Supramolecular organogels based on mesogenic 2,7-difunctionalized triphenylenes as a simple system for water content assessment in light alcohols

Article abstract of DOI:10.1039/c9nj04834k

A series of three triphenylene compounds-denoted 2,7-THTP-DiCnOH-bearing four hexyloxy ancillary chains and two variable-length alkoxy chains terminally functionalized with hydroxyl groups have been synthesized and characterized. The studied compounds exhibited thermotropic mesomorphism; the detailed nature of the mesophases was found to depend on the relative positions of the terminal functional groups relative to the crown formed by the ancillary chains. All the studied compounds were able to act as supramolecular gelators in a variety of alcohols; their organogelating ability has been rationalized in terms of physicochemical parameters like the dielectric constant, which allowed us to establish very precise predictive "solvent gelation windows" for each compound. Remarkably stable gels have been detected for 2,7-THTP-DiC6OH in methanol. As a proof of principle, we present the water sensing performance as a rapid method for the assessment of water content in alcohol samples based on the influence that the water content exerts on the gels' thermostability.

Full text of DOI:10.1039/c9nj04834k

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Supramolecular organogels based on mesogenic 2,7-
difunctionalized triphenylenes as simple system for water content
assessment in light alcohols.
Received 00th January 20xx,
Accepted 00th January 20xx
Nahir Vadra,a Cristián Huck-Iriart,b Lisandro J. Giovanetti,c Pablo H. Di Chenna,d and Fabio D.
DOI: 10.1039/x0xx00000x
Cukiernik*a
www.rsc.org/
A series of three triphenylene compounds -denoted 2,7-THTP-DiCnOH- bearing four hexyloxy ancillary chains and two
variable-length alkoxy chains terminally functionalized with hydroxyl groups have been synthesized and characterized. The
studied compounds exhibited thermotropic mesomorphism; the detailed nature of the mesophases was found to depend
on the relative positions of the terminal functional groups relative to the crown formed by the ancillary chains. All the
studied compounds were able to act as supramolecular gelators in a variety of alcohols, their organogelating ability has
been rationalized in terms of physicochemical parameters like dielectric constant, which allowed to establish very precise
predictive “solvent gelation windows” for each compound. Remarkably stable gels have been detected for 2,7-THTP-
DiC6OH in methanol. As a proof of principle, we present the water sensing performance as a rapid method for the
assessment of water content in alcohols samples based on the influence that the water content exerts on
gels´thermostability.
for n = 3)3 and on the nature of the bridging group X (e.g.: OR
chains usually give rise to Colh mesophases, O-C(O)R
Introduction
Hexasubstituted triphenylenes (TPs) bearing long aliphatic
chains at the 2,3,6,7,10,11- positions (scheme 1) exhibit a
remarkable ability to act as structural organizers. Indeed, in
the bulk state, such compounds can self-organize into liquid
crystalline (LC) phases and, in the presence of organic solvents,
some of them have shown to yield supramolecular gels.1 2 The
detailed structural features of their LC phases (type of
organization, structural parameters, thermal range, etc)
depend on the chain length n (e.g.: for X = O, columnar
hexagonal mesophases Colh are observed for n = 4 - 13 but not
substituents usually lead to rectangular Colr mesophases,
whereas the compound with SC6H12 chains exhibited a Colh
mesophase with helical superstructure).4 Moreover, several
kindred compounds, in which the core is not rigorously
triphenylene,
but
nitrogenated
analogs,
like
hexaazatriphenylenes5 also exhibit Col mesophases.
Intercalation of acceptor moieties like trinitrofluorenone (TNF)
between TP cores promotes the occurrence of columnar
nematic (Nc) or Colh mesophases in otherwise non-mesogenic
TP-based polymers6 as well as switching between Colr and Colh
X(CH2)nCH3
CH3(CH2)nX
3
6
X(CH2)nCH3
CH3(CH2)nX
2
7
a. Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales,
Departamento de Química Inorgánica, Analítica y Química Física and CONICET–
Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio
Ambiente y Energía (INQUIMAE), Buenos Aires C1428EGA, Argentina
b. Escuela de Ciencia y Tecnología, CONICET, Universidad Nacional de San Martín
(UNSAM), Campus Miguelete, 25 de Mayo y Francia, San Martín B1650KNA,
Buenos Aires, Argentina
10
X(CH2)nCH3
11
CH3(CH2)nX
c. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad
de Ciencias Exactas, Universidad Nacional de la Plata, CONICET, casilla de correo
16, sucursal 4, 1900, La Plata, Argentina
Scheme 1: General structure of 2,3,6,7,10,11-hexa-substituted
triphenylenes
mesophases in TP-based oligomers7.
When the hexasubstituted TP bears one or more terminal
functional groups, the range of self-organizing possibilities
increases remarkably.8 9 These terminal functional groups can:
i) interact through non-covalent or excluded volume
d. Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y
Técnicas, Unidad de Microanálisis y Métodos Físicos Aplicados a la Química
Orgánica (UMYMFOR), Departamento de Química Orgánica, Facultad de Ciencias
Exactas y Naturales, Pabellón 2, Ciudad Universitaria, Buenos Aires C1428EGA
Electronic Supplementary Information (ESI) available: Temperature variable WAXS
and SAXS experiments, calculation of molecular volumes in the Col LC phase, extra
SEM images of xerogels, additional images of gels, detailed 1H-NMR spectra of the
three compounds. See DOI: 10.1039/x0xx00000x
interactions, thus modifying the structure of the LC phase in
pure compounds,10
ii) allow the incorporation of TP
11 12
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the organogelating ability in different solvents. In this paper
we focus on the molecular features giving rise to the
View Article Online
DOI: 10.1039/C9NJ04834K
2 n=6,10
OH
HO
n
5
HBr/toluene
a
6
7
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9
HO
Br
n
3: a: n=6
b: n=10
b
c
OH
O(CH2)n
OH
OC6H13
OC6H13
C6H13
O
O
5: a: n=4
C6H13
O
O
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b: n=6
c: n=10
C6H13
K2CO3
C6H13
OC6H13
OH
O(CH2)n
OC6H13
25
45
65
85
105
125
OH
1
2,7-THT-DiCnOH
O
O
Br
CH3CN
(N(Et)4)I
Fig. 1 DSC traces of compound: 5a (a), 5b (b) and 5c (c)
experimental trends; and additionally we suggest a simple
method, based on these compounds, to assess the water
content of light alcohol samples.
O(CH2)3COOEt
OC6H13
LiH4Al
THF
C6H13
O
O
C6H13
OC6H13
O(CH2)3COOEt
4
Results and Discussion
Synthesis and Characterization:
Scheme 2: Synthesis of 2,7 THTP-DiCnOH compounds
Target compounds have been prepared by attaching to the
moieties in multiblock architectures, either as discrete
molecules13 14 15 16 17 18or extended main-chain19 20 21or side-
chain22 23 24 25 26 polymeric liquid crystals. iii) self-assemble in a
liquid media by reversible interactions among them or with
solvent molecules, yielding different types of supramolecular
33
2,7-THTP-DiOH precursor (1, synthesized after Cecchi et al
)
two aliphatic chains of variable length containing terminal
hydroxyl functional groups (Scheme 3). In the n = 10 and 6
cases, the precursor has directly been etherified with the
corresponding α,ω-bromoalcohol 2. In the n = 4 case, due to
some difficulties found in the purification of the synthesized 4-
bromo-butanol ascribed to its higher volatility, etherification
of 2,7-THTP-DiOH has been carried out with a commercial
bromoester, followed by reduction of the resulting TP-diester
4 to the targeted diol. All synthesized compounds have been
characterized by 1H-NMR, 13C-NMR, elemental analysis, and
MS-ESI (see Experimental section and supplementary
Information).
organogels27 28 29 30 31 32
.
The number, nature and position of the terminal functional
groups are key factors defining the supramolecular self-
assembly they can build up.
