Calix[4]arenes substituted on the narrow rim with malononitrile and cobalt bis(dicarbollide) anion

Article abstract of DOI:10.1055/s-0029-1217061

Nitrile groups are suitable precursors for amino functions to which various other groups can be attached. Thus, the reaction of the l,3-bis(3-bromopropyl ether) or l,3-bis(4-bromobutyl ether) of tert-butylcalix[4]arene with methylmalononitrile has been st

Full text of DOI:10.1055/s-0029-1217061

PAPER
4063
Calix[4]arenes Substituted on the Narrow Rim with Malononitrile and Cobalt
Bis(dicarbollide) Anion
C
alix[4]ar
u
enes Substitu
n
ted with Ma
m
lononitrile
a
nd Cob
e
a
lt Bis(dic
a
i
rbollide)
A
nio
Z
n
hao,a Michael Bolte,b Crenguţa Dordea,a Bohumir Grüner,c Volker Böhmer*a
a
Abteilung Lehramt Chemie, Fachbereich Chemie, Pharmazie und Geowissenschaften, Johannes Gutenberg-Universität Mainz,
Duesbergweg 10–14, 55099 Mainz, Germany
Fax +49(6131)3925419; E-mail: vboehmer@mail.uni-mainz.de
Fachbereich Chemie und Pharmazeutische Wissenschaften, Institut für Anorganische Chemie, Johann Wolfgang Goethe-Universität,
Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
b
c
Institute of Inorganic Chemistry, AS ČR, Area of Research Institutes 1001, 25068 Husinec-Řež, Czech Republic
Received 26 May 2009; revised 27 July 2009
due to its conformational mobility, we envisaged the bind-
ing of two malononitrile units via carbon linkers7 to the
distal oxygen functions of a calix[4]arene, leaving the oth-
er two hydroxy groups for the usual attachment of the an-
Abstract: Nitrile groups are suitable precursors for amino func-
tions to which various other groups can be attached. Thus, the reac-
tion of the 1,3-bis(3-bromopropyl ether) or 1,3-bis(4-bromobutyl
ether) of tert-butylcalix[4]arene with methylmalononitrile has been
studied in order to attach four nitrile groups to the narrow rim. Bi- ionic Cosan groups.
macrocyclic dinitriles were formed in 70% yield with malononitrile,
and tetranitriles in 85% yield with methylmalononitrile. Subsequent
alkylation of the tetranitriles with cobalt dioxane–bis(dicarbollide)
gave dianionic calix[4]arenes, isolated as the cesium salts in 68%
and 89% yield. Two compounds were characterized by single crys-
tal X-ray analysis.
Key words: calixarenes, boron, clusters, alkylation, nitriles
Calixarenes in general and, due to their well-defined con-
formations, calix[4]arenes in particular have been fre-
quently used as platforms for the assembly of various
functional groups.1 The attachment of four carbamoyl-
methylphosphinoxide (CMPO) groups to their wide rim
Figure 1
12 or narrow rim 23 (Figure 1), usually achieved by acyla-
tion of the respective tetramines, led to extractants for lan-
At a first glance, the covalent connection of malononitrile
thanides and actinides with drastically increased
efficiency compared to a single CMPO molecule [e.g., the
technically used (N,N-diisobutylcarbamoylmethyl)phe-
nyloctylphosphine oxide]. The required tetraamino-
calix[4]arenes for the synthesis of narrow-rim CMPOs are
usually obtained by reduction of cyanoalkyl ethers or by
hydrazinolysis of phthalimido residues. Recently, we
could show that the combination of two CMPO functions
with two anionic cobalt bis(dicarbollide)(1–) (Cosan)
groups (i.e., calixarenes 3) leads to a further drastic in-
crease in the extraction ability;4,5 Am3+ is removed from a
5 × 10–8 M aqueous solution to more than 99% by a single
extraction step with a 3 × 10–6 M solution of 3 (n = 4) in
hexyl methyl ketone–dodecane. On the other hand, the ex-
traction ability strongly decreases (by two to three orders
of magnitude) when the number of CMPO groups in 1 is
reduced from four to three.6 We therefore aimed to com-
bine four CMPO functions with two Cosan groups on a
calixarene platform. Since we excluded a calix[6]arene
to the distal oxygen functions of a calix[4]arene might
seem complicated. It requires a bifunctional linker, e.g. an
a,w-dibromoalkane, while malononitrile itself is bifunc-
tional under C-alkylation conditions and four oxygen
functions can be alkylated in the calix[4]arene (see
Scheme 1); however, the 1,3-di-O-alkylation is easily
possible8 with an excess of 1,4-dibromobutane in reflux-
ing acetonitrile. Potassium carbonate as base clearly pre-
vents further O-alkylation of 5b, which was obtained in
65% yield. Even better yields (up to 90%) were obtained
for 5a with 3-bromopropanol under Mitsunobu condi-
tions.
