Modulating Chalcogen Bonding and Halogen Bonding Sigma‐Hole Donor Atom Potency and Selectivity for Halide Anion Recognition

A series of acyclic anion receptors containing chalcogen bond (ChB) and halogen (XB) donors integrated into a neutral 3,5-bis-triazole pyridine scaffold are described, in which systematic variation the electronic-withdrawing nature aryl substituents reveal dramatic modulation sigma-hole donor atom potency for recognition. Incorporation strongly electron-withdrawing perfluorophenyl units appended to triazole heterocycle telluro- or iodo- atoms, directly linked tellurium dramatically enhances binding receptors, most notably ChB XB displaying over thirty-fold eight-fold increase chloride affinity, respectively, relative unfluorinated analogues. Linear free energy relationships based halide recognition behaviour is highly sensitive local electronic environments. This especially case those Te centre (3⋅ChB), where remarkable enhancement strength selectivity lighter halides observed as ability Te-bonded group increases, highlighting exciting opportunity fine-tune affinity ChB-based receptor systems.