Communications
Table 1: Association constants (Ka, mÀ1) and NH chemical shifts of
complexes (CD3CN) formed between 1 and 2 and anions.
[2] a) J. W. Pflugrath, F. A. Quiocho, Nature 1985, 314, 257 – 260;
b) H. Luecke, F. A. Quiocho, Nature 1990, 347, 402– 406; c) R.
Dutzler, E. B. Campbell, M. Cadene, B. T. Chait, R. MacKinnon,
Nature 2002, 415, 287 – 294.
Anion
NH chemical shift[a]
Association constant
[b]
(d, ppm)
(Ka, mÀ1
)
[3] For selected recent examples of (thio)ureido-based receptors,
see: a) A. V. Koulov, T. N. Lambert, R. Shukla, M. Jain, J. M.
Boon, B. D. Smith, H. Li, D. N. Sheppard, J.-B. Joos, J. P. Clare,
A. P. Davis, Angew. Chem. 2003, 115, 5081 – 5083; Angew. Chem.
Int. Ed. 2003, 42, 4931 – 4933; b) C. R. Bondy, P. Gale, S. J. Loeb,
J. Am. Chem. Soc. 2004, 126, 5030 – 5031; c) M. Vµzquez, L.
Fabbrizzi, A. Taglietti, R. M. Pedrido, A. M. Gonzµlez-Noya,
M. R. Bermejo, Angew. Chem. 2004, 116, 1996 – 1999; Angew.
Chem. Int. Ed. 2004, 43, 1962– 1965; d) J. Y. Kwon, Y. J. Jang,
S. K. Kim, K.-H. Lee, J. S. Kim, J. Yoon, J. Org. Chem. 2004, 69,
5155 – 5157; e) S. Zhang, L. Echegoyen, J. Am. Chem. Soc. 2005,
127, 2006 – 2011; f) J. P. Clare, A. J. Ayling, J.-B. Joos, A. L.
Sission, G. Magro, M. N. PØrez-Payµn, T. N. Lambert, R. Shukla,
B. D. Smith, A. P. Davis, J. Am. Chem. Soc. 2005, 127, 10739 –
10746; g) E. J. Cho, B. J. Ryu, Y. J. Lee, K. C. Nam, Org. Lett.
2005, 7, 2607 – 2609.
1
2
1
2
FÀ[c]
13.9
13.0
12.7
12.6
12.5
12.4
12.3
11.9
11.3
13.9
12.8
12.5
12.3
12.1
12.0
11.8
11.5
10.9
2.0108
5.9106
5.6108
6.5106
AcOÀ
H2PO4
ClÀÀ
2.1106
3.2106
À
1.5106
2.1106
N3
HSO4
8.8105
9.1105
6.5105
6.8105
À
3.9105
3.9105
À
NO3
CNÀ
BrÀ
6.5104
7.5104
K1 =1.9103
K1 =1.9103
K2 =10
K2 =14
IÀ
11.0
10.7
K1 =3.1102
K2 =6
K1 =3.0102
K2 =5
[a] The NH chemical shifts of the free macrocycles 1 and 2 are d=10.9
and 10.6 ppm, respectively. [b] Titrations were all duplicated in CH3CN at
295Æ1 K and the errors in the Ka values were within Æ6%. The CH3CN
containing less than 0.05% water was used directly as purchased. [c] The
association constants between macrocycles and fluoride ions were
determined by competition experiments with chloride by using 1H NMR
spectroscopy.
[4] For selected recent examples of amido-based receptors, see:
a) S. O. Kang, J. M. Llinares, D. Powell, D. Van der Velde, K.
Bowman-James, J. Am. Chem. Soc. 2003, 125, 10152– 10153;
b) K. Choi, A. D. Hamilton, J. Am. Chem. Soc. 2003, 125,
10241 – 10249; c) D. Curiel, P. D. Beer, Chem. Commun. 2005,
1909 – 1911.
[5] a) P. A. Gale, J. L. Sessler, V. Krµl, Chem. Commun. 1998, 1 – 8;
b) P. A. Gale, P. Anzenbacher, Jr., J. L. Sessler, Coord. Chem.
Rev. 2001, 222, 57 – 102; c) P. Piątek, V. M. Lynch, J. L.
Sessler, J. Am. Chem. Soc. 2004, 126, 16073 – 16076; d) K. A.
Nielsen, W.-S. Cho, J. O. Jeppesen, V. M. Lynch, J. Becher, J. L.
Sessler, J. Am. Chem. Soc. 2004, 126, 16296 – 16297; e) J. L.
Sessler, E. Katayev, G. D. Pantos, P. Scherbakov, M. D. Reshe-
tova, V. N. Khrustalev, V. M. Lynch, Y. A. Ustynyuk, J. Am.