Unexpectedly, however, the subsequent monoalkylation
of malononitrile with 5a,b was more difficult. Even with
a 20-fold excess, the dialkylation could not be avoided,
and the bimacrocyclic 1,3-bridged calix[4]arenes 6a and
6b were readily obtained in 70% yield.9 To attach two
dinitrile units to the calixarene, we therefore had to use
methylmalononitrile, which cannot be dialkylated. Com-
pounds 7a and 7b were thus prepared in about 85% yield
(Scheme 1).
SYNTHESIS 2009, No. 23, pp 4063–4067
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Advanced online publication: 19.10.2009
DOI: 10.1055/s-0029-1217061; Art ID: T10709SS
© Georg Thieme Verlag Stuttgart · New York

4064
J. Zhao et al.
PAPER
Scheme 1 Synthesis of the narrow-rim malononitrile–calix[4]arene derivatives 6, 7 and 8: i) 5a: Br(CH2)3OH, DIAD, THF, r.t., 3 h; 5b:
Br(CH2)4Br, K2CO3, MeCN, reflux, 2 d; ii) CH2(CN)2, NaOMe, THF, r.t., 2 d; iii) 7a: CH3CH(CN)2, NaOMe, THF, r.t., 2 d; 7b: CH3CH(CN)2,
K2CO3, acetone, reflux, 12 h; iv) NaH, cobalt dioxane–bis(dicarbollide), toluene–DME (3:1), r.t., 12 h.
Two cobalt bis(dicarbollide)(1–) anions could be attached tion of 6a in acetonitrile and of 7a in ethyl acetate–
to the tetranitriles 7a and 7b by O-alkylation of the re- chloroform. Compound 6a contains two independent mol-
maining two hydroxy groups of the calixarene with the ecules with slightly different shape in the asymmetric
cosan-dioxane
derivative
[8-O(CH2CH2)2O-1,2- unit, which are shown in Figure 2a. An unambiguous de-
C2B9H10)(1¢,2¢-C2B9H11)-3,3¢-Co]. This method has al- scription of the shape of a calixarene is possible using the
ready proved to be very effective for the introduction of torsion angles around the Ar–CH2 bonds,12 with alternat-
the bulky and hydrophobic cobalt bis(dicarbollide) cluster ing sign of the angles being characteristic for a molecule
to the narrow rim of calix[4]arenes.4,5 The respective di- in the cone conformation. Easier to visualize are the incli-
anionic species 8a and 8b were formed almost exclusively nation angles of the aromatic units with respect to the ref-
as the cone-isomers, according to the NMR spectra of the erence plane defined by the four methylene carbon atoms
crude products. Both compounds were isolated as the ce- (Table 1). Two molecules of acetonitrile are incorporated
sium salts in good yields (68% and 89%) after simple per molecule of 6a, one of which is included in the cavity
crystallization from dichloromethane–hexane.
Single crystals of 6a10 and 7a11 suitable for X-ray diffrac-
tion analysis were obtained by slow evaporation of a solu-
as is often found for calix[4]arenes with a (more or less
regular) cone conformation. The second molecule fills
gaps in the crystal lattice.
