Click Synthesis of Shape-Persistent Azodendrimers and their Orthogonal Self-Assembly to Nanofibres

Article abstract of DOI:10.1071/CH17644

The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has been efficiently utilized to synthesize a series of dendrons with amino functionalities. The aminodendrons successfully underwent azodimerization to furnish a series of pyridyl- A nd

Full text of DOI:10.1071/CH17644

CSIRO PUBLISHING
Aust. J. Chem.
Full Paper
https://doi.org/10.1071/CH17644
Click Synthesis of Shape-Persistent Azodendrimers and
their Orthogonal Self-Assembly to Nanofibres
A B
,
A
Tamer El Malah
and Hany F. Nour
A
National Research Centre, Chemical Industries Research Division, Department of
Photochemistry, 33 El Buhouth Street, PO Box 12622, Giza, Egypt.
Corresponding author. Email: tmara_nrc3000@yahoo.com
B
The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction has been efficiently utilized to synthesize a series
of dendrons with amino functionalities. The aminodendrons successfully underwent azodimerization to furnish a series of
pyridyl- and phenyl-based azodendrimers with peripheral alkyl or ether side chain substituents. The molecular structures
of the azodendrimers were fully assigned using different spectroscopic techniques, such as 1H NMR and 13C NMR, and the
molecular weights were determined using MALDI-TOF mass spectrometry. The molecular self-assembly of the
azodendrimers was investigated by scanning electron microscopy and transmission electron microscopy, which revealed
the formation of highly ordered and uniform self-assembled nanofibres.
Manuscript received: 16 December 2017.
Manuscript accepted: 17 May 2018.
Published online:
14 June 2018.
dendritic skeleton.[17–19] In continuation of our work on devel-
oping new generations of dendrimer discs, we reported on the
click synthesis of dendron and dendrimer systems with triazole-
linked pyridine core units and investigated their MSA in
water.[20–22] Moreover, we studied the effect of applying an
external trigger, such as the addition of metal ions or change of
pH on the conformational structure of the triazolo-pyridine core
of the dendrons.[20–22] Herein, we report on the synthesis of
aminodendrons and azodendrimers with a trans-azobenzene and
pyridine central core loaded with peripheral long alkyl or ether
substituents and investigate their MSA behaviour.
Introduction
Over the past decades, molecular self-assembly (MSA) has
emerged as an important and leading field in supramolecular
chemistry.[1] Nature remains one of the best inspiration sources
for supramolecular chemists, particularly in the construction of
intriguing molecular self-assembled architectures through
extremely precise molecular recognition processes. The com-
plementary base-pairing of the DNA double helix is an ideal
example, in which the nitrogen bases are held together via a
network of complementary hydrogen-bonding interactions.[2]
Another well-known model demonstrating MSA in biological
systems is the bilayer self-assembly of the phospholipids to form
biological membranes, in which the hydrophobic fatty acid
chains are sorted inside the bilayer and the polar hydrophilic
constituents are oriented in the opposite phase towards the
surrounding medium.[3] The study of MSA of simple archi-
tectures can provide valuable clues towards better understand-
ing of the assembly mechanisms of more complex systems, such
as proteins or lipids. A spontaneous self-assembly of molecules
to well-organized aggregations can occur with the aid of non-
covalent interactions, such as hydrogen bonding,[4,5] p–p
stacking,[6,7] van der Waals forces,[8] electrostatic interac-
tions[9,10] or charge transfer from an electron-rich donor to an
electron-deficient acceptor.[11,12] These interactions are weak
and dynamic by nature; however, on aggregation, the molecules
usually attain new features, giving them superior potential in
comparison with the non-assembled counterparts. Among the
synthetic architectures exhibiting MSA, dendrimers and den-
drons have gained considerable interest owing to the large
number of substituents that can be loaded on a single molecule,
which induces orthogonal-type MSA.[13–15] Azodendrimers in
particular have gained significant attention owing to their ability
to undergo reversible cis–trans isomerization.[16] The photo-
isomerizable units can be located as part of an interior or exterior
Results and Discussion
The first generation (G1) azodendrimers 5a and 5b were
obtained in three synthetic steps as shown in Scheme 1. The
aromatic azides possessing a long alkyl chain 1a or an ether side
chain 1b successfully underwent CuI-catalyzed 1,3-dipolar
cycloaddition reactions with the 5-nitrobenzene 2 possessing
two free terminal alkyne groups to afford the nitrodendrons 3a
and 3b respectively. The reactions involve in situ generation
of CuI from CuSO4 and sodium ascorbate in the presence of the
tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) as a
stabilizing ligand for CuI in the aqueous t-BuOH organic
medium. The reduction of the nitro groups of the dendrons 3a
and 3b was conducted by using Pd/C (10 wt-%) in ethyl acetate
under hydrogen to afford the aminodendrons 4a and 4b. It is
noteworthy that anilines can undergo oxidative-type dimeriza-
tion on treatment with an excess of the mercury(II) oxide/iodine
reagent to form azobenzene derivatives.[23] This synthetic pro-
tocol offers many advantages, such as the mild reaction condi-
tions, high efficiency, and, more importantly, the selective
dimerization. The mechanism of the dimerization reaction was
reported to proceed via a repeated process of interactions of the
Journal compilation ꢀ CSIRO 2018
www.publish.csiro.au/journals/ajc

B
T. El Malah and H. F. Nour
NO2
NH2
NO2
2
N
N
N
N
N
N
N
N
N3
CuSO4
N
N
N
N
Na ascorbate, TBTA
EtOAc, Pd/C
H2 (2 bar)
O
R
O
R
H2O, t-BuOH, CH2Cl2, 25οC
O
O
O
O
O
O
O
O
O
O
O
R
O
O
O
R
R
R
O
R
O
O
O
1a,1b
R
R
R
4a (90 %)
4b (72 %)
3a (88 %)
3b (64 %)
HgI/I2
CH2Cl2
R
O
O
R
O
O
N
N
Ph
Ph
N
N
N
N
N
O
O
N
N
N
Ph
R
R
Trz
Trz
O
R
O
O
Trz
O
N
N
N
Ph
N
Ph
O
R
O
N
Trz
Ph
N
O
R
O
O
R
O
5a (79 %)
5b (76 %)
a, R ϭ (CH2)15CH3
b, R ϭ CHCH3CH2O(CH2CH2O)3CH3
Scheme 1. Synthetic route for the azodendrimers 5a and 5b (Ph ¼ phenyl and Trz ¼ triazolyl).
HgO/I2 reagent with the nitrogen atom of the aniline inducing an
electron transfer followed by subsequent dimerization.[23] The
aminodendrimers 4a and 4b were utilized to furnish the entire
structural framework of the dendrimers 5a and 5b. The treat-
ment of amines 4a or 4b with 1.5 equiv. of HgO/I2 reagent
afforded the corresponding azodendrimers 5a (79 %) and 5b
(76 %) respectively. To the best of our knowledge, this is the first
report of the synthesis of azodendrimers using this standard
synthetic procedure. Similarly to the azodendrimers 5a and 5b,
azodendrimers 10a–d possessing pyridyl moieties as central
core units were prepared from the CuI-catalyzed cycloaddition
reactions of aryl azides 1a and 6b–d with 2,6-diethynyl-4-
nitropyridine 7 to afford the nitrodendrons 8a–d in good yields
(Scheme 2).
