Functional Molecules for Grafting onto Ionic Surfaces

Article abstract of DOI:10.1002/ejoc.201501077

The 2D adsorption of molecules onto insulating surfaces is of increasing interest for future devices in emerging technologies such as molecular electronics, sensors, single-molecule optics, and on-surface synthesis. However, most attempts to stabilize molecular structures on these substrates have been hampered by weak molecule-surface interactions and so there is a need to develop organic molecules bearing suitable grafting groups. We report herein the synthesis of a series of molecules designed to be physisorbed onto alkali halide crystalline surfaces. They comprise a rigid central benzene or triphenylene core bearing, respectively, two or six alkyl ether chains terminated by cyano, carboxylic, α-amino acids, or 1,2,3-triazoles as anchoring groups. Two series of molecules designed for grafting onto KBr or NaCl surfaces have been prepared. The molecules comprise a rigid central benzene or triphenylene core bearing, respectively, two or six alkyl ether chains terminated by cyano, carboxylic, α-amino acids, or 1,2,3-triazoles as anchoring groups.

Full text of DOI:10.1002/ejoc.201501077

DOI: 10.1002/ejoc.201501077
Full Paper
Molecules for Grafting
Functional Molecules for Grafting onto Ionic Surfaces
Adeline R. Pujol,[a,b] Sonia Bataillé,[a] and André Gourdon*[a]
Abstract: The 2D adsorption of molecules onto insulating sur- ing groups. We report herein the synthesis of a series of mol-
faces is of increasing interest for future devices in emerging
technologies such as molecular electronics, sensors, single-mol-
ecule optics, and on-surface synthesis. However, most attempts
to stabilize molecular structures on these substrates have been
hampered by weak molecule–surface interactions and so there
is a need to develop organic molecules bearing suitable graft-
ecules designed to be physisorbed onto alkali halide crystalline
surfaces. They comprise a rigid central benzene or triphenylene
core bearing, respectively, two or six alkyl ether chains termi-
nated by cyano, carboxylic, α-amino acids, or 1,2,3-triazoles as
anchoring groups.
Introduction
been shown to adsorb rather effectively, but the number of
functions still has to be considerably extended to optimize
these interactions and master the OIHE on this type of sub-
strate.
We describe herein the preparation of two series of mol-
ecules designed for NC-AFM experiments on alkali halide sur-
faces. The molecules comprise a rigid central benzene or tri-
The adsorption and diffusion of organic molecules onto inor-
ganic surfaces has recently become of particular importance for
several fields of interest, such as molecular electronics, sensors,
and organic photocatalysis. Investigations in these areas have
now been rendered possible by the recent rapid development
of atomic force microscopy in the noncontact (or frequency
modulation) mode (NC-AFM),[1] but so far little is known, for
example, of the detailed adsorption mechanisms and the bal-
ance between molecule–substrate and molecule–molecule in-
teractions. The main problem in this field remains the fact that
molecule–surface interactions are in general weak, often
weaker than intermolecular interactions, leading to desorption
or to diffusion and 3D growth instead of 2D supramolecular
assembly. In the last few years many studies have been focused
on alkali metal halide surfaces as models for the study of or-
ganic/inorganic heteroepitaxy (OIHE)[2] because these surfaces
are stable and easy to prepare under ultra-high vacuum condi-
tions (UHV) even though the molecule–surface interactions are
in general very weak. Consequently, there is a general need to
investigate these interactions on the atomic scale to be able to
design and tailor molecules that adsorb strongly on dielectric
surfaces such as KBr, KCl, or NaCl. One solution we have been
exploring in recent years is the conception and synthesis of
molecules comprising aromatic or polyaromatic rigid cores
equipped with several flexible chains terminating with anchor-
ing groups that interact locally with the surface ions. So far,
groups possessing a large dipole moment (such as cyano) have
[a] NanoSciences Group, CEMES-CNRS,
29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4,
France
E-mail: andre.gourdon@cemes.fr
http://www.cemes.fr/GNS
[b] Université de Toulouse, UPS,
118 route de Narbonne, 31062 Toulouse Cedex 9, France
Supporting information and ORCID(s) from the author(s) for this article
are available on the WWW under http://dx.doi.org/10.1002/
ejoc.201501077.
Figure 1. Hydroquinone and hexahydroxytriphenylene derivatives designed
for physisorption on alkali metal halide surfaces.
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phenylene core bearing, respectively, two or six alkyl ether
chains terminated by cyano, carboxylic, α-amino acids, or 1,2,3-
triazoles as anchoring groups (Figure 1).
Results and Discussion
Cyano Derivatives
The cyano group is the most used grafting group in this type
of experiment for several reasons, namely the ease of prepara-
tion and thermal stability of molecules comprising this func-
tional group, which allows the sublimation required for transfer
onto surfaces under UHV. An investigation of the adsorption
and diffusion properties of syn-5,10,15-tris(cyanophenyl-
methyl)truxene onto a KBr(001) nanostructured surface showed
that molecules diffused along the monolayer step edges and
were immobilized at kink sites.[3] An extensive DFT simulation
demonstrated that the control of anchoring and diffusion was
dependent on the number of anchoring groups acting inde-
pendently; this requires a flexibility of the anchoring branch to
allow the individual groups to bind to specific sites on the sur-
face. The adsorption of rigid mono- and dicyanopentahelicenes
onto a Suzuki (001) surface[4] confirmed that a perfect match
between the distances of the substituents and the cations was
required and that the cyano groups were in a perpendicular
position on top of the surface cations, allowing compensation
of the net dipole. Taking these facts into account, we have de-
signed a series of dicyano/hexacyano-functionalized molecules
to study their interactions on NaCl(001) and KBr(001) surfaces.
The synthesis involves a one-step Williamson etherification of
hydroquinone/catechol/hexahydroxytriphenylene (HHTP) and
5-bromovaleronitrile/5-bromobutyronitrile under mild condi-
tions (K2CO3 in dry DMF), as shown in Schemes 1 and 2.
Scheme 3. Scholl condensation of 11 to give the HHTP derivative 2.
Although the condensation of 1,2-substituted catechol by
oxidative coupling is a standard route to many hexyloxytriphen-
ylenes,[5] it is often limited to poorly reactive substituted chains.
Several oxidizing groups have been used, such as FeCl3,[6,7]
VOCl3,[8] and MoCl5.[9,10] Waldvogel and co-workers showed that
it was possible to cyclotrimerize 1,3-benzodioxole disubstituted
at the 2-position by chains bearing reactive groups such as es-
ters by using MoCl5,[10–12] and we used similar conditions to
prepare 2 by this route.
We studied the adsorption of 2 on KBr(001) surfaces by NC-
AFM coupled with Kelvin probe force microscopy (KPFM) under
ultra-high vacuum at room temperature.[13] Two types of
monolayers were identified, one in which the molecules lie flat
on the surface and another in which they stand approximately
upright. In the flat-lying adsorption geometry, the molecule–
surface interaction is dominated by the electrostatic interaction
of the cyano group with the K+ cations leading to a total ad-
sorption energy of 1.8 eV. In the vertical geometry, the mol-
ecules form π-stacked rows aligned along the polar direction of
the surface. Only two of the cyano groups interact with the
surface cations, contributing approximately 0.4 eV to the ad-
sorption energy; the stabilization (total adsorption energy ca.