Figure 2 a) Two crystallographically different molecules of 6a with acetonitrile molecules (shown with thermal ellipsoids) included in the
cavities; b) molecular conformation of 7a.
Synthesis 2009, No. 23, 4063–4067 © Thieme Stuttgart · New York

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Calix[4]arenes Substituted with Malononitrile and Cobalt Bis(dicarbollide) Anion
4065
1H, 1H{11B}, 1H{11Bselective}, 1H–1H COSY, 11B and 11B{1H} NMR
spectra for compounds 8 were measured on a Varian Mercury Plus
400 MHz spectrometer (400 MHz for 1H, 128 MHz for 11B). Chem-
ical shifts are referenced to the residual solvent peaks; 11B NMR
signals are referenced to BF3⋅OEt2 as external standard. Mass spec-
tra were recorded on a Waters Micromass Q-ToF Ultima 3 (for
compounds 6 and 7) or on a Thermo Finnigan LCQ Fleet Ion Trap
mass spectrometer (for compounds 8). All solvents were HPLC
grade and were used without further purification. Column chroma-
tography was performed on silica gel 60 (0.035–0.070 mm, Acros).
Table 1 Comparison of the Shape of 6a and 7a Using the Torsion
Angles around the Ar–CH2 Bonds and the Inclination of the Phenolic
Units with Respect to the Molecular Main Plane, Defined by the Car-
bon Atoms C1, C2, C3, C4 of the Methylene Bridges (Oxygen Func-
tions at Carbon Atoms C12, C22, C32, C42)
6a(1)
6a(2)
7a
Torsion angles
C42–C43–C1–C11
C43–C1–C11–C12
C12–C13–C2–C21
C13–C2–C21–C22
C22–C23–C3–C31
C23–C3–C31–C32
C32–C33–C4–C41
C33–C4–C41–C42
–87.87
101.40
–93.11
82.34
–89.46
100.05
–91.26
90.38
–77.60
Intensity data were collected on a STOE IPDS II two-circle diffrac-
tometer with graphite–monochromated Mo Ka radiation at 173 K.
The structures were solved by direct methods using the program
SHELXS14 and refined against F2 with full-matrix least-squares
techniques using the program SHELXL.14 Hydrogen atoms bonded
to carbon were included at calculated positions with fixed displace-
ment parameters. Hydrogen atoms bonded to oxygen were freely re-
fined. Two tert-butyl groups and one acetonitrile molecule in 6a are
disordered over two positions.
113.03
–102.61
68.82
–86.46
102.70
–95.74
81.36
–96.11
96.29
–75.20
113.74
–103.74
70.76
–92.18
85.92
Calix[4]arene 6a
A soln of bis(3-bromopropyl ether) 5a (200 mg, 0.225 mmol) in an-
hyd THF (30 mL) was added to a freshly prepared sample of sodium
malononitrile, obtained by dissolving malononitrile (297 mg, 4.5
mmol) and 1.0 equiv of NaOMe in MeOH (30 mL), followed by
evaporation of the solvent. NaI (0.2 g) was added, and the mixture
was stirred under N2 at r.t. for 2 d. Then, the THF was evaporated
and the residue was taken up in CHCl3 (100 mL). The organic layer
was washed with 1 M HCl (3 × 50 mL), H2O (50 mL) and brine (50
mL), and then dried (MgSO4). Evaporation of the solvent and puri-
fication by column chromatography (hexane–EtOAc, 4:1) afforded
6a as a white powder; yield: 127 mg (71%).
Inclination of the aromatic rings
C11–C16
C12–C26
C31–C36
C41–C46
66.60
66.31
63.19
61.85
55.79
80.73
37.88
91.76
40.64
52.82
68.92
52.29
Mp 283–285 °C (dec).