2925.24 (Fig. 2). The proposed fragmentation mechanism of the
azodendrimer 10a is shown in the Supplementary Material.
The synthesis of the higher-generation (G2) azodendrimer 16
bearing a peripheral long ether corona is outlined in Scheme 3.
The two terminal alkyne functionalities of the 2,6-diethynyl-4-
nitropyridine 7 were coupled with the azide group of the aryl
azide 11 via the standard click synthetic approach to form the
nitrodendron 12. Treatment of the obtained nitrodendron 12
with sodium azide in a mixture of acetone/water under reflux
afforded the azidodendron 13,[24] which was further subjected to
the click reaction with 2,6-diethynyl-4-nitropyridine 7 to form
the corresponding second-generation nitrodendron 14.
The aminodendron 15 was obtained from the nitrodendron 14
by reduction with Pd/C (10 wt-%) in ethyl acetate under an
atmosphere of hydrogen. The dimerization of 15 on treatment
with HgO/I2 furnished azodendrimer 16 in good yield (61 %).
The structure of azodendrimer 16 was completely assigned
using the different spectroscopic tools. The 1H NMR spectrum
of azodendrimer 16 showed the 1,2,3-triazolyl CH signal at
d 8.72 and 8.79 ppm. It also showed the pyridyl CH signal at
d 8.63–8.68 ppm. The phenyl CH signals appeared at d 9.02
and 9.20 ppm. The 13C NMR spectrum of azodendrimer 16
showed the characteristic signal of the ester carbonyl group at
d 164.13 ppm.
Thereafter, the nitrodendrons 8a–d were reduced to the
aminodendrons 9a–d followed by subsequent dimerization on
treatment with the HgO/I2 reagent to yield the corresponding
azodendrimers 10a–d in 65–82 % yields. All the dendrons and
azodendrimers were separated and purified by column chroma-
tography and their chemical structures were characterized using
various spectroscopic techniques as illustrated in the Supple-
1
mentary Material. For example, the H NMR spectrum of the
azodendrimer 10a showed the expected signals of the 1,2,3-
triazolyl CH, phenyl CH, and pyridyl CH moieties at d 8.72,
8.77, and 8.96 ppm respectively. The 13C NMR spectrum
showed the characteristic signal of the ester carbonyl function-
ality at d 164.61 ppm (Supplementary Material and Fig. 1). The
MALDI-TOF (matrix-assisted laser desorption ionization-time-
of-flight mass) mass spectrum of the azodendrimer 10a showed
the expected sodiated molecular ion peak as ([M þ Naþ]) at m/z
The MALDI-TOF mass spectrum of azodendrimer 16
showed the expected molecular ion peak at m/z 4946.97 as
[M þ Hþ]. The morphology of compound 5a was investigated
using scanning electron microscopy (SEM) and transmission
electron microscopy (TEM). The SEM images of 5a revealed
the formation of well-ordered aggregations of elongated soft and

Clicking Azodendrimers and Assembly to Nanofibres
C
NO2
NH2
N
NO2
N
N
7
N
N
N
N
N
N
N
N
N3
CuSO4
N
N
N
N
R1
R2
R1
R2
R1
R2
Na ascorbate, TBTA
R1
Pd/C, EtOAc
H2 (2 bar)
R1
R2
H2O, t-BuOH, CH2Cl2, 25ЊC
R2
R2
R2
8a (84 %), 8c
R2
9a (88 %), 9c
R2
R2
1a, 6b (69 %)
6c, 6d (72 %)
9b (91 %), 9d (89 %)
8b (86 %), 8d (85 %)
HgI/I2
CH2Cl2
R2
R1
R2
R1
N
N
N
N
N
N
Ph
Trz
R2
R2
N
R2
Ph
Trz
N
N
N
N
N
Py
N
Py
R2
Trz
Ph
N
N
N
N
N
Trz
Ph
R1
R2
R1
R2
10a (76 %), 10b (79 %)
10c (65 %), 10d (82 %)
a, R1 ϭ H, R2 ϭ COO(CH2)15CH3
b, R1 ϭ H, R2 ϭ COO(CH2)3CH3
c, R1 ϭ O(CH2)17CH3, R2 ϭ H
d, R1 ϭ H, R2 ϭ COOC(CH3)3
Scheme 2. Synthetic route for the azodendrimers 10a–d (Ph ¼ phenyl, Py ¼ pyridyl, and Trz ¼ triazolyl).
O
O
O
O
N
O
O
N
N
N
N
O
O
N
N
N
O
O
O
O
N
N
N
N
N
N
N
N
O
10a
O
O
O
8.9 8.8 [ppm]
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
[ppm]
Fig. 1. 1H NMR spectrum of azodendrimer 10a (CDCl3, 300 MHz, d in ppm).

D
T. El Malah and H. F. Nour
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
TEM investigation of the morphology of the azodendrimers
revealed formation of extended nanofibres for one azoden-
drimer via molecular self-organization. We envisaged that the
p-stacking interactions of the core aromatic units and the
entanglement of the alkyl substituents most probably played a
significant role in the formation of the observed self-assembled
nanofibre association. Molecular modelling studies were uti-
lized to predict the preferred conformational structures of
the 1,2,3-triazole rings and showed preferential existence of the
azodendrimers in an anti–anti conformation. Unfortunately, the
azo-chromophores of the phenyl or pyridyl-based dendrimers
did not exhibit cis–trans isomerization on irradiation with UV
light, most probably owing to the steric hindrance of the
peripheral alkyl and ether chains.
1712.897
1635.993
1675.934
2925.244
1001.609
1000
1500
2000
2500
3000
m/z
Experimental
Materials and General Methods
Fig. 2. Mass spectrum of compound 10a (MALDI-TOF, 2-[(2E)-3-(4-tert-
butylphenyl)-2-methylprop-2-enylidene]malononitrile (DCTB) matrix):
m/z 2925.244 ([M þ Naþ]).