In the present study, we analyze the organizing ability of three
different TPs “decorated” with hydroxyl groups in the terminal
positions of the alkoxy chains located at the 2 and 7 positions
of an hexa(alkoxy)triphenylene bearing four linear hexyloxy
chains in the other positions (2,7-THTP-DiCnOH, scheme 2).
The three compounds differ in the length of the spacer
between the OH functional groups and the TP core (n= 4, 6 and
10). The shortest spacer (n = 4) places the OH groups inside
the “crown” formed by the aliphatic chains, the intermediate
one (n = 6) locates them exactly at the edge, and the longer
Mesomorphic Properties:
Mesophases characterization:
Mesomorphic properties of all three studied compounds have
been studied by Polarized Optical Microscopy (POM),
Differential Scanning Calorimetry (DSC) and variable-
temperature Wide-Angle X-ray Scattering (Tvar-WAXS); Small-
Angle X-rays Scattering (SAXS) has been used in some cases to
assess specific structural aspects of the LC phases of the
studied compounds.
The n = 4 compound 2,7-THTP-DiC4OH exhibits, on cooling,
two successive LC phases: a nematic one (N) from 100 to 90ºC,
and a rectangular columnar one (Colr) between 90 and 88ºC.
The DSC trace of this compound (Figure 1a) shows only one
peak on cooling and one peak on heating. Nevertheless, POM
allowed to identify a slightly marbred texture appearing at
98ºC from the non-birrefringent isotropic liquid (Figure 2a),
and a distinctive second texture characterized by Malta
O(CH2)nOH
OC6H13
C6H13
O
O
n= 4,6,10
C6H13
OC6H13
O(CH2)nOH
Scheme 3: Structure of triphenylene derivatives studied in the present work.
THTP stands for tetra(hexyloxy)triphenylene
one (n = 10), outside this region. For each one of these
compounds we studied the mesomorphic properties as well as
b
a
c
d
Fig. 2 Typical textures observed by POM: compound 5a 98°C (a), 87°C (b), compound 5b 82°C (C) and compound 5c 44°C (d)
2 | J. Name., 2012, 00, 1-3
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Crosses (Figure 2b) that was detected in experiments 4 (top), which also collects the relevant WAXS and SAXS
conducted under very careful cooling conditions, below 90ºC. patterns for each of the studied compounds. DSC runs (Figure
View Article Online
DOI: 10.1039/C9NJ04834K
The nature of each of these two mesophases has been firmly 2b) only show the endothermic peak corresponding to clearing
established through Tvar-WAXS experiments (Figure 3). The near 97ºC on heating and its exothermic counterpart on
WAXS diffraction pattern collected at 92ºC shows a low-angle cooling (ca. 60ºC), the latter certainly corresponds to
peak narrower than the one found at higher temperatures (the crystallization, as revealed by Tvar-WAXS (Figure S2).
detailed evolution of its full-width at mid-height –FWMH-, The heaviest n = 10 homolog exhibits a monotropic mesophase
showing its abrupt increase at the transition temperature, is between 46 and 39ºC. Indeed, its DSC trace (Figure 1c) shows
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shown on supplementary Figure S1) while at wide angles only
a broad halo at ca. 19º is seen. On these basis, the high
temperature mesophase of 2,7-THTP-DiC4OH is assigned as
ND. Between 90 and 88ºC, the wide angle region exhibits, at
ca. 25°, a weak peak corresponding to π-stacking, thus
confirming the ordered columnar nature of this phase (Figure
3 and Table 1); narrow peaks at low angles, indexed as 11 and
20, complete the picture of a Colr mesophase.
one endothermic peak on heating and two exothermic peaks
900
600
a
-CH2-
83°C
39°C
n=6
300
0
2
12
22
32
1800
2 
b
c
1200
600
0
11
20
n=10
-CH2-
110ºC
2
3
4
5
2
6
7
8
2
12
22
32
2000
1500
1000
500
0
2
10
18
26
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n=4
11
20
88°C
92°C
0
0
0
0
-CH2- - Stacking
92ºC
2
3
4
5
2
6
7
8
2
12
22
32
600
400
200
0
d
-CH2-
2
10
18
26
34
n=4
0
2
12
22
32
90ºC
2
0
0
Fig. 4 WAXS patterns of each of the LC phases opf the three 2,7-THTP-DiCnOH
compounds studied in this work. Also shown: SAXS details of the Colr phases.
2
10
18
26
34
on cooling. POM in this intermediate phase (Figure 2d) shows
a texture compatible with Col mesophases, with small
different regions. WAXS (Figure S3) reveals a low degree of
organization both in the high temperature phase (isotropic
liquid), and in the phase present at room temperature
(amorphous solid). Nevertheless, the WAXS pattern
corresponding to the phase present at intermediate
temperatures corresponds to an ordered material, with peaks
both in the low-angle region and the region corresponding to
aliphatic chains (ca. 19º i.e. 4.5 Å). A detailed analysis of this
intermediate phase, carried out by SAXS (Figure 4b) allows to
assign this phase as LC Colr, with cell parameters a = 40.8 Å and
b = 21.7Å. In some patterns (Figure S4), additional peaks,
corresponding to a superimposed crystalline phase, are also
detected, in agreement with the two coexisting textures
observed by POM, a kinetic issue associated to the monotropic
character of the LC phase.
0
0
0
88ºC
2
10
18
26
34
0
86ºC
0
0
2
10
18
26
34
2
Fig. 3 WAXS patterns for 2,7-THTP-DiC4OH at various temperatures.
The n = 6 homolog 2,7-THTP-DiC6OH exhibits a monotropic
nematic mesophase (N) in a narrow thermal range, which in
turn depends on the cooling rate. Indeed, some experiments
showed a “mosaic” texture at ca. 80ºC, whereas others did
not. A WAXS pattern of this compound in the N phase,
detected by this technique from 84 to 82ºC, is shown on Figure
Molecular analysis of the mesomorphic trends:
n
Phases
Lattice
parameters [Å]
a=38.5;b=19.4
-
d spacing [Å] Obsd
Miller
indices
20; 11
-
(calcd)
퐈 ∙ ퟏퟎퟎ°퐂 ∙ 퐍 ∙ ퟗퟎ°퐂 ∙ 퐂퐨퐥퐫 ∙ ퟖퟖ°퐂 ∙ 퐂퐫
퐈 ∙ ퟖퟒ°퐂 ∙ 퐍 ∙ ퟖퟐ°퐂 ∙ 퐂퐫
4
6
19.3 (19.3); 17.3 (17.3)
-
퐈 ∙ ퟒퟔ°퐂 ∙ 퐂퐨퐥퐫 ∙ ퟑퟗ°퐂 ∙ 퐂퐫
10
a= 40.8; b=21.7
20.4 (20.4); 19.1 (19.1);
14.7 (14.9)
20;11; 21
Table 1. Phase sequence and structure for the three studied compounds
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As described above, Colr mesophases have been detected for groups can be dominant thus yielding a ND rather than a Colh
2,7-THTP-DiC4OH and 2,7-THTP-DiC10OH but not for 2,7- mesophase.
View Article Online
DOI: 10.1039/C9NJ04834K
THTP-DiC6OH. It suggests that the relative length of the Previous reported studies on tetra(pentyloxy)triphenylenes
ancillary vs. functionalized chains plays a significant role in the bearing two alkoxy chains terminally functionalized with
occurrence of such rectangular mesophases, which seem to hydroxyl groups at different positions (2,3-; 3,6- and 2,7-)
appear when the functionalized chains in the 2 and 7 positions seem to agree with this behavior.9,39,40 Detailed comparisons
are either longer or shorter than the ancillary ones. This fact of those results with the ones we report here are precluded
can be interpreted on the basis of a simple geometrical model, due to the lack of detailed information about the precise
schematically depicted in Figure 5: in the case of the n=6 nature of some of the reported phases (unidentified discotics,
derivative, the six aliphatic chains (which are likely non-reported POM textures or XRD patterns) and even some
conformationally disordered, as in the models nowadays inconsistencies among different sources in the reported phase
accepted for columnar mesophases)34 35 36 37 are of the same sequences (phases´ nature and/or transition temperatures).
length and can thus give rise to a discotic molecular geometry. Nevertheless, it seems clear from those reports that
In the case of the n=10 homolog, the two functionalized chains compounds in which the bridging chains are as long as the
(also “molten”) are longer than the four ancillary ones, thus ancillary ones give rise to less ordered mesophases (or even
yielding an overall elliptical molecular geometry. A similar lack of mesomorphism at all), as we find for the compounds
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situation can be suggested for the n = 4 derivative, where the
studied here. Indeed, the mesomorphic behavior arises from a
ancillary chains might be forced to further coil/fold in order to delicate balance between geometrical features, core-core,
interchain and lateral interactions, in turn depending on the
terminal functional groups.