Figure 2b shows the molecular shape of compound 7a,
which assumes a strongly pinched cone conformation,
again typical for 1,3-diethers of calix[4]arenes. Both aro-
matic rings bearing the ether groups are ‘nearly parallel’
(interplanar angle 17.5°), while the phenolic units are
strongly bent outwards (interplanar angle 101.5°). A visu-
1H NMR (400 MHz, CDCl3): d = 8.99 (s, 2 H, OH), 7.08 (s, 4 H,
ArH), 7.00 (s, 4 H, ArH), 4.18 (d, J = 12.9 Hz, 4 H, ArCH2Ar), 4.12
(t, J = 4.6 Hz, 4 H, OCH2), 3.40 (d, J = 12.9 Hz, 4 H, ArCH2Ar),
2.87 (m, 4 H, OCH2CH2), 2.47 (m, 4 H, OCH2CH2CH2), 1.20 (s, 18
H, t-Bu), 1.19 (s, 18 H, t-Bu).
13C NMR (100 MHz, CD2Cl2): d = 150.7, 149.0, 148.9, 143.1,
al inspection already reveals a more regular cone confor- 134.3, 128.2, 126.8, 125.8, 116.3, 73.7, 34.9, 34.7, 34.3, 32.9, 31.9,
31.5, 29.7, 27.5.
MS (FD): m/z = 794.6 [M+].
mation for 6a in comparison to 7a. This is also expressed
by the torsion angles and the inclination angles listed in
Table 1.
Calix[4]arene 6b
In conclusion, we have shown that the attachment of four
nitrile functions to the narrow rim of a calix[4]arene is
possible by reaction of 1,3-bis(bromoalkoxy)calix[4]ar-
enes with methylmalononitrile; the analogous reaction
with malononitrile, however, leads to macrocyclic 1,3-di-
ether derivatives with two nitrile groups. The attachment
of two Cosan functions to the remaining phenolic hydroxy
groups was also possible. We expect that the new anionic
species 8a,b will serve as useful precursors for a variety
of functional ionic molecules which should be available,
for instance, by reduction of the nitrile groups and subse-
quent acylation to introduce ligating functions such as
CMPO or picolinamide.13 These studies are currently in
progress in our laboratories.
The 1,3-bridged calix[4]arene 6b was obtained analogously, start-
ing from bis(4-bromobutyl ether) 5b (200 mg, 0.218 mmol); yield:
126 mg (70%).
Mp >300 °C (dec).
1H NMR (400 MHz, CDCl3): d = 7.47 (s, 2 H, OH), 7.06 (s, 4 H,
ArH), 6.78 (s, 4 H, ArH), 4.20 (d, J = 12.9 Hz, 4 H, ArCH2Ar), 4.06
(t, J = 5.1 Hz, 4 H, OCH2), 3.32 (d, J = 12.9 Hz, 4 H, ArCH2Ar),
2.39 (m, 4 H, OCH2CH2), 2.17 (m, 4 H, OCH2CH2CH2), 2.06 (m, 4
H, OCH2CH2CH2CH2), 1.28 (s, 18 H, t-Bu), 0.93 (s, 18 H, t-Bu).
13C NMR (100 MHz, CD2Cl2): d = 151.3, 150.7, 148.2, 142.5,
133.1, 127.5, 126.7, 126.3, 117.1, 76.0, 35.9, 35.4, 34.7, 34.2, 32.7,
31.9, 31.6, 30.7, 20.7.
MS (FD): m/z = 822.5 [M+].
Calix[4]arene 7a
1,3-Bis(4,4-dicyanopentyloxy)calix[4]arene 7a was prepared under
the conditions described for 6a using methylmalononitrile instead
of malononitrile. Starting from 5a (1.00 g, 1.13 mmol), pure 7a was
isolated by column chromatography (hexane–EtOAc, 4:1) as a
white powder; yield: 875 mg (87%).
Melting points were determined on a Buchi melting point B-545 or
1
a MEL-TEMP II apparatus and are uncorrected. H and 13C NMR
spectra for compounds 6 and 7 were recorded on a Bruker Avance
DRX-400 spectrometer at 400 and 100.6 MHz, respectively. The
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4066
J. Zhao et al.
PAPER
Mp 282–284 °C.
