Carbon–Bromide Bond Activation by Bidentate Halogen, Chalcogen, Pnicogen, and Tetrel Bonds

Halogen, chalcogen, pnictogen, and tetrel bonds in organocatalysis have gained noticeable attention. In this work, carbon-bromide bond activation in the Ritter reaction by bidentate imidazole-type halogen, chalcogen, pnicogen, and tetrel bond donors was studied by density functional theory. All of the above four kinds of catalysts exhibited excellent catalytic performance. σ-hole interactions were formed between the Br atom of the reactant and the halogen, chalcogen, pnicogen, and tetrel bond donors, which elongated the C-Br bond and caused the rearrangement of the electron density of the precomplexes, resulting in the breaking of the C-Br bond and Br abstraction. Notably, the catalytic activity of the chalcogen bond is the best, followed by that of the halogen bond. Although the catalytic activity of pnicogen and tetrel bond catalysts is not as good as that of the halogen bond and chalcogen bond, they can still be used as effective substitutes for the halogen bond and chalcogen bond, providing more choices for noncovalent catalysis. Furthermore, within the same group, the fifth-period atomic catalyst is more effective than the fourth-period one for halogen, chalcogen, pnicogen, and tetrel bond donor catalysts.