A second pertinent comparison can thus be made with other
di-decorated TP, particularly with those containing two
carboxylic moieties –strong H-bond donor and acceptor- as
terminal functional groups. The thermotropic mesomorphism
of some derivatives terminally decorated at the 2,3- or 2,7-
positions have been studied.11,41,42 In most cases, they
exhibited monotropic Col mesophases, also dependent on the
cooling rate. A lack of mesomorphism has been pointed out for
derivatives in which the length of the bridging chain largely
exceeds that of the ancillary chains. It has been pointed out
that the strong intermolecular interactions mediated by the
carboxylic groups, able to fully develop when the functional
groups are not hindered by the “crown”, preclude columnar
mesomorphism by avoiding free rotation around the molecular
Fig. 5 Schematic sketch of the molecular geometries of 2,7-THTP-DiCnOH compounds.
axis. Within the framework of this analysis, in our 2,7-THTP-
Red: rather discoid form of the compound bearing six aliphatic chains of approximately
DiCnOH series, terminal OH groups behave as intermediate H-
the same length (n = 6). Blue: elliptic form suggested for the other derivatives, arising
bonding moieties, in agreement with their mesomorphic
from longer bridging (blue) than ancillary (brown) chains (n = 10) or further
properties.
folding/coiling of the ancillary chains filling the void space around the short
functionalized chains (n = 4).
fill the void space created by the shorter bridging chains,
yielding again an elliptical molecular geometry. It should be
pointed out that the molecular volumes calculated for the two
compounds exhibiting Colr mesophases (see ESI for details)
agree with those measured for closely related compounds in
columnar mesophases, yield plausible bulk densities, and
Organogelating ability:
Supramolecular gels formation, structure and stability:
Organogelating properties of the three compounds were
studied using the inverted tube method;
summarized on Table 2. The three compounds were able to
form supramolecular gels on small alcohols such as methanol,
43
the results are
suggest
a volume contribution per added methylene
ethanol and 2-propanol after
a heating-cooling process
consistent with the one found in other homologous series38.
rendering translucid or turbid gels depending on concentration
(Figure S5). To accelerate the gelling process it was necessary
to cool down to 0oC but, once formed, the gels were stable at
room temperature. Gels of compounds 2,7-THTP-DiC4OH and
2,7-THTP-DiC10OH were stable for a few hours at room
temperature and then slowly started to exudate solvent,
evidenced by tube inversion. However, gels of compound 2,7-
THTP-DiC6OH from alcohol and alcohol/water 85/15 mixture
were stable for at least three months not observing fluidity or
liquid exudation during that period of time. As can be also
seen in table 2, compounds 2,7-THTP-DiC6OH and 2,7-THTP-
The lack of intracolumnar diffraction peaks at ca 3.5 Å in the
case of the n = 10 derivative suggests that the interactions
between terminal hydroxyl groups prevail over π-stacking,
thus avoiding intracolumnar order. It seems it can only
manifest when hydroxyl groups are hindered by the ancillary
aliphatic chains, (as in the case of the n = 4 derivative). The
absence of an organized Col mesophase for the n = 6
derivative seems in line with this reasoning: although the
overall shape is discoid, lateral interactions between hydroxyl
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DiC4OH are better gelators than 2,7-THTP-DiC10OH reflected birefringence was not observed supporting the absence of
in their lower critical concentration for gelation (CCG) and also crystallites or liquid crystal transitions.
have a wider gelling scope since they are also able to form gels These first results suggest that the two smaller homologs of
in n-butanol and acetonitrile. Only when temperature was this series are better supramolecular organogelators than the
raised and reached the transition temperature (Tgel) the bigger one that has the hydroxyl groups outside the alkyl
material material fell down. The Tg vs concentration crown. This statement seems in line with the lower gelling
View Article Online
DOI: 10.1039/C9NJ04834K
dependence was also explored, they all exhibited the expected ability of 2,7-THTP-DiC10OH: gels formed by this compound
max
behavior for supramolecular gels, i.e. Tgel (Gel-to-sol transition require higher concentrations and exhibit Tgel
lower than
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temperature) increasing with concentration up to a plateau 30°C, instead of ca. 50ºC found for 2,7-THTP-DiC6OH and 2,7-
THTP-DiC4OH.
n
solvent
The gels formed with 2,7-THTP-DiC4OH in methanol have a
higher thermostability than those formed by this gelator in
other monoalcohols like ethanol, 2-propanol or 1-butanol.
Indeed, Tgel in methanol is systematically 10-15 °C higher than
that for the other solvents at similar concentrations below the
CCG. Although Tgelmax is approximately the same (≈ 50ºC) in the
studied solvents, this value is reached in methanol at a lower
concentration (3.5% wt./v), roughly one third of the
concentration needed to reach saturation in the other
solvents.
10
6
4
TG (2%) TG (0.2%) TG (0.8%)
TG (4%) TG (1.6%) TG (1%)
TG (6%) TG (1.5%) TG (1.7%)
Methanol
Ethanol
2-Propanol
n-Butanol
Acetonitrile
S
I
TG (2%) TG (2.8%)
TG (0.5%)
TG (4%)
I
I
S
I
I
1-4 butanediol
1,4-butanediol
S
I
S
I
Pentanol
n-heptane
n-Heptano
The most stable gels obtained from 2,7-THTP-DiC6OH were
those of methanol and acetonitrile. Gels produced by this
S
S
S
S
S
S
I
I
S
S
S
S
S
S
I
cyclohexane
Pentane
compound in 2-propanol, n-butanol and ethanol exhibited
S
S
S
S
S
I
max
lower Tgel (Tgel
ca. 25ºC). SAXS experiments on ethanol,
Dichloromethane
Acetone
methanol and acetonitrile gels of this derivative were
2
determined (Figure 7). They show two peaks in a 1:
Toluene
positional ratio in all cases, thus suggesting a tetragonal array
of triphenylenes. Although the structural parameter a = 20.5 Å
is the same in the three cases, showing the same kind of
structural organization independent on solvent nature, the
detected peaks are significantly narrower in acetonitrile than
in methanol or ethanol, showing the structural organization is
longer range in ACN. This result is in line with the thermal
stability of the respective gels; indeed, Tgel shows a marked
correlation with the degree of structural organization of the
gels (Figure S6).
To get an insight into the morphology of the self-assembled
supramolecular structures of the organogels we also
performed SEM microscopy to the xerogels. High vacuum
drying provoked the collapse of the microstructure of the
systems so we slowly evaporated the solvent at room
temperature and atmospheric pressure and the solids so
obtained were metalized with a film of platinum before
analysis. The images obtained can be seen in Figure 8. All the
Ethyl acetate
Ethyleneglycol
Table 2. Gelation test results: after a heating-cooling to 0ºC process the system
was classified as: TG: Turbid gel, S: soluble; I: insoluble. Critical Concentration for
Gelation (CCG) is shown between brackets (% wt./V). Initial concentration was
10% wt./V except for 2,7-THTP-DiC4OH in methanol were it was 5% wt./V.
zone where a maximum Tg (Tgelmax) is reached (Figure 6). It is
worthy to note that in some cases this saturation behavior
yielded a well-defined maximum value in Tgel. The gel-sol
transitions of the gels were also studied by POM and
50
n=4
40
30
20
10
0
0
2
4
6
8
10
12
Gelator concetration( mg/100l)
40
30
20
10
0
Methanol
Ethanol
n=6
Methanol
1,5
2-Propanol
Butanol
Ethanol
Acetonitrile
Acetonitrile
1
0
2
4
6
8
10
12
0,5
0
Gelator concetration( mg/100l)
30
20
10
0
n=10
2
3
4
5
2
6
7
8
Figure 7 – SAXS pattern of the gels formed by 2,7-THTP-DiC6OH, with three
different solvents; peaks are indexed as the 10 and 11 reflexions of a tetragonal
array.
