 h at 25 °C. The liquid was decanted and
0.35 (SiO2, toluene/ethyl acetate 20:1). 1H NMR (400 MHz, 25 °C,
concentrated to 100 mL. Water (50 mL) and methanol (50 mL)
were added, and the aqueous layer was extracted with petroleum
ether (3ϫ75 mL). The combined organic solutions were washed
3
3
CDCl3): δ = 7.88 (d, J = 8.3 Hz, 2 H, 2-H, 6-H Ph), 7.50 (d, J =
3
8.3 Hz, 2 H,3-H, 5-H Ph), 6.66 (s, 2 H, 2-H, 6-H PhЈ), 4.05 (t, J
3
= 6.7 Hz, 2 H, OCH2), 3.87 (t, J = 6.5 Hz, 4 H,OCH2), 1.79–1.86 with brine (3ϫ50 mL) and dried (MgSO4). Column chromato-
(m, 2 H, β-CH2), 1.68–1.73 (m, 4 H,β-CH2), 1.25–1.48 (m, 30 H, graphy gave 23a as colorless oil (5.80 g, 82%). Rf = 0.39 (toluene/
1
CH2), 0.86 (m, 9 H, CH3) ppm. 13C NMR (75 MHz, 25 °C,
petroleum ether 1:3). H NMR (400 MHz, 25 °C, C6D6): δ = 7.26
3
CDCl3): δ = 153.0 (C-3, C-5 PhЈ), 138.1 (C-4 PhЈ), 132.6 (C3, C-5 (s, 1 H, 1-H vin), 6.72 (s, 2 H, 2-H, 6-H Ph), 4.19 (t, J = 6.4 Hz,
Ph), 127.2 (C-2, C-6 Ph), 126.3 (C-4 Ph), 123.3 (C-1 Ph), 117.8 2 H, OCH2), 3.76 (t, 3J = 6.4 Hz, 4 H, OCH2), 1.88 (m, 2 H, β-
(CC-1 PhЈ), 109.7 (C-2, C-6 PhЈ), 87.5 (C-1 In), 92.8 (C-2 In), 69.1, CH2), 1.55–1.70 (m, 6 H, CH2), 1.24–1.44 (m, 32 H, CH2), 0.89–
73.6 (OCH2), 32.0, 31.9, 30.3, 29.6, 29.4, 26.1, 22.7 (CH2, sup.), 0.93 (m, 9 H, CH3) ppm. 13C NMR (75 MHz, 25 °C, C6D6): δ =
14.1 (CH , sup.) ppm (C-5 Tet n.d.). IR (neat): ν = 2922, 2853, 153.3 (C-3, C-5 Ph), 139.6 (C-4 Ph), 137.3 (α-C vin), 130.0 (C-1
˜
3
2719, 2610, 2203, 1606, 1570, 1504, 1465, 1428, 1416, 1352, 1256,
1235, 1157, 1113, 1028, 993, 844, 750, 699 cm–1. FD-MS: m/z (%)
= 630.9 (100) [M]+, 1263.1 (10) [M2]+. HRMS: calcd. for
C39H58N4O3Na [M + Na]+ 653.4407, found 653.4387.
Ph), 107.5 (C-2, C-6 Ph), 88.2 (β-C vin), 69.0, 73.2 (OCH2), 32.0,
31.9, 30.7, 29.7, 29.5, 29.4, 26.3, 26.2, 22.8, (CH2 sup.), 14.1 (CH3
sup.) ppm. IR (film): ν = 2926, 2855, 1576, 1501, 1466, 1428, 1381,
˜
1331, 1239, 1115, 866, 836, 722 cm–1. FD-MS: m/z (%) = 646.9
(100) [M]+. C32H54Br2O3 (646.59): calcd. C 59.44, H 8.42; found C
59.35, H 8.36.
