Anion−Anion Assembly:  A New Class of Anionic Supramolecular Polymer Containing 3,4-Dichloro-2,5-diamido-substituted Pyrrole Anion Dimers

Gale, Philip A.; Navakhun, Korakot; Camiolo, Salvatore; Light, Mark E.; Hursthouse, Michael B.

doi:10.1021/ja027118v

Cited by 123 publications

(42 citation statements)

References 16 publications

(19 reference statements)

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“…Although pincer‐like coordination with the pyrrole hydrogen atom might have been anticipated, exposure of the ligand to fluoride led to deprotonation of the pyrrole NH group. A similar reaction was also observed for 6 , as described above 19. Gale suggests that a three‐step complexation process occurs in anion binding: 1) The initial equivalent of fluoride added is coordinated, and a downfield shift of the CH protons on the aromatic ring is observed in the NMR spectrum; 2) With the second equivalent of fluoride, the pyrrole NH group is deprotonated, and bifluoride (FHF − ) is formed; 3) The third equivalent of fluoride is then coordinated.…”

Section: Spherical Anionssupporting

confidence: 83%

“…In the solid state, each Cl − ion is bound by three NH groups: two amide groups (N⋅⋅⋅Cl=3.27 and 3.28 Å) and a pyrrole donor (N⋅⋅⋅Cl=3.07 Å) 18. Crystallization in the presence of n Bu 4 N + F − , however, results in deprotonation of the pyrrole owing to the highly basic nature of F − in acetonitrile, which results in polymeric chains 19…”

Section: Spherical Anionsmentioning

confidence: 99%

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Amide‐Based Ligands for Anion Coordination

2006

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Anion recognition is an active area of research in supramolecular chemistry. The rapidly increasing amount of structural data now allows anion coordination chemistry to be formalized in terms of coordination numbers and geometries based on hydrogen-bonding interactions between the host (ligand) and the guest (anion). This Minireview targets just one class of anion receptors, namely, amide-based ligands. The structural data for a series of five anion shapes are compiled according to coordination number, and distinct commonalities are observed within a given anion topology. The results also indicate a number of similarities between the coordination of anions and transition-metal ions.

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Section: Spherical Anionssupporting

confidence: 83%

Section: Spherical Anionsmentioning

confidence: 99%

Amide‐Based Ligands for Anion Coordination

2006

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“…We rationalize these findings in terms of deprotonation of the strapping pyrrole subunit in the presence of excess fluoride anion. Such an interpretation is consistent with the enhanced acidity expected for the pyrrole within the strap due to the electron withdrawing esters used to tether it to the rest of the receptor [9, 10]. …”

Section: Resultssupporting

confidence: 66%

Anion binding behavior of heterocycle-strapped calix[4]pyrroles

Gross

Yoon

Lynch

et al. 2009

J Incl Phenom Macrocycl Chem

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A comparative study of the halide and benzoate anion binding properties of a series of phenyl, pyrrole, and furan-strapped calix[4]pyrroles has been carried out. These receptors, which have previously been shown to bind the chloride anion (Yoon et al., Angew. Chem., Int. Ed. 47(27):5038–5042, 2008), were found to bind bromide and benzoate anion (studied as the corresponding tetrabutyl-ammonium salts) with near equal affinity in acetonitrile, albeit less well than chloride, as determined from ITC measurements or NMR spectroscopic titrations. This stands in marked contrast to the parent octamethylcalix[4]pyrrole, where the carboxylate anion affinities are substantially higher than those for bromide anion under identical conditions. This finding is rationalized in terms of tighter binding cavity present in the strapped systems. For all three anions for which quantitative data could be obtained (i.e., Cl−, Br−, PhCO2−), the pyrrole-strapped system displayed the highest affinity, although the relative enhancement was found to depend on the anion in question. In the specific case of fluoride anion binding to the pyrrole-strapped receptor, two modes of interaction are inferred, with the first consisting of binding to the calix[4]pyrrole via NH-anion hydrogen bonds, followed by a process that involves deprotonation of the strapped pyrrolic NH proton. A single crystal X-ray diffraction analysis provides support for the first of these modes and further reveals the presence of a methanol molecule bound to the fluoride anion.

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“…10b). In the solid state, the two half molecules are essentially planar, whereas the complete molecule is twisted such that the angle between the pyrrole rings is 61.79(5) [58]. Further, single-crystal X-ray analysis of the Cl À complex of p-phenylene-bridged 18 as a TBA salt shows a [1 + 2]-type binding mode [59].…”

Section: Guanidinocarbonylpyrrole-based Anion Receptorsmentioning

confidence: 99%

Acyclic Oligopyrrolic Anion Receptors

Maeda

2010

Topics in Heterocyclic Chemistry

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Recent progress in the guest-binding and supramolecular chemistry of anion-responsive acyclic oligopyrroles is summarized here in this chapter. The hydrogen-bonding properties of the pyrrole NH sites determine anion binding in acylic oligopyrroles such as guanidinocarbonyl and amidopyrroles, dipyrrins and their analogs, dipyrrolylquinoxalines, and boron complexes of dipyrrolyldiketones. Linear oligopyrroles can be incorporated as subunits in various macromolecules and complexes by means of covalent and noncovalent interactions; in fact, boron complexes of dipyrrolyldiketones form assembled structures and, with the appropriate substituents, soft materials such as anion-responsive supramolecular gels.

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Anion−Anion Assembly: A New Class of Anionic Supramolecular Polymer Containing 3,4-Dichloro-2,5-diamido-substituted Pyrrole Anion Dimers

Cited by 123 publications

References 16 publications

Amide‐Based Ligands for Anion Coordination

Amide‐Based Ligands for Anion Coordination

Anion binding behavior of heterocycle-strapped calix[4]pyrroles

Acyclic Oligopyrrolic Anion Receptors

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