0
2
4
6
8
10
12
Gelator concetration (mg/100L)
Fig. 6 Tgel vs concentration plot for 2,7-THTP-DiC4OH (top), 2,7-THTP-DiC6OH (mid) and
2,7-THTP-DiC10OH (bottom).
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xerogels showed the characteristic morphology of the cross-
linked fibrillar network usually observed in supramolecular
gels. As can be seen the xerogels of 2,7-THTP-DiC6OH show a
less defined microstructure probably due to the collapse of
the crossed-linked system. Even though, the fibrillar network
is clearly visible in all xerogels with fibers several tens of
microns in length and widths between 60-80 nm (extra SEM
images can be found at figure S7). This suggests the presence
of a self-assembled fibrillar network on the gel phase.
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DOI: 10.1039/C9NJ04834K
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Fig. 8 SEM images of 2,7-THTP-DiCnOH xerogels obtained from methanol (a) n= 4 (b) n=
6 and (c) n= 10 and from 2-propanol (d) n= 4 (e) n= 6 and (f) n= 10
Solvent parameters “windows” for gelation: gelation
solvents prediction:
As a general trend, solvents able to be gelled by the studied
compounds seem to be small alcohols with dielectric
constants in the range ca. 14 to 37 for 2,7-THTP-DiC4OH and
2,7-THTP-DiC6OH and 18 to 37 for 2,7-THTP-DiC10OH.
Solvents not fulfilling both conditions cannot be gelled with
any of the studied compounds. As representative examples
alcohols with lower and higher dielectric constant i.g pentanol
(ε 13.9) and 1,4-butanediol (ε 32.9) respectively, do not form
gels in the presence of the studied compounds. A remarkable
case is n-butanol: it can be gelled by 2,7-THTP-DiC4OH and
2,7-THTP-DiC6OH, but not by 2,7-THTP-DiC10OH which is
highly soluble in that solvent. The difference in the gelating
ability of this compound for n-butanol (ε = 17.8) and 2-
propanol (ε = 18.3) allows for a precise determination of the
lower limit of its gelation window, and reflects the delicate
balance of factors governing supramolecular gels formation.
An exception to these general trend is acetonitrile (ACN)
which, despite not fulfilling either of the two conditions, do
form stable gels with both 2,7-THTP-DiC4OH and 2,7-THTP-
DiC6OH . Perhaps the H-bond acceptor character of ACN
accounts for this behavior.
Fig. 9 Solvent gelation scope or “gelation windows” based on solvent´s dielectric
constants (ε). Top: 2,7-THTP-DiC4OH, middle: 2,7-THTP—DiC6OH, bottom: 2,7-THTP-
DiC10OH. Full green circles: measured Tgel in alcohols (10% wt./v concentration was
used in all cases except for n=4 in methanol were a 5% concentration was used); full blue
square: measured Tgel in ACN; down red arrows: ε of the alcohols not forming gels; up
orange arrows: ε of other solvents not forming gels, grey area: gelation window
established for each gelator on the basis of the preceding points; open green circles:
experimental Tgel in alcohols where gelation is predicted (see text); open red circle:
prediction of no gel formation. Code: 1: n-heptane, 2: cyclohexane, 3: n-pentane, 4:
toluene, 5: ethyl acetate, 6: dichloromethane, 7: 1-pentanol, 8: 1-butanol, 9: acetone, 10:
2-propanol, 11: ethanol, 12: 1:1 ethanol:methanol mixture, 13: methanol, 14: 2,4-
butanediol, 15: ethylenglycol, 16: acetonitrile, 17: cyclohexanol, 18: 1-propano Ploted
temperatures arise from duplicate uns; their uncertainties are less than ± 1ºC.
The “gelation windows” built up with these simultaneous
conditions (Figure 9), allowed us to predict the gelation of n-
propanol for the three TP-based gelators, a prediction
confirmed by experiments performed with the inverted tube
method. Moreover, the “gelation windows” predict gelation
of cyclohexanol for the n = 4 and 6 but not for the n = 10
derivatives, in perfect agreement with our experimental
findings.
Another useful tool used with success to predict the solvent
supramolecular gelation scope of low molecular weight
organogelators involves the determination of a gelling zone in
a three-dimensional diagram known as the Hansen space44
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where the three Hansen solubility parameters: dispersive
interactions (d), dipolar interactions (p) and hydrogen-bond Inspection of Table 3 shows that as the chain length increases,
interactions (H) are plotted. The corresponding diagram for both Tgel and ΔHgel decrease. Indeed, for 2,7-THTP-DiC10OH,
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DOI: 10.1039/C9NJ04834K
the three compounds studied here is shown in Figure 10.
the only solvent in which measurement was possible was
A “gelation region” is clearly seen; it involves intermediate H methanol: in ethanol and 2-propanol the gels broke during
values, in agreement with the gelation ability found for light manipulation, exuding solvent. The gel formed by 2,7-THTP-
alcohols and for ACN with the lighter gelator homologs. In DiC6OH in methanol exhibits Hgel = 165 kJ/mol, significantly
agreement with the previous method, both ACN and higher than the enthalpies measured for all the other solvents.
cyclohexanol, being gelated by the n = 4 and 6 but not n = 10 DSC results for 2,7-THTP-DiC4OH in Methanol are in
derivative, lie near the frontier of this general “gelation agreement with the peculiar thermic behavior observed with
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region”.
the inverted tube method: although Hgel is similar to the
values found for the other solvents, the maximum thermal
stability is reached at half the concentration (5%). It is worthy
to note the outstanding stability of the gels formed by 2,7-
THTP-DiC6OH in methanol compared to the others, with Hgel
more than twice the value found for any other system, thus
showing a high selectivity for this solvent. The cooling curves
were also measured but the transitions were wider and
hysteresis was observed. Opening the sealed pan it was
evident that some solvent evaporated after the sol phase was
reached and, though, the cooling curves were not
representative of the same system due to a change in
concentration. For the same reason, subsequent heating
curves were not measured.
H = 165
Kj/mol
H = 124
Kj/mol
T=50ºC
Figure 10: 3-D representation of the Hansen Space and gelation ability
of 2,7-THT-DiCnOH (n = 4, 6, 10) for different solvents. Green symbols
correspond to solvents gelled by all gelators; red symbols to solvents
that cannot be gelled; orange symbols correspond to n-butanol and
ACN that cannot be gelled by 2,7-THT-DiC10OH. Blue symbols
correspond to the solvents for which a prediction about gelation has
been made following the gelation window criterion based on the
dielectric constant. Axis corresponds to the Hansen´s parameters.
Solvents´code as in Figure 9.
H = 115
Kj/mol
T=40ºC
T=38ºC
Temperature (°C)
Fig. 11 DSC traces for gels of 2 7-THT-DiC6OH in methanol at different concentrations
Water influence on gel formation: a simple method for the
assessment of water content in alcohols:
A closer look to the gel-sol transition and the gels stabilities
DSC studies of the supramolecular gels showed a strong
dependence on concentration of both Tgel and ΔHgel (see Figure
11 as an example). This trend can be ascribed to the fact that
an increase in gelator concentration should yield an increase in
the number of formed fibers, thus increasing its crosslinking; a
higher crosslinking degree is expected to increase both Tgel and
ΔHgel. Taking this into account, enthalpies associated to gel
breaking have been measured at the highest possible
concentration in each case, in order to be able to perform
meaningful comparisons. The obtained results are collected on
Table 3.
