Supramolecular assembly and host-guest interaction of crown ether with inorganic acid and organic amine containing carboxyl groups

Article abstract of DOI:10.1039/c3nj01005h

Four rotator-stator assembly complexes: benzoic-4-methylammonium- tetrafluoroborate-15-crown-5 ([C₈H₁₀NO₂-(15- crown-5)]⁺[BF₄]^-, 1); benzoic-4-methylammonium- perchlorate-15-crown-5 ([C

Full text of DOI:10.1039/c3nj01005h

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Supramolecular assembly and host–guest
interaction of crown ether with inorganic acid
and organic amine containing carboxyl groups†
Cite this: New J. Chem., 2014,
38, 723
Yang-Hui Luo, Shu-Wang Ge, Wen-Tao Song and Bai-Wang Sun*
Four rotator–stator assembly complexes: benzoic-4-methylammonium-tetrafluoroborate-15-crown-5
([C8H10NO2-(15-crown-5)]+[BF4]À, 1); benzoic-4-methylammonium-perchlorate-15-crown-5 ([C8H10NO2-
(15-crown-5)]+[ClO4]À, 2); benzoic-4-methylammonium-tetrafluoroborate-18-crown-6 ([C8H10NO2-
(18-crown-6)]+[BF4]À, 3); benzoic-m-ammonium-tetrafluoroborate-18-crown-6 ([C7H8NO2-(18-crown-6)]+
[BF4]À, 4), for the investigation of the supramolecular assembly and host–guest interaction of crown ethers,
have been synthesized and characterized. The results revealed that the variation of crown ethers, the substitu-
ent position of carboxyl group, as well as the different kinds of inorganic anions all can lead to quite another
geometry and directionality of both the anilinium rotors and crown ether stators, which lead to entirely differ-
ent supramolecular architectures. It is interesting that the optimal distances from the mean O-plane where
found for the 18-crown-6 macrocycle with the ammonium cation, and the conformation of the macrocycle
was badly affected in complexes with shorter or longer distances. We also studied the Raman spectroscopy
of the five complexes, which give further inspection of the intermolecular interactions.
Received (in Montpellier, France)
26th August 2013,
Accepted 12th November 2013
DOI: 10.1039/c3nj01005h
www.rsc.org/njc
characterized.13–16 For example, Luo16 and his co-workers utilized
dichloroacetate as the pendulum-like motions combined with the
Introduction
As one of the well-known symbols in supramolecular chemistry, 18-crown-6 molecular rotor, which formed a novel supra-molecular
crown ethers have been the subject of various studies in supra- potassium hydrogen bis(dichloroacetate)-18-crown-6 displaying a
molecular chemistry and crystal engineering in recent years,1–6 reversible phase transition. Xiong17 and his co-workers have
especially for the investigation of host–guest interactions in the introduced 4-methoxyanilinium into the cavity of 18-crown-6
construction of supramolecular architectures.7–9 In these, crown and obtained a novel supra-molecular bola-like second-order
ethers acted as macrocyclic hosts, serving as building blocks to ferroelectric phase-transition material. In the field of molecular
create a variety of molecularly assembled architectures with com- machine design, the crown ethers often act as good molecular
+
plementary guest molecules. The assembled architectures were stators which can easily anchor the protonated R–NH3 cation
constructed by multiple noncovalent interactions, such as hydro- (R = aryl ring) into the cavity of crown ethers, and the utilization
gen bonding, pÁÁÁp stacking, charge transfer, and hydrophobic of the R group as a molecular rotor or pendulum unit to create
interactions between two complementary compounds, which leads desirable properties has also been investigated.17 However, the
not only to good binding affinity, but also to the formation of influence of R group containing carboxyl groups on the supra-
complexes with a fixed host–guest geometry and directionality.10
Crown ethers also have been used to construct stable complexes directionality of crown ethers still remains unexplored.
