![synthesis of heterocalix[n]bipyrroles](heterocalix2.gif)
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| Anion Sensing
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| Calix[n]pyrroles |
Expanded Porphyrins |
Schiff
Base Macrocycles |
| Unlike their smaller
counterparts, expanded porphyrins have been shown to bind
anions rather well. The Sessler group is interested in exploring
the anion binding properties of expanded porphyrins developed in this
group as well as the anion binding properties of calix[n]pyrroles and
expanded Schiff base macrocycles. We are interested in
synthesizing macrocycles that selectively bind anions such as chloride,
benzoate, peroxynitrate and pertechnetate. |
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| In an ongoing effort
to extend the chemistry of calix[n]pyrroles, numerous analogues have
been reported by our group. The most recent anologue, shown
below, has been made from a straightforward condensation reaction of
1,3-bis(pyrrol-2-yl)benzene with acetone. The resulting 2+2, 3+3
and 4+4 macrocyles and their anion binding affinities have been proven
through x-ray crystallography, 1H NMR and ITC. The 2+2 macrocyle,
shown below has been shown to display a higher binding affinity than
its precurson, calix[4]pyrrole. |
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| Jonathan L. Sessler,
Deqiang An, Won-Seob Cho, Vincent Lynch, Manuel Marquez, Calix[n]bispyrrolylbenzenes:
Synthesis, Characterization, and Preliminary Anion Binding
Studies Chem.
Euro. J.,
11(7), 2005, 2001-2011. |
| As the traditional
calix[4]pyrrole is known for its high affinity towards small anions
such as fluoride, chloride and phosphate, we seek to create
calix[n]pyrroles with a larger cavity for selective binding to larger
anions such as bromide and iodide. |
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| Shown above are the syntheses of
calix[3]bipyrrole (10) and calix[4]bipyrrole (11).
Macrocycle 10 was shown to bind strongly with
bromide and chloride anions and is a
good receptor for bromide and iodide anions, most likely due to its
cavity size. |
| Sessler, J. L.; An, Deqiang; Cho,
Won-Seob; Lynch, Vincent. Calix[n]bipyrroles: Synthesis,
characterization, and anion-binding studies. Angew. Chem. Int. Ed., Eng. 2003,
42(20), 2278-2281 |
| We are interested in
synthesizing larger calix[n]pyrroles or calix[n]phyrins that will be
able to selectively bind larger anions or anions of differing shapes.
Towards this goal, we have recently reported
calix[2]bipyrrole[2]furan and calix[2]bipyrrole[2]thiophene, shown below, which shows
a
preference for the 'Y' shaped carboxylate anion. |
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| Sessler, Jonathan L.; An, Deqiang;
Cho, Won-Seob; Lynch, Vincent. Calix[2]bipyrrole[2]furan and
Calix[2]bipyrrole[2]thiophene: New Pyrrolic Receptors Exhibiting a
Preference for Carboxylate Anions. Journal of the
American Chemical Society 2003, 125(45), 13646-13647 |
| Expanded Porphyrins |
| Sapphyrin, shown below |
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| Sessler,
Jonathan L.; Davis, Julian M.; Kral, Vladimir; Kimbrough, Thomas;
Lynch, Vincent. Water soluble sapphyrins: potential
fluorescent phosphate anion
sensors. Organic & Biomolecular
Chemistry 2003, 1(22), 4113-4123 For more sapphyrin work: 1. V. Král, H. Furuta, K. Shreder, V. Lynch and J. L. Sessler, J. Am. Chem. Soc., 1996, 118, 1595–1607 2. B. L. Iverson, K. Shreder, V. Král, P. Sansom, V. Lynch and J. L. Sessler, J. Am. Chem. Soc., 1996, 118, 1608–1616 3. V. Král, J. Davis, A. Andrievsky, J. Kralová, A. Synytsya, P. Poucková and J. L. Sessler, J. Med. Chem., 2002, 45(5), 1073–1078 |
| Schiff
Base Macrocycles |
| Receptors with a high sulfate/nitrate selectrivity is very important in the area of waste remediation. In collaboration with Moscow State Univerisity, we have devolped a pyridine-2,6-dicarboxamide moiety within a dipyrromethane-based macrocycle and have show that, in acetonitrile solution, it binds sulfate anion with high selectivity relative to nitrate anion. |
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| Sessler, Jonathan L.; Katayev, Evgeny; Pantos, G. Dan; Ustynyuk, Yuri A. Synthesis and study of a new diamidodipyrromethane macrocycle. An anion receptor with a high sulfate-to-nitrate binding selectivity. Chemical Communications (2004), (11), 1276-1277. |