Addition of a small amount of water, up to 20 %, increases the
stability of the gels formed by 2,7-THT-DiC6OH and 2,7-THT-
DiC10OH in ethanol, as can be inferred from the increase in
both Tgel and Hgel (Table 4). These ethanol/water gels were
stable for at least three months at room temperature. Addition
of water to 2-propanol has the same effect for the n=10
gelator while it does not affect the stability of the gels formed
by the n=6 derivative. On the other hand, the addition of
Tgel ,in °C (Hgel, in kJ/mol)
Solvent
Methanol
n=6
n=10
30 (38)
NO GEL
X
Tgel , in °C (Hgel, in kJ/mol)
50 (165)
NO GEL
28 (32)
41 (88)
31 (30)
33 ( 26)
Solvent
Methanol
Ethanol
n=4
56 (61)
53 (63)
46 (50)
X
n=6
50 (165)
28 (32)
31 (30)
X
n=10
30 (38)
x
Methanol-Water 9:1
Ethanol
2-Propanol
Butanol
x
Ethanol-Water 9:1
2-popanol
44 (31)
X
NO GEL
NO GEL
Acetonitrile
57 (85)
53 (44)
2-Propanol-Water 9:1
34 (15)
Table 3 - Temperatures (± 1ºC) and enthalpies (± 5 %) for the gel-sol transition
measured by DSC for gel breaking. X: non-measured due to mechanical breaking of the
corresponding gel during handling. 10%wt./v concentration was used in all cases
except for n=4 in methanol were a 5% concentration was used.
Table 4 – Thermal properties of the gels formed by 2,7-THTP-DiCnOH
in light alcohol:water mixtures compared to those in pure alcohols
(uncertainties as in Table 3).
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water to methanol has a strongly destabilizing effect: 2,7-THT-
DiCnOH no longer form gels under these conditions but
rending dissolved.
Experimental
Physicochemical measurements:
Elemental analyses were carried out at Servicio a Terceros of
INQUIMAE, on a Carlo Erba CHNS-O EA1108 analyzer. H and
13C NMR spectra were measured at UMYMFOR on a Bruker
AM500 spectrometer, using CDCl3 as solvent and its residual
peaks as internal references (7.26 ppm for 1H and 77.0 ppm for
13C). Mass spectra were recorded in a Xevo G2S QTof (CIBION)
with ESI ion source.
Mesomorphic properties have been studied by means of
variable temperature polarizing optical microscopy (POM),
Differential Scanning Calorimetry (DSC) and variable
temperature wide and small angle X-ray scattering (WAXS and
SAXS). POM was carried out between crossed polarizers using
a Leitz DMRX microscope equipped with a Leitz 1350 hot-
stage. DSC experiments were performed on a Shimadzu DSC-
50 calorimeter. SAXS/WAXS experiments were performed at
INIFTA facilities using a XEUSS 1.0 (XENOCS) with a Cu Kɑ
radiation parallel x-ray beam microsource. A Plilatus 100K
was employed with 533 cm sample detector distance for SAXS
geometry and 10 cm for WAXS experiments. Samples were
placed in borosilicate capillars and inside a temperature
controlled sample-holder from Linkam®. Each sample was
kept at a temperature above the isotropic phase transition for
at least 30 minutes before cooling down with a 1ºC/min
cooling rate.
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The sensitivity of some gels´ thermostability to the presence of
small amounts of water suggested that the measurement of
the Tg of a gel at a known concentration of gelator would be a
useful semiquantitative method to assess for the water
content in some light alcohols. Following this idea, we first
tried to establish the detection limit of this method: ethanol or
2-propanol solutions of either 2,7-THT-DiC6OH or 2,7-THT-
DiC10OH, in concentrations below the critical concentration
for gel formation at 0ºC were prepared, then increasing
amounts of water were added to each solution until a stable
gel was obtained. The so obtained water detection limits are
collected in Table 5.
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n
6
Solvent (%wt/V)
Water Detection Limit
Ethanol (1,4)
2-Propanol (1)
Ethanol (2)
1%
3%
2%
6%
10
2-propanol (4)
Table 5. Detection limit of water in light alcohols
It is worthy to note that, using this visual method, 2,7-THT-
DiC6OH allows for the detection of water even when its
content is as low as 1 % in ethanol or 3% in 2-propanol. 2,7-
THT-DiC6OH exhibits some advantages when compared to 2,7-
THT-DiC10OH for the purpose of water detection: not only its
detection limit is lower, but also a lower concentration is
required (Table 5).
Gelation studies:
The gelation ability was investigated by a typical inverted tube
experiment. A mixture of a defined amount of gelator and a
volume of the solvent (10% wt./v) in a closed flask was heated
and shaken until the solid was dissolved and then cooled down
to 0°C. If a stable gel was observed after inversion of the flask,
it was considered a gel (G). The critical concentration for
gelation (CCG) was determined by subsequent dilution of the
original organogel followed by heating-cooling process until
gel formation was not observed. The xerogels were prepared
by slow evaporation of solvent at room temperature.
SEM pictures of xerogels were taken on a Carl Zeiss NTS SUPRA
40FEG scattering electron microscope and xerogels were. Prior
to examination the xerogels were coated with a thin layer of
platinum.
As a proof of principle for the quantitative determination of
water content in ethanol, a calibration curve Tgel vs water
content has been constructed using
a
1.4% wt./v
concentration of 2,7-THT-DiC6OH (Figure 12), varying the
water content in the range for which gelation was observed (1
to 20 %). It allows for a quantitative assessment of water
content in a given sample of ethanol, just by preparing a 1.4%
solution of 2,7-THT-DiC6OH (heating previously for dissolution
and cooling to 0°C) and measuring its Tgel by the inverted tube
method. No need for sophisticated equipment is required but
a calibrated thermometer. The curve also shows that if the
water content exceeds 10%, a stable gel is obtained at room
temperature without cooling, which provides a visual method
Synthesis:
2,7-Dihydroxy-tetrakis(hexyloxy)triphenylene (1):
This compound was synthetized following
methodology.33
a reported
6-Bromohexan-1-ol (3a):
Compound 2a was prepared according to the method
described by Chong et al . An HBr 47% aqueous solution (0.58
ml, 3.73 mmol) was added to a solution of 1,2-hexanediol
(0.44 g; 3.73 mmol) in toluene (6ml). The resulting mixture was
stirred and heated at reflux for 3 hs. Water (5ml) was added
and the solution was extracted with ether. The organic phase
was washed with 1 M aqueous NaOH. The organic phase was
dried with anhydrous Na2SO4, then filtered and the solvent
45
(dissolve, stir and look) to qualitatively decide whether a
sample of Ethanol contains or not (more than 10%) water.
Figure 12 – Water content dependence of Tgel for 2,7-THTP-DiC6OH/Ethanol gels.
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Uncertainties in individual Tgel easurements are less than 1ºC; curves (not shown)
linking the “upper” and “lower” confidence limits of individual measurements
allow to estimate the uncertainty of this mehod as 1-2 % for low water content
and 2-3 % for water content higher than 10 %.
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evaporated under reduced pressure to dryness. The crude
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product was purified by column chromatography (silicagel, 6,6'-((3,6,10,11-Tetrakis(hexyloxy)tripheDnOyIl:e1n0e.1-023,97/-C9NJ04834K
cyclohexane/ethyl acetate 85:15) to yield a yellow oil (0.45 g, diyl)bis(oxy))bis(hexan-1-ol) (5b)
1
74%). H-NMR (500 MHz, CDCl3) δ 3.66 (t, J = 6.6Hz, 2H); 3.43 6-bromohexan-1-ol (3a) (0.45 g, 2.48 mmol) was added to a
(t, J = 6.8 Hz, 2H); 1.89 (m, 2H); 1.61 (m, 2H); 1.52 (m, 2H); mixture of 2,7-dihydroxy-tetrakis(hexyloxy)triphenylene (1)
1.41(m, 2H).
