Halogen bonding articles from across Nature Portfolio

Halogen bonding is widely adopted in organic synthesis and supramolecular crystal engineering but application of halogen bonding in the design of stimuli-responsive materials is challenging. Here, the authors report a liquid crystalline network that contains dynamic halogen-bond crosslinks and possesses reversible thermo-responsive shape memory behaviour.

Halogen-mediated interactions control molecular recognition in many chemical and biological systems. Here, the authors demonstrate two types of Br⋯Br contacts and their importance in chiral on-surface crystallization.

Halogen-bonded co-crystals of a fluorinated azobenzene derivative and a volatile co-former can be cut, carved or engraved with micrometre-scale precision using low-power visible light. The proposed mechanism involves the local evaporation of the volatile component followed by recrystallization of the azobenzene co-former near the edge of the irradiation area.

Organogel formation was observed immediately during the addition of diisocyanate to a solution of para-substituted bis(3-aminopropyl)hexaisobutyl-substituted cage octasilsesquioxane (T₈ cage) monomer at room temperature when above the critical gel concentrations (C_gs). T₈-polyureas with phenylurea moieties promoted organogel formation in comparison with T₈-polyureas with nonphenylurea moieties. The substitution of methyl groups at the ortho position of the phenylurea groups provided lower C_gs. Increasing the intermolecular interaction between the ureido groups in the T₈-polyurea enhanced organogel formation, which was supported by the FT-IR analysis of the dried gels.

Current models of halogen bonding describe the σ-symmetric component of this interaction but do not contemplate the possibility of π-covalency. Here the authors provide experimental and computational evidence of π-covalency in halogen bonds involving radical cation halogen bond donors.

Carbon atoms of various species typically function as acceptors of noncovalent interactions when they are part of a π-system. Here, the authors report their discovery of a noncovalent halogen bond involving the isocyano carbon lone pair, which results in adducts with strongly reduced isocyanide odor.