5-[4-(2-{4-[2-[3,4,5-Tris(octyloxy)phenyl]ethynyl]phenyl}ethynyl)-
phenyl]-2H-tetrazole (29): According to procedure D, diyne 25
(176 mg, 0.3 mmol), 20 (76 mg, 0.28 mmol), Pd(PPh3)2Cl2 (11 mg), [3,4,5-Tris(octyloxy)phenyl]acetylene (23): 3,4,5-Tris(octyloxy)-ω,ω-
CuI (6 mg), PPh3 (8 mg), and one drop of trihexylamine in DMF/ dibromstyrol (23a) (3.88 g, 6 mmol) was dissolved in anhydrous
aq. K2CO3 (9:1, 70 mL) gave 29 (133 mg, 65%) as a light yellow THF (220 mL) in a Schlenk flask, and the solution was deaerated
1
solid; m.p. 163 °C. Rf = 0.25 (toluene/ethyl acetate 15:1). H NMR
by three freeze–pump–thaw cycles. At –78 °C, nBuLi (2.5 m,
3
(400 MHz, 25 °C, CDCl3): δ = 7.97 (d, J = 8.2 Hz, 2 H, 2-H. 6-H 8.4 mL) was added, and the mixture was stirred (24 h at –78 °C
3
Ph), 7.53 (d, J = 8.2 Hz, 2 H, 3-H, 5-H Ph), 7.42 (s, 4 H, 2-H, 3-
and 24 h at r.t.). NH4Cl (satd. aq., 50 mL) was added, and the
organic layer was separated, washed with brine (3ϫ30 mL), dried
H, 5-H, 6-H PhЈ), 6.69 (s, 2 H, 2-H, 6-H, PhЈЈ), 4.06 (t, 3J = 6.7 Hz,
3
2 H, OCH2), 3.90 (t, J = 6.5 Hz, 4 H, OCH2), 1.70–1.80 (m, 6 H, (MgSO4), and concentrated. The residue was filtered through silica
β-CH2), 1.44 (m, 6 H, CH2) 1.27 (m, 24 H, CH2), 0.85–0.88 (m, 9
gel to give 23 as a colorless oil (2.69 g, 92%). 1H NMR (400 MHz,
H, CH3) ppm. 13C NMR (75 MHz, 25 °C, CDCl3): δ = 156.3 (C-5 25 °C, C6D6): δ = 6.87 (s, 2 H, 2-H, 6-H Ph), 4.15 (t, J = 6.4 Hz,
3
3
Tet), 152.9 (C-3, C-5 PhЈЈ), 138.0 (C-4 PhЈЈ), 132.2 (C-3, C-5 Ph), 2 H, 2 H, OCH2), 3.56 (t, J = 6 Hz, 4 H, 4 Hz, OCH2), 2.80 (s, 1
131.5, 131.6 (C-2, C-3, C-5, C-6 PhЈ), 127.4 (C-2, C-6 Ph), 126.2 H, Ph-CC-H), 1.86 (qui, 2 H, β-CH2), 1.57–1.60 (m, 8 H, CH2),
(C-4 Ph), 123.5 (C-1 Ph, C-4 PhЈ), 122.4 (C-1 PhЈ), 118.1 (C-1 1.24–1.32 (m, 26 H, CH2), 0.89–0.93 (m, 9 H, CH3) ppm. 13C NMR
PhЈЈ), 109.7 (C-2, C-6 PhЈЈ), 91.7 (C-1, C-2 InЈ, sup.), 90.2 (C-1
In), 88.1 (C-2 In), 69.0, 74.3 (OCH2), 31.9, 31.8, 30.3, 29.7, 29.5, (C-1 Ph), 111.0 (C-2, C-6 Ph), 84.3 (C-2 In), 76.1 (C-1 In), 68.7,
29.3, 29.2, 26.1, 22.7, 22.6, (CH2, sup.), 14.1 (CH3, sup.) ppm. IR 73.2 (OCH2), 32.0, 31.9, 30.7, 29.7, 29.5, 29.4, 26.3, 26.1, 22.8 (CH2
(75 MHz, 25 °C, C6D6): δ = 153.4 (C-3, C-5 Ph), 140.2 (C-4), 117.0
(KBr): ν = 3427, 2926, 2855, 2210, 1654, 1611, 1573, 1511, 1465, sup.), 14.1 (CH sup.) ppm. IR (film): ν = 3313, 2926, 2855, 2105,
˜
˜
3
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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/KAP1
Date: 09-04-14 17:41:45
Pages: 12
H. Detert et al.
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2010, 96, 183305/1–183305/3.
(2-{4-[2-[3,4,5-Tris(octyloxy)phenyl]ethynyl]phenyl}ethynyl)trimethyl-
silane (25a): (a) According to procedure D, 31 (177 mg, 0.7 mmol),
23 (399 mg, 0.82 mmol), Pd(PPh3)2Cl2 (14 mg), CuI (8 mg), PPh3
(10 mg), and one drop of trihexylamine in DMF/1 m K2CO3 (aq.,
70 mL) gave 25a as a colorless oil (270 mg, 50%). Rf = 0.30 (PE/
Tol, 10:1). (b) nBuLi (0.75 mL, 2.5 m) was added to a cooled
(–78 °C) solution of 23 (730 mg, 1.5 mmol) in THF (10 mL), and
ZnBr2 (anhydrous, 440 mg, 1.95 mmol) was added. The mixture
was warmed to 25 °C and transferred by cannula to a stirred solu-
tion of Pd(PPh3)2Cl2 (135 mg, 0.13 mmol), PPh3(79 mg, 0.3 mmol),
and 31 (658 mg, 2.6 mmol) in absolute THF (15 mL). After com-
pletion of the reaction, NH4Cl (satd. aq., 100 mL) was added, and
the mixture was extracted with ethyl acetate (2ϫ50 mL). The com-
bined organic solutions were washed with water and brine and
dried (MgSO4). Purification by chromatography (Rf = 0.29 PE/Tol.