(0.45 g, 0.76 mmol) and anhydrous potassium carbonate (1 g)
in butanone (15 ml). The mixture was refluxed for 26 hs under
argon atmosphere, then water (5 ml) was added and the
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10-Bromodecan-1-ol (3b):
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Compound 2b was prepared following a similar procedure, solution was extracted with dichlorometane (2x10 ml). The
using 0.44 ml (2.57 mmol) of 47% HBr (ac) and 0.45 g (2.57 organic phase was washed with 1 M HCl, dried with Na2SO4
mmol) of 1,2-decanediol of in toluene (10 ml), and refluxing and the solvent evaporated under reduced pressure. The
for
6 h. The crude product was purified by column crude product was purified by column chromatography (silica,
chromatography (silica, cyclohexane/ethyl acetate 90:10) to cyclohexane/ethyl acetate 70:30) and recrystallized from n-
1
1
yield a yellow oil (0.45 g, 77%). H-NMR (500 MHz, CDCl3) δ heptane, to yield a beige solid (0.40 g, 68%). m.p.: 101ºC. H-
3.66 (t, J=6.6 Hz, 2H); 3.43 (t, 6.9 Hz, 2H); 1.87 (m, 2H); 1.59 NMR (500 MHz, CDCl3) δ 7.87 (S, 6H), 4.25 (m, 12H), 3.76 (t, J =
(m, 2H); 1.44 (m, 2H), 1.31 (m, 10H).
6.5, 4H), 2.9-1.9 (m, 12H), 1.72-1.51 (m, 20H), 1.48-1.24 (m,
16H), 0.98 (t, J = 7 Hz, 12H) (Figure S8). 13C-NMR: 149; 148,94,
Diethyl 4,4'-((3,6,10,11-tetrakis(hexyloxy)triphenylene-2,7- 123,70; 123,62; 107,37; 69,78; 69,55; 62,95; 32,74; 31,69;
diyl)bis(oxy))dibutanoate (4) 29,45; 29,43; 26,02; 25,87; 25,87; 25,86; 25,65; 22,68; 14,07.
A solution of ethyl 4-bromobutanoate (0.25 ml, 1.8 mmol) HRMS (ESI) m/Z: M+ measured (calculated) 860.6190
dissolved in CH3CN (6 ml) was added to a mixture of 2,7- (860.6166). Elemental analysis: Measured (calculated) for
dihydroxy-tetrakis(hexyloxy)triphenylene (1) (0.3 g, 0.45 C54H84O8 %C: 74.9 (75.3); %H: 9.8 (9.8)
mmol), tetraethylammonium iodide (0.03 g), and anhydrous
potassium carbonate (0.64 g) in 15 ml of CH3CN. The resulting 10,10'-((3,6,10,11-Tetrakis(hexyloxy)triphenylene-2,7-
mixture was refluxed for 27 hs, then cooled down to room diyl)bis(oxy))bis(decan-1-ol) (5c):
temperature and poured into CHCl3 (20 ml). The solids were 10-bromodecan-1-ol (3b) (0.45 g, 1.9 mmol) was added to a
filtered off, the organic layer was dried with Na2SO4 and the mixture of 2,7-dihydroxy-tetrakis(hexyloxy)triphenylene (1)
solvent was evaporated under reduced pressure. The crude (0.38 g, 0.57 mmol)) and anhydrous potassium carbonate (1 g)
product was purified by column chromatography (silica, in butanone (15 ml). The resulting mixture was refluxed for 26
cyclohexane/dichloromethane 20:80) to yield a beige solid hs under argon atmosphere. Water (5ml) was added and the
(0.35 g, 87%). 1H-NMR (500 MHz, CDCl3) δ 7.90 (S, 2H); 7.88 (S, solution was extracted with dichlorometane (2x10 ml). The
2H); 7.85 (S, 2H, 4.32 (t, J=6.2 Hz, 4H); 4.26 (m, 8H); 4.19 (m, organic phase was washed with 1 M HCl, dried (Na2SO4) and
4H); 2.67 (t, J=7.2 Hz, 4H), 2.28 (m, 4H); 1.95 (m, 8H); 1.6 (m, evaporated under reduced pressure. The crude product was
8H), 1.43 (m, 16H); 0.96 (t, H=7 Hz, 12H); 0.91 (t, J=7.1Hz, 6H)
purified by column chromatography (silica, cyclohexane/
acetone 85:15) and recrystallized from n-heptane, to yield a
beige solid (0.36 g, 65%). m.p.: 51ºC. 1H-NMR (500 MHz, CDCl3)
δ 7.86 (S, 6H), 4.25 (m, 12H), 3.66 (t, J = 6.5, 4H), 2.08-1.86 (m,
4,4'-((3,6,10,11-Tetrakis(hexyloxy)triphenylene-2,7-
diyl)bis(oxy))bis(butan-1-ol) (5a)
A solution of compound 4 (0.35 g, 0.39 mmol) in dried THF (10 12H), 1.59 (m, 20H), 1.36 (m, 32H), 0.98 (t, J = 6.6Hz, 12H).
ml) was added dropwise to a mixture of LiAlH4 (0.1 g, 2.63 (Figure S8) 13C-NMR: 148.47; 123.62; 107.38; 69.71; 63.09;
mmol) and THF (10 ml) keeping the temperature controlled by 31.70; 29.59; 29.50; 25.87; 22.68; 14.08. HRMS (ESI) m/Z: M+
an ice bath. After the addition, the ice bath was removed and measured (calculated) 972.7426 (972.7418) Elemental
the solution stirred for 4 hs. Methanol (5 ml) and water (5 ml) analysis: measured (calculated) for C62H100O8 (973.45) %C: 76.2
were added. The mixture was extracted with CH2Cl2 (2x10ml) (76.5); %H: 10.3 (10.3)
and the organic phase was dried with Na2SO4 and evaporated
under reduced pressure. The crude product was purified by Conclusions
column chromatography (silica, cyclohexane/ethyl acetate This work confirmed previous suggestions stating that the
80:10) and recrystallized from n-heptane, to yield a beige solid position of the terminal functional group with respect to the
(0.31 g, 79%). m.p.: 95ºC. 1H-NMR (500 MHz, CDCl3) δ 7.86 (S, crown defined by the ancillary aliphatic chains is a key
2H), 7.85 (S, 2H), 7.84(S, 2H), 4.32 (t, J = 5.9 Hz, 4H), 4.26 (t, J = parameter defining the LC properties (kind of mesophase,
6.6 Hz, 8H), 3.83 (q, J = 5.7 Hz, 4H), 2.10 (m, 4H), 1.99 (m, 12H), thermal stabilty) of difunctionalized triphenylenes. Moreover,
1.35-1.66 (m, 24H), 0.96 (t, 12H) (Figure S8). 13C-NMR: 149.08; both the number of terminal functional groups and its nature
148.72 ; 148.45; 123.65 123.60, 123.45 ; 107.34; 106.65; play a crucial role on these properties. Thus, mesophase
106.45, 69.76, 69.40; 69.31; 62.36; 31.71; 31.68; 30.08; 29.45; formation, thermal stability and structure clearly rely on a
29.30; 25.93; 25.88; 25.83; 22.68; 14.08. HRMS (ESI) m/Z: M+ subtle balance of molecular parameters, allowing for the
measured (calculated) 804.5551 (804.5540). Elemental interpretation of the experimental trends, but making difficult
analysis: measured (calculated) for C50H76O8 % C 74.0 (74.6); % confident predictions. The mesomorphic trends of the series
H 9.7 (9.5) .
studied here seem to suggest H-bonding interactions can
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There are no conflicts to declare.
prevale over π-π stacking giving rise to ND or Colr mesophases
instead of the Colr found in the case the hydroxyl groups are
hindered by the crown.