with alkali and transition-metal ions and hydrogenate cations via Hence, in this work, we studied detailed the influences
molecular assembly behaviour of host–guest geometry and the
hydrogen bonds, which act as ideal candidates for the formation of of R group containing carboxyl groups on the supramolec-
molecular stators for the design of phase change materials and ular assembly behaviour of crown ethers, and we obtained
ferroelectric molecular materials.11,12 To date, numerous derivatives four supramolecular architectures (Scheme 1): benzoic-4-
and complexes based on crown ethers have been synthesized and methylammonium-tetrafluo-roborate-15-crown-5 ([C8H10NO2-
(15-crown-5)]+ [BF4]À, 1); benzoic-4-methylammonium-perchlorate-
15-crown-5 ([C8H10NO2-(15-crown-5)]+[ClO4]À, 2); benzoic-4-
School of Chemistry and Chemical Engineering, Southeast University,
Nanjing 210096, P. R. China. E-mail: chmsunbw@seu.edu.cn;
methylammonium-tetrafluoroborate-18-crown-6 ([C8H10NO2-
Fax: +86-25-52090614; Tel: +86-25-52090614
(18-crown-6)]+[BF4]À, 3); benzoic-m-ammonium-tetrafluoroborate-
† Electronic supplementary information (ESI) available. CCDC 946942, 946943,
18-crown-6 ([C7H8NO2-(18-crown-6)]+[BF4]À, 4). We found that the
946956 and 946959. For ESI and crystallographic data in CIF or other electronic
format see DOI: 10.1039/c3nj01005h
variation of the crown ethers as well as the substituent position of
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Scheme 1 Molecular structure of complexes 1–4.
the carboxyl group leads to quite another geometry and directionality and 3 (benzoic-4-methylammonium-tetrafluoroborate-18-crown-6)
of the anilinium rotors, which resulted in entirely different supra- were selected in this section. The only difference between 1 and 2
molecular architectures. We also studied the Raman spectroscopy of is in the lattice inorganic anions (Fig. 1). Crystal structural
the four complexes, which provided supporting evidence for the con- determinations revealed that 1 and 2 were all crystallized in the
clusions. These results are of importance not only for the evaluation monoclinic P21/n space group, the basic unit of 1 was
of the specific case of these crown ethers’ systems, but also for composed of one [C8H10NO2-15-crown-5]+ complex cation and
À
other host–guest systems where fascinating structures and proper- one BF4 anion, and the basic unit of 2 is similar to 1 with a
À
À
ties are possible. The influence of the R group containing carboxyl ClO4 anion instead of a BF4 anion. For complex 1, the
groups on the dielectric properties will be investigated in the future. protonated benzoic-4-methylammonium cation joins with one
15-crown-5 molecule to form a rotator–stator assembly through
four N–HÁ Á ÁO hydrogen-bonding interactions (distances are
Results and discussion
Supramolecular assembly of 4-aminomethyl benzoic acid with
within the common range of 3.015 (7) and 2.913 (7) Å,
Table 1). It is interesting that the 15-crown-5 macrocycle in
complex 1 showed nearly ‘‘chair like’’ conformations with O1,
15-crown-5 and 18-crown-6
O2, O4, and O5 forming a mean O-atom plane, (O1 and O4
atoms are located above the mean O-atom plane with distances
Complexes 1 (benzoic-4-methylammonium-tetrafluoroborate-
15-crown-5), 2 (benzoic-4-methylammonium-perchlorate-15-crown-5)
Fig. 1 The basic unit of complexes 1–3, hydrogen atoms were omitted for clarity ((i) À1/2 + x, 1/2 À y, À1/2 + z; (ii) x, Ày, À1/2 + z).