All solvents and chemicals were used as received without
purification, including (1-(3-dimethyl-aminopropyl)-3-ethyl-
carbodiimide hydrochloride (EDC), 4-dimethylaminopyridine
(DMAP), tetraethyleneglycol monomethyl ether, triethyle-
neglycol monomethyl ether, TBTA, citrazinic acid, 1-hex-
adecanol, t-BuOH, n-butanol, palladium on activated carbon
(Pd/C), mercury(II) oxide, and iodine. All reactions other than
the hydrogenations were conducted under argon. The copper
(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition reaction
was performed in the dark under argon and solid sodium
ascorbate and concentrated aqueous CuSO4 solutions (10 mg
CuSO4/0.3 mL of H2O) were used as in situ sources of CuI. An
aqueous EDTA disodium salt solution (16 g Lꢀ1 Na2EDTA),
adjusted to pH ,8–9, was used to remove the Cu ions during
the aqueous extractions. Column chromatography was used for
purification using 130–400-mesh silica gel as a stationary
phase with the eluents specified. The microanalysis experi-
ments were carried out by the Microanalytical Laboratory,
National Research Centre, Cairo, Egypt, and results were
found to be within ꢁ0.2 of the calculated values. 1H NMR and
13C NMR spectra were recorded on a 300-MHz (75.6 MHz for
13C NMR) Bruker DPX 300 spectrometer (Microanalytical
Centre, Cairo University) at 238C using residual protonated
solvent signals as internal standard (1H NMR: d (CHCl3)
7.26 ppm and 13C NMR: d (CHCl3) 77.16 ppm). The coupling
constants are given in Hertz (Hz). Assignments are based on the
chemical shifts (Ar is used as an abbreviation for the aromatic
phenyl group as well as triazole rings). Mass spectrometry was
performed on a Thermo LTQ FT instrument (electrospray
ionization (ESI), ESI-high-resolution mass spectrometry
(HRMS); additives of mixtures of MeOH/H2O/formic acid (75/
25/0.5 %), MSI Concept 1H (electron impact (EI), 70 eV ion-
ization) and an QSTARXL Applied Biosystems ESI Q-TOF
equipment with an ion spray voltage (ISV) of 950 V. The
MALDI-TOF spectra were recorded on a Bruker Autoflex3
Spectrometer. Ultra performance liquid chromatography
(UPLC) separations were performed using Waters Alliance
systems (mixtures and gradient mixtures of acetonitrile/water,
flow 0.6 mL minꢀ1) equipped with a 100 ꢂ 2.1-mm Aquity
HSST3 column (1.8 mm phenylhexyl material) and consisted of
a Waters Separations Module 2695, a Waters 996 diode array
detector, and a Waters ZQ 2000 mass detector. Exact condi-
tions are specified when describing the corresponding sub-
stances. Signals were detected by UV between 200 and 400 nm
(MaxPlot). Compounds 1a,[43] 1b,[24] 2,[22] 6c,[20] 7,[44] 8c,[22]
uniform nanofibre architectures with an average diameter of
155.6–250.3 nm (Fig. 3 and Supplementary Material). The
formation of nanofibres via MSA has been extensively studied
and reported in the literature.[25–40] Interestingly, the long
fibrous strand of 5a tangled uniformly with the adjacent analo-
gues to form bundles of fibrous materials with larger width. The
TEM images confirmed this result and provided even clearer
structures as shown in Fig. 3. We assumed that the p-stacking of
the aromatic core units, as well as the interdigitation of the alkyl
chains, most likely led to the formation of the well-ordered and
uniform assemblies of compound 5a. The peripheral alkyl side
chains could facilitate the entanglement between the molecules
and the p-stacking facilitates intermolecular stacking interac-
tions. In order to gain more insight into the mechanism of self-
assembly forming the extended nanofibres illustrated in Fig. 3,
we performed molecular mechanics calculations on the azoden-
drimers 5a and 10b using HyperChem (Fig. 4).[41,42]
Compound 5a can adopt either an anti–anti conformation or
a syn–syn structure owing to the free rotation around the
C
Triazole–CAromatic (CTrz–CAr) bond; however, azodendrimer
5a was rather expected to adopt the anti–anti conformer in
order to overcome steric hindrance between the long alkyl
substituents and consequently construct the observed nanofibres
(Fig. 4). The azodendrimer 10a, which incorporated pyridine
core units was found to preferentially assume an anti–anti
conformation in order to avoid repulsion of the nitrogen lone
pair of the triazole and pyridine rings. This result is in good
agreement with the reported X-ray structure and the 2D-NOESY
NMR experiments of the analogous triazole-based folda-
mers.[22] Therefore, azodendrimers 10a–d and 16 are expected
to favour anti–anti conformations for both steric hindrance and
electronic repulsion reasons that destabilize the extended syn–
syn conformers.
Conclusion
The CuI-catalyzed azide–alkyne cycloaddition (CuAAC)
reaction has been exploited for the synthesis of the first (G1)
and second (G2) generations of aminodendrons bearing long
alkyl and ether side chains. The azodimerization of the ami-
nodendrons occurred efficiently on the treatment of the ami-
nodendrons with an excess of HgO/I2 reagent. The SEM and

Clicking Azodendrimers and Assembly to Nanofibres
E
NO2
NO2
N
N3
N
N
7
N
N
N
N
N
N
N
N3
CuSO4
N
N
N
N
NaN3, acetone
Na ascorbate, TBTA
N
O
R
O
R
O
O
80ЊC
O
H2O, t-BuOH, CH2Cl2, 25ЊC
O
O
O
O
O
O
O
O
O
O
R
O
R
R
R
O
11 (55 %)
O
O
O
R
R
R
R
12 (66 %)
13 (91 %)
NO2
CuSO4
Na ascorbate, TBTA
H2O, t-BuOH, CH2Cl2, 25ЊC
N
7
R
R
R
R
O
O
O
O
R
O
R
R
R
O
O
O
O
O
O
O
R
O
R
O
R
O
R
O
O
O
O
O
O
O
O
O
N
N
N
N
N
N
N
N
N
Pd/C, EtOAc
H2 (2 bar)
O
O
R
O
O
R
N
N
R
N
R
N
N
N
N
N
N
N
N
N
N
N
N
O
O
O
O
N
N
N
N
N
N
N
N
N
N
N
N
N
N
R
N
N
N
N
R
O
O
O
O
NH2
15 (82 %)
NO2
14 (92 %)
O
R
O
R
O
N
N
O
N
N
N
R
O
N
R
O
O
O
HgI/I2
CH2Cl2
N
N
N
N
N
N
N
N
N
N
N
O
O
N
N
N
R
O
N
N
O
R
N
N
O
O
N
O
N
R
N N
R
N
N
N
O
N
N
N
N
N
N
N
N
N
O
R
O
O
R
N
O
N
N
N
O
O
R
O
R
O
O
O
O
O
R
R
16 (61 %)
R ϭ (CH2CH2O)3CH3
Scheme 3. Synthetic route for the second-generation G2 dendrimer 16.
9c,[22] and 5-azidoisophthalic acid[45] were prepared according
to the literature. SEM analysis was performed using a Quanta
FEG 250 instrument and the TEM measurements were con-
ducted on a JEM-2100 electron microscope, National Research
Centre, Cairo.
General Procedure for the Synthesis of Nitro Derivatives
3a, 3b, 8a, 8b, 8d, 12, and 14
A three-necked flask was charged with diethynyl 2 or 7
(1 equiv.) and azido derivatives 1a, 1b, 6b, 6d, 11, or 13
(2 equiv.), sodium ascorbate (0.2 equiv.), TBTA (0.1 equiv.),
and a solvent mixture of H2O/t-BuOH/CH2Cl2 (1 : 2 : 8). The
flask was evacuated, flushed with argon repeatedly (3 cycles),
CuSO4.5H2O was added (0.1 equiv.), and the mixture was
stirred at rt for 24 h in the dark. After the acetylene starting
material was consumed as indicated by TLC monitoring
(light petroleum/ethyl acetate 7 : 3), the mixture was
diluted with CH2Cl2 and transferred into a separation funnel
for extraction. The organic phase was washed with an aque-
ous Na2EDTA solution (1ꢂ) and the aqueous phase was
General Procedure for the Synthesis of Azidoderivatives
1a, 6b, 6d, and 11
5-Azidoisophthalic acid (1 equiv.), a mixture of (1-hexadecanol,
n-butanol, t-BuOH and triethyleneglycol monomethyl ether)
(2 equiv.), and DMAP (2 equiv.) were dissolved in CH2Cl2,
cooled to 08C, and EDC (4 equiv.) was added. The solution was
allowed to warm to room temperature (rt) and stirred for addi-
tional 2 days.

