Influence of the Number and Geometry of Binding Sites on Host–Guest Affinity: Imidazolium‐Substituted Receptor Molecules for Small Inorganic Anions

Fahlbusch, Tilmann; Frank, M.; Schatz, J.; Schmaderer, Harald

doi:10.1002/ejoc.200500825

Cited by 39 publications

(29 citation statements)

References 25 publications

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“…308 All receptors were found to have a similar binding affinity for dihydrogenphosphate ( K ≈ 2000 M -1 ) in DMSO- d 6 as inferred from 1 H NMR spectroscopic studies. This observation led these researchers to propose that only two imidazolium units of each receptor are involved in phosphate anion recognition.…”

Section: Major Phosphate-binding Functionalitiesmentioning

confidence: 67%

Artificial Receptors for the Recognition of Phosphorylated Molecules

et al. 2011

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Section: Major Phosphate-binding Functionalitiesmentioning

confidence: 67%

Artificial Receptors for the Recognition of Phosphorylated Molecules

et al. 2011

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“…[40] It is known that polar calixarenes form host-guest complexes with aromatic compounds [31] and imidazolium groups can act as recognition elements for anions. [43] Microsolubilization of hydrophobic starting material by a host-guest complex formed in an inverse phase-transfer catalysis is conceivable [31] as well as activation of the base [42] by complexation of the counteranion.…”

Section: Resultsmentioning

confidence: 99%

The Suzuki Coupling of Aryl Chlorides in Aqueous Media Catalyzed by in situ Generated Calix[4]arene‐Based N‐Heterocyclic Carbene Ligands

2006

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We report on the use of an in situ system for the catalytic Suzuki cross‐coupling reaction of chlorobenzenes and benzeneboronic acid to yield biphenyls. Calix[4]arene‐based imidazolium salts were used as precursors of N‐heterocyclic carbene ligands and Pd(OAc)2 as the palladium source. In dioxane as the organic medium, the steric demands of the substituents on the calixarene skeleton and on the imidazolium moiety parallel the catalytic activity; the best catalytic results were obtained by using dimesityl‐ or 2,6‐diisopropylphenyl‐substituted calixarene‐imidazolium salts. Among the bases tested Cs2CO3 and CsF were the most effective. The catalytic protocol established for organic solvents could also be used for the Suzuki cross‐coupling reaction in aqueous solution. In dioxane/water (50:50) the activity is nearly the same as in pure dioxane and in pure water, an environmentally friendly and cheap solvent, a 60 % level of reactivity was maintained; here the calixarene ligand precursor 3a showed the highest activity. Nonmacrocyclic compounds used for comparison showed considerably lower catalytic ability proving that calix[4]arene‐based imidazolium salts are attractive supramolecular skeletons for the N‐heterocyclic carbene ligands used in selective Suzuki cross‐coupling reactions of aryl chlorides in aqueous solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…Recently, a number of ferrocene-based benzimidazolium receptors have been reported [33e38]. The interaction between the benzimidazolium salts and anion is based on (CeH) þ $$$X À type ionized hydrogen bonds [39], showing the C-2 proton in the benzimidazolium ring is relatively strong hydrogen bonding sites [40e44]. Such receptors formed by combining ferrocene with benzimidazolium moieties utilize both redox-active and hydrogen bond interactions to recognize anion [45].…”

Section: Introductionmentioning

confidence: 99%