10:1) gave a colorless oil (712 mg, 72 %). 1H NMR (400 MHz,
CDCl3): δ = 7.41 (s, 4 H, Ph), 6.70 (s, 2 H, 2-H, 6-H PhЈ), 3.95 (m,
6 H, OCH2), 1.70–1.80 (m, 6 H, CH2), 1.41–1.46 (m, 6 H, CH2),
1.26–1.29 (m, 24 H, CH2), 0.85–0.88 (m, 9 H, CH3), 0.23 (s, 9 H,
Si-CH3) ppm. 13C NMR (75 MHz, in CDCl3): δ = 153.0 (C-3, C-
5, PhЈ), 139.2 (C-4 PhЈ), 131.8, 131.3 (C-2, C-3, C-5, C-6 Ph), 123.4,
122.7 (C-1, C-4 Ph), 117.3 (C-1 PhЈ), 110.1 (C-2, C-6 PhЈ), 104.7
(C-2 In), 96.2 (C-1 In), 91.7 (C-2 InЈ), 87.8 (C-1 InЈ), 73.5, 69.1
(OCH2), 31.9, 31.8, 30.3, 29.5, 29.3, 26.1, 26.1, 22.7 (CH2), 14.1
[3]
[4]
[5]
[6]
[7]
[8]
(CH ), 0.02 (SiCH ) ppm. IR (film): ν = 2954, 2926, 2855, 2208,
˜
3
3
2157, 1574, 1509, 1469, 1418, 1383, 1354, 1250, 1232, 1115, 1019,
863.5, 841, 760, 723, 629 cm–1. FD-MS: m/z (%) = 659.1 (100)
[M]+, 660.1 (54), 1319.6 (1) [M2]+.
[9]
5-[2-(4-Ethynylphenyl)ethynyl]-1,2,3-tris(octyloxy)benzene
(25):
K2CO3 (44 mg, 0.2 mmol) was added to a solution of 25a (231 mg.
0.35 mmol) in dichloromethane/methanol (1:1, 30 mL), and the
suspension was stirred under N2 for 16 h at 25 °C. The mixture
was washed with water and brine, dried (MgSO4), concentrated,
and filtered through silica gel to yield 25 as a yellow oil (185 mg,
1
90%). H NMR (400 MHz, CDCl3): δ = 7.44 (s, 4 H, Ph), 6.71 (s,
2 H, 2-H, 6-H PhЈ), 3.96 (m, 6 H, OCH2), 3.15 (s, 1 H, CC-H),
1.70–1.80 (m, 6 H, CH2), 1.41–1.46 (m, 6 H, CH2), 1.26–1.29 (m,
24 H, CH2), 0.85–0.88 (m, 9 H, CH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 153.0 (C-3, C-5, PhЈ), 139.3 (C-4 PhЈ), 131.3, 132.0
(C-2, C-3, C-5, C-6 Ph), 123.8, 121.7 (C-1, C-4 Ph), 117.3 (C-1
PhЈ), 110.1 (C-2, C-6 PhЈ), 91.9 (C-2 InЈ), 87.6 (C-1 InЈ), 83.2 (C-
2 In), 78.9 87.8 (C-1 In), 73.5, 69.1 (OCH2), 31.9, 31.8, 30.3, 29.5,
[10]
29.3, 26.1, (22.7, CH ), 14.1 (CH ) ppm. IR (film): ν = 3302, 2926,
˜
2
3
2209, 1731, 1573, 1508, 1467, 1419, 1383, 1353, 1255, 1233, 1115,
837, 722 cm–1. FD-MS: m/z (%) = 586.9 (100) [M]+.
Supporting Information (see footnote on the first page of this arti-
cle): 1H and 13C NMR spectra and UV/Vis/fluorescence spectra of
1–12.
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Published Online: ᭿
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11

Job/Unit: O40088
/KAP1
Date: 09-04-14 17:41:45
Pages: 12
H. Detert et al.
FULL PAPER
Dendritic Molecules
Star-shaped and dendritic molecules with a
triphenyl-tristriazolotriazine core and flex-
ible side chains are prepared from tetra-
zoles and cyanuric chloride. The optical,
nonlinear optical, and thermotropic
properties of these compounds as well as
their phenylethynyl homologues are re-
ported.
S. Glang, T. Rieth, D. Borchmann,
I. Fortunati, R. Signorini,
H. Detert* ...................................... 1–12
Arylethynyl-Substituted Tristriazolotriaz-
ines: Synthesis, Optical Properties, and
Thermotropic Behavior
Keywords: Liquid crystals / Conjugated oli-
gomers / Chromophores / Fluorescence /
Nonlinear optics / Heterocycles
12
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