F
T. El Malah and H. F. Nour
(a)
(b)
(d)
(c)
Fig. 3. SEM images of the azodendrimer 5a at (a) 5 mm, (b) 1 mm scale, and TEM images of the azodendrimer 5a at (c) 1 mm and (d) 0.5 mm scale.
5a
10a
Fig. 4. Energy-minimized structures of azodendrimers 5a and 10a.
extracted with CH2Cl2 (3ꢂ). The combined organic
phases were washed with an aqueous Na2EDTA solution (2ꢂ)
and brine. The organic phase was dried over anhydrous
MgSO4, filtered, and the solvent was evaporated under
vacuum.
the mixture was filtered through a Celite pad and the solvent was
evaporated under vacuum.
General Procedure for the Synthesis of Azoderivatives 5a,
5b, 10a–d, and 16
A suspension of the amino derivative 4a, 4b, 9a–d, or 15
(0.5 mmol), mercury(II) oxide (red, 0.75 mmol) and iodine
(0.75 mmol) in CH2Cl2 (5 mL) was stirred at room temperature
for 1 h. The resultant precipitate (HgI2) was removed by suction
filtration. The filtrate and the CH2Cl2 washings (5 mL) were
combined, washed with a diluted aqueous solution of 5 %
Na2S2O3 (5 mL) and water (5 mL), dried over anhydrous
Na2SO4, and the solvent evaporated under vacuum. The crude
General Procedure for the Synthesis of Amino Derivatives
4a, 4b, 9a, 9b, 9d, and 15
In a round-bottomed flask, nitro derivatives 3a, 3b, 8a, 8b, 8d, or
14 (28.5 mmol) were dissolved in 50 mL of ethyl acetate, 795 mg
Pd on charcoal (10 wt-%) was added, and the stirred mixture was
degassed at rt under vacuumand flushed with H2 (3cycles). After
stirring for 24 h at rt under H2 atmosphere (2 bar, 200000 Pa),

Clicking Azodendrimers and Assembly to Nanofibres
G
product was flash-chromatographed on a silica gel column with
light petroleum and CH2Cl2 (2 : 1).
(m, 8H, CH2), 3.58–3.72 (m, 48H, CH2), 5.31–5.35 (m, 4H,
CO2CH), 7.23 (br s, 2H, ArNH2), 7.67 (s, 1H, ArH), 8.51 (s, 2H,
ArH), 8.58–8.59 (m, 6H, ArH), 8.60 (ss, 2H, ArH). dC (75 MHz,
CDCl3) 16.73 (CHCH3), 58.88 (OCH3), 70.40 (CH2), 70.51
(CH2), 70.57 (CH2), 70.79 (CH2), 71.24 (CH2), 71.83 (CH2),
73.56 (CH2), 76.92 (CH2), 77.17 (CH2), 77.38 (CH2), 77.43
(CH2), 112.25 (CAr), 113.32 (CAr), 118.34 (CAr), 124.80 (CAr),
130.25 (CAr), 131.36 (CAr), 132.75 (CAr), 137.28 (CAr), 147.67
(CAr), 148.45 (CAr), 164.08 (CO2), UPLC Rt5.58, 98.10 %
peak area. m/z (HRMS ESI) 1372.67 [M þ Hþ]; Calc. for
C66H97N7O24: 1372.67.
Tetrahexadecyl 5,50-((5-nitro-1,3-phenylene)bis(1H-1,2,3-
triazole-4,1-diyl))diisophthalate 3a
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7 : 3) as a beige
solid (88 %). TLC (light petroleum/ethyl acetate 7 : 3) Rf 0.37.
dH (300 MHz, CDCl3) 0.86 (t, 3J 6.0, 12H, CH3), 1.23–1.44 (m,
104H, CH2), 1.78–1.86 (m, 8H, CH2), 4.39 (t, 3J 9.0, 8H,
CO2CH2), 8.65 (s, 2H, ArH), 8.69 (ss, 4H, ArH), 8.75–8.79 (m,
4H, ArH), 8.83 (t, 3J 3.0, 1H, ArH). dC (75 MHz, CDCl3) 14.12
(CH3), 22.67 (CH2), 25.95 (CH2), 28.66 (CH2), 29.30 (CH2),
29.37 (CH2), 29.54 (CH2), 29.62 (CH2), 29.68 (CH2), 29.70
(CH2), 31.89 (CH2), 66.25 (OCH2), 118.43 (CAr), 120.18 (CAr),
124.86 (CAr), 128.21 (CAr), 130.61 (CAr), 132.38 (CAr), 133.11
(CAr), 137.04 (CAr), 146.35 (CAr), 149.30 (CAr), 164.48 (CO2).
m/z (EI) 1505.08 [M þ Naþ]; Calc. for C90H143N7O10: 1505.08.
Azodendrimer 5a
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7/3) as a yellow
compound (79 %). TLC (light petroleum/ethyl acetate 6 : 4) Rf
0.49. dH (300 MHz, CDCl3) 0.87 (t, 3J 6.0, 24H, CH3), 1.25–1.47
(m, 208H, CH2), 1.79–1.89 (m, 16H, CH2), 4.42 (t, 3J 9.0, 16H,
CO2CH2), 8.66 (s, 4H, ArH), 8.68 (ss, 8H, ArH), 8.74–8.76 (m,
8H, ArH), 8.84 (t, 3J 3.0, 2H, ArH). dC (75 MHz, CDCl3) 14.11
(CH3), 22.69 (CH2), 25.97 (CH2), 28.67 (CH2), 29.31 (CH2),
29.36 (CH2), 29.56 (CH2), 29.63 (CH2), 29.67 (CH2), 29.71
(CH2), 31.92 (CH2), 66.26 (OCH2), 118.44 (CAr), 120.17 (CAr),
124.88 (CAr), 128.19 (CAr), 130.63 (CAr), 132.41 (CAr), 133.0
(CAr), 136.99 (CAr), 146.32 (CAr), 149.31 (CAr), 164.46 (CO2).
m/z (MALDI-TOF, DCTB (trans-2-[3-(4-tert-butylphenyl)-2-
methyl-2-propenylidene]malononitrile) matrix) 2923.16 [M þ
Naþ]; Calc. for C180H286N14O16: 2923.19.
Tetra((R)-2,5,8,11-tetraoxatetradecan-13-yl) 5,50-
((5-nitro-1,3-phenylene)bis(1H-1,2,3-triazole-4,1-diyl))
diisophthalate 3b
The title compound was separated and purified by column
chromatography (CH2Cl2/acetone 7 : 3) as a yellow oil (64 %).
TLC (CH2Cl2/acetone 7 : 3) Rf 0.36. dH (300 MHz, CDCl3) 1.34
(d, 2J 6.41, 12H, CHCH3), 3.25 (ss, 12H, OCH3), 3.39–3.51 (m,
8H, CH2), 3.53–3.72 (m, 48H, CH2), 5.32–5.36 (m, 4H,
CO2CH), 8.64 (ss, 4H, ArH), 8.69–8.71 (m, 2H, ArH), 8.72 (s,
2H, ArH), 8.74 (s, 2H, ArH), 8.83 (s, 1H, ArH). dC (75 MHz,
CDCl3) 16.72 (CHCH3), 58.95 (OCH3), 70.43 (CH2), 70.61
(CH2), 70.63 (CH2), 70.85 (CH2), 71.37 (CH2), 71.88 (CH2),
73.62 (CH2), 76.80 (CH2), 77.10 (CH2), 77.34 (CH2), 118.45
(CAr), 120.32 (CAr), 124.79 (CAr), 128.43 (CAr), 130.86 (CAr),
132.55 (CAr), 133.08 (CAr), 136.89 (CAr), 146.41 (CAr), 149.51
(CAr), 163.85 (CO2). UPLC Rt 5.26 min, 100 % peak area. m/z
(HRMS ESI) 1424.62 [M þ Naþ]; Calc. for C66H95N7O26:
1424.62.