724 | New J. Chem., 2014, 38, 723--729
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Table 1 Geometrical parameters for hydrogen bonds in complexes 1–4
+D–HÁ Á ÁA
Complex
D–HÁ Á ÁA
D–H (Å)
HÁ Á ÁA (Å)
DÁ Á ÁA (Å)
(deg)
Symmetry operation
1
N1–H1CÁ Á ÁO3
N1–H1CÁ Á ÁO2
N1–H1DÁ Á ÁO6
N1–H1DÁ Á ÁO1
N1–H1EÁ Á ÁO4
N1–H1EÁ Á ÁF3
0.89
0.89
0.89
0.89
0.89
0.89
2.27
2.34
2.30
2.28
2.29
2.27
3.097(7)
3.015(7)
2.997(7)
2.913(7)
2.934(8)
2.924(8)
154
132
135
128
129
130
Àx + 1, Ày + 1, Àz + 1
x + 1/2, Ày + 3/2, z À 1/2
2
3
4
O6–H6CÁ Á ÁO11
N1–H1CÁ Á ÁO3
N1–H1DÁ Á ÁO5
N1–H1EÁ Á ÁO9
0.82
0.89
0.89
0.89
2.08
2.19
2.13
2.26
2.903(9)
3.074(6)
2.936(8)
3.061(11)
179
173
150
149
Àx + 1, Ày + 1, Àz + 1
x + 1/2, Ày + 1/2, z + 1/2
x + 1/2, Ày + 1/2, z + 1/2
N1–H1AÁ Á ÁO3
N1–H1AÁ Á ÁO8
N1–H1BÁ Á ÁO5
N1–H1CÁ Á ÁO7
0.89
0.89
0.89
0.89
2.02
2.36
2.11
2.02
2.866(7)
2.927(7)
2.898(7)
2.896(9)
159
122
148
168
x, Ày, z + 1/2
x, Ày, z + 1/2
x, Ày, z + 1/2
x, Ày, z + 1/2
O2–H2Á Á ÁO1
N1–H2AÁ Á ÁO3
N1–H2BÁ Á ÁO7
N1–H2CÁ Á ÁO5
0.82
0.89
0.89
0.89
1.88
2.07
2.03
2.00
2.675(6)
2.952(6)
2.909(7)
2.885(7)
165
173
169
176
Àx, Ày + 1, Àz + 1
Àx + 1, Ày + 1, Àz + 1
Àx + 1, Ày + 1, Àz + 1
Àx + 1, Ày + 1, Àz + 1
À
0.062 (7) and 0.0379 (7) Å, while O2 and O5 atoms are below the complex cation, one BF4 anion, and one water molecule
plane with distances 0.0371 (7) and 0.0628 (7) Å, respectively), and (Fig. 1). The protonated benzoic-4-methylammonium cation
the O3 atom was located 0.9848 (7) Å lower than the plane (Fig. 1). joins with one 18-crown-6 molecule to form a rotator–stator
The N1 atom of the benzoic-4-methylammonium cation is in the assembly through six N–HÁ Á ÁO hydrogen-bonding interactions
perching position, lying 1.6052 (10) Å higher than the best plane (distances are within the common range of 2.950 (9) and
of the oxygen atoms of the crown ring, rather than in the nesting 2.866 (7) Å, which are shorter than those in 1 and 2, Table 1).
position. The torsion angle between the aminomethyl group and The symmetry of the 18-crown-6 in 3 was found to be nearly an
the normal to the best plane is 165.02 (6)1. For complex 2, the ideal crown ‘‘round’’ ‘‘D3d like’’ conformation, where oxygen
deviations of the oxygen atoms were found to be 0.0669 (5) and atoms of the 18-crown-6 in the structure are, as a rule, dis-
0.0385 (5) Å above the mean O-atom plane for O1 and O4 atoms, placed alternately above and below the median plane of the
while the O2 and O5 atoms were 0.0396 (5) and 0.0659 (5) Å below ring, forming two approximately parallel and nearly equilateral
the mean O-atom plane, respectively (Table 2). These deviations triangles, with O3, O5, and O8 atoms are located below the
were larger than in 1, while the O3 atom was located 0.9819 (5) Å mean O-atom plane (0.2143 (9), 0.2106 (9), and 0.1217 (9) Å,
lower than the plane, a distances that is shorter than in 1. The N1 respectively), and O4, O6, and O8 atoms above the plane
atom of the benzoic-4-methylammonium cation lies 1.600 (10) Å (0.2459 (9), 0.1470 (9) and 0.1537 (9) Å, respectively). The N1
higher than the best plane of the oxygen atoms, and the torsion atom of the benzoic-4-methylammonium cation lies 1.1442 (10)
angle between the aminomethyl group and the normal to the best Å higher than the best plane of the oxygen atoms of the crown
plane is 112.93 (10)1, which was also much smaller than that in 1. ring, which is much shorter than that for 15-crown-5. The
From these results we can conclude that the ClO4À anion leads to torsion angle between the aminomethyl group and the normal
more distortion of tÀhe crown macrocycle and the ammonium to the best plane is 144.94 (8)1.
cation than the BF4 anion due to its larger steric effect, and
Shown in Fig. 2 are the connecting and stacking motif
this conclusion was in accordance with the lattice volume: the of complexes 1 and 2. The adjacent complex cations in 1
volume of 1 and 2 were found to be 2242.3 (8) and 2287.7 (8) Å3, were connected with each other through N–HÁ Á ÁO hydrogen-
respectively.
bonding interactions (distances of 2.997 (7) Å) into inÀfinite 1D
Complex 3 crystallizes in the monoclinic C2/c space group; chain structure in Á Á ÁABABÁ Á Á fashion) and the BF4 anions
the basic unit is composed of one [C8H10NO2-18-crown-6]+ were distributed in the two sides of the chain (Fig. 2a and b).