2.5 eV) is gained by this intermolecular interaction.
These results suggest that the dipolar moment of the nitrile
group may not be high enough for strong adsorption, which
prompted us to explore the preparation of the analogous deriv-
ative 4 bearing a carboxylic group.
Scheme 1. Preparation of 1 (1,4 isomer, n = 2, yield: 50 %) and 11 (1,2 isomer,
n = 1, yield: 71 %).
Carboxylic Derivatives
2,3,6,7,10,11-Hexakis(3-carboxypropyloxy)triphenylene
(4) can be obtained as a gel by the reaction of HHTP with
methyl 4-bromobutanoate in a basic medium to give the
hexamethyl ester 12 in 30 % yield, a procedure similar to that
of Bibal and co-workers.[14] for the synthesis of water-soluble
hosts. Compound 12 was then hydrolyzed by aqueous sodium
Scheme 2. Synthesis of 2 from HHTP.
The hexakis(cyanopropyloxy)triphenylene 2 can also be ob- hydroxide to give 4 in 70 % yield (Scheme 4). Attempts to pre-
tained in low yield by the Scholl condensation of 11 by reaction pare 4 by the condensation of 4,4′-(1,2-phenylenedioxy)di-
with MoCl5 in cold dichloromethane (Scheme 3).
butanoic ester[15] were unsuccessful.
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Scheme 5. Synthesis of 3.
the lactone after 90 min in D2O at room temperature. The
amine and carboxylic functions were then protected by stand-
ard procedures to give methyl 4-bromo-2-(tert-butoxycarbonyl-
amino)butanoate (Scheme 5).[18,19]
Scheme 4. Preparation of 4.
The HHTP α-amino acid derivative 7 was obtained similarly
by Williamson etherification of HHTP in DMF to give the pro-
tected amino acid 14, which was then deprotected in two steps
to give 7 as a dark gel in 26 % yield (two steps from 14;
Scheme 6).
α-Amino Acid Derivatives
A third grafting group that can be envisioned is the α-amino
acid. In particular, in their zwitterionic forms, these functions
could show strong electrostatic interactions with the local par-
tial charges of dielectric surfaces such as alkali halides provided
that there is commensurability between the local surface char-
ges and zwitterionic charges. Similar hypotheses have been
used by Loppacher and co-workers in the study of the self-
organization of the zwitterion 4-methoxy-4′-(3-sulfanato-
propyl)stilbazolium on KCl(001).[16] In this compound the sulf-
onato end-group, which carries a negative charge, is linked by
an alkyl chain to the pyridinium ring carrying a positive charge,
and the distance between the opposite charges in the trans
isomer is around 1 nm. A first rapid evaluation shows that the
carboxylate–ammonium distance in α-amino acids (ca. 2.8 Å)
matches the sodium–chloride distance in NaCl(001) (2.82 Å).
This observation led us to design compounds 3 and 7 bearing
2-aminobutanoic chains (Scheme 5).
The hydroquinone/catechol and HHTP α-amino acid deriva-
tives were obtained by their reactions with methyl 4-bromo-2-
(tert-butoxycarbonylamino)butanoate in anhydrous DMF in the
presence of potassium carbonate. Its preparation requires the
synthesis of 2-amino-4-bromobutanoic acid, which can be effi-
ciently and rapidly obtained in quantitative yield by microwave
irradiation in HBr/AcOH in 45 min (compared with 4 h by stand-
ard heating at 75 °C).[17] It must be underlined that this ring-
opening is reversible in water and we have shown by NMR anal-
ysis that half of the 2-amino-4-bromobutanoic acid returned to
Scheme 6. Three steps synthesis of 7.
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Attempts to apply the Scholl condensation to the catechol
derivative according to Scheme 7 were unsuccessful, leading
only to the decomposition of the catechol derivative 15.
Scheme 9. Preparation of 8 and 9 (total yield from 16: 56 %; from 17: 36 %).
Scheme 7. Attempted synthesis of 14 by the Scholl condensation reaction.
yne in a better yield (66 %) but with a significantly longer reac-
tion time (9 d).
1,2,3-Triazole Derivatives
A fourth grafting group potentially suitable for strong electro-
static interactions with alkali halide surfaces is 1,2,3-triazole. In-
deed, the local dipole moment of 1,2,3-triazole is 4.23 D, similar
to that of carboxylic acid (4.25 D), whereas it is 4.38 D for 1-
hexyl-1,2,3-triazole.
The hydroquinone derivatives 5 and 6 were obtained by
CuAAC reactions starting from the dialkynes 16 and 17, respec-
tively, as shown in Scheme 8.
Scheme 10. Preparation of 10 from HHTP.
From 21, the target compound 10 was obtained in 50 %
yield following the CuAAC procedure developed for hydroquin-
one analogues (Scheme 10). Compound 10 is very similar to
the recently described triazole HHTP derivative prepared by
Bhalla et al.,[21] which shows a very interesting gel-to-sol phase
transition selectively controlled by interaction with Cd2+ ions
and can work as an efficient and sensitive fluorescent sensor
for nitroaromatic explosives.
Attempts to prepare analogues of 10 by a convergent ap-
proach according to Scheme 11 have so far been unsuccessful,
probably due to the fragility of the intermediate 22 towards
the Lewis acids required for the Scholl condensation.
Scheme 8. Preparation of 5 and 6 from 16 and 17, respectively.
Dialkyne 17 itself was obtained in two steps by the conden-
sation of (6-bromohex-1-yn-1-yl)triisopropylsilane with hydro-
quinone, followed by the deprotection of the alkyne by tetra-
butylammonium fluoride (TBAF; total yield: 70 %).
Similarly, the 1,2,3-triazoles 8 and 9 bearing a hydrogen
atom at the 1-position were obtained by the reaction of 16 and
17 with azidomethyl pivalate under standard CuAAC conditions.
The pivalate protecting group was then removed by basic treat-
ment followed by acidification to give 8 and 9 in yields of 90
and 85 %, respectively. Both compounds are very insoluble
(Scheme 9).
The HHTP hexasubstituted analogue 21 was obtained by
Williamson etherification with (6-bromohex-1-yn-1-yl)triiso-
propylsilane, followed by standard TIPS deprotection by TBAF
(Scheme 10). This route was preferred to the recently published
procedure by Stackhouse and Hird[20] in which 21 was obtained
by the condensation of HHTP with unprotected 6-chlorohex-1-
Scheme 11. Attempted trimerization of 22 by the Scholl condensation reac-
tion.
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1
3
yield. H NMR (300 MHz, CD2Cl2): δ = 6.82 (s, 4 H, Har.), 3.94 (t, J =
Conclusions
3
6 Hz, 4 H, CH2-O), 2.43 (t, J = 7 Hz, 4 H, CH2-CN), 1.95–1.78 (m, 8
H, CH2) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 153.4 (Cq,ar.), 120.0
(Cq,nitrile), 115.7 (CHar.), 67.7 (CH2-O), 28.7 (CH2), 22.8 (CH2), 17.3
(CH2CN) ppm. MS (DCI, NH3): calcd. for [M + NH4]+ 290.2; found
290.2. HRMS (DCI, CH4): calcd. for C16H21N2O2 273.1603 [M + H]+;
found 273.1591. C16H20N2O2 (272.15): calcd. C 70.56, H 7.40, N 10.29;
found C 68.30, H 7.41, N 9.97.