Azodendrimer 5b
The title compound was separated and purified by column
chromatography (CH2Cl2/acetone 7 : 3) as a yellow compound
(76 %). TLC (CH2Cl2/acetone 7 : 3) Rf 0.34. dH (300 MHz,
CDCl3) 1.35 (d, 2J 6.47, 24H, CHCH3), 3.25 (ss, 24H, OCH3),
3.42–3.52 (m, 16H, CH2), 3.54–3.72 (m, 96H, CH2), 5.34–5.38
(m, 8H, CO2CH), 8.65 (ss, 8H, ArH), 8.68–8.69 (m, 4H, ArH),
8.72 (s, 4H, ArH), 8.74 (s, 4H, ArH) 8.85 (s, 2H, ArH). dC
(75 MHz, CDCl3) 16.74 (CHCH3), 58.93 (OCH3), 70.44 (CH2),
70.56 (CH2), 70.61 (CH2), 70.83 (CH2), 71.39 (CH2), 71.87
(CH2), 73.59 (CH2), 76.82 (CH2), 77.08 (CH2), 77.33 (CH2),
119.58 (CAr), 120.16 (CAr), 125.03 (CAr), 128.32 (CAr), 130.82
(CAr), 132.57 (CAr), 133.03 (CAr), 137.06 (CAr), 146.38 (CAr),
149.43 (CAr), 164.00 (CO2). UPLC Rt5.31, 96.81 % peak area.
m/z (HRMS ESI) 2740.25 [M þ Hþ]; Calc. for C132H190N14O48:
2740.29.
Tetrahexadecyl 5,50-((5-amino-1,3-phenylene)bis(1H-
1,2,3-triazole-4,1-diyl))diisophthalate 4a
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 8 : 2) as a beige
solid (90 %). TLC (light petroleum/ethyl acetate 8 : 2) Rf 0.42.
dH (300 MHz, CDCl3) 0.90 (t, 3J 6.0, 12H, CH3), 1.27–1.52 (m,
104H, CH2), 1.84–1.91 (m, 8H, CH2), 4.43 (t, 3J 6.0, 8H,
CO2CH2), 4.75 (br s, 2H, ArNH2), 7.85 (s, 2H, ArH), 8.69 (s, 4H,
ArH), 8.75–8.79 (s, 5H, ArH). dC (75 MHz, CDCl3) 14.12
(CH3), 22.74 (CH2), 26.11 (CH2), 28.70 (CH2), 29.32 (CH2),
29.40 (CH2), 29.62 (CH2), 29.66 (CH2), 29.73 (CH2), 29.76
(CH2), 32.04 (CH2), 66.25 (OCH2), 109.65 (CAr), 120.21 (CAr),
125.37 (CAr), 128.82 (CAr), 130.38 (CAr), 132.96 (CAr), 137.44
(CAr), 149.56(CAr), 150.19 (CAr), 155.36 (CAr), 164.09 (CO2).
UPLC Rt 5.58, 99.15 % peak area. m/z (HRMS ESI) 1475.11
[M þ Naþ]; Calc. for C90H145N7O8: 1475.11.
Dibutyl 5-azidoisophthalate 6b
The title compound was separated and purified by column
chromatography (light petroleum/CH2Cl2 7 : 3) as a white
powder (69 %). TLC (light petroleum/CH2Cl2 7 : 3) Rf 0.58. dH
(300 MHz, CDCl3) 1.02 (t, 3J 7.37, 6H, 2CH3), 1.42–1.55 (m,
3
4H, 2CH2), 1.72–1.82 (m, 4H, 2CH2), 4.36 (t, J 6.66, 4H,
CO2CH2), 7.85 (ss, 2H, ArH), 8.42 (s, 1H, ArH). dC (75 MHz,
CDCl3) 13.72 (CH3), 19.22 (CH2), 30.66 (OCH2), 123.85 (CAr),
126.79 (CAr), 132.62 (CAr), 141.09 (CAr), 165.00 (CO2). m/z (EI,
37–508C) 320.21 [M þ Hþ]; Calc. for C16H21N3O4: 320.21.
Tetra((R)-2,5,8,11-tetraoxatetradecan-13-yl) 5,50-((5-
amino-1,3-phenylene)bis(1H-1,2,3-triazole-4,1-diyl))
diisophthalate 4b
Di-tert-butyl 5-azidoisophthalate 6d
The title compound was separated and purified by column
chromatography (CH2Cl2/acetone 7 : 3) as a yellow oil (72 %).
TLC (CH2Cl2/acetone 7 : 3) Rf 0.37. dH (300 MHz, CDCl3) 1.33
The title compound was separated and purified by column
chromatography (light petroleum/CH2Cl2 8/2) as a white pow-
der (72 %). TLC (light petroleum/CH2Cl2 8 : 8) Rf 0.56. dH
(300 MHz, CDCl3) 1.61 (s, 18H, 6CH3), 7.78 (s, 2H, ArH), 8.33
2
(d, J 6.47, 12H, CHCH3), 3.25 (ss, 12H, OCH3), 3.51–3.57

H
T. El Malah and H. F. Nour
(s, 1H, ArH). dC (75 MHz, CDCl3) 28.08 (CH3), 82.09 (OC),
123.43 (CAr), 126.68 (CAr), 133.91 (CAr), 140.71 (CAr), 164.13
(CO2). m/z (EI, 37–508C) 342.15 [M þ Naþ]; Calc. for
C16H21N3O4: 342.14.
(CAr), 130.37 (CAr), 132.89 (CAr), 137.45 (CAr), 149.64 (CAr),
150.14 (CAr), 154.41 (CAr), 164.72 (CO2). UPLC Rt 3.42,
99.23 % peak area. m/z (HRMS ESI) 1476.10 [M þ Naþ]; Calc.
for C89H144N8O8: 1476.10.
Tetrahexadecyl 5,50-((4-nitropyridine-2,6-diyl)bis
(1H-1,2,3-triazole-4,1-diyl))diisophthalate 8a
Tetrabutyl 5,50-((4-aminopyridine-2,6-diyl)bis(1H-1,2,3-
triazole-4,1-diyl))diisophthalate 9b
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7 : 3) as a beige
solid (84 %). TLC (light petroleum/ethyl acetate 7 : 3) Rf 0.38.
dH (300 MHz, CDCl3) 0.88 (t, 3J 6.0, 12H, CH3), 1.26–1.50 (m,
104H, CH2), 1.80–1.90 (m, 8H, CH2), 4.43 (t, 3J 6.0, 8H,
CO2CH2), 8.74 (ss, 4H, ArH), 8.79 (s, 2H, ArH), 8.92 (ss, 4H,
ArH). dC (75 MHz, CDCl3) 14.12 (CH3), 22.69 (CH2), 25.98
(CH2), 28.66 (CH2), 29.30 (CH2), 29.37 (CH2), 29.56 (CH2),
29.62 (CH2), 29.67 (CH2), 29.70 (CH2), 31.92 (CH2), 66.31
(OCH2), 112.41 (CAr), 121.22 (CAr), 125.24 (CAr), 130.74 (CAr),
133.05 (CAr), 137.08 (CAr), 147.71 (CAr), 152.49 (CAr), 155.76
(CAr), 164.56 (CO2). m/z (EI) 1506.07 [M þ Naþ]; Calc. for
C89H142N8O10: 1506.07.