Table 2 Summary of the deviations (Å) of oxygen atoms from the median O-plane of 18-crown-6 in complexes 1–4 and the distances (Å) of N atoms
from the median O-plane
Complex
Deviations above
Deviations below
Average
Distances
1
2
3
4
0.062(7)
0.0379(7)
0.0385(5)
0.2106(9)
0.504(6)
0.0371(7)
0.0396(5)
0.2459(9)
0.4834(6)
0.0628(7)
0.0659(5)
0.147(9)
0.9848(7)
0.9819(5)
0.1537(9)
0.5714(6)
0.1974(7)
0.1988(5)
0.1822(9)
0.3693(6)
1.6052(7)
1.6(5)
1.1442(9)
0.9957(6)
0.0669(5)
0.2143(9)
0.5803(6)
0.1217(9)
0.0532(6)
0.0237(6)
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Fig. 2 Connecting and stacking motif of complexes 1 and 2; hydrogen atoms were omitted for clarity and hydrogen bonds were shown in dashed lines.
(a) 1D chain connecting motif of 1; (b) diagram of 1D chain viewed from one end; (c) 3D stacking motif of 1; (d) 2D wave plane of complex 2; (e) 3D
stacking motif of 2.
Fig. 3 (a) Packing motif of the double-component unit of 3, the plane separation is highlighted; (b) 1D stacking motif of the double-component units.
À
(distances of 4.957 (6) Å) in a Á Á ÁA–AÁ Á Á fashion, with the BF4
anions located in the upper left and lower right positions
(Fig. 3a). The different double-component units then stacked
parallel into a 1D motif with a distance of 4.957 (5) Å between
adjacent 18-crown-6 macrocycles (Fig. 3b). The different 1D motif
further stacked in parallel into a 3D structure (Fig. S2, ESI†).
Supramolecular assembly of m-aminobenzoic acid with 18-
crown-6
m-Aminobenzoic acid was selected for the investigation of
the influence of the substituent-position of the carboxyl group
on the supramolecular assembly fashion of the crown ether
Fig. 4 The basic unit of complex 4, hydrogen atoms was omitted for complex. Crystal structural determinations reveal that com-
clarity ((i) 1 À x, 1 À y, 1 À z).
plexes 4 (benzoic-m-ammonium-tetrafluoroborate-18-crown-6)
%
crystallize in a triclinic P1 space group, the basic unit is
composed of one [C7H8NO2-18-crown-6]+ complex cation and
À
The different 1D chains then further stack with each other into one BF4 anion (Fig. 4). In the complex cation, the protonated
a 3D motif (Fig. 2c). For complex 2, the primary 1D motif was benzoic-m-ammonium cation joins with one 18-crown-6 mole-
identical to 1 (Fig. S1, ESI†). It is interesting that the benzoic- cule to form a rotator–stator assembly via six N–HÁ Á ÁO hydrogen-
À
4-methylammonium cations and ClO4 anions constructed a bonding interactions (distances are within the common range
2D wave plane via an R42(26) and R42(38) motif (Fig. 2d), and the of 3.003 (6) and 2.856 (7) Å, Table 1). It is interesting that the
15-crown-5 macrocycles hang on the two sides of the wave 18-crown-6 stator in 4 demonstrates a ‘‘boat’’ rather than ‘‘D3d
plane, then the 2D structures interact with each other via the like’’ conformation, with O3 and O6 atoms located on both ends
macrocycles into a 3D motif (Fig. 2e).
of the ‘‘boat’’ and deviate 0.5803 (6) and 0.5040 (6) Å above the
For complex 3, the primary structure is double-components mean O-atom plane of 18-crown-6, respectively, while the O4, O5,
of the basic unit, which was packed via slight pÁ Á Áp interactions O7 and O8 atoms are located on the bottom of the ‘‘boat’’ and
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Fig. 5 Connecting and stacking motif of complex 4, hydrogen atoms were omitted for clarity and hydrogen bonds were shown in dashed lines.