A series of molecules designed for experiments on alkali halide
surfaces have been synthesized by functionalizing hydroquin-
one and hexahydroxytriphenylene with alkyl chains terminated
with cyano, carboxylic acid, triazole, or amino acid groups.
Scholl condensations of catechol derivatives to form the tri-
phenylene core turned out to be unsuccessful.
2,3,6,7,10,11-Hexakis(cyanopropoxy)triphenylene (2) from
HHTP: Potassium carbonate (1.93 g, 13.9 mmol, 25 equiv.) and 4-
bromobutyronitrile (0.39 mL, 3.9 mmol, 7 equiv.) were added to
anhydrous DMF (11 mL) and the mixture was degassed by argon
bubbling for 2 min, followed by the addition of HHTP (180 mg,
0.55 mmol, 1 equiv.). After stirring at room temp. under argon for
48 h, the mixture was poured into water (110 mL). Neutralization
Experimental Section
General Methods: Dry DMF was from Acros Organics or Sigma
Aldrich. THF was distilled over sodium/benzophenone. Other sol-
vents were dried with molecular sieves prior to use. Flash column
chromatography was performed on silica gel (60 Å pore size, 40–
63 μm Merck). Reactions were monitored by TLC on plates coated
with silica gel (Merck 60 F254). Detection was achieved by using UV
light and by charring the plate at around 200 °C after dipping it in
an ethanolic solution of potassium permanganate. The yields refer
to chromatographically and spectroscopically (1H and 13C NMR) ho-
mogeneous materials unless otherwise stated. NMR spectra were
recorded with Bruker Avance 300, 400, and 500 MHz spectrometers
and were calibrated by using residual undeuteriated solvent as the
internal reference (CDCl3 at δH = 7.26 ppm, δC = 77.16 ppm, CD2Cl2
at δH = 5.33 ppm, δC = 53.84 ppm). Chemical shifts are reported in
ppm on the δ scale and coupling constants are in Hz. The abbrevia-
tions used to describe the multiplicities are as follows: s = singlet,
br. s = broad singlet, d = doublet, t = triplet, dd = doublet of dou-
blets, q = quintuplet, m = multiplet. Mass spectra were recorded at
the Service Commune de Spectrometrie de Masse of the University
Paul Sabatier (Toulouse 3, France). Elemental analyses were per-
formed by the Service d'Analyse de l'ICSN (Paris, France). Microwave
heating was carried out in sealed vials with a CEM-Discovery mono-
mode microwave apparatus under the specified conditions (power,
temperature, time).
1,2-Bis(prop-2-ynyloxy)benzene,[22] methyl 2-amino-4-bromobut-
anoate,[18] methyl 4-bromo-2-(tert-butoxycarbonylamino)butano-
ate,[19] hexyl azide,[23] azidomethyl pivalate,[24] and (6-bromohex-1-
ynyl)triisopropylsilane[25] were obtained according to the published
procedures. HHTP[26] was obtained from hexamethoxytriphenylene
(HMTP)[27] according to literature procedure. When required, HHTP
was purified before use according to the following procedure: par-
tially oxidized HHTP (198 mg) was added to warm (75 °C), degassed
distilled water (30 mL). After stirring for 5 min under argon, sodium
hydrosulfite (250 mg) was added. The mixture was filtered under
argon as soon as the mixture changed from violet to clear grey. The
beige solid was then washed with water and dried under vacuum
at 40 °C to give pure HHTP in nearly quantitative yield.
with a 5
M solution of sulfuric acid gave a precipitate that was
filtered, washed with water, and dried. Recrystallization from ethyl
acetate gave 2 as a grey powder in 46 % yield. Rf = 0.5 (TLC, DCM/
AcOEt, 7:3). 1H NMR (300 MHz, CD2Cl2): δ = 7.91 (s, 6 H, Hd), 4.37 (t,
3
3
3J = 6 Hz, 12 H, Hc), 2.71 (t, J = 7 Hz, 12 H, Ha), 2.27 (m, J = 7 Hz,
12 H, Hb) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 148.9 (Cq,ar.), 124.2
(Cq,nitrile), 107.9 (CHar.), 67.6 (CH2-O), 26.0 (CH2), 14.7 (CH2) ppm.
HRMS (DCI, CH4): calcd. for C42H43N6O6 727.3244 [M + H]+; found
727.3275.
1,2-Bis(cyanopropoxy)benzene (11): Catechol (913 mg, 8.3 mmol,
1 equiv.) and potassium carbonate (4.2 equiv., 4.762 g, 34.5 mmol)
were added to anhydrous DMF (20 mL), After 2 min of argon bub-
bling, 4-bromobutyronitrile (1.8 mL) was added and the mixture
was stirred under argon at 80 °C for 16 h. After cooling to room
temp., water (3 mL) and DCM (30 mL) were added and the organic
phase was extracted with DCM (3 × 20 mL), washed with water
(20 mL), and dried with MgSO4. Filtration and distillation of solvents
gave a residue hat was purified by chromatography on silica gel
using hexane/DCM (80 to 100 %) as eluent. Compound 11 was ob-
tained as white crystals in 71 % yield. 1H NMR (300 MHz, CDCl3):
3
3
δ = 6.93 (s, 4 H, Hd), 4.11 (t, J = 6 Hz, 4 H, Hc), 2.63 (t, J = 7 Hz, 4
H, Ha), 2.16 (m, 4 H, Hb) ppm. MS (ESI): calcd. for [M + H]+ 245.1;
found 245.1.
2,3,6,7,10,11-Hexakis(cyanopropyloxy)triphenylene (2) from
11: A degassed solution of 11 (270 mg, 11 mmol, 1 equiv.) in anhy-
drous DCM (3.4 mL) at 0 °C was rapidly added under argon to a
solution of MoCl5 (1.046 g, 3.83 mmol, 3.45 equiv.) in anhydrous
DCM (34 mL). The mixture was stirred under argon at 2 °C for 2 h.
Then a saturated aqueous solution of NaHCO3 (60 mL) and AcOEt
(60 mL) were added. The organic phase was extracted with ethyl
acetate (3 × 20 mL) and dried with MgSO4. After distillation of the
solvents, the residue was purified by column chromatography (SiO2:
DCM/AcOEt, 7:3) to give 2 as a gel in 10 % yield. 1H NMR (300 MHz,
3
3
CD2Cl2): δ = 7.91 (s, 6 H), 4.36 (t, J = 6 Hz, 12 H), 2.71 (t, J = 7 Hz,
12 H), 2.27 (m, 12 H) ppm. MS (ESI): calcd. for [M + H]+ 727.3; found
727.3.
Caution should be exercised when using azides. Both organic and
inorganic azides can be heat- and shock-sensitive and can decom-
pose explosively.