(m, 4 H, OCH2), 3.25 (d, J = 12.4 Hz, 4 H, ArCH2Ar), 2.42 (m, 4 H,
OCH2CH2CH2), 2.27 (m, 4 H, OCH2CH2CH2), 1.97 [s, 6 H,
CH3C(CN)2], 1.22 (s, 18 H, t-Bu), 1.03 (s, 18 H, t-Bu).
1H{11Bselective} NMR (400 MHz, acetone-d6): d = 2.94 (s, 2 H,
H10¢), 2.76 (s, 4 H, H4¢,7¢), 2.71 (s, 2 H, H10), 2.55 (s, 2 H, H8¢),
2.94, 2.91, 1.81 (3 × s, 12 H, H4,7,9,12,9¢,12¢), 1.67 (s, 4 H,
H5¢,11¢), 1.55 (s, 4 H, H5,11), 1.48 (s, 2 H, H6¢), 1.45 (s, 2 H, H6).
11B NMR (128 MHz, acetone-d6, BF3 OEt2): d = 22.22 (s, 2 B, B8),
4.46 (d, J = 140 Hz, 2 B, B8¢), 0.51 (d, J = 139 Hz, 2 B, B10¢), –2.38
(d, J = 140 Hz, 2 B, B10), –4.27 (d, J = 150 Hz, 4 B, B4¢,7¢), –7.26,
–7.79 (2 × d, 12 B, B4,7,9,12,9¢,12¢), –17.16 (d, J = 162 Hz, 4 B,
B5¢,11¢), –20.32 (d, J = 152 Hz, 4 B, B5,11), –22.15 (d, J = 184 Hz,
2 B, B6¢), –28.12 (d, J = 140 Hz, 2 B, B6).
1H NMR (400 MHz, CDCl3): d = 7.08 (s, 4 H, ArH), 6.91 (s, 2 H,
OH), 6.76 (s, 4 H, ArH), 4.19 (d, J = 12.9 Hz, 4 H, ArCH2Ar), 4.08
(t, J = 6.0 Hz, 4 H, OCH2), 3.34 (d, J = 12.9 Hz, 4 H, ArCH2Ar),
2.42 (m, 4 H, OCH2CH2), 2.30 (m, 4 H, OCH2CH2CH2), 1.90 [s, 6
H, CH3C(CN)2], 1.30 (s, 18 H, t-Bu), 0.92 (s, 18 H, t-Bu).
13C NMR (100 MHz, CD2Cl2): d = 151.2, 150.1, 148.4, 142.7,
133.1, 127.6, 126.8, 126.2, 117.0, 75.5, 36.5, 34.7, 34.3, 32.7, 32.3,
31.9, 31.5, 27.0, 25.5.
MS (FD): m/z = 889.3 [M+].
Calix[4]arene 7b
To obtain 1,3-bis(5,5-dicyanohexyloxy)calix[4]arene 7b, a soln of
methylmalononitrile (435 mg, 5.44 mmol) in anhyd acetone (20
mL) was added to a suspension of K2CO3 (1.5 g, 10.9 mmol) in the
same solvent (20 mL). The mixture was stirred for 30 min, 5b (1.0
g, 1.09 mmol) and KI (0.5 g) were added, and the resulting mixture
was stirred overnight under reflux. The solvent was evaporated and
the dry residue was taken up in CHCl3 (100 mL). The organic layer
was washed with 1 M HCl (3 × 50 mL), H2O (50 mL) and brine (50
mL), and then dried (MgSO4). Evaporation of the solvent and puri-
fication by column chromatography (hexane–EtOAc, 4:1) afforded
7b as a white powder; yield: 818 mg (82%).
ESI-MS: m/z (%) = 854.67 (100), 856.64 (5) [M2–].