Chem. Soc. 2005, 127, 11442– 11446.
[6] For reviews, see: a) J. L. Sessler, J. M. Davis, Acc. Chem. Res.
2001, 34, 989 – 997; b) J. L. Sessler, S. Camiolo, P. A. Gale, Coord.
Chem. Rev. 2003, 240, 17 – 55.
[7] For a review, see: P. A. Gale, Chem. Commun. 2005, 3761 – 3772.
[8] For indolocarbazole-based anion sensors, see: D. Curiel, A.
Cowley, P. D. Beer, Chem. Commun. 2005, 236 – 238.
[9] a) T. M. Cresp, J. Ojima, F. Sondheimer, J. Org. Chem. 1977, 42,
2130 – 2138; b) Y. Tobe, N. Utsumi, K. Kawabata, A. Nagano, K.
Adachi, S. Araki, M. Sonada, K. Hirose, K. Naemura, J. Am.
Chem. Soc. 2002, 124, 5350 – 5364.
[10] For the preparation of an indole ring, see: J. Ezquerra, C.
Pedregal, C. Lamas, J. Org. Chem. 1996, 61, 5804 – 5812.
[11] Compound 3 was prepared from 4-tert-butylanilne in two steps,
and compound 6 was prepared by the reaction of 4 with
(dimethylamino)acetaldehyde diethyl acetal (see the Supporting
Information).
the binding mode of alkali metals with crown ethers having
small cavities.[18] As anticipated from the cavity size, macro-
cycles 1 and 2 generally show similar binding affinities toward
anions. The association constants for a series of halides
decrease dramatically in the order FÀ > ClÀ @ BrÀ > IÀ. This
large difference is probably attributed to the charge density of
the anion surfaces and to the size complementarities of the
anions and the internal cavity. Finally, it should be noted that
there is a good linear relationship between the binding
affinities and the NH chemical shifts of the complexes (see
the Supporting Information).
In conclusion, macrocycles 1 and 2 strongly bind various
anions through hydrogen-bonding interactions and function
as chemosensors capable of distinguishing between anions on
1
the basis of the H NMR chemical shifts of the complex. We
are currently developing more practical and selective chemo-
sensors for anionic species by incorporating a chromophore or
a fluorophore and by tuning the cavity size.
Received: September 2, 2005
Published online: November 10, 2005
[12] The coupling reactions in the presence of copper iodide and/or at
higher temperature under various conditions always resulted in
complicated mixtures without any discrete, separable spots on
the TLC plates and a major product in the 1H NMR spectra.
[13] A. Soheili, J. Albaneze-Walker, J. A. Murry, P. G. Dormer, D. L.
Hughes, Org. Lett. 2003, 5, 4191 – 4194.
Keywords: anions · heterocycles · hydrogen bonds ·
macrocycles · sensors
.
[14] For the synthesis of sp3-carbon-bridged, puckered calix[n]in-
doles, see: a) D. StC. Black, M. C. Bowyer, N. Kumar, P. S. R.
Mitchell, J. Chem. Soc. Chem. Commun. 1993, 819 – 821; b) D.
StC. Black, D. C. Craig, N. Kumar, Tetrahedron Lett. 1995, 36,
8075 – 8078.
[1] For reviews, see: a) P. D. Beer, Acc. Chem. Res. 1998, 31, 71 – 80;
b) P. D. Beer, P. A. Gale, Angew. Chem. 2001, 113, 502– 532;
Angew. Chem. Int. Ed. 2001, 40, 486 – 516; c) C. R. Bondy, S. J.
Loeb, Coord. Chem. Rev. 2003, 240, 77 – 99; d) K. Choi, A. D.
Hamilton, Coord. Chem. Rev. 2003, 240, 101 – 110; e) P. A. Gale,
Coord. Chem. Rev. 2003, 240, 191 – 221; f) C. Suksai, T.
Tuntulani, Chem. Soc. Rev. 2003, 32, 192– 202; g) R. Martínez-
Mµæez, F. Sancenón, Chem. Rev. 2003, 103, 4419 – 4476; h) C.
Bowman-James, Acc. Chem. Res. 2005, 38, 671 – 678.
[15] Single crystals of 2·Bu4N+ClÀ were obtained by slow vapor
diffusion of diethyl ether into a solution of 2 and Bu4N+ClÀ (1:1)
in CH3CN/CH2Cl2. The data collection was performed at
À1008C with MoKa radiation (l = 0.71073 ) on a Bruker
SMART CCD equipped with a graphite crystal, incident-beam
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Angew. Chem. Int. Ed. 2005, 44, 7926 –7929