2,3,6,7,10,11-Hexakis[3-(methoxycarbonyl)propyloxy]triphen-
ylene (12): Cesium carbonate (2.54 g, 7.8 mmol, 10 equiv.) and
methyl 4-bromobutanoate (0.9 mL, 7.1 mmol, 9 equiv.) were added
1,4-Bis(cyanobutoxy)benzene (1): Hydroquinone (500 mg,
4.5 mmol, 1 equiv.) and potassium carbonate (6 equiv., 4.53 g,
27.9 mmol) were added to anhydrous DMF (10 mL). Argon was to anhydrous DMF (8 mL). After 2 min argon bubbling, HHTP
then bubbled (2 min) through the solution, 5-bromovaleronitrile
(2 equiv., 1.12 mL, 9.7 mmol) was added and the mixture stirred for
(253 mg, 0.8 mmol, 1 equiv.) was added and the mixture was stirred
under argon at room temp. for 24 h. Then water (18 mL) was added
16 h at 60 °C under argon. After cooling to room temp., water to the mixture, which was then filtered. The gel was then washed
(20 mL) and DCM (20 mL) were added and the mixture extracted
with DCM (3 × 20 mL). The combined organic phases were dried
with MgSO4. After distillation of the solvents, column chromatogra- pound 12 was obtained as a gel in 30 % yield. H NMR (300 MHz,
with water and dissolved in DCM. The organic phase was then ex-
tracted with DCM (3 × 10 mL), dried with MgSO4, and filtered. Com-
1
3
phy (SiO2: DCM/AcOEt, 0 to 10 %) gave 1 as white crystals in 50 %
CD2Cl2): δ = 7.91 (s, 6 H, Hd), 4.30 (t, J = 6 Hz, 12 H, Hc), 3.70 (s, 18
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H, He), 2,64 (t, 3J = 7 Hz, 12 H, Ha), 2.22 (m, 12 H, Hb) ppm. 13C NMR
(300 MHz, CD2Cl2): δ = 173.9 (Cq,ester), 149.1 (Cq,ar.), 123.9 (Cq,ar.),
107.5 (CHar.), 68.6 (CH2-O), 51.8 (CH3), 30.7 (CH2,ester), 25.1
solid in a yield of 37 %. 1H NMR (500 MHz, D2O/MeOD): δ = 6.97 (s,
4 H, Har.), 4.21 (m, 6 H), 2.49–2.35 (m, 4 H) ppm. 13C NMR (125 MHz,
D2O/MeOD): δ = 172.9 (Cq,acid), 153.5 (Cq,ar.), 116.8 (CHar.), 65.8 (CH2-
(CH2int) ppm. MS (DCI, NH3): calcd. for [M + NH4]+ 942.4; found O), 52.5 (CH), 30.5 (CH2) ppm. MS (ESI): calcd. for [M + H]+ 313.1;
942.0. C42H60O18: calcd. C 62.33, H 6.54; found C 62.23, H 6.50.
found 313.4. HRMS (DCI, CH4): calcd. for C14H21O6N2 313.1400 [M +
H]+; found 313.1400. C14H20O6N2·2(C2HF3O2): calcd. C 40.01, H 4.10,
N 5.18; found C 40.73, H 5.56, N 6.46.
2,3,6,7,10,11-Hexakis(4-carboxypropyloxy)triphenylene (4):
Aqueous sodium hydroxide (1.3
M, 2 mL) was added to a solution
of 12 (250 mg) in THF/H2O (3:1, 2 mL) and the mixture was stirred
for 16 h at room temperature. The solvents were then evaporated
1,2-Bis[3-(methoxycarbonyl)-3-(tert-butoxycarbonylamino)-
propyloxy]benzene (15): Potassium carbonate (578 mg,
4.12 mmol, 5 equiv.) and methyl 4-bromo-2-(tert-butoxycarbonyl-
amino)butanoate (718 mg, 2.43 mmol, 2.9 equiv.) were mixed in
anhydrous DMF (8.5 mL). The mixture was purged by argon bub-
bling for 2 min. Then catechol (92 mg, 0.84 mmol, 1 equiv.) was
added to the mixture, which was stirred at 60 °C for 16 h. After
cooling to room temp., water was added (15 mL) and the organic
phase was extracted with DCM (3 × 15 mL) and washed with water
(2 × 10 mL). The combined organic phases were dried with MgSO4.
After distillation of the solvents, the residue was purified by column
chromatography (SiO2: Hex/AcOEt, 0 to 30 %) to give 15 as a color-
less oil (yield: 90 %). Rf = 0.2 (TLC, Hex/AcOEt, 7:3). 1H NMR
(300 MHz, CD2Cl2): δ = 6.90 (s, 4 H, Ha), 6.10–5.60 (br., 2 H), 4.56–
4.28 (br., 2 H), 4.20–3.98 (m, 4 H, Hb), 3.71 (s, 6 H, Hd), 2.44–2.12 (m,
4 H, Hc), 1.42 (2 s, 18 H, He) ppm. 13C NMR (75 MHz, CD2Cl2): δ =
173.0 (Cq,ester), 155.8 (Cq), 148.8 (Cq), 121.8 (CHar.), 114.2 (CHar.), 79.9
(Cq,tBu), 66.3 (CH2-O), 66.1 (CH2-O), 52.5 (CH3), 52.0 (CH), 31.9 (CH2),
28.4 (CH3) ppm. MS (DCI, NH3): calcd. for [M + H]+ 541.3; found
541.0. HRMS (DCI, CH4): calcd. for C26H40O10N2Na 563.2581 [M +
Na]+; found 563.2582; calcd. for C26H40O10N2K 579.2320 [M + K]+;
found 579.2316. C26H40O10N2: calcd. C 57.76, H 7.46, N 5.18; found
C 55.69, H 7.06, N 4.72.
and the residue dissolved in water (2 mL). Dropwise addition of 1
M
HCl to pH 1 gave a precipitate that was filtered and dried under
vacuum. Compound 4 was obtained as a white powder in a yield
1
of 70 %. H NMR (500 MHz, MeOD/H2O): δ = 7.91 (s, 6 H, Hd), 4.28
3
3
(t, J = 6 Hz, 12 H, Hc), 2.62 (t, J = 7 Hz, 12 H, Ha), 2.20 (qt, 12 H,
Hb) ppm. 13C NMR (125 MHz, MeOD/H2O): δ = 178.0 (Cq,COOH), 149.9
(Cq,ar.), 124.9 (Cq,ar.), 108.1 (CHar.), 69.5 (CH2-O), 31.9 (CH2), 26.1
(CH2) ppm. MS (DCI, NH3): calcd. for [M – H]+ 839.3; found 839.9.
C42H48O18 (820.28): calcd. C 59.99, H 5.75; found C 57.77, H 5.78.