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DOI: 10.1039/C9NJ04834K
Acknowledgements
The ability of the terminal hydroxyl groups to be involved in
intermolecular H-bonds, together with - stacking
interactions between the TP cores, seems also to be directing
the hierarchical self-assemble that forms a 3D fibrillar network
that lead to the organogelating nature of the three studied
compounds. Indeed, they form stable gels both with aliphatic
alcohols (provided the dielectric constant fit specific ranges)
and ACN, an H-bond acceptor. This fact suggests solvent
molecules are directly involved in the supramolecular
organization, as confirmed by the fact that the structure of the
gels is different from that of the bulk compounds, and by the
thermal data. The high selectivity of 2,7-THTP-DiC6OH to
methanol, giving rise to very stable gels exhibiting ΔHgel as high
as 165 kJ/mol, support this hypothesis.
We acknowledge CONICET (grant PIP 201101-01035 and
doctoral fellowship to NV) and UBACyT (grants
20020170100512BA and 20020150100121BA) for financial
support. CHI, LG, PHDC and FDC are members of the research
staff of CONICET. We thank Dr. V. Manzano for her help in
synthetic aspects of this work as well as Dr. L. Rossi for helpful
discussions about rectangular mesophases.
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Notes and references
Except for methanol, it has been observed that an increase in
the length n of the bridging chains decrease the stability of the
organogels formed by 2,7-THTP-DiCnOH compounds, as seen
both in the thermal stability and the gelling critical
concentration.
This behavior differs from the one found for the
monohydroxylated analogues30, where an increase in the
length of the bridging chain has been found to increase the
organogelating ability of the corresponding 2-PHTP-CnOH
(PHTP= Pentakis hexyloxy triphenylene) compounds. In that
homologous series, weak gels have been found for n = 4 and 6
derivatives while the gels formed by the n = 10 derivative are
stronger, a fact interpreted in terms of the ability of the
hydroxyl group to easier interact when it is located beyond the
limit of the “crown” described above. The presence of a
second hydroxyl groups certainly modifies the properties of
the organogels, as seen from both structural aspects (the
tetragonal structure of the gels obtained here for MeOH, EtOH
and ACN differ form that obtained for the monohydroxy
derivatives) and thermal properties: taking the n=10
derivatives as an example, the corresponding Tgel for 2,7-THTP-
DiC10OH is 18ºC higher than that for 2-PHTP-C10OH., very
likely through a different 3-D self-assembly pattern. Indeed,
the tetragonal array found here seem to be possible thanks to
the presence of two hydroxyl groups per gelator molecule.
Beyond the molecular aspects of the soft phases (LC and gels)
yielded by 2,7-THTP-DiCnOH compounds, and the potential
applications they can be found in the future as soft materials,
the increase in thermal stability observed with the increase in
water content prompted us to investigate the use of this effect
as an easy and practical method to establish the presence of
water in light alcohols, and even to estimate its amount. This
interesting preliminary result, together with the remarkable
water compatibility (reflected in the increased stability
observed in its presence) also makes this organogel material a
promising versatile matrix for applications that may require
contact with an aqueous environment.
1 P. R. A. Chivers, D. K. Smith, “Shaping and structuring
supramolecular gels.” Nat Rev Mater, 2019, 4, 463–478.
2 E. R. Draper, D. J. Adams “Low-Molecular-Weight Gels: The
State of the Art.” Chem., 2017, 3, 390–410.
3 A. N. Cammidge, R. J. Bushby “Synthesis and Structural
Features” in Handbook of Liquid Crystals Vol. 2B 1998, D.
Demus, J. Goodby, G. W. Gray, H.-W. Spiess, V. Vill Eds.
Wiley-VCH:Weinheim
4 E. Fontes, P. A. Heiney, W. H. de Jeu “Liquid-Crystalline and
Helical Order in a Discotic Mesophase”, Phys. Rev. Lett.,
1988, 41, 1202-1205.
5 J. L. Segura, R. Juárez, M. Ramos, C. Seoane,
“Hexaazatriphenylene (HAT) derivatives: from synthesis to
molecular design, self-organization and device applications”,
Chem. Soc. Rev., 2015, 44, 6850-6885.
6 H. Ringsdorf, R. Wüstefeld, E. Zerta, M. Ebert, J. H.
Wendorff “Induction of Liquid Crystalline Phase: Formation
of Discotic Systems by Doping Amorphous Polymers with
Electron Acceptors” Angew. Chem. Int. Ed. Engl., 1989, 28,
914-918.
7 M. Gupta, S. P. Gupta, S. K. Pal “TNF Induced Switching of
Columnar Rectangular to Hexagonal Assemblies in a New
Class of Triphenylene Based Room Temperature Discotic
Liquid Crystal” J. Phys, Chem. B, 2017, 121, 8593–8602.
8 S. K. Pal, S. Setia, B. S. Avinash, S. Kumar “Triphenylene-
based discotic liquid crystals: recent advances”, Liq. Cryst.,
2013, 40, 1769–1816.
9 T. Wöhrle, I. Wurzbach, J. Kirres, A. Kostidou, N.
Kapernaum, J. Litterscheidt, J. C. Haenle, P. Staffeld, A. Baro,
F. Giesselmann, S. Laschat “Discotic Liquid Crystals” Chem.
Conflicts of interest
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
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Page 11 of 13
New Journal of Chemistry
Please do not adjust margins
Journal Name
ARTICLE
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ04834K
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Rev. 2016, 116, 1139–1241.
structure–properties relationship of main chain discotic
10 A. N. Cammidge, A. R. Beddall, H. Gopee, “Unexpected
mesophase behaviour in novel triphenylene multi-alkenes”
Tetrahedron Lett., 2007, 48, 6700–6703.
liquid crystalline polyethers: effects of the spacer lengths and
substitution positions”, Polym. Chem., 2016, 7, 3013-3025.
22 M. Werth, H. W. Spiess “The role of the spacer in discotic
polymers”, Makromol. Chem., Rapid Commun., 1993, 14,
11 W. Wan, P. Y. Wang, H. Zh. Jiang, J. Hao “Synthesis and
Characterization of Triphenylene Derivatives Containing Two 329-338.
Terminal Functional Groups at the Periphery”, Mol. Cryst.
Liq. Cryst., 2008, 482, 42–56.
23 J. Ban, S. Chen, C. Li, X. Wanga, H. Zhang “Influence of the
spacer and molecular weight on the phase behavior of side-
12 S. Sauer, N. Steinke, A. Baro, S. Laschat, F. Giesselmann, W. chain liquid crystalline polymers containing triphenylene
Kantlehner “Guanidinium Chlorides with Triphenylene
Moieties Displaying Columnar Mesophases”, Chem. Mater.,
2008, 20, 1909–1915.
discotic mesogen units as side groups”, Polym. Chem., 2014,
5, 6558-6568.
24 I. Tahar-Djebbar, F. Nekelson, B. Heinrich, B. Donnio, D.
Guillon, D. Kreher, F. Mathevet, A.J. Attias, “Lamello-
Columnar Mesophase Formation in a Side-Chain Liquid
Crystal π-Conjugated Polymer Architectutre” Chem. Mater.,
2011, 23, 4653-4656.
13 L. Cui, J. P. Collet, G. Xu, L. Zhu “Supramolecular Self-
Assembly in a Disk-Cube Dyad Molecule Based on
Triphenylene and Polyhedral Oligomeric Silsesquioxane
(POSS)” Chem. Mater., 2006, 18, 3503-3512.
14 E. Tritto, R. Chico, G. Sanz-Enguita, C. L. Folcia, J. Ortega, S. 25 M. Okazaki, K. Kawata, H. Nishikawa, M. N. Kawata
Coco, P. Espinet “Alignment of Palladium Complexes into
Columnar Liquid Crystals Driven by Peripheral Triphenylene
Substituents”, Inorg. Chem., 2014, 53, 3449-3455.
15 S. K. Gupta, V. A. Raghunathan, V. Lakshminarayanan, S.
Kumar “Novel Benzene-Bridged Triphenylene-Based Discotic
Dyads”, J. Phys. Chem. B, 2009, 113, 12887–12895.