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 8 : 2) as a beige
solid (91 %). TLC (light petroleum/ethyl acetate 8 : 2) Rf 0.41.
dH (300 MHz, CDCl3) 0.98 (t, 3J 7.23, 12H, CH3), 1.45–1.56 (m,
8H, CH2), 1.75–1.87 (m, 8H, CH2), 4.46 (t, 3J 6.67, 8H,
CO2CH2), 4.78 (brs, 2H, ArNH2), 8.62 (s, 4H, ArH), 8.60 (s, 2H,
ArH), 8.84 (s, 2H, ArH), 8.92 (s, 2H, ArH). dC (75 MHz, CDCl3)
13.76 (CH3), 19.20 (CH2), 30.65 (CH2), 65.87 (OCH2), 108.45
(CAr), 120.37 (CAr), 125.76 (CAr), 130.51 (CAr), 132.93 (CAr),
137.12 (CAr), 147.54 (CAr), 154.07 (CAr), 155.74 (CAr), 164.72
(CO2). m/z (EI, 37–508C) 803.35 [M þ Hþ]; Calc. for
C41H48N8O8: 803.35.
Tetra-tert-butyl 5,50-((4-aminopyridine-2,6-diyl)bis(1H-
1,2,3-triazole-4,1-diyl))diisophthalate 9d
Tetrabutyl 5,50-((4-nitropyridine-2,6-diyl)bis(1H-1,2,3-
triazole-4,1-diyl))diisophthalate 8b
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 8 : 2) as a beige
solid (89 %). TLC (light petroleum/ethyl acetate 8 : 2) Rf 0.40.
dH (300 MHz, CDCl3) 1.65 (s, 36H, 12CH3), 4.85 (brs, 2H,
ArNH2), 7.58 (s, 2H, ArH), 8.59–8.60 (ss, 4H, ArH), 8.65 (t, 3J
3.0, 2H, ArH), 8.74 (s, 2H, ArH). dC (75 MHz, CDCl3) 28.09
(CH3), 82.35 (OC), 118.10 (CAr), 121.39 (CAr), 124.92 (CAr),
130.70 (CAr), 134.32 (CAr), 136.75 (CAr), 147.72 (CAr), 149.08
(CAr), 154.59 (CAr), 164.11 (CO2). m/z (EI, 37–508C) 781.37
[M þ Hþ]; Calc. for C41H48N8O8: 781.37.
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7 : 3) as a beige
solid (86 %). TLC (light petroleum/ethyl acetate 7 : 3) Rf 0.39.
dH (300 MHz, CDCl3) 0.99 (t, 3J 7.21, 12H, CH3), 1.43–1.54 (m,
8H, CH2), 1.76–1.87 (m, 8H, CH2), 4.47 (t, 3J 6.65, 8H,
CO2CH2), 8.60 (s, 4H, ArH), 8.62 (s, 2H, ArH), 8.86 (s, 2H,
ArH), 8.93 (s, 2H, ArH). dC (75 MHz, CDCl3) 13.72 (CH3),
19.18 (CH2), 30.64 (CH2), 65.97 (OCH2), 113.30 (CAr), 121.26
(CAr), 124.96 (CAr), 130.53 (CAr), 132.92 (CAr), 137.05 (CAr),
147.56 (CAr), 152.40 (CAr), 155.71 (CAr), 164.45 (CO2). UPLC
Rt 4.46, 98.62 % peak area. m/z (HRMS ESI) 811.34 [M þ Hþ];
Calc. for C41H46N8O10: 811.34.
Azodendrimer 10a
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 6 : 4) as a yellow
compound (76 %). TLC (light petroleum/ethyl acetate 6 : 4) Rf
0.43. dH (300 MHz, CDCl3) 0.88 (t, 3J 6.0, 24H, CH3), 1.26–1.49
(m, 208H, CH2), 1.81–1.90 (m, 16H, CH2), 4.43 (t, 3J 6.0, 16H,
CO2CH2), 8.72 (s, 4H, ArH), 8.77 (ss, 12H, ArH), 8.96 (s, 4H,
ArH). dC (75 MHz, CDCl3) 14.11 (CH3), 22.69 (CH2), 26.00
(CH2), 28.69 (CH2), 29.34 (CH2), 29.37 (CH2), 29.59 (CH2),
29.67 (CH2), 29.71 (CH2), 31.92 (CH2), 66.22 (OCH2), 113.04
(CAr), 120.96 (CAr), 125.17 (CAr), 130.46 (CAr), 132.88 (CAr),
137.28 (CAr), 148.54 (CAr), 151.50 (CAr), 158.50 (CAr), 164.61
(CO2). m/z (MALDI-TOF, DCTB 2925.24 [M þ Naþ]; Calc. for
Tetra-tert-butyl 5,50-((4-nitropyridine-2,6-diyl)bis(1H-1,2,3-
triazole-4,1-diyl))diisophthalate 8d
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7 : 3) as a beige
solid (85 %). TLC (light petroleum/ethyl acetate 7 : 3) Rf 0.38.
dH (300 MHz, CDCl3) 1.66 (s, 36H, CH3), 8.61–8.62 (ss, 4H,
ArH), 8.68 (t, 3J 3.0, 2H, ArH), 8.86 (s, 2H, ArH), 8.87 (s, 2H,
ArH). dC (75 MHz, CDCl3) 28.11 (CH3), 82.81 (OC), 112.25
(CAr), 121.28 (CAr), 124.74 (CAr), 130.65 (CAr), 134.34 (CAr),
136.73 (CAr), 148.52 (CAr), 151.67 (CAr), 155.71 (CAr), 163.86
(CO2). m/z (EI, 37–508C) 833.32 [M þ Naþ]; Calc. for
C41H46N8O10: 833.32.
C
178H284N16O16: 2925.18.
Azodendrimer 10b
Tetrahexadecyl 5,50-((4-aminopyridine-2,6-diyl)bis
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 6 : 4) as a yellow
compound (79 %). TLC (light petroleum/ethyl acetate 6 : 4) Rf
0.45. dH (300 MHz, CDCl3) 1.03 (t, 3J 7.4, 24H, CH3), 1.44–1.56
(m, 16H, CH2), 1.75–1.85 (m, 16H, CH2), 4.48 (t, 3J 6.71, 16H,
CO2CH2), 8.61 (ss, 8H, ArH), 8.68 (s, 4H, ArH), 8.85 (s, 4H,
ArH), 8.95 (s, 4H, ArH). dC (75 MHz, CDCl3) 13.74 (CH3),
19.21 (CH2), 30.63 (CH2), 65.95 (OCH2), 113.32 (CAr), 121.27
(CAr), 124.95 (CAr), 130.51 (CAr), 132.90 (CAr), 136.98 (CAr),
147.58 (CAr), 152.41 (CAr), 155.74 (CAr), 164.41 (CO2). m/z
(MALDI-TOF, DCTB matrix) 1557.73 [M þ Hþ]; Calc. for
C82H92N16O16: 1557.70.