1,4-Bis[3-(methoxycarbonyl)-3-(tert-butoxycarbonylamino)-
propyloxy]benzene (13): Potassium carbonate (638 mg,
4.62 mmol, 5.6 equiv.) and methyl 4-bromo-2-(tert-butoxycarbonyl-
amino)butanoate (609 mg, 2.06 mmol, 2.5 equiv.) were mixed in
anhydrous DMF (5 mL). The mixture was purged by argon bubbling
and then hydroquinone (90 mg, 0.82 mmol, 1 equiv.) was added to
the mixture, which was stirred at 60 °C for 16 h. After cooling to
room temp., water (20 mL) was added and the organic phase was
extracted with DCM (4 × 20 mL), and washed with brine (15 mL)
and water (15 mL). The combined organic phases were dried with
MgSO4. After distillation of the solvents under vacuum, the residue
was purified by chromatography (SiO2: Hex/AcOEt, 0 to 30 %). Com-
pound 13 was obtained as a white powder in a yield of 70 %. Rf =
2,3,6,7,10,11-Hexakis[3-(methoxycarbonyl)-3-(tert-butoxycarb-
onylamino)propyloxy]triphenylene (14): A large excess of potas-
sium carbonate (1.816 g, 13.3 mmol, 21 equiv.) and methyl 4-
bromo-2-(tert-butoxycarbonylamino)butanoate (1.240 g, 4.20 mmol,
6.7 equiv.) were mixed in anhydrous DMF (10 mL). The mixture was
degassed by argon purging for 2 min. Then HHTP (204 mg,
0.63 mmol, 1 equiv.) was added and the mixture was stirred under
argon at 60 °C for 42 h. After cooling to room temp., water (30 mL)
was added and the organic phase was extracted with DCM
(3 × 30 mL) and washed with water (2 × 15 mL). The combined or-
ganic phases were the dried with MgSO4. After removal of the sol-
vent, the raw product was purified by silica gel chromatography
using DCM/AcOEt (0 to 30 %) as eluent. Compound 14 was ob-
tained as a white solid (yield: 70 %). Rf = 0.5–0.6 (CCM, DCM/AcOEt,
1
0.2 (TLC, Hex/AcOEt, 7:3). H NMR (300 MHz, CDCl3): δ = 6.77 (s, 4
H, Ha), 5.32 (m, 2 H, Hf), 4.47 (m, 2 H, Hd), 3.97 (t, 3J = 6 Hz, 4 H,
Hb), 3.74 (s, 6 H, He), 2.35–2.11 (m, 4 H, Hc), 1.42 (s, 18 H, Hg) ppm.
13C NMR (75 MHz, CDCl3): δ = 172.8 (Cq,ester), 155.4 (Cq,amide), 153.0
(Cq,ar.), 115.6 (CHar.), 80.1 (Cq,tBu), 64.9 (CH2-O), 52.5 (CH3), 51.4 (CH),
31.9 (CH2), 28.4 (CH3,tBu) ppm. MS (ESI): calcd. for [M + H]+ 558.3;
found 558.5. HRMS (DCI, CH4): calcd. for C26H40O10N2Na 563.2581
[M + Na]+; found 563.2585; calcd. for C26H40O10N2K 579.2320 [M +
K]+; found 579.2324. C26H40O10N2: calcd. C 57.76, H 7.46, N 5.18;
found C 57.65, H 7.50, N 5.02.
1,4-Bis[3-amino-3-(methoxycarbonyl)propyloxy]benzene: Com-
pound 13 (290 mg, 537 mmol, 1 equiv.) was dissolved in a mixture
of triethylsilane (150 μL) and DCM (1.35 mL). The solution was
cooled to 0 °C and TFA (1.5 mL) was added. The mixture was stirred
at 0 °C for 15 min, and then at room temp. for 1 h. After distillation
of the solvents, the residue was recrystallized from EtOH/Et2O. 1,4-
Bis[3-amino-3-(methoxycarbonyl)propyloxy]benzene was obtained
as a white solid (yield: 99 %). 1H NMR (300 MHz, MeOD): δ = 6.90
(s, 4 H, Har.), 4.27 (t, 3J = 6 Hz, 2 H), 4.12 (m, 4 H), 3.84 (s, 6 H,
CH3), 2.43–2.34 (m, 4 H) ppm. 13C NMR (75 MHz, MeOD): δ = 170.8
(Cq,ester), 154.2 (Cq,ar.), 116.6 (CHar.), 65.2 (CH2-O), 53.7 (CH3), 51.9
(CH), 31.3 (CH2) ppm. MS (ESI): calcd. for [M + H]+ 341.2; found
341.0. HRMS (DCI, CH4): calcd. for C16H25O6N2 341.1713 [M + H]+;
found 341.1707. C16H24O6N2·2(C2HF3O2): calcd. C 42.26, H 4.61, N
4.93; found C 42.14, H 4.58, N 4.58.
1
7:3). H NMR (300 MHz, CD2Cl2): δ = 7.88 (s, 6 H, Ha), 6.26–5.70 (br.,
6 H), 4.60 (m, 6 H), 4.50–4.26 (m, 12 H, Hb), 3.74 (s, 18 H, Hd), 2.58–
2.28 (m, 12 H, Hc), 1.42 (2 s, 54 H, He) ppm. 13C NMR (75 MHz,
CD2Cl2): δ = 173.1 (Cq,ester), 155.9 (Cq), 148.8 (Cq), 124.0 (Cq), 107.4
(CHar.), 80.0 (Cq,tBu), 66.5 (CH2-O), 52.3 (CH3), 52.1 (CH), 32.0 (CH2),
28.4 (CH3) ppm. MS (ESI): calcd. for [M + Na]+ 1637.7; found 1637.8.
HRMS (DCI, CH4): calcd. for C78H114N6O30Na 1637.7477 [M + Na]+;
found 1637.7524. C78H114N6O30: calcd. C 57.98, H 7.11, N 5.20; found
C 55.79, H 6.86, N 5.09.
2,3,6,7,10,11-Hexakis(3-methoxycarbonyl-3-aminopropyl-
oxy)triphenylene: Compound 14 (286 mg, 0.18 mmol, 1 equiv.)
was dissolved in a mixture of triethylsilane (200 μL) and DCM
(3.90 mL). The mixture was then cooled to 0 °C and TFA was added
(1.95 mL). After stirring for 15 min at 0 °C and then for 1 h at room
1,4-Bis(3-amino-3-carboxypropyloxy)benzene (3): 1,4-Bis[3-
amino-3-(methoxycarbonyl)propyloxy]benzene (345 mg,
0.61 mmol) was dissolved in an aqueous solution of HBr (48 %, temp., the solvents were evaporated. The solid residue was then
2 mL) and the mixture was heated at reflux for 4 h. After cooling
to room temp., the solvents were evaporated and the residue was
recrystallized from water. Compound 3 was obtained as a white
recrystallized from EtOH/Et2O to give 2,3,6,7,10,11-hexakis(3-me-
thoxycarbonyl-3-aminopropyloxy)triphenylene as a gel (yield: 70 %).
