Abstract:A ditopic tetrapodal imidazolium-based 1,3-alternate calix[4]arene host binds anions as 1 : 2 complexes via a range of CH...anion hydrogen bonds. Allosteric enhancement of the affinity for the second chloride anion is observed. X-Ray crystal structures of the chloride, bromide and nitrate complexes suggest that this behaviour is linked to inter-binding site communication mediated by the calixarene framework. The imidazolium groups exist as either in-out or out-out conformers with respect to the calixarene, wit… Show more
“…The presence of anion-interactions in these structures may facilitate the use of imidazolium salts as anion-binders. [36,37] Reaction should be taken when interpreting the ESI+ mass spectra of copper(I)-NHC complexes, since their labile nature can lead to ligand scrambling resulting in the appearance of bis-NHC species in samples of pure mono-NHC compounds. This ligand scrambling behaviour is well documented for silver(I)-NHC complexes.…”
Section: A Potential Strategy For the Stabilisation And Examination Omentioning
The preparation of a series of imidazolium salts bearing N-allyl substituents, and a range of substituents on the second nitrogen atom with varying electronic and steric properties, is reported.
“…The presence of anion-interactions in these structures may facilitate the use of imidazolium salts as anion-binders. [36,37] Reaction should be taken when interpreting the ESI+ mass spectra of copper(I)-NHC complexes, since their labile nature can lead to ligand scrambling resulting in the appearance of bis-NHC species in samples of pure mono-NHC compounds. This ligand scrambling behaviour is well documented for silver(I)-NHC complexes.…”
Section: A Potential Strategy For the Stabilisation And Examination Omentioning
The preparation of a series of imidazolium salts bearing N-allyl substituents, and a range of substituents on the second nitrogen atom with varying electronic and steric properties, is reported.
“…The angle C8-H8A···Cl1 is 126.04°, suggesting the ionic − hydrogen bond is weaker than that observed other receptors [61,62]. Moreover, the crystal structure reveals that the chloride anion forms strong hydrogen bonds with two urea protons (H3B, and H4C), as well as forming a hydrogen bond with a proton of the aromatic benzene ring (H4A).…”
Section: Solid State Crystal Structure Ofmentioning
“…In the thiourea example, a bidirectional PET-based system was shown to be responsive to AcO -and H 2 PO 4 -anions as well as fluoride (Veale et al, 2009). The importance of allosteric effects has been assessed in a tetrapodal imidazolium-derived calix [4]arene receptor that recognises a range of anions (Willans et al, 2009). The use of porphyrin and N-confused porphyrin systems to detect anions has also been progressed (Toganoh et al, 2009).…”
Section: The Development Of Imaging Methodsmentioning
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