(1H-1,2,3-triazole-4,1-diyl))diisophthalate 9a
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 8 : 2) as a beige
solid (88 %). TLC (light petroleum/ethyl acetate 7 : 3) Rf 0.40.
dH (300 MHz, CDCl3) 0.92 (t, 3J 6.0, 12H, CH3), 1.29–1.51 (m,
104H, CH2), 1.83–1.92 (m, 8H, CH2), 4.45 (t, 3J 6.0, 8H,
CO2CH2), 4.70 (brs, 2H, ArNH2), 7.60 (s, 2H, ArH), 8.75 (s, 4H,
ArH), 8.79 (s, 4H, ArH). dC (75 MHz, CDCl3) 14.15 (CH3),
22.73 (CH2), 26.03 (CH2), 28.71 (CH2), 29.35 (CH2), 29.41
(CH2), 29.60 (CH2), 29.67 (CH2), 29.71 (CH2), 29.74 (CH2),
31.96 (CH2), 66.22 (OCH2), 105.75 (CAr), 120.26 (CAr), 125.16

Clicking Azodendrimers and Assembly to Nanofibres
I
Azodendrimer 10c
Tetrakis(2-(2-(2-methoxyethoxy)ethoxy)ethyl) 5,50-((4-
azidopyridine-2,6-diyl)bis(1H-1,2,3-triazole-4,1-diyl))
diisophthalate 13
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 7 : 3) as a yel-
low compound (65 %). TLC (light petroleum/ethyl acetate
6 : 4) Rf 0.50. dH (300 MHz, CDCl3) 0.87–0.83 (m, 12H, CH3),
1.01–1.36 (m, 120H, CH2), 1.71–1.75 (m, 8H, CH2), 4.06 (t, 3J
6.49, 8H, OCH2), 7.08–7.13 (m, 8H, ArH), 7.40–7.45 (m, 4H,
Tetrakis(2-(2-(2-methoxyethoxy)ethoxy)ethyl) 5,50-((4-nitro-
pyridine-2,6-diyl)bis(1H-1,2,3-triazole-4,1-diyl))diisophtha-
late 12 (1 equiv.) was dissolved in 20 mL of acetone, a solution
of NaN3 (897 mg, 13.8 mmol, 23 equiv.) in 5 mL of water was
added, and the reaction mixture was stirred at 808C for 4 h. The
reaction mixture was poured onto water, extracted with CH2Cl2
(3ꢂ), and washed with brine. The organic phase was dried over
anhydrous MgSO4, filtered, and the solvent evaporated under
vacuum to afford a yellow oil (91 %). TLC (CH2Cl2/acetone
7 : 3) Rf 0.34. dH (300 MHz, CDCl3) 3.18 (s, 12H, OCH3), 3.38–
3.73 (m, 40H, CH2), 4.73–4.77 (m, 8H, CO2CH2), 8.12 (s, 2H,
ArH), 8.47–8.54 (m, 6H, ArH), 8.97 (s, 2H, ArH). dC (75 MHz,
CDCl3) 58.86 (OCH3), 64.85 (CH2), 66.42 (CH2), 68.93 (CH2),
70.50 (CH2), 70.62 (CH2), 70.73 (CH2), 71.95 (CH2), 109.56
(CAr), 118.15 (CAr), 121.68 (CAr), 124.56 (CAr), 128.90 (CAr),
129.86 (CAr), 130.27 (CAr), 136.22 (CAr), 150.45 (CAr), 151.14
(CAr), 163.97 (CO2). UPLC Rt 4.35, 93.15 % peak area. m/z
(HRMS ESI) 1167.47 [M þ Hþ]; Calc. for C53H70N10O20:
1167.48.
3
4
ArH), 7.82–7.84 (dd, J 7.87, J 1.6, 4H, ArH), 8.75 (s, 4H,
ArH), 8.83 (s, 4H, ArH). dC (75 MHz, CDCl3) 14.14 (CH3),
22.71 (CH2), 25.97 (CH2), 28.97 (CH2), 29.18 (CH2), 29.38
(CH2), 29.44 (CH2), 29.53 (CH2), 29.63 (CH2), 29.66 (CH2),
29.68 (CH2), 29.71 (CH2), 31.94 (CH2), 69.26 (OCH2), 111.57
(CAr), 113.43 (CAr), 121.25 (CAr), 125.06 (CAr), 125.45 (CAr),
126.19 (CAr), 130.52 (CAr), 146.35 (CAr), 150.73 (CAr), 153.13
(CAr), 155.65 (CAr). m/z (MALDI-TOF, calibration matrix
2,5-dihydroxybenzoic acid) 1830.37 [M þ Hþ]; Calc. for
C
114H172N16O4: 1830.38.
Azodendrimer 10d
The title compound was separated and purified by column
chromatography (light petroleum/ethyl acetate 6 : 4) as a yellow
compound (82 %). TLC (light petroleum/ethyl acetate 6 : 4) Rf
0.51. dH (300 MHz, CDCl3) 1.69 (s, 72H, CH3), 8.68 (ss, 8H,
ArH), 8.72 (t, 3J 3.0, 4H, ArH), 8.79 (s, 4H, ArH), 8.91 (s, 4H,
ArH). dC (75 MHz, CDCl3) 28.12 (CH3), 82.79 (OC), 112.24
(CAr), 121.34 (CAr), 124.93 (CAr), 130.67 (CAr), 134.30 (CAr),
136.81 (CAr), 147.60 (CAr), 152.50 (CAr), 155.70 (CAr), 163.63
(CO2). m/z (MALDI-TOF, DCTB matrix) 1579.64 [M þ Naþ];
Calc. for C82H92N16O16: 1579.68.
Octakis(2-(2-(2-methoxyethoxy)ethoxy)ethyl) 5,50,500,5000-
((((4-nitropyridine-2,6-diyl)bis(1H-1,2,3-triazole-4,1-diyl))
bis(pyridine-4,2,6-triyl))tetrakis(1H-1,2,3-triazole-4,1-diyl))
tetraisophthalate 14
The title compound was synthesized following the previously
described general synthetic procedure for the nitro derivatives
and was separated and purified by column chromatography
(CH2Cl2/CH3OH 100 : 2) as a yellow oil (92 %). TLC (CH2Cl2/
CH3OH 100 : 2) Rf 0.35. dH (300 MHz, CDCl3) 3.31 (s, 24H,
OCH3), 3.48–3.57 (m, 16H, CH2), 3.61–3.78 (m, 48H, CH2),
3.85–3.92 (m, 16H, CH2), 4.46–4.55 (m, 16H, CO2CH2), 8.65–
8.82 (m, 18H, ArH), 8.95 (s, 4H, ArH), 9.21 (s, 2H, ArH). dC
(75 MHz, CDCl3) 58.87 (OCH3), 64.86 (CH2), 66.38 (CH2),
68.87 (CH2), 70.50 (CH2), 70.54 (CH2), 70.68 (CH2), 71.84
(CH2), 109.31 (CAr), 117.08 (CAr), 121.70 (CAr), 124.63 (CAr),
128.95 (CAr), 130.36 (CAr), 132.23 (CAr), 136.68 (CAr), 145.42
(CAr), 147.46 (CAr), 148.13 (CAr), 149.54 (CAr), 151.13 (CAr),
164.25 (CO2). UPLC Rt 4.65, 75 % peak area. m/z (HRMS ESI)
2505.06 [M þ Naþ]; Calc. for C115H144N22O42: 2504.98.