16 A. Zelcer, B. Donnio, C. Bourgogne, F. D. Cukiernik, D.
Guillon “Mesomorphism of Hybrid Siloxane-Triphenylene
Star-shaped Olygomers”, Chem. Mater., 2007, 19, 1992 -
2006.
“Polymerizable discoticnematic triphenylene derivatives and
their application to an optically anisotropic film”, Polym. Adv.
Technol., 2000, 11, 398-403.
26 S. Disch, H. Finkelmann, H. Ringsdorf, P. Schuhmacher
“Macroscopically Oriented Discotic Columnar Networks”,
Macromolecules, 1995, 28, 2424-2428.
27 I. Muñoz Resta, V. E. Manzano, F. Cecchi, C. C. Spagnuolo,
F. D. Cukiernik, P. H. Di Chenna “Supramolecular Assembly of
pH-Sensitive Triphenylene Derived π-Gelators and Their
Application as Molecular Template for the Preparation of
Silica Nanotubes”, Gels, 2016, 2, 7.
17 K. Q. Zhao, Y. F. Bai, P. Hu, B. Q. Wang, Y. Shimizu,
“Synthesis of Triphenylene Discotic Liquid Crystal Dimers:
Click Chemistry As an Efficient Tool” Mol. Cryst. Liq. Cryst.,
2009, 509, 77[819]–88[830].
28 Y. F. Bay, K. Q. Zhao, P. Hu, B. Q. Wang, Y. Shimizu
“Synthesis of Amide Group Containing Triphenylene
Derivatives as Discotic Liquid Crystals and Organic Gelators”
Mol. Cryst. Liq. Cryst., 2009, 509, 60[802]-76[818].
29 M. Kimura, T. Hatanaka, H. Nomoto, J. Takizawa, T.
Fukawa, Y. Tatekawi, H. Shirai “Self-Assembled Helica
Nanofibers Made of Achiral Molecular Disks Having
18 I. Paraschiv, K. de Lange, M. Giesbers, B. van Lagen, F. C.
Grozema, R. D. Abellon, L. D. A. Siebbeles, E. J. R. Sudhölter,
H. Zuilhof, A. T. M. Marcelis “Hydrogen-bond stabilized
columnar discotic benzenetrisamides with pendant
triphenylene groups”, J. Mater. Chem., 2008, 18, 5475–5481. Molecular Adapter” Chem. Mater., 2010, 22, 5732-5738.
19 B. Huser, T. Pakula, H. W. Spiess “Macroscopic Ordering of
Liquid-Crystalline Polymers with Discotic Mesogens”,
Macromolecules, 1989, 22, 1960-1963.
30 A. Kotlewski, B. Norder, W. F. Jager, S. J. Pickena, E.
Mendes, “Can Morphological transitions in fibrils drive
stiffness of gels formed by discotic liquid crystal
organogelators?”, Soft Matter, 2009, 5, 4905-4913.
20 S. Kumar “Triphenylene-based discotic liquid crystal
dimers, oligomers and polymers “, Liq. Cryst., 2005, 32, 1089- 31 M. Ikeda, M. Takeuchi, S. Shinkai “Unusual emission
1113.
properties of a triphenylene-based organogel system” Chem.
Commun., 2003, 1354-1355.
21 S. Zhang, C. Zhang, J. Wang, F. Hong, X. Hao, A. Zhang, Y.
Wang, H. Wu, W. Zhang, J. Pu “Systematic studies on
32 J. E. Meegan, X. Yang, R. Rungsirisakun, S. C. Cosgrove, R. J.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 11
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New Journal of Chemistry
Page 12 of 13
ARTICLE
Journal Name
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ04834K
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Bushby, A. Sadeghpour, M. Rappolt, R. Brydsonc, R. J. Ansell
“Synthesis and organogelating behaviour of amino acid-
functionalised triphenylenes” Soft Matter, 2017, 13, 5922-
5932.
42 F. Cecchi, PhD Thesis “Trifenilenos mesogénicos
funcionalizados: organizadores estructurales de materiales
poliméricos” Universidad de Buenos Aires, 2012.
43 S. R. Raghavan, B. H. Cipriano “Gel formation: phase
diagrams using tabletop rheology and calorimery” in
Molecular Gels. Materials with Self-Assembled Fibrillar
Networks, 2006, R. Weiss, P. Terech, Eds.,
33 F. Cecchi, A. Zelcer, P. Alborés, D. Guillon, B. Heinrich, B.
Donnio, F. D. Cukiernik, “A convenient synthesis of a 2,7-
difunctional tetra(alkoxy)triphenylene involving 4,4´-
diacetoxy-3,3´-dialkoxybiphenyl as a key precursor and its
conversion to extended hybrid mesogenic compounds”, Liq.
Cryst., 2013, 40, 1121 - 1134.
Springer:Dordrecht, Chap. 8, 241-252.
44 J. Bonnet, G. Suissa, M. Raynal, L. Bouteiller “Organogel
formation rationalized by Hansen solubility parameters: dos
and don'ts”. Soft Matter, 2014, 10, 3154–3160.
34 E. Fontes, P. A. Heiney, M. Ohba, J. N. Haseltine, A. B.
Smith III “Molecular disorder in columnar-phase discotic
liquid-crystal strands”, Phys. Rev. A, 1988, 37, 1329-1334
45 J. M. Chong, M. A. Heuft, P. Rabbat “Solvent Effects on the
Monobromination of α,ω-Diols: A Convenient Preparation of
35 X. Yang, D. A. Waldman, S. L. Hsu, S. A. Nitzsche, R. Thakur, ω-Bromoalkanols”, J. Org. Chem., 2000, 65, 5837-5838
D. M. Collard, C. P. Lillya, and H. D. Stidham “Spectroscopic
characterization of mesogen order in discotic liquid crystal”,
J. Chem. Phys., 1988, 89, 5950-5955.
36 L. Carpentier , M. Bée , A.M. Giroud-Godquin , P. Maldivi,
J.C. Marchon “Alkyl chain motions in columnar mesophases.
A quasielastic neutron scattering study of dicopper
tetrapalmitate” Mol. Phys., 1989, 68, 1367-1378.
37 T. Bottazzi, F. Cecchi, A. Zelcer, B. Heinrich, B. Donnio, D.
Guillon, F. D. Cukiernik “Thermotropic mesomorphism of
mixed-valent diruthenium aliphatic carboxylates with axial
anion bearing two aliphatic chains”, J. Coord. Chem. 2013,
66, 3380-3390.
38 I. Paraschiv, P. Delfoterie, M. Giesbers, M. A. Posthumus,
A. T. M. Marcelis, H. Zuilhof, E. J. R. Sudho “Asymmetry in
liquid crystalline hexaalkoxytriphenylene discotics”, Liq.
Cryst. 2005, 32, 977–983.
39 S. Kumar , P. Schuhmacher, P. Henderson, J. Rego, H.
Ringsdorf “Synthesis of New Functionalized Discotic Liquid
Crystals for Photoconducting Aplications”, Mol. Cryst. Liq.
Cryst., 1996, 288, 211-222.
40 P. Henderson, D. Beyer, U. Jonas, O. Karthaus, H.
Ringsdorf, P. A. Heiney, N. C. Maliszewskyj, S. S. Ghosh,
Oksana, Y. Mindyuk, J. Y. Josefowicz “Complex Ordering in
Thin Films of Di- and Trifunctionalized
Hexaalkoxytriphenylene Derivatives”, J. Am. Chem. Soc.,
1997, 119, 4740-4748.
41 W. Wan, H. Monobe, T. Sugino, Y. Tanaka, Y. Shimizu
“Mesomorphic Properties and Hydrogen Bonding Formation
of Asymmetrical Triphenylene Discotic Liquid Crystals”, Mol.
Cryst. Liq. Cryst., 2001, 364, 597-603.
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Illustrated Synopsis for TOC:
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Self-assembly of di-hydroxylated
triphenylenes in columnar
mesophases and organogels depends
on the spacer length and allows water
quantification in alcohols
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