Xâ
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X Halogen Bond-Induced Supramolecular Helices.
Angew Chem Int Ed Engl
; 61(2): e202113786, 2022 01 10.
Article
en En
| MEDLINE
| ID: mdl-34729878
ABSTRACT
The halogen bond is the attractive interaction between the electrophilic region of a halogen atom and the nucleophilic region of another molecular entity, emerging as a favorable manner to manipulate supramolecular chirality in self-assemblies. Engineering halogen bonded helical structures remains a challenge due to its sensitivity to solvent polarity and competitive forces like hydrogen bonds. Herein, we report a Xâ
â
â
X (X=Cl, Br, I) type weak halogen bond that induces the formation and evolution of supramolecular helical structures both in solid and solution state. The π-conjugated phenylalanine derivatives with F, Cl, Br and I substitution self-assembled into 21 helical packing driven by hydrogen bond and halogen bond, respectively. The specific molecular geometries of π-conjugated amino acids gave rise to multiple noncovalent forces to stabilize the Xâ
â
â
X halogen bond with small bond energies ranging from -0.69 to -1.49â
kcal mol-1 . Halogen bond induced an opposite helicity compared to the fluorinated species, accompanied by the inversed circularly polarized luminescence.
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MEDLINE
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En
Revista:
Angew Chem Int Ed Engl
Año:
2022
Tipo del documento:
Article