Calix[4]arene 8b
Calix[4]arene 7b (400 mg, 0.43 mmol) was dissolved in anhyd tol-
uene–DME (3:1, 25 mL) and deprotonated with solid 96% NaH (23
mg, 0.91 mmol). Then, a soln of cobalt dioxane–bis(dicarbollide)
(370 mg, 0.90 mmol) in the same solvent (15 mL) was added by sy-
ringe and the mixture was stirred for 16 h at r.t. The product was iso-
lated as described for compound 8a and recrystallized (twice from
CH2Cl2–hexane) to give Cs2·8b as an orange powder; yield: 780 mg
(89%); HPLC purity check: 97.6%.
Mp 167–169 °C.
Mp 202–204 °C.
1H NMR (400 MHz, CDCl3): d = 7.06 (s, 2 H, OH), 7.06 (s, 4 H,
ArH), 6.76 (s, 4 H, ArH), 4.21 (d, J = 13.3 Hz, 4 H, ArCH2Ar), 3.99
(t, J = 6.1 Hz, 4 H, OCH2), 3.31 (d, J = 13.3 Hz, 4 H, ArCH2Ar),
2.17 (m, 4 H, OCH2CH2), 2.10 (m, 4 H, OCH2CH2CH2), 2.01 (m, 4
H, OCH2CH2CH2CH2), 1.85 [s, 6 H, CH3C(CN)2], 1.29 (s, 18 H, t-
Bu), 0.92 (s, 18 H, t-Bu).
13C NMR (100 MHz, CD2Cl2): d = 151.2, 150.1, 148.2, 142.4,
133.3, 127.6, 126.6, 126.1, 117.1, 76.1, 39.4, 34.7, 34.3, 32.6, 32.4,
31.9, 31.5, 29.7, 25.3, 22.6.
1H NMR (400 MHz, acetone-d6): d = 6.93 (s, 8 H, ArH), 4.53 (d,
J = 12.0 Hz, 4 H, ArCH2Ar), 4.25 (s, 8 H, cage CH), 4.19 (t, J = 7.4
Hz, 4 H, OCH2), 4.05 (t, J = 5.4 Hz, 8 H, OCH2), 3.70 (m, 4 H,
OCH2), 3.68 (m, 4 H, OCH2), 3.25 (d, J = 11.6 Hz, 4 H, ArCH2Ar),
2.27 (m, 4 H, OCH2CH2CH2), 1.92 [s, 6 H, CH3C(CN)2], 1.81 (m, 4
H, OCH2CH2CH2), 1.63 (m, 4 H, OCH2CH2CH2CH2), 1.13 (s, 36 H,
t-Bu).
1H{11Bselective} NMR (400 MHz, acetone-d6): d = 2.94 (s, 2 H,
H10¢), 2.76 (s, 4 H, H4¢,7¢), 2.71 (s, 2 H, H10), 2.58 (s, 2 H, H8¢),
2.94, 2.03, 1.83 (3 × s, 12 H, H4,7,9,12,9¢,12¢), 1.66 (s, 4 H,
H5¢,11¢), 1.63 (s, 4 H, H5,11), 1.56 (s, 2 H, H6¢), 1.43 (s, 2 H, H6).
11B NMR (128 MHz, acetone-d6, BF3 OEt2): d = 23.25 (s, 2 B, B8),
4.51 (d, J = 134 Hz, 2 B, B8¢), 0.44 (d, J = 143 Hz, 2 B, B10¢), –2.51
(d, J = 150 Hz, 2 B, B10), –4.32 (d, J = 152 Hz, 4 B, B4¢,7¢), –7.15,
–7.99 (2 × d, 12 B, B4,7,9,12,9¢,12¢), –17.08 (d, J = 152 Hz, 4 B,
B5¢,11¢), –20.20 (d, J = 156 Hz, 4 B, B5,11), –21.91 (d, J = 180 Hz,
2 B, B6¢), –28.26 (d, J = 155 Hz, 2 B, B6).
MS (FD): m/z = 916.1 [M+ – H].