1H NMR (300 MHz, MeOD): δ = 8.09 (s, 6 H, Har.), 4.93 (br., 12 H),
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3
4.58 (m, 12 H), 4.49 (t, J = 6 Hz, 6 H), 3.87 (s, 9 H, CH3), 3.85 (s, 9
(Na2SO4). After distillation of solvents and chromatography (SiO2:
DCM/AcOEt, 0 to 20 %), compound 5 was obtained as a white pow-
der in 85 % yield. Rf = 0.6 (TLC, DCM/AcOEt, 8:2). 1H NMR (300 MHz,
CD2Cl2): δ = 7.61 (s, 2 H, Ha), 6.93 (s, 4 H, Hc), 5.11 (s, 4 H, Hb), 4.33
H, CH3), 2.71–2.51 (m, 12 H, CH2) ppm. 13C NMR (75 MHz, MeOD):
δ = 170,8 (Cq,ester), 163.1 (q, 2JC–F = 30 Hz), 149.0 (Cq,ar.), 125.3 (Cq,ar.),
118.2 (q, 1JC–F = 300 Hz), 107.9 (CHar.), 66.5 (CH2-O), 53.9 (CH3), 52.4
(CH), 31.1 (CH2) ppm. MS (ESI): calcd. for 1015.5 [M + H]+; found
1015.3. C60H72F18N6O30: calcd. C 42.41, H 4.27, N 4.95; found C 41.14,
H 4.21, N 4.73.
3
(t, J = 7 Hz, 4 H, Hd), 1.88 (m, J = 7 Hz, 4 H), 1.31 (m, 12 H), 0.88
(t, 3J = 7 Hz, 6 H, He) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 153.2
(Cq,ar.), 144.2 (Cq,triazole), 123.0 (=CH), 116.1 (CHar.), 62.9 (CH2), 50.7
(CH2), 31.5 (CH2), 30.6 (CH2), 26.5 (CH2), 22.8 (CH2), 14.1 (CH3) ppm.
MS (DCI, NH3): calcd. for [M + H]+ 441.3; found 441.3. C24H36O2N6:
calcd. C 65.43, H 8.24, N 19.07; found C 65.29, H 8.47, N 18.72.
2,3,6,7,10,11-Hexakis(3-amino-3-carboxypropyl)triphenylene
(7): 2,3,6,7,10,11-Hexakis(3-methoxycarbonyl-3-aminopropyloxy)tri-
phenylene (108 mg, 0.064 mmol) was dissolved in a 48 % aqueous
solution of HBr (2 mL). The mixture was heated at reflux for 4 h.
After cooling and evaporation of the solvents, 7 was obtained as a
1,4-Bis(1-hexyl-1,2,3-triazol-4-ylbutoxy)benzene (6): Dialkyne 17
(40 mg, 148 μmol, 1 equiv.) and hexyl azide (2.3 equiv., 44 mg,
346 μmol) were added to THF/water (1:1, 10 mL), followed by cop-
per sulfate (17 mg, 90 μmol, 0.6 equiv.) and sodium ascorbate
(22 mg, 220 μmol, 1.5 equiv.). The mixture was vigorously stirred at
room temp. for 16 h. Then ethyl acetate (15 mL) and water (5 mL)
were added. The organic phase was extracted with AcOEt (2 × 5 mL)
and the combined organic phases were washed with water
(2 × 4 mL) and brine (4 mL) and dried over Na2SO4. After distillation
of the solvents, chromatography of the residue (SiO2: DCM/AcOEt, 0
to 100 %) gave 6 as a white powder (yield: 90 %). 1H NMR (300 MHz,
CD2Cl2): δ = 7.30 (s, 2 H, Ha), 6.80 (s, 4 H, He), 4.28 (t, 3J = 7 Hz, 4
H, Hb), 3.92 (m, 3J = 6 Hz, 4 H, Hd), 2.75 (m, 3J = 7 Hz, 4 H, CH2),
1.82 (m, 12 H, CH2), 1.31 (m, 12 H, CH2), 0.88 (t, 3J = 7 Hz, 6 H,
Hc) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 153.5 (Cq), 147.6 (Cq,triazole),
120.9 (=CH), 115.6 (CHar.), 68.5 (CH2-O), 50.5 (CH2-N), 31.5 (CH2), 30.6
(CH2), 29.3 (CH2), 26.5 (CH2), 26.4 (CH2), 25.7 (CH2), 22.8 (CH2), 14.1
(CH3) ppm. MS (DCI, NH3): calcd. for [M + H]+ 525.4; found 525.3.
1
black gel in 37 % yield. The product was purified by HPLC. H NMR
(300 MHz, D2O): δ = 7.37 (s, 6 H, Har.), 4.37–4.13 (m, 18 H), 2.59–2.40
(m, 12 H) ppm. 13C NMR (125 MHz, D2O/MeOD): δ = 173.8 (Cq,acid),
147.8 (Cq,ar.), 123.9 (Cq,ar.), 106.5 (CHar.), 66.4 (CH2-O), 53.1 (CH), 30.5
(CH2) ppm. MS (ESI): calcd. for [M + H]+ 931.4; found 931.5.
1,4-Bis[6-(triisopropylsilyl)hex-5-ynyloxy]benzene: Argon was
bubbled for 2 min through a mixture of potassium carbonate
(608 mg, 4.4 mmol, 6.8 equiv.) and (6-bromohex-1-yn-1-yl)triiso-
propylsilane (442 mg, 1.4 mmol, 2.2 equiv.) in anhydrous DMF
(5 mL). Then hydroquinone (71 mg, 0.65 mmol, 1 equiv.) was added
and the mixture was stirred at 60 °C for 16 h under argon. After
cooling to room temp., water (15 mL) and DCM (15 mL) were added
and the organic phase was extracted with DCM (2 × 20 mL) and
washed with water (20 mL). The combined organic phases were
then dried with MgSO4. After distillation of the solvents, the residue
was purified by chromatography on SiO2 with a mixture hexane/
AcOEt (0 to 5 %) as eluent to yield 1,4-bis[6-(triisopropylsilyl)hex-5-
ynyloxy]benzene as a white powder in 70 % yield. Rf = 0.5 (TLC,
C30H48O2N6: calcd. C 68.67, H 9.22, N 16.02; found C 68.38, H 9.21,
N 15.99.
1
Hex/AcOEt, 95:5). H NMR (300 MHz, CD2Cl2): δ = 6.81 (s, 4 H, He),
1,4-Phenylenebis[4-(oxymethyl)-1H-1,2,3-triazol-1-ylmethyl]
Bis(2,2-dimethylpropanoate) (18): Dialkyne 16 (106 mg,
570 μmol, 1 equiv.) and azidomethyl pivalate (197 mg 1.25 mmol,
2.2 equiv.) were added to THF/water (1:1, 2 mL), followed by copper
sulfate (72 mg, 380 μmol, 0.7 equiv.) and sodium ascorbate (81 mg,
800 μmol, 1.4 equiv.), and the mixture was vigorously stirred at
room temp. for 16 h. The organic phase was extracted with DCM
(3 × 4 mL), washed with water (2 × 4 mL), and dried with Na2SO4.
