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Advantages of Organic Halogen Bonding for Halide Recognition.

ABSTRACT: The study of hydrogen bonding organocatalysis is rapidly expanding. Much research has been directed at making catalysts more active and selective, with less attention on fundamental design strategies. This study systematically increases steric hindrance at the active site of pH switchable urea organocatalysts. Incorporating strong intramolecular hydrogen bonds from protonated pyridines to oxygen stabilizes the active conformation of these ureas thus reducing the entropic penalty that results from substrate binding. The effect of increasing steric hindrance was studied by single crystal X-ray diffraction and by kinetics experiments of a benchmark reaction.

SUBMITTER: Wageling NB

PROVIDER: S-EPMC8188850 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Methanesulfonyl-polarized halogen bonding enables strong halide recognition in an arylethynyl anion receptor.

Project description:A 3,5-bis((2-iodophenyl)ethynyl)pyridinium scaffold was synthesized which introduces the use of methanesulfonyl withdrawing groups to polarize iodine halogen bonding units for anion binding. We investigate the capability of this receptor to bind halides in polar media, while further probing the structure-property relationship of this well-polarized yet under-explored halogen bonding system.

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Project description:The synthesis and ion-pair binding properties of a heteroditopic [2]catenane receptor exhibiting highly potent and selective recognition of sodium halide salts are described. The receptor design consists of a bidentate halogen bonding donor motif for anion binding, as well as a di(ethylene glycol)-derived cation binding pocket which dramatically enhances metal cation affinity over previously reported homo[2]catenane analogues. 1H NMR cation, anion and ion-pair binding studies reveal significant positive cooperativity between the cation and anion binding events in which cation pre-complexation to the catenane subsequently 'switches-on' anion binding. Notably, the heteroditopic catenane displayed impressive selectivity for sodium halide recognition over the corresponding potassium halides. We further demonstrate that the catenane is capable of extracting solid alkali metal salts into organic media. Crucially, the observed solution phase binding selectivity for sodium halides translates to superior functional extraction capabilities of these salts relative to potassium halides, overcoming the comparatively higher lattice enthalpies NaX > KX dictated by the smaller alkali metal sodium cation. This is further exemplified in competitive solid-liquid experiments which revealed the exclusive extraction of sodium halide salts from solid mixtures of sodium and potassium halide salts.

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Mechanical Bond Enhanced Lithium Halide Ion-Pair Binding by Halogen Bonding Heteroditopic Rotaxanes.

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Evidence for halogen bond covalency in acyclic and interlocked halogen-bonding receptor anion recognition.

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Anion Recognition by Neutral and Cationic Iodotriazole Halogen Bonding Scaffolds.

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| S-EPMC8199927 | biostudies-literature

Active-Metal Template Synthesis of a Halogen-Bonding Rotaxane for Anion Recognition.

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| S-EPMC4736451 | biostudies-other

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| S-EPMC8456845 | biostudies-literature

Hydrosulfide (HS<sup>-</sup> ) Recognition and Sensing in Water by Halogen Bonding Hosts.

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| S-EPMC8596634 | biostudies-literature

Selective Nitrate Recognition by a Halogen-Bonding Four-Station [3]Rotaxane Molecular Shuttle.

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| S-EPMC5113793 | biostudies-literature

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