Neutral halogen‐bonded O−I−N complexes were prepared from in situ formed carbonyl hypoiodites and aromatic organic bases. The carbonyl hypoiodites have a strongly polarized iodine atom with larger σ‐holes than any known uncharged halogen bond donor. Modulating the Lewis basicity of the selected pyridine derivatives and carboxylates leads to halogen‐bonded complexes where the classical O−I⋅⋅⋅N halogen bond transforms more into a halogen‐bonded COO−⋅⋅⋅I−N+ ion‐pair (salt) with an asymmetric O−I−N moiety. X‐ray analyses, NMR studies, and calculations reveal the halogen bonding geometries of the carbonyl hypoiodite‐based O−I−N complexes, confirming that in the solid‐state the iodine atom is much closer to the N‐atom of the pyridine derivatives than its original position at the carboxylate O‐atom.

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The copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) using the conventional Sharpless-Fokin catalyst that consists of CuSO 4 + Na ascorbate, the most well-known and used "click" reaction, is considerably accelerated by the addition of a tris(triazolyl)-polyethylene glycol (tris-trz-PEG) amphiphilic ligand in water under ambient conditions. Only parts-per-million Cu I were necessary to reach quantitative yields with TON up to 86000 and TOF 3600 h -1 . The ligand was fully recycled, and the catalyst reused at least 6 times without decomposition. Large-scale syntheses were also successfully achieved with 93 % yield. The catalyst was applied to the efficient synthesis of various useful functional products with medicinal, catalytic, targeting, and labeling properties.