After distillation of the solvents, the residue was dissolved in ethyl
acetate (5 mL) and filtered through Celite to give 18 as a white
3
3
3.93 (t, J = 6 Hz, 4 H, Hd), 2.33 (t, J = 7 Hz, 4 H, Ha), 1.89 (m, 4 H,
Hc), 1.70 (m, 4 H, Hb), 1.07 (m, 42 H, Hf) ppm. 13C NMR (75 MHz,
CD2Cl2): δ = 153.6 (Cq,ar.), 115.7 (CHar.), 109.2 (Cq), 80.8 (Cq), 68.4
(CH2-O), 28.9 (CH2), 26.0 (CH2), 20.0 (CH2), 18.9 (CH3,TIPS), 11.7
(CHTIPS) ppm. MS (DCI, NH3): calcd. for [M + NH4]+ 600.5; found
600.3. C36H62O2Si2: calcd. C 74.16, H 10.72; found C 73.02, H 10.87.
1,4-Bis(hex-5-ynyloxy)benzene (17): TBAF (0.6 mL, 2.07 mmol,
11 equiv.) was added to a solution of 1,4-bis[6-(triisopropylsilyl)-
hex-5-ynyloxy]benzene (106 mg, 0.18 mmol, 1 equiv.) in anhydrous
THF (4 mL). The mixture was stirred at room temp. for 4 h, and then
a saturated aqueous solution of NH4Cl (4 mL) was added. The or-
ganic phase was extracted with DCM (3 × 4 mL), washed with water
(4 mL), and the combined organic phases dried with MgSO4. After
distillation of the solvents, the residue was purified by column chro-
matography on silica gel using hexane/AcOEt (95:5) as eluent to
give 17 as a white powder (yield: 99 %). Rf = 0.3 (TLC, Hexane/
1
powder in 70 % yield. H NMR (300 MHz, CD2Cl2): δ = 7.87 (s, 2 H,
Ha), 6.92 (m, 4 H, Hc), 6.22 (s, 4 H, Hd), 5.13 (s, 4 H, Hb), 1.17 (s, 18
H, He) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 177.9 (Cq,ester), 153.1
(Cq), 145.0 (Cq), 124.6 (=CH), 116.2 (CHar.), 70.1 (CH2), 62.7 (CH2), 39.0
(Cq,tBu), 26.9 (CH3) ppm. MS (DCI, NH3): calcd. for [M + H]+ 501.2;
found 501.3. C24H32O6N6: calcd. C 57.59, H 6.44, N 16.79; found C
57.37, H 6.62, N 16.32.
1
AcOEt, 95:5). H NMR (300 MHz, CD2Cl2): δ = 6.81 (s, 4 H, He), 3.92
1,4-Phenylenebis[4-(4-oxybutyl)-1H-1,2,3-triazol-1-ylmethyl]
Bis(2,2-dimethylpropanoate) (19): Dialkyne 17 (110 mg,
407 μmol, 1 equiv.), azidomethyl pivalate (2.5 equiv., 158 mg,
1.006 mmol), copper sulfate (53 mg, 278 μmol, 0.7 equiv.), and so-
dium ascorbate (60 mg, 593 μmol, 1.5 equiv.) were added to THF/
water (1:1, 4 mL). The mixture was vigorously stirred at room temp.
for 16 h. Then AcOEt (5 mL) and water (5 mL) were added, the
organic phase was extracted with DCM (2 × 4 mL), washed with
ammonium chloride (6 mL), distilled water (6 mL), and dried with
(t, 3J = 7 Hz, 4 H, Hd), 2.27 (dt, 3J = 7, 4J = 3 Hz, 4 H, Ha), 2.00 (t,
4J = 3 Hz, 2 H, Hf), 1.85 (m, 4 H, Hc), 1.69 (m, 4 H, Hb) ppm. 13C
NMR (75 MHz, CD2Cl2): δ = 153.5 (Cq,ar.), 115.6 (CHar.), 84.5 (Cq), 68.7
(CH), 68.3 (CH2-O), 28.8 (CH2), 25.5 (CH2), 18.5 (CH2) ppm. MS (DCI,
NH3): calcd. for [M + NH4]+ 288.2; found 288.2. C18H22O2: calcd. C
79.96, H 8.20; found C 78.80, H 8.40.
1,4-Bis(1-hexyl-1,2,3-triazol-4-ylmethoxy)benzene (5): Dialkyne
16 (149 mg, 800 μmol, 1 equiv.) and hexyl azide (2.1 equiv., 212 mg,
1.67 mmol) were added to THF/water (1:1, 6 mL). Then copper Na2SO4. After distillation of the solvents, 19 was purified by chroma-
sulfate (63 mg, 330 μmol, 0.4 equiv.) and sodium ascorbate (70 mg
690 μmol, 0.9 equiv.) were added. The mixture was kept at room
temp. under vigorous stirring for 16 h. After addition of AcOEt
(15 mL) and water (5 mL), the organic phase was extracted with (t, J = 6 Hz, 4 H, Hc), 2.77 (t, J = 7 Hz, 4 H, Hb), 1.81 (m, 8 H), 1.17
DCM (2 × 10 mL), washed with water (2 × 10 mL), and dried
tography over silica gel using DCM/AcOEt (0 to 30 %) as eluent to
give the product as a white powder (yield: 56 %). 1H NMR (300 MHz,
CD2Cl2): δ = 7.57 (s, 2 H, Ha), 6.80 (s, 4 H, Hd), 6.18 (s, 4 H, He), 3.92
3
3
(s, 18 H, Hf) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 177.9 (Cq,ester),
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153.5 (Cq,ar.), 148.7 (Cq,triazole), 122.4 (=CH), 115.6 (CHar.), 70.0 (N-CH2-
O), 68.4 (CH2-O), 39.0 (Cq,tBu), 29.2 (CH2), 26.9 (CH3), 26.2 (CH2), 25.5
(CH2) ppm. MS (DCI, NH3): calcd. for [M + H]+ 585.3; found 585.4.
azide (50 mg, 393 μmol, 7.5 equiv.) were added to THF/water (1:1,
6 mL), followed by copper sulfate (18 mg, 95 μmol, 1.8 equiv.) and
sodium ascorbate (24 mg, 237 μmol, 4.5 equiv.). After 16 h of vigor-
ous stirring at room temp., AcOEt (15 mL) and water (5 mL) were
added and the organic phase was extracted with AcOEt (2 × 5 mL),
washed with aqueous NH4Cl (2 × 10 mL), brine (10 mL), and water
(10 mL), and dried with Na2SO4. After distillation of the solvents,
the residue was purified by chromatography (SiO2: AcOEt/MeOH,
98:2) to give 10 as a white powder in a yield of 50 %. 1H NMR
(300 MHz, CD2Cl2): δ = 7.84 (s, 6 H, Hd), 7.35 (s, 6 H, Ha), 4.26 (m,
1,4-Bis[(1H-1,2,3-triazol-4-yl)methoxy]benzene (8): Compound
18 (140 mg, 280 μmol, 1 equiv.) was added to a mixture of THF
(7 mL) and a 1
M aqueous solution of sodium hydroxide (7 mL), and
the mixture was stirred at 50 °C for 16 h. Then the mixture was
diluted with water (3 mL) and hydrochloric acid (37 %) was added
to neutral pH. Compound 8 precipitated, was filtered, and then
dried under vacuum (white powder, 80 % yield). 1H NMR (500 MHz,
DMSO): δ = 7.94 (s, 2 H, Hb), 6,96 (s, 4 H, Hd), 5.11 (s, 4 H, Hc), 3.34
(br., 2 H, NHa) ppm. The 13C NMR spectrum could not be recorded
because of the low solubility 8. MS (FAB): calcd. for [M + H]+ 273.1;
found 273.1.
