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. 2010 Aug 11;51(32):4233-4236.
doi: 10.1016/j.tetlet.2010.06.036.

Cooperative NH⋯O and CH⋯O interactions for sulfate encapsulation in a thiophene-based macrocycle

Musabbir A Saeed  1 , Douglas R Powell, Frank R Fronczek, Md Alamgir Hossain
Affiliations

Cooperative NH⋯O and CH⋯O interactions for sulfate encapsulation in a thiophene-based macrocycle

Musabbir A Saeed et al. Tetrahedron Lett. .

Abstract

A thiophene-based macrocycle containing four secondary and two tertiary amines has been synthesized and its binding affinity has been investigated toward sulfate anion in solution and solid states. Structural analysis of the sulfate salt suggests that the ligand in its hexaprotonated form, is capable of encapsulating one sulfate within the cavity through cooperative NH⋯O and CH⋯O interactions. As investigated by (1)HNMR titrations, the lignad forms a 1:1 complex with sulfate in water at pH 2.1, showing a binding constant (K) of 3200 M(-1). The formation of the complex has been further confirmed by ESI-MS, indicating that the complex can exist in solution with a considerable stability.

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Figures

Figure 1
Figure 1
Crystal strucrure of H6L(SO4)]4+ motif showing encapsulated sulfate: (A) side view, (B) view along the tertiary N-N axis and (C) two symmetry related mirror images with disordered sulfate ion. External sulfates and water molecules are not shown for clarity.
Figure 2
Figure 2
Partial 1H NMR spectra of tosylated salt of L (5mM) with the increasing amount of sodium sulfate (50 mM) in D2O at pH 2.1. a = NCH3, b = NCH2, c = NCH2CH2 and d = ArCH2.
Figure 3
Figure 3
1H NMR titration curves for sulfate binding with H6L(OTs)6 in D2O at pH = 2.1. Net changes in the chemical shifts of a = NCH3, b = NCH2 and c = NCH2CH2 are shown against the anion concentration.
Figure 4
Figure 4
ESI-MS (positive ion mode) spectrum of the sulfate complex. The solution was prepared from the sulfate salt of L (1.0×10-5 M) in MeOH/H2O (50:50).
See this image and copyright information in PMC

References

    1. Bowman-James K. Acc Chem Res. 2005;38:671–678. - PubMed
    2. Gale PA. Acc Chem Res. 2006;39:465–475. - PubMed
    3. Hossain MA. Curr Org Chem. 2008;12:1231–1256.
    4. Caltagirone C, Gale PA. Chem Soc Rev. 2009;38:520–563. - PubMed
    1. Young RW. J Cell Biol. 1973;57:175–189. - PMC - PubMed
    1. Pflugrath JW, Quiocho FA. Nature. 1985;314:257–260. - PubMed
    1. Mullen KM, Beer PD. Chem Soc Rev. 2009;38:1701–1713. - PubMed
    1. Sessler JL, Katayev E, Pantos GD, Ustynyuk YA. Chem Commu. 2004:1276–1277. - PubMed
    2. Fowler CJ, Haverlock TJ, Moyer BA, Shriver JA, Gross DE, Marquez M, Sessler JL, Hossain MA, Bowman-James K. J Am Chem Soc. 2008;130:14386–14387. - PMC - PubMed

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