(a) Connecting motif of the dimer unit of 4; (b) 1D packing motif of 4, pÁ Á Áp interactions were highlighted; (c) 3D stacking motif of 4.
deviate 0.0532 (6), 0.4834 (6), 0.0237 (6) and 0.5714 (6) Å below
the mean O-atom plane, respectively. The distances of the oxygen
atoms above and below the median O-plane of the three com-
plexes are summarized in Table 2. The N1 atom of the benzoic-
m-ammonium cation lies 0.9957 (9) Å from the best plane of the
oxygen atoms of the crown ring, which is much shorter than the
same distance in 1–3 (Table 2). The benzene ring is almost
vertical to the median O-plane with dihedral angle of 77.26 (10)1.
The complex cation in 4 formed a dimer unit via O–HÁ Á ÁO
hydrogen-bonding interactions (distances of 2.675 (6) Å)
between the adjacent carboxyl group (Fig. 5a), then the differ-
ent dimer units packed by pÁ Á Áp interactions between two of the
Fig. 6 Raman spectroscopy of complexes 1–4.
Table 3 Crystal data and structure refinement for complexes 1–4
Complex
1
2
3
4
Formula
Formula weight
C
18H30BF4NO7
C18H30ClNO11
471.88
C20H34BF4NO8
503.29
C19H32BF4NO8
489.27
459.24
Crystal system
Space group
Monoclinic
P21/n
Monoclinic
P21/n
Monoclinic
C2/c
Triclinic
P1
%
a/Å
b/Å
c/Å
a/1
9.5060(19)
15.001(3)
15.777(3)
90.00
94.68(3)
90.00
2242.3(8)
4
1.360
9.5970(19)
15.241(3)
15.677(3)
90.00
93.90(3)
90.00
2287.7(8)
4
1.370
23.270(5)
12.926(3)
19.947(4)
90.00
117.76(3)
90.00
5309(2)
8
1.304
9.3105(19)
10.982(2)
11.809(2)
82.80(3)
89.03(3)
85.61(3)
1194.4(4)
2
b/1
g/1
V/Å3
Z
D calc. (Mg mÀ3
T/K
)
1.360
293(2)
0.122
293(2)
0.122
293(2)
0.224
293(2)
0.117
m (mmÀ1
)
Cryst. dimensions
No. of reflns collected
No. of unique reflns
No. of params
0.3 Â 0.2 Â 0.1
0.3 Â 0.2 Â 0.1
0.2 Â 0.1 Â 0.1
0.2 Â 0.2 Â 0.2
4112
4212
4882
5434
1646
260
1.025
0.0847, 0.1971
0.1399, 0.1500
946942
2129
281
1.075
0.0948, 0.2520
0.1670, 0.3016
946943
1922
357
1.020
0.0789, 0.1651
0.1678, 0.2047
946956
1621
300
0.942
0.1125, 0.2889
0.2934, 0.3904
946959
Goodness-of-fit on F2
R1, wR2 (I > 2s(I))
R1, wR2 (all data)
CCDC no.
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benzene rings in adjacent dimer units (distance of 3.766 (9) Å) Sigma Aldrich and used as received without further purifica-
into a 1D structure along b axis (Fig. 5b). The different 1D tion. Methanol was commercially available from Sinopharm
structures further stacked into a 3D motif (Fig. 5c).
Chemical Reagent Co., Ltd and used as received without further
Table 2 summarizes the distances that the oxygen atoms purification. Elemental analyses were performed using a Vario-
deviate from the median O-plane of the crown ether (15-crown-5 EL III elemental analyzer for carbon, hydrogen, and nitrogen
and 18-crown-6) and the distances of the N1 atoms from the of the complexes 1–4. Raman spectra were recorded using a
median O-plane for complexes 1–4. From the comparison between Raman microscope (Kaiser Optical Systems, Inc., Ann Arbor,
the average value of the deviation and the distances of N1 atoms MI, USA) with 785 nm laser excitation. The spectra were
from the median O-plane, we may concluded that the anilinium obtained for one 2 min exposure of the CCD detector in the
showed closer interaction with 18-crown-6 than with 15-crown-5, wavenumber range 50–3500 cmÀ1
and the distances of N1 atoms from the median O-plane of
.