Calix[4]arene 8a
Calix[4]arene 7a (175 mg, 0.197 mmol) was dissolved in anhyd tol-
uene–ethylene glycol dimethyl ether (DME) (3:1, 15 mL) and
deprotonated with solid 96% NaH (10 mg, 0.40 mmol). Then, a soln
of cobalt dioxane–bis(dicarbollide) (180 mg, 0.44 mmol) in the
same solvent (15 mL) was added by syringe. The mixture was
stirred overnight at r.t., the reaction was quenched by the addition
of H2O (5 mL) and a few drops of 3 M AcOH, and the solvents were
evaporated under reduced pressure. The residue was treated with
Et2O (25 mL) and 3 M HCl (20 mL). The organic layer was washed
with 3 M HCl (3 × 15 mL) and then with H2O (2 × 15 mL). H2O (15
mL) was added again and the ether was evaporated under reduced
pressure at r.t. The remaining water was decanted and aq MeOH
was added to dissolve the orange residue. The crude cesium salt was
precipitated by adding CsCl in excess to this solution. After allow-
ing the mixture to stand for 3 h, the precipitate was collected by fil-
tration, then washed with 30% MeOH (2 × 5 mL) and dried under
reduced pressure. The solid was dissolved in CH2Cl2 (15 mL, to
which three drops of MeOH were added), the solution was filtered
from an insoluble white solid, and the filtrate was overlaid with hex-
ane and left to crystallize. The solid was collected and recrystallized
(twice from CH2Cl2–hexane) to give Cs2·8a as an orange microcrys-
talline powder; yield: 265 mg (68%); HPLC purity check (see ref.5):
98.2%.
ESI-MS: m/z (%) = 868.20 (100), 871.70 (4) [M2–], 1760.06 (10),
1766.20 (1) [M + Na]+.
Acknowledgment
This work has been financially supported by the European Commis-
sion in the framework of the research program on management and
storage of radioactive waste (Contracts No. FI4W-CT96-0022 and
No. FIKW-CT-2000-00088). Partial support from GA CR (Grant
No. 104/09/0668) and Research Plan AS CR (AV0Z40320502) to
B.G. is appreciated. We thank Mrs M. Kvičalová for the MS mea-
surements of 8a and 8b.
References
(1) For reviews, see: (a) Calixarenes 2001; Asfari, Z.; Böhmer,
V.; Harrowfield, J.; Vicens, J., Eds.; Kluwer Academic
Publishers: Dordrecht, 2001. (b) Böhmer, V. Calixarenes,
In The Chemistry of Phenols; Rappoport, Z., Ed.; Wiley &
Sons: Chichester, 2003.
Mp 218–221 °C.
1H NMR (400 MHz, acetone-d6): d = 7.06 (s, 4 H, ArH), 6.79 (s, 4
H, ArH), 4.52 (d, J = 12.4 Hz, 4 H, ArCH2Ar), 4.23 (s, 8 H, cage
CH), 4.21 (t, J = 7.6 Hz, 4 H, OCH2), 4.13 (t, J = 5.2 Hz, 4 H,
OCH2), 3.95 (t, J = 5.2 Hz, 4 H, OCH2), 3.66 (m, 4 H, OCH2), 3.63
Synthesis 2009, No. 23, 4063–4067 © Thieme Stuttgart · New York

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Calix[4]arenes Substituted with Malononitrile and Cobalt Bis(dicarbollide) Anion
4067
(2) (a) Arnaud-Neu, F.; Böhmer, V.; Dozol, J.-F.; Grüttner, C.;
(9) A reaction of 5b with malononitrile in THF at –78 °C using
LDA as base led to a complicated mixture from which the
expected tetranitrile could be isolated in 12% yield.
(10) Crystal data for 6a: C53H66N2O4⋅2MeCN, M = 877.19,
monoclinic, a = 13.8422(4) Å, b = 18.3275(6) Å,
Jakobi, R. A.; Kraft, D.; Mauprivez, O.; Rouquette, H.;
Schwing-Weill, M.-J.; Simon, N.; Vogt, W. J. Chem. Soc.,
Perkin Trans. 2 1996, 1175. (b) Matthews, S. E.; Saadioui,
M.; Böhmer, V.; Barboso, S.; Arnaud-Neu, F.; Schwing-
Weill, M.-J.; Garcia Carrera, A.; Dozol, J.-F. J. Prakt.