Bis-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)
5-azidoisophthalate 11
The title compound was separated and purified by column
chromatography (CH2Cl2/acetone 9 : 1) as a yellow oil
(55 %). TLC (CH2Cl2/acetone 9 : 1) Rf 0.41. dH (300 MHz,
CDCl3) 3.34 (s, 6H, OCH3), 3.53–3.50 (m, 4H, CH2),
3.71–3.61 (m, 12H, CH2), 3.85–3.82 (m, 4H, CH2), 4.51–
4.48 (m, 4H, CO2CH2), 7.86 (d, 2J 1.45, 2H, ArH), 8.44 (t, 3J
2.9, 1H, ArH). dC (75 MHz, CDCl3) 58.98 (OCH3), 64.69
(CH2), 68.99 (CH2), 70.54 (CH2), 70.59 (CH2), 70.64 (CH2),
71.81 (CH2), 124.15 (CAr), 127.08 (CAr), 132.24 (CAr),
141.12 (CAr), 164.86 (CO2). UPLC Rt 2.10 min, 100 % peak
area. m/z (HRMS ESI) 522.20 [M þ Naþ]; Calc. for
C22H33N3O10: 610.20.
Octakis(2-(2-(2-methoxyethoxy)ethoxy)ethyl) 5,50,500,5000-
((((4-aminopyridine-2,6-diyl)bis(1H-1,2,3-triazole-4,1-
diyl))bis(pyridine-4,2,6-triyl))tetrakis(1H-1,2,3-triazole-4,
1-diyl))tetraisophthalate 15
Tetrakis(2-(2-(2-methoxyethoxy)ethoxy)ethyl) 5,50-((4-
nitropyridine-2,6-diyl)bis(1H-1,2,3-triazole-4,1-diyl))
diisophthalate 12
The title compound was synthesized following the previously
described general synthetic procedure of the amino derivatives
and was separated and purified by column chromatography
(CH2Cl2/CH3OH 100 : 2) as a yellow oil (82 %). TLC (CH2Cl2/
CH3OH 100 : 2) Rf 0.34. dH (300 MHz, CDCl3) 3.29 (s, 24H,
OCH3), 3.46–3.54 (m, 16H, CH2), 3.60–3.76 (m, 48H, CH2),
3.83–3.91 (m, 16H, CH2), 4.45–4.57 (m, 16H, CO2CH2), 7.06
(brs, 2H, ArNH2), 8.64–8.85 (m, 18H, ArH), 9.18 (ss, 6H, ArH).
dC (75 MHz, CDCl3) 58.84 (OCH3), 64.85 (CH2), 66.37 (CH2),
68.88 (CH2), 70.48 (CH2), 70.56 (CH2), 70.71 (CH2), 71.83
(CH2), 108.36 (CAr), 117.10 (CAr), 121.75 (CAr), 124.61 (CAr),
128.92 (CAr), 130.35 (CAr), 132.57 (CAr), 136.59 (CAr), 145.49
(CAr), 147.36 (CAr), 148.07 (CAr), 149.65 (CAr), 151.14 (CAr),
164.15 (CO2). UPLC Rt 5.65, 60 % peak area. m/z (HRMS ESI)
2498.10 [M þ Naþ]; Calc. for C115H146N22O40: 2498.
The title compound was separated and purified by column
chromatography (CH2Cl2/acetone 7 : 3) as a yellow oil (66 %).
TLC (CH2Cl2/acetone 7 : 3) Rf 0.36. dH (300 MHz, CDCl3)
3.26 (s, 12H, OCH3), 3.41–3.53 (m, 8H, CH2), 3.56–3.72 (m,
32H, CH2), 4.75–4.78 (m, 8H, CO2CH2), 8.56 (s, 2H, ArH),
8.69 (s, 2H, ArH), 8.75 (s, 2H, ArH), 9.03 (s, 4H, ArH). dC
(75 MHz, CDCl3) 58.91 (OCH3), 64.87 (CH2), 66.41 (CH2),
68.89 (CH2), 70.52 (CH2), 70.58 (CH2), 70.69 (CH2), 71.87
(CH2), 109.53 (CAr), 118.12 (CAr), 121.71 (CAr), 124.67 (CAr),
128.92 (CAr), 130.37 (CAr), 132.30 (CAr), 149.62 (CAr), 151.28
(CAr), 164.34 (CO2). UPLC Rt 3.12 min, 100 % peak area. m/z
(HRMS ESI) 1171.47 [M þ Hþ]; Calc. for C53H70N8O22:
1171.47.

J
T. El Malah and H. F. Nour
Azodendrimer 16
[17] X. Shen, H. Liu, Y. Li, S. Liu, Macromolecules 2008, 41, 2421. doi:10.
1021/MA7027566
[18] L.-X. Liao, F. Stellacci, D. V. McGrath, J. Am. Chem. Soc. 2004, 126,
The title compound was separated and purified by column
chromatography (CH2Cl2/CH3OH 100 : 4) as yellow oil (61 %).
TLC (CH2Cl2/CH3OH 100 : 4) Rf 0.33. dH (300 MHz, CDCl3)
3.32 (s, 48H, OCH3), 3.50–3.52 (m, 32H, CH2), 3.63–3.75 (m,
96H, CH2), 3.88–3.91 (m, 32H, CH2), 4.45–4.57 (m, 32H,
CO2CH2), 8.63–8.79 (m, 36H, ArH), 9.02 (s, 8H, ArH), 9.20 (s,
4H, ArH). dC (75 MHz, CDCl3) 58.91 (OCH3), 64.85 (CH2),
66.37 (CH2), 68.90 (CH2), 70.49 (CH2), 70.55 (CH2), 70.66
(CH2), 71.84 (CH2), 109.32 (CAr), 118.17 (CAr), 121.72 (CAr),
124.64 (CAr), 129.11 (CAr), 130.37 (CAr), 132.20 (CAr), 136.71
(CAr), 144.58 (CAr), 147.41 (CAr), 148.14 (CAr), 149.53 (CAr),
151.00 (CAr), 164.13 (CO2). m/z (MALDI-TOF, DCTB matrix)
4946.97 [M þ Hþ]; Calc. for C230H288N44O80: 4946.99.
2181. doi:10.1021/JA036418P
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Supplementary Material
1H NMR and 13C NMR spectra, and SEM and TEM images of
azodendrimer 10a are available on the Journal’s website.
[26] C. C. Lee, C. Grenier, E. W. Meijer, A. P. H. J. Schenning, Chem. Soc.
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Conflicts of Interest
The authors declare no conflicts of interest.
[28] H. Li, X. Zheng, H. Su, J. W. Y. Lam, K. S. Wong, S. Xue, X. Huang,
X. Huang, B. S. Li, B. Z. Tang, Sci. Rep. 2016, 6, 1927. doi:10.1038/
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