Preparation of the complexes
18-crown-6 showed an optimum value of around 1.14 (9) Å, with
which, the 18-crown-6 macrocycle displays minimum distortion.
Distances shorter or longer than this value all lead to more
distortion of the 18-crown-6 macrocycle. These results were in
accordance with the distances of the hydrogen bonds in Table 1.
The preparation of complexes 1–4 was performed using a slow
evaporation technique; a 35 mL methanol–water (2: 1 v/v) system
was used. They were all obtained from a methanol–water solvent
system using 1 : 1 : 1 stoichiometric mixtures of 18-crown-6,
organic amines and inorganic acids. Complex 1, elemental
analysis anal. calcd (%): C, 47.03; N, 3.05; H, 6.53. Found: C,
48.30; N, 3.48; H, 7.01. Complex 2, elemental analysis anal.
calcd (%): C, 45.77; N, 2.97; H, 6.36. Found: C, 44.68; N, 2.31; H,
6.76. Complex 3, elemental analysis anal. calcd (%): C, 46.04; N,
2.68; H, 6.91. Found: C, 45.07; N, 2.45; H, 7.15. Complex 4,
elemental analysis anal. calcd (%): C, 46.60; N, 2.86; H, 6.54.
Found: C, 47.07; N, 2.25; H, 6.15.
Raman spectroscopy of the complexes 1–4
Fig. 6 shows the Raman spectroscopy of complexes 1–4 in the
region of 3500–50 cmÀ1. The region around 2900 cmÀ1 may be
attributed to the nearly ideal crown ‘‘round’’ ‘‘D3d like’’ con-
formations of the crown ether macrocycles, and this was absent
for the Raman spectroscopy of 4 due to the ‘‘boat’’ conforma-
tion of the 18-crown-6 macrocycle in it. The region between
1500–50 cmÀ1 can be attributed to the organic anilinium and
inorganic anions, and there were no visible differences between
the complexes 1–3 within this region.
X-ray crystallographic study
The single-crystal X-ray diffraction data of the complexes 1–4
were collected at 293 K with graphite-monochromated Mo-Ka
radiation (l = 0.071073 nm) equipped with Rigaku SCXmini
diffractometer.18 The lattice parameters were integrated using
vector analysis and refined from the diffraction matrix. The
absorption correction was carried out using a Bruker SADABS
program with a multi-scan method.19 The crystallographic
data, data collection, and refinement parameters for complexes
1–4 were given in Table 3. The structures were solved by a
full-matrix least-squares methods on all F2 data, and the
SHELXS-97 and SHELXL-97 programs20 were used for structure
solution and refinement respectively. All non-hydrogen atoms
were refined anisotropically and the hydrogen atoms were
geometrically fixed.
Conclusions
In conclusion, the influences of different kinds of crown ethers,
the substituent position of carboxyl group, and different kinds of
inorganic anions on the supramolecular assembly and host–guest
interaction of crown ethers rotator–stator complexes have been
investigated detailed. The host–guest interaction of 15-crown-5
with 4-methylamino benzoic acid resulted in a 1D chain via
N–HÁ ÁÁO hydrogen-bonding interactions, while 18-crown-6 with
4-methylamino benzoic acid packed by pÁÁÁp intermolecular
interactions. The meta-position of the carboxyl group (m-amino
benzoic acid) leads to dimer units via O–HÁ ÁÁO hydrogen-bonding
interactions and a ‘‘boat’’ conformation of 18-crown-6 rather than
‘‘D3d like’’ conformation as seen with 4-methylamino benzoic
acid. It is interesting that the optimal distances from the mean
O-plane where found for the 18-crown-6 macrocycle with the
ammonium cation, and the conformation of the macrocycle was
badly affected in complexes with shorter or longer distances. This
was confirmed by the Raman spectroscopy. These results are
important not only for the evaluation of the specific case of this
work, but also for other host–guest systems with crown ethers.
Acknowledgements
This work has been supported by the Scientific Research Founda-
tion of Graduate School of Southeast University (YBJJ1340), Funda-
mental Research Funds for the Central Universities (CXZZ12_0119),
Natural Science Foundation of China (21371031) and Funds for the
Ministry of Science and Technology (212401025).
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