Chem. 1999, 341, 264.
c = 42.7189(11) Å, b = 97.642(2)°, V = 10741.2(5) Å3,
T = 173(2) K, space group P21/c, Z = 8, m(Mo Ka) = 0.068
mm–1, 95208 reflections measured, 19962 unique reflections
which were used in all calculations. The final wR(F2)[I >
2s(I)] was 0.2685. Crystallographic data in CIF format have
been deposited with the Cambridge Crystallographic Data
Centre, reference no. CCDC 642222, and can be obtained on
application to CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK; Fax: +44(1223)336033; E-mail:
(3) (a) Barboso, S.; Garcia Carrera, A.; Matthews, S. E.;
Arnaud-Neu, F.; Böhmer, V.; Dozol, J.-F.; Rouquette, H.;
Schwing-Weill, M.-J. J. Chem. Soc., Perkin Trans. 2 1999,
719. (b) Casnati, A.; Fontanella, M.; Sansone, F.; Ungaro,
R.; Böhmer, V.; Saadioui, M.; Liger, K.; Dozol, J.-F.
Tetrahedron 2006, 62, 6749.
(4) Mikulášek, L.; Grüner, B.; Danila, C.; Böhmer, V.;
Čáslavský, J.; Selucký, P. Chem. Commun. 2006, 4001.
(5) Mikulášek, L.; Grüner, B.; Dordea, C.; Rudzevich, V.;
Böhmer, V.; Haddaoui, J.; Hubscher-Bruder, V.; Arnaud-
Neu, F.; Čáslavský, J.; Selucký, P. Eur. J. Org. Chem. 2007,
4772.
(6) Arnaud-Neu, F.; Barboso, S.; Böhmer, V.; Brisach, F.;
Delmau, L.; Dozol, J.-F.; Mogck, O.; Paulus, E. F.; Saadioui,
M.; Shivanyuk, A. Aust. J. Chem. 2003, 56, 1113.
(7) Dendritic octa-CMPO derivatives of calix[4]arenes with
nitrogen atoms as branching points showed only weak
extractabilities, probably due to a protonation of the tertiary
amines in acidic media; see: Wang, P.; Saadioui, M.;
Schmidt, C.; Böhmer, V.; Host, V.; Desreux, J. F.; Dozol,
J.-F. Tetrahedron 2004, 60, 2509.
deposit@ccdc.cam.ac.uk.
(11) Crystal data for 7a: C58H72N4O4, M = 889.20, triclinic,
a = 10.3770(4) Å, b = 13.3048(6) Å, c = 20.2318(9) Å,
a = 92.798(3)°, b = 90.151(3)°, g = 93.368(3)°, V = 2785.1
(2) Å3, T = 173 (2) K, space group P1, Z = 2, m(Mo Ka) =
0.066 mm–1, 77572 reflections measured, 11334 unique
reflections which were used in all calculations. The final
wR(F2)[I > 2s(I)] was 0.1509. Crystallographic data in CIF
format have been deposited with the Cambridge
Crystallographic Data Centre, reference no. CCDC 642221.
(12) Ugozzoli, F.; Andreetti, G. D. J. Inclusion Phenom. Mol.
Recognit. Chem. 1992, 13, 337.
(13) Casnati, A.; Della Ca’, N.; Fontanella, M.; Sansone, F.;
Ugozzoli, F.; Ungaro, R.; Liger, K.; Dozol, J.-F. Eur. J. Org.
Chem. 2005, 2338.
(8) Li, Z.-T.; Ji, G.-Z.; Zhao, C.-X.; Yuan, S.-D.; Ding, H.;
Huang, C.; Du, A.-L.; Wei, M. J. Org. Chem. 1999, 64,
3572.
(14) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112.
Synthesis 2009, No. 23, 4063–4067 © Thieme Stuttgart · New York