3
3J = 7 Hz, 24 H, Hc, He), 2.82 (t, J = 7 Hz, 12 H, Hb), 1.96 (m, 24 H),
1.83 (m, 12 H), 1.28 (m, 36 H), 0.86 (m, 18 H, Hf) ppm. 13C NMR
(125 MHz, CD2Cl2): δ = 149.3 (Cq,ar.), 148.0 (Cq,triazole), 123.7 (Cq,ar.),
121.0 (=CH), 107.2 (CHar.), 69.5 (CH2), 50.4 (CH2), 31.5 (CH2), 30.6
(CH2), 26.5 (CH2), 25.8 (CH2), 22.8 (CH2) ppm. MS (DCI, CH4): calcd.
for [M + H]+ 1569.1; found 1569.3.
1,4-Bis[4-(1H-1,2,3-triazol-4-yl)butoxy]benzene (9): Compound
19 (93 mg, 159 μmol, 1 equiv.) was added to a mixture of THF
1,2-Bis[(1-hexyl-1H-1,2,3-triazol-4-yl)methoxy]benzene (22):
1,2-Bis(prop-2-ynyloxy)benzene (251 mg, 1.35 mmol, 1 equiv.) and
hexyl azide (379 mg, 2.98 mmol, 2,2 equiv.) was added to THF/
water (1:1, 4 mL), followed by copper sulfate (152 mg, 0.80 mmol,
0.6 equiv.) and sodium ascorbate (177 mg, 1.75 mmol, 1.3 equiv.).
The mixture was vigorously stirred at room temp. for 24 h. The
organic phase was extracted with ethyl acetate (3 × 4 mL), washed
with water (2 × 10 mL), and dried with Na2SO4. After distillation of
the solvents, column chromatography (SiO2: DCM/AcOEt, 0 to 20 %)
gave 22 as a white powder in 86 % yield. Rf = 0.6 (TLC, DCM/AcOEt,
(7 mL) and a 1
M aqueous solution of sodium hydroxide (7 mL), and
the mixture was stirred for 16 h at 50 °C. Then water (2.5 mL) was
added and a 37 % solution of hydrochloric acid was added to neu-
tral pH. A white precipitates formed, which was filtered and dried
in an oven. Compound 9 was obtained as a white powder in a yield
1
of 65 %. H NMR (300 MHz, DMSO): δ = 7.60 (s, 2 H, Hb), 6.82 (s, 4
3
3
H, He), 3.90 (t, J = 7 Hz, 4 H, Hd), 3.34 (br., 2 H, NHa), 2.69 (t, J =
7 Hz, 4 H, Hc), 1.72 (m, 8 H, CH2) ppm. The 13C NMR spectrum could
not be recorded because of the low solubility 9.
1
2,3,6,7,10,11-Hexa[6-(triisopropylsilyl)hex-5-ynyloxy]triphenyl-
8:2). H NMR (300 MHz, CD2Cl2): δ = 7.68 (s, 2 H, Ha), 7.09–6.89 (m,
3
3
ene (20): Potassium carbonate (1.746 g, 12.6 mmol, 21 equiv.) and 4 H, Hc), 5.19 (s, 4 H, Hb), 4.32 (t, J = 7 Hz, 4 H, Hd), 1.88 (m, J =
3
(6-bromohex-1-yn-1-yl)triisopropylsilane (1.205 g, 3.81 mmol, 7 Hz, 4 H), 1.31 (m, 12 H), 0.88 (t, J = 7 Hz, 6 H, He) ppm. 13C NMR
6.4 equiv.) were added to dry DMF (10 mL) under argon. After 2 min (75 MHz, CD2Cl2): δ = 148.9 (Cq,ar.), 144.0 (Cq,triazole), 123.4 (=CH),
of argon bubbling, HHTP (194 mg, 0.60 mmol, 1 equiv.) was added
and the mixture was stirred at 60 °C for 16 h under argon. After
cooling to room temp., water (60 mL) was added and the organic
phase was extracted with DCM (3 × 30 mL) and washed with water
(30 mL). The combined organic phases were then dried under
MgSO4 and the solvents rotoevaporated. The compound was puri-
fied by column chromatography over SiO2 using hexane/DCM (5:5)
as eluent. Compound 20 was obtained as a white powder in 48 %
yield. Rf = 0.5 (TLC, hexane/DCM, 1:1). 1H NMR (300 MHz, CD2Cl2):
δ = 7.86 (s, 6 H, He), 4.28 (t, J = 6 Hz, 12 H, Hd), 2.44 (t, J = 7 Hz,
12 H, Ha), 2.08 (m, 12 H, Hc), 1.85 (m, 12 H, Hb), 1,11–0.88 (m, 126
H, Hf ) ppm. 13C NMR (75 MHz, CD2Cl2): δ = 149.4 (Cq,ar.), 123.9
(Cq,ar.),109.2 (CHar.),107.5 (CHar.), 80.7 (Cq), 69.3 (CH2), 28.9 (CH2), 26.0
(CH2), 20.0 (CH2), 18.8 (CH), 11,7 (CH3) ppm. MS (DCI, CH4): calcd.
for [M + H]+ 1442.2; found 1742.2.
122.2 (CHar.), 115.5 (CHar.), 63.4 (CH2-O), 50.7 (CH2-N), 31.5 (CH2), 30.5
(CH2), 26.5 (CH2), 22.8 (CH2), 14.1 (CH3) ppm. MS (DCI, NH3): calcd.
for [M + H]+ 441.3; found 441.3.
Acknowledgments
The Agence Nationale de la Recherche (ANR) MOLSIC is grate-
fully acknowledged for funding. A. P. thanks the French Minis-
tère de l'Enseignement Supérieur et de la Recherche for a Ph. D.
grant.
3
3
Keywords: Synthesis design · Surface chemistry · Grafting ·
Ion–molecule interactions · Amino acids · Nitrogen heterocycles
2,3,6,7,10,11-Hexakis(hex-5-ynyloxy)triphenylene (21):[20] A 1
M
solution of TBAF in THF (1.2 mL, 1.2 mmol, 30 equiv.) was added to
a solution of 20 (250 mg, 0,14 mmol, 1 equiv.) in anhydrous THF
(15 mL). The mixture was stirred for 4 h at room temp. and then
the reaction was quenched by the addition of a saturated aqueous
solution of ammonium chloride (20 mL). The organic phase was
extracted with DCM (25 mL) and washed with brine (20 mL). The
combined organic phases were dried with MgSO4. After distillation
of the solvents, the product was purified by chromatography over
SiO2 (hexane/DCM, 50 to 100 %) to give 21 as a white powder in
99 % yield; Rf = 0.6 (TLC, DCM). 1H NMR (300 MHz, CD2Cl2): δ = 7.85
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(s, 6 H, Hd), 4.26 (t, J = 6 Hz, 12 H, Hc), 2.37 (dt, J = 7, J = 3 Hz,
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Received: August 19, 2015
Published Online: November 30, 2015
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© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim