Self-assembly of 5,11,17,23-tetranitro-25,26,27,28-tetramethoxythiacalix[4] arene with neutral molecules and its use for anion recognition

Article abstract of DOI:10.1016/j.tet.2012.10.101

Methylation of 5,11,17,23-tetranitrothiacalix[4]arene with diazomethane leads to the tetramethoxy derivative, which was studied using single-crystal X-ray crystallography. It revealed that this compound, albeit in the 1,3-alternate conformation, can form the inclusion complexes with various solvent molecules possessing acidic methyl groups (ethyl acetate, nitromethane, acetone, acetonitrile) and creates interesting infinite channels filled with solvent molecules. The subsequent transformation of nitro groups into the ureido moieties gave receptors capable of anion recognition even in a highly HB-competitive solvent like DMSO.

Full text of DOI:10.1016/j.tet.2012.10.101

Tetrahedron 69 (2013) 1397e1402
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Self-assembly of 5,11,17,23-tetranitro-25,26,27,28-
tetramethoxythiacalix[4]arene with neutral molecules
and its use for anion recognition
a
a
b
ꢀ
ꢁ a
ꢁ b
ꢀ
ꢁ d
ꢁ
Michaela Mackova , Michal Himl , Jan Budka , Michaela Pojarova , Ivana Císarova , Vaclav Eigner ,
ꢁ e
ꢀꢁ
ꢁ c
ꢁ
a,
*
ꢀ
Petra Curínova , Hana Dvorakova , Pavel Lhotak
a
ꢁ
Department of Organic Chemistry, Institute of Chemical Technology, Technicka 5, 16628 Prague 6, Czech Republic
b
ꢁ
Department of Solid State Chemistry, Institute of Chemical Technology, Technicka 5, 16628 Prague 6, Czech Republic
c Laboratory of NMR Spectroscopy, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, Czech Republic
d Department of Inorganic Chemistry, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic
e
ꢁ
Institute of Chemical Process Fundamentals, v.v.i., Academy of Sciences of the Czech Rep., Rozvojova 135, 165 02 Prague 6, Czech Republic
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 13 July 2012
Received in revised form 11 October 2012
Accepted 29 October 2012
Available online 28 November 2012
Methylation of 5,11,17,23-tetranitrothiacalix[4]arene with diazomethane leads to the tetramethoxy de-
rivative, which was studied using single-crystal X-ray crystallography. It revealed that this compound,
albeit in the 1,3-alternate conformation, can form the inclusion complexes with various solvent mole-
cules possessing acidic methyl groups (ethyl acetate, nitromethane, acetone, acetonitrile) and creates
interesting infinite channels filled with solvent molecules. The subsequent transformation of nitro
groups into the ureido moieties gave receptors capable of anion recognition even in a highly HB-
competitive solvent like DMSO.
Keywords:
Thiacalixarenes
Alkylation
Ó 2012 Elsevier Ltd. All rights reserved.
Self-assembly
CHe
p interactions
Receptor
Anion recognition
1. Introduction
receptors. They can be easily reduced to the corresponding
amino-substituted derivatives and subsequently transformed into
Easy derivatization of basic calix[n]arene1 skeletons makes
these compounds ideal candidates for many potential applications
in supramolecular chemistry. In this context, albeit known for more
than one decade,2 thiacalixarenes are only rarely used in the design
of more sophisticated receptors and host molecules. While the
chemistry of classical calixarenes has been well established during
the last three decades, only a few generally applicable de-
rivatization methods have been described so far in the thiacalix-
arene series.3 Not surprisingly, it is just the absence of the solid
reliable derivatization techniques, which hinders a broader appli-
cation of thiacalix[4]arenes in supramolecular chemistry. Conse-
quently, a completion of our fragmentary knowledge dealing with
the chemistry of thiacalix[4]arene 1 could help with further ex-
ploitation of these highly interesting compounds.
various functional groups.1
Recently, it was shownthat nitration of alkylated thiacalix[4]arenes
surprisingly proceeds to the meta position4 of the upper rim, which
leads to unusual derivatization pattern inaccessible in classical calix-
arene series. In other words, if we need p-nitro substituted thiacalix-
arenes alkylated on the lower rim, they cannot be prepared by
common nitration procedures, but rather by the alkylation of com-
pounds bearing already the nitro groups in para-positions. As
5,11,17,23-tetranitrothiacalix[4]arene 2 is accessible5 by direct nitra-
tion of basic thiacalix[4]arene 1 we have chosen this compound as
a starting point for the lower-rim-alkylation study. In this paper we
report on the successful alkylation of compound 2 with diazomethane,
the inclusion behaviour of the tetramethylated product, and the anion
recognition ability of the corresponding tetraurea derivatives.
Nitro-substituted calix[4]arenes are commonly used as useful
synthetic intermediates in the design of novel calixarene-based
2. Results and discussion
First, we attempted the alkylation of starting tetranitro de-
rivative 2 with propyl iodide using reaction conditions known
from classical calixarene chemistry. Unfortunately, none of the
* Corresponding author. Tel.: þ420 220445055; fax: þ420 220444288; e-mail
ꢁ
addresses: lhotakp@vscht.cz, pavel.lhotak@vscht.cz (P. Lhotak).
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2012.10.101

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M. Mackova et al. / Tetrahedron 69 (2013) 1397e1402
1398
well-established methods led to isolable products. Thus, PrI/NaH/
DMF or PrI/K2CO3/MeCN did not give the corresponding alkylation
product.6 Similar negative results were obtained using PTC condi-
tions (PrI/KOH/toluene/TBAB) previously used for dialkylation of
basic thiacalixarenes.7 Even more reactive methyl iodide or methyl
triflate did not show any reactivity towards nitro-substituted
thiacalixarene 2.
To determine the preferred conformation of tetramethoxy de-
rivative 3 in CD2Cl2 solution a dynamic 1H NMR measurements
were carried out. Lowering the temperature down to 193 K led to
the appearance of new sets of signals, corresponding to one major
and two minor conformers in an 80:10:10 ratio. The conformation
of the major component was determined unequivocally as 1,3-al-
ternate using the 1D NOE experiments, where spatial contacts be-
tween aromatic and methoxy protons were observed.
Unfortunately, the conformations of the minor components could
not be assigned, as even at this low temperature a slow chemical
exchange still occurred, which hampered the reliable identification
of the minorities (Scheme 1).
It is known from the chemistry of classical calixarenes that
nitro-substituted phenol rings can be alkylated using diazo-
methane.8 Hence, we decided to use this agent for thiacalix[4]arene
analogue 2. Interestingly, we found that the choice of solvent is of
great importance. Reaction carried out in 1,2-dichloroethane for 7
days at room temperature gave compound 3 only in 33% yield. On
the other hand, chloroform as solvent under the same reaction
conditions led smoothly to tetrasubstituted compound 3 in 67%
yield (Table 1). DMF or DMSO gave very complicated mixtures of
products where the presence of partly methylated compounds was
proven using the mass spectrometry. Thus, the signal at m/
z¼716.98 [MꢀH]ꢀ corresponded to trimethoxy substituted de-
rivative, while the peak at m/z¼702.96 [MꢀH]ꢀ agreed with
dimethoxy compound. Structure of compounds 3 cannot be easily
proven by NMR spectroscopy as the spectra at room temperature
consist of very broad signals due to the conformational movements
of individual phenolic rings through the thiacalixarene cavity. Al-
though this phenomenon makes NMR spectra useless for structure
determination at room temperature, the ESI MS spectrum of
compound 3 (negative mode) confirmed the expected molecular
peak at m/z¼730.99 (100% intensity) corresponding to [MꢀH]ꢀ ion.
The preferred conformation of 3 in the solid state was un-
equivocally proven by X-ray crystallography. Suitable single crystals
were grown by slow evaporation of the acetonitrile solution.
Compound 3 adopts a 1,3-alternate conformation, and it crystallizes
in monoclinic form, space group P21/n. Thiacalixarene 3 forms a 1:1
complex with solvent molecule (MeCN), which is held in the thia-
calixarene cavity (Fig. 1a). This is a rather unexpected fact, as the
1,3-alternate conformations possess a very narrow internal cavity,
which cannot accommodate bigger host molecules.9 Hence, the
cone conformers have been mainly used for binding of neutral
molecules so far.1 The methyl group of acetonitrile is oriented to-
wards the cavity of thiacalixarene, but the C atom remains at the
very edge of the cavity formed by aromatic units (Fig. 1b). We can
assume the contribution of the CeH/
p
interactions,10 which are
responsible for binding of neutral compounds with acidic methyl
groups in the cone conformers.11 Interestingly, the CN group of
acetonitrile is oriented towards the cavity of the neighbour thia-
calixarene molecule and it is held by both nitro groups as a pincer,
obviously using the electrostatic interactions with highly polarized
nitro groups. As a result, the infinite channel of the 1,3-alternates
filled with molecules of acetonitrile is formed (Fig. 1c). This ar-
rangement based on the interactions of neutral molecules with the
Table 1
Alkylation conditions survey for compound 2a
Run
Solvent
Time [h]
3 [Yield %]
1b
2
3
CHCl3
1,2-Dichloroethane
DMF
144
144
120
120
67
33
5c
1,3-alternate conformation represents
a rather unique self-
assembly pattern in calixarene or thiacalixarene chemistry.12
A similar shallow binding mode of methyl group can be seen in
the complex with nitromethane, which was obtained by slow
evaporation of the corresponding nitromethane solution. Com-
pound 3 forms the complex with three solvent molecules (space
4
DMSO
6c
a
Starting compound (100 mg) in 30 ml of solvent stirred with 10 equiv of
diazomethane at room temperature.
b
Separated by column chromatography, 1.0 g scale.
Complex reaction mixture with partly alkylated isomers.
c
Scheme 1. Reagents and conditions: (i) HNO3/AcOH; (ii) CH2N2, CHCl3, 7 days (67%); (iii) H2/Pd, EtOAc (90%); (iv) p-R-C6H4eN]C]O, CH2Cl2, room. temperature, 7 days, (88% for
5a, 61% for 5b).

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M. Mackova et al. / Tetrahedron 69 (2013) 1397e1402
1399
similar reaction with p-nitrophenyl isocyanate gave product, which
was insoluble in all common organic solvents.
The complexation ability of ligands 5a,b was studied by stan-
dard 1H NMR titration experiments. The corresponding anions (Clꢀ,
Brꢀ, H2PO4ꢀ, benzoate, acetate) were used in the form of tetrabu-
tylammonium salts to minimize possible interactions of counter-
cation with the cavity of thiacalixarene. Anions were dissolved in
DMSO-d6 and added gradually to the solution of 5 in the same
solvent to achieve the maximum host:guest ratios around 1:20.
The addition of anions to 5 led to the remarkable down-field
shifts of ureido NH signals thus indicating the complexation phe-
nomenon under fast exchange conditions. Thus, upon the addition
of 12 equiv of AcOꢀ to 5a the signals of ureido NH bonds (8.50 and
8.67 ppm) shifted down-field to 11.64 and 11.76 ppm, respectively.
The unusually high CIS values (>3.1 ppm) indicate very strong
hydrogen-bonding interactions between the ureido eNHe func-
tions and anion. Despite the usage of a highly competitive solvent
towards HB interactions (DMSO-d6), similar CIS values were ob-
served for all anions measured. The binding constants were de-
termined from the complexation induced shifts (CIS) of NH protons,
Fig. 2a shows a typical binding isotherm corresponding to the for-
mation of a 1:1 complex.13 The stoichiometry of the complexes was
also verified by the independent Job plot analysis (Fig. 2b). As
shown in Table 2 both receptors 5a and 5b can bind all selected
anions irrespective of their various geometries (spherical, trigonal,
tetrahedral). Due to the presence of methyl groups the conforma-
tion of receptors 5a and 5b is not immobilized. Hence, the 1:1
stoichiometry of complexes could be explained by the coordination
of anion to the receptor in the cone conformation as this arrange-
ment would enable the participation of all ureido functions. An-
other possible explanation could be based on the allosteric
behaviour of the 1,3-alternate conformation where only one half of
Fig. 1. The X-ray structures of complex 3$CH3CN: (a) site view, (b) top view, (c) the
infinite channel motif; and complex 3$3CH3NO2: (d) site view, (e) top view with in-
cluded solvent molecule, (f) the infinite channel motif.
group P21/c) where one methyl group is in the cavity (Fig. 1d) and
the remaining two nitromethane molecules are located outside the
thiacalixarene within the crystal lattice (Fig. 1e). Again, the 1,3-al-
ternate conformer holds the methyl group at the edge of the aro-
matic cavity allowing the interconnection of two neighbour
molecules via electrostatic interactions. This results in the same
type of infinite channel (Fig. 1f) as described above for acetonitrile.
It seems that the unexpected binding ability towards neutral
molecules is a general phenomenon in the case of nitro-substituted
compound 3. It can be evidenced by two more complexes 3*3C3H6O
(acetone complex) and 3*C4H8O2 (ethyl acetate) possessing the
same binding modes and characteristics features (shallow inclusion
of methyl group into the aromatic cavity and the formation of
infinite channels in case of the acetone complex).
To demonstrate the synthetic usefulness of this novel tetrani-
trothiacalix[4]arene derivative we attempted the transformation of
3 into the corresponding anion receptors bearing ureido moieties
on the upper rim. Thus, tetranitro derivative 3 was reduced using
hydrogenation on Pd/C in ethyl acetate at room temperature to
yield amino substituted compound 4 in 90% yield. This compound
was then reacted with p-tolyl isocyanate or p-butylphenyl iso-
cyanate in DCM at room temperature to give the target receptors 5a
and 5b in 88% and 61% yields, respectively. The isocyanates were
chosen due to the relatively good solubility of the products formed,
Fig. 2. (a) Binding isotherm for 5a with benzoate anion; (b) Job plot for the same
system (1H NMR titration, DMSO-d6, 300 MHz, 298 K).

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M. Mackova et al. / Tetrahedron 69 (2013) 1397e1402
1400
Table 2
Starting compounds 2 were prepared according to known
procedures.
Binding constants K [Mꢀ1] of receptor 5a and 5b with selected anions (1H NMR ti-
tration, DMSO-d6, 300 MHz, 298 K)
Aniona
K [Mꢀ1
]
4.2. Synthesis of 5,11,17,23-tetranitro-25,26,27,28-tetramethox-
ythiacalix[4]arene 3
5a
5b
Clꢀ
67ꢃ7
250ꢃ40
19ꢃ2
Brꢀ
31ꢃ10
135ꢃ14
180ꢃ60
Tetranitrothiacalix[4]arene 2 (1.00 g, 1.48 mmol) was suspended
in chloroform (100 ml) and diazomethane (100 ml of 1 M solution
in Et2O, Caution!) was added carefully. The reaction mixture was
stirred at room temperature and the reaction progress was moni-
tored by TLC. After 144 h the reaction was quenched by dropwise
addition of acetic acid (10 ml). The reaction mixture was then
evaporated to dryness and the residue was purified by column
chromatography (silica gel, CHCl3 as eluent) to yield 720 mg (67%)
of tetramethoxy derivative 3 as a yellow powder, mp: 317e318 ꢂC
PhCOOꢀꢀ
170ꢃ60
270ꢃ60
H2PO4
a
Anions were added as tetrabutylammonium salts.
molecule interacts with anion.14 As revealed from the NOE mea-
surements,15 the absence of interactions between methyl and aro-
matic units indicate the receptor could adopt the cone
conformation in solution. The situation doesn’t change upon the
addition of anions, again no contacts between methyl and aromatic
hydrogens were observed. On the other hand, the crystallographic
study of free ureido derivative 5a confirmed (Fig. 3) that compound
adopts the 1,3-alternate conformation in the solid state. The crys-
tallization from DMSO yielded the complex with 1:4 stoichiometry,
where one DMSO molecule is located in the cavity and three other
solvent molecules outside the cavity of calixarene.
(chloroform). 1H NMR (CDCl3, 300 MHz, 298 K):
d 3.80 (br s, 12H,
eCH3), 8.36 (br s, 8H, AreH); MS (ESI-) m/z for C28H20N4O12S4
calculated: 732.00, found: 730.99 [MꢀH]ꢀ (100%). EA calcd for
C28H20N4O12S4, C, 45.90; H, 2.75; N, 7.65%; S, 17.50. Found C, 46.10;
H, 2.84; N, 7.78; S, 17.62%.
4.3. Synthesis of 5,11,17,23-tetraamino-25,26,27,28-tetrametho-
xythiacalix[4]arene 4
Tetramethoxy derivative 3 (0.100 g, 0.137 mmol) was dissolved
in 50 ml of ethyl acetate. Then, catalyst 10% Pd/C was added
(100 mg) and the reaction mixture was stirred at room temperature
for 72 h under hydrogen atmosphere using balloon. The catalyst
was filtered out, and the filtrate was evaporated to dryness. Product
was isolated (0.082 g, 90%) as a yellow powder and due to the
possible instability was used immediately in the next step without
any subsequent purification. 1H NMR (300 MHz, CDCl3, 293 K)
d
(ppm): 3.40e3.80 (br s, 8H, eNH2), 6.40e6.80 (br s, 8H, AreH). MS
(ESIþ): calcd for C28H28N4O4S4: 612.10, found: m/z 613.24 [MþH]þ.
4.4. Synthesis of 5,11,17,23-tetrakis(N0-(p-methyl-phenyl)ure-
ido)-25,26,27,28-tetramethoxythiacalix[4]arene 5a
Fig. 3. The X-ray structure of complex 5a$4DMSO.
4-Methylphenyl isocyanate (217 mg, 1.63 mmol) was added to
a solution of thiacalix[4]arene 4 (100 mg, 0.163 mmol) in 30 ml of
dry CH2Cl2 under nitrogen atmosphere. The resulting solution was
stirred for 6 days at room temperature. The precipitate formed was
filtered off to give a grey crystalline compound (88%), mp: >350 ꢂC
3. Conclusions
In conclusion, a direct substitution of the lower rim of thiacalix
[4]arene has been carried out using diazomethane as an alkylating
agent. The corresponding tetramethoxythiacalix[4]arene 3 adopts
a 1,3-alternate conformation in the solid state, which is capable of
forming inclusion complexes with solvent molecules via interesting
self-assembly motifs. The reduction of the nitro compound and
subsequent reaction with isocyanates led to the ureido functions,
which can be used for anion recognition even in a highly HB-
competitive solvent like DMSO.
(CH2Cl2). 1H NMR (300 MHz; DMSO-d6, 293 K)
d (ppm): 2.21 (s,12H,
AreCH3), 3.48 (br s, 12H, eOCH3), 7.04 (d, 8H, AreH, J¼8.5 Hz), 7.27
(d, 8H, AreH, J¼7.9 Hz), 7.54 (s, 8H, AreH), 8.46 (s, 4H, eNH), 8.63
(s, 4H, eNH). 13C NMR (75 MHz, DMSO-d6, 293 K)
d (ppm) 20.3,
118.2, 118.4, 122.0, 129.1, 130.7, 135.3, 137.0, 152.5, 154.9. TOF MS
(ESþ): calcd for C60H56N8O8S4: 1144.31, Found: m/z (rel intensity, %)
1167.3 (100) [MþNa]þ.
4.5. Synthesis of 5,11,17,23-tetrakis(N0-(p-butyl-phenyl)ure-
4. Experimental
4.1. General
ido)-25,26,27,28-tetramethoxythiacalix[4]arene 5b
4-Butylphenyl isocyanate (285 mg, 1.63 mmol) was added to
a solution of thiacalix[4]arene 4 (100 mg, 0.163 mmol) in 30 ml of
dry CH2Cl2 under nitrogen atmosphere. The resulting solution was
stirred for 6 days at room temperature. The precipitate formed was
filtered off to give a yellow crystalline compound (61%), mp:
Melting points were measured on Heiztisch Mikroskop e Pol-
ytherm A (Wagner & Munz, Germany) and are not corrected. The IR
spectra were measured on an FT-IR spectrometer Nicolet 740 in
CHCl3 and/or in KBr. 1H NMR spectra were recorded on a Varian
Gemini 300 spectrometer. Dichloromethane used for the reaction
was dried with CaH2 and stored over molecular sieves. The purity of
the substances and the courses of reactions were monitored by TLC
using TLC aluminium sheets with Silica gel 60 F254 (Merck). Pre-
parative TLC chromatography was carried out on 20ꢁ20 cm glass
plates covered by Silica gel 60 GF254 (Merck).
>350 ꢂC (CH2Cl2). 1H NMR (300 MHz; DMSO-d6, 293 K)
d (ppm):
0.87 (t, 12H, eCH3, J¼7.3 Hz), 2.50 (t, 8H, AreCH2e, overlapped by
signal of DMSO), 1.26 (m, 8H, eCH2), 1.49 (m, 8H, eCH2); 3.50 (br s,
12H, eOCH3), 7.05 (m, 8H, AreH), 7.27 (m, 8H, AreH), 7.54 (s, 8H,
AreH), 8.47 (s, 4H, eNH), 8.63 (s, 4H, eNH). 13C NMR (75 MHz,
DMSO-d6, 293 K)
d (ppm) 13.8, 21.7, 33.3, 34.1, 118.5, 122.1, 128.4,
135.2, 135.8, 137.1, 152.5, 154.9. TOF MS (ESþ): calcd for

ꢀ
ꢁ
M. Mackova et al. / Tetrahedron 69 (2013) 1397e1402
1401
C72H80N8O8S4: 1312.50, Found: m/z (rel intensity, %) 1335.49 (100)
[MþNa]þ.
direct methods16 using the CRYSTALS suite of programs17 and an-
isotropically refined by full matrix least squares on F2 value to final
R¼0.062 and Rw¼0.155 using 11,577 independent reflections
4.6. Crystallographic measurements
(
Qmax¼68.3ꢂ), 973 parameters and 108 restrains. The positions of
disordered dimethyl sulfoxide molecules were found from the
electron density maps. All distances between neighbouring atoms
and angles were fixed. Site occupancies were assigned resulting in
similar thermal parameters for both group positions. The hydrogen
atoms attached to carbon were placed in calculated positions, those
attached to nitrogen atoms were found in difference electron
4.6.1. Crystallographic data for C28H20N4O12S4*C2H3N (3$acetonitri-
le). Mr¼773.81, crystal dimensions 0.37ꢁ0.22ꢁ0.11 mm, space
ꢂ
ꢂ
ꢂ
group P21/n, a¼9.8719(4) A, b¼19.0555(8) A, c¼17.8895(8) A,
3
ꢂ
b
m
¼99.723(4)ꢂ, V¼3316.9(2) A , Z¼4, rcalcd¼1.549 g/cm3,
¼3.269 mmꢀ1. X-ray intensity data were measured at 150 K on
ꢂ
a XCALIBUR PX diffractometer (Oxford Diffraction) equipped with
density maps, refined with distance restrains (NeH 0.86 A), and
ꢂ
CCD detector using Cu-K
a
(
l
¼1.5418 A), and the structure was
then refined with riding constraints. The structure was deposited
into Cambridge Structural Database under number CCDC 887653.
solved by direct method16 using the CRYSTALS suite of programs;17
34,845 reflections collected, 6762 unique reflections (Rint¼0.074),
data/restraints/parameters 3277/0/460, final R indices (I>2s(I))
Acknowledgements
ꢂꢀ3
R1¼0.0516 and wR2¼0.0552, Drmax Drmin¼0.49/ꢀ0.62 e A . The
/
structure was deposited into Cambridge Structural Database under
number CCDC 809961.
This research was supported by the Czech Science Foundation
(Nr. 203/09/0691), by the Grant Agency of the Academy of Sciences
of the Czech Republic (Nr. IAAX08240901). I.C. would like to thank
the Ministry of Education, Youth and Sports of the Czech Republic
(Nr. MSM0021620857).
4.6.2. Crystallographic data for C28H20N4O12S4*3 CH3NO2 (3$3 ni-
tromethane). Mr¼915.87, crystal dimensions 0.35ꢁ0.20ꢁ0.09 mm,
ꢂ
ꢂ
space group P21/c, a¼10.0770(2) A, b¼20.3030(5) A,
3
ꢂ
c¼19.6290(4) A,
b
¼97.8560(14)ꢂ, V¼3978.27(15) A , Z¼4,
ꢂ
Supplementary data
rcalcd¼1.529 g/cm3,
m
¼0.324 mmꢀ1. X-ray intensity data were
measured at 150 K on a KappaCCD diffractometer equipped with
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2012.10.101.
These data include MOL files and InChiKeys of the most important
compounds described in this article.
ꢂ
graphite monochromated Mo-K
a
(l
¼0.71073 A), and the structure
was solved by direct method16 using the CRYSTALS suite of pro-
grams;17 17,838 reflections collected, 9108 unique reflections
(Rint¼0.029), data/restraints/parameters 6694/30/568, final R in-
dices (I>2
s
(I)) R1¼0.0506 and wR2¼0.0565, Drmax Drmin¼0.55/
/
ꢂꢀ3
References and notes
ꢀ0.62 e A . The structure was deposited into Cambridge Structural
Database under number CCDC 809962.
1. For books on calixarenes and their applications, see: (a) Gutsche, C. D. Calix-
arenes An Introduction, 2nd ed.; The Royal Society of Chemistry, Thomas Gra-
ham House: Cambridge, 2008; (b) Calixarenes in the Nanoworld; Vicens, J.,
Harrowfield, J., Backlouti, L., Eds.; Springer: Dordrecht, 2007; (c) Calixarenes
4.6.3. Crystallographic data for
C28H20N4O12S4*3 C3H6O (3$3
acetone). Mr¼906.95, crystal dimensions 0.50ꢁ0.50ꢁ0.40 mm,
€
2001; Asfari, Z., Bohmer, V., Harrowfield, J., Vicens, J., Eds.; Kluwer Academic:
ꢂ
ꢂ
space group I41/acd, a¼20.5900(2) A, b¼20.5900(2) A,
Dordrecht, 2001; (d) Mandolini, L.; Ungaro, R. Calixarenes in Action; Imperial
College: London, 2000.
c¼19.5790(2) A, V¼8300.48(14) A , Z¼8, rcalcd¼1.452 g/cm3,
3
ꢂ
ꢂ
¼0.303 mmꢀ1. X-ray intensity data were measured at 150 K on
2. Kumagai, H.; Hasegawa, M.; Miyanari, S.; Sugawa, Y.; Sato, Y.; Hori, T.; Ueda, S.;
Kamiyama, H.; Miyano, S. Tetrahedron Lett. 1997, 38, 3971e3972.
3. For reviews on thiacalixarenes, see: (a) Morohashi, N.; Narumi, F.; Iki, N.;
Hattori, T.; Miyano, S. Chem. Rev. 2006, 106, 5291e5316; (b) Lhotak, P. Eur. J. Org.
Chem. 2004, 1675e1692.
m
a
KappaCCD diffractometer equipped with graphite mono-
ꢂ
chromated Mo-K
a
(l
¼0.71073 A), and the structure was solved by
direct method using the SHELX97 suite of programs;18 8936 re-
4. For direct meta-substitution of thiacalixarenes, see: (a) Kundrat, O.; Kroupa, J.;
flections collected, 2387 unique reflections (Rint¼0.0094), data/re-
€
Bohm, S.; Budka, J.; Eigner, V.; Lhotak, P. J. Org. Chem. 2010, 75, 8372e8375; (b)
straints/parameters 2387/0/154, final R indices (I>2
s
(I)) R1¼0.0621
€
Kundrat, O.; Cisarova, I.; Bohm, B.; Pojarova, M.; Lhotak, P. J. Org. Chem. 2009,
ꢂꢀ3
74, 4592e4596; (c) Kundrat, O.; Dvorakova, H.; Eigner, V.; Lhotak, P. J. Org.
Chem. 2010, 75, 407e411; (d) Kundrat, O.; Dvorakova, H.; Cisarova, I.; Pojarova,
M.; Lhotak, P. Org. Lett. 2009, 11, 4188e4191.
and wR2¼0.2268, Drmax
/Drmin¼0.471/ꢀ0.489 e A . Cambridge
Structural Database under number CCDC 809963.
5. (a) Desroches, C.; Parola, S.; Vocanson, F.; Perrin, M.; Lamartine, R.; Letoffe, J.-
M.; Bouix, J. New J. Chem. 2002, 26, 651e655; (b) Hu, X.; Zhu, Z.; Shen, T.; Shi, X.;
Ren, J.; Sun, Q. Can. J. Chem. 2004, 82, 1266e1270; (c) Agrawal, Y. K.; Pancholi, J.
P. Synth. Commun. 2008, 38, 2446e2458.
4.6.4. Crystallographic data for
C28H20N4O12S4*C4H8O2 (3$ethyl
acetate). Mr¼820.825, crystal dimensions 0.50ꢁ0.40ꢁ0.25 mm,
ꢂ
ꢂ
ꢂ
space group P21/c, a¼10.225(2) A, b¼19.889(4) A, c¼35.167(7) A,
6.
A successful alkylation of compound 2 with allyl bromide was reported:
3
ꢂ
ꢂ
b
¼96.21(3) , V¼7100(2) A , Z¼4, rcalcd¼1.531 g/cm3,
m
¼0.343 mmꢀ1
.
Kasyan, O.; Thondorf, I.; Bolte, M.; Kalchenko, V.; Boehmer, V. Acta Crystallogr.,
Sect. C 2006, 62, o289eo294.
7. Himl, M.; Pojarova, M.; Stibor, I.; Sykora, J.; Lhotak, P. Tetrahedron Lett. 2005, 46,
461e464.
8. Yang, G.; Jin, C.; Li, Y.; Hong, J.; Miao, R.; Zhao, C.; Guo, Z.; Zhu, L. J. Incl. Phenom.
Macrocycl. Chem. 2005, 52, 119e127.
X-ray intensity data were measured at 150 K on a KappaCCD dif-
fractometer equipped with graphite monochromated Mo-K
a
ꢂ
(l
¼0.71073 A), and the structure was solved by direct method using
the SHELX97 suite of programs;18 31,954 reflections collected,16,310
unique reflections (Rint¼0.0268), data/restraints/parameters 16,310/
9. For complexation of small neutral molecules (gases) by the cavity of 1,3-al-
ternates see: Rudkevich, D. M. Eur. J. Org. Chem. 2007, 20, 3255e3270.
76/1002, final R indices (I>2
s(I)) R1¼0.0722 and wR2¼0.1925, Drmax
/
10. For review on CHe
p interactions, see: (a) Nishio, M. Phys. Chem. Chem. Phys.
ꢂꢀ3
2011, 13, 13873e13900; (b) Nishio, M. CrystEngComm 2004, 6, 130e158.
Drmin¼1.600/ꢀ2.210 e A . The structure was deposited into Cam-
11. (a) Takemura, H.; Yonebayashi, Y.; Nakagaki, T.; Shinmyozu, T. Eur. J. Org. Chem.
bridge Structural Database under number CCDC 809964.
ꢁ
2011, 10, 1968e1971; (b) Lhotak, P.; Zieba, R.; Hromadko, V.; Stibor, I.; Sykora, J.
Tetrahedron Lett. 2003, 44, 4519e4522.
12. For some examples, see: (a) Thallapally, P. K.; Lloyd, G. O.; Atwood, J. L.; Bar-
bour, L. J. Angew. Chem., Int. Ed. 2005, 44, 3848e3851; (b) Lhotak, P.; Himl, M.;
Stibor, I.; Sykora, J.; Dvorakova, H.; Lang, J.; Petrickova, H. Tetrahedron 2003, 59,
7581e7585.
13. The complexation constants for tetrabutylammonium acetate measured under
the same conditions and solved for 1:1 stoichiometry exhibited relatively high
errors for both ligands: K5a¼200ꢃ110 Mꢀ1, K5b¼180ꢃ100 Mꢀ1. This could be
explained by the presence of other species in the system, most probably the
complexes with 2:1 stoichiometry (anion:calix).
4.6.5. Crystallographic data for C60H56N8O8S4*4(C2H6SO) (5a$4
DMSO). M¼1457.96, monoclinic system, space group C2/c,
¼99.369(3)ꢂ,
ꢂ
ꢂ
ꢂ
b
a¼25.2859(6) A, b¼13.7065(2) A, c¼41.6751(10) A,
3
Z¼8, V¼14,251.1(6) A , Dcalcd¼1.359 g/cm3,
m
(Cu-K
a
)¼2.86 mmꢀ1
,
ꢂ
crystal dimensions of 0.08ꢁ0.12ꢁ0.24 mm. Data were collected at
190(2) K on a XcalburOnyxCCD diffractometer with graphite
monochromated Cu-Ka radiation. The structure was solved by

ꢀ
ꢁ
M. Mackova et al. / Tetrahedron 69 (2013) 1397e1402
1402
14. For this behaviour of calixarene based anionic receptors, see: Budka, J.; Lhotak,
P.; Michlova, V.; Stibor, I. Tetrahedron Lett. 2001, 42, 1583e1586.
16. Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.; Giacovazzo, C.; Gua-
gliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. J. Appl. Crystallogr. 1999,
32, 115e119.
17. Betteridge, P. W.; Carruthers, J. R.; Cooper, R. I.; Prout, K.; Watkin, D. J. J. Appl.
Crystallogr. 2003, 36, 1487.
15. The 1H NMR spectrum at room temperature shows only broad diffuse signals
(see Supplementary data), and all our attempts at obtaining meaningful NOE
signals have failed. Unfortunately, the solvent used for the measurements
(DMSO-d6) does not allow the lowering of the temperature.
18. Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112e122.