Halogen Bond Unlocks Ultra-High Birefringence.
Angew Chem Int Ed Engl
; : e202411503, 2024 Jul 10.
Article
en En
| MEDLINE
| ID: mdl-38985723
ABSTRACT
Anisotropy is crucial for birefringence (Δn) in optical materials, but optimizing it remains a formidable challenge (Δn >0.3). Supramolecular frameworks incorporating π-conjugated components are promising for achieving enhanced birefringence because of their structural diversity and inherent anisotropy. Herein, we first synthesized (C6H6NO2)+Cl- (NAC) and then constructed a halogen-bonded supramolecular framework I+(C6H4NO2)- (INA) by halogen aliovalent substitution of Cl- with I+. The organic moieties are protonated and deprotonated nicotinic acid (NA), respectively. The antiparallel arrangement of birefringent-active units in NAC and INA leads to significant differences in the bonding characteristics between the interlayer and intralayer domains. Moreover, the [Oâ
â
â
I+â
â
â
N] halogen bond in 1D [I+(C6H4NO2)-] chain exhibits stronger interactions and stricter directionality, resulting in a more pronounced in-plane anisotropy between the intrachain and interchain directions. Consequently, INA exhibits exceptional birefringent performance, with a value of 0.778 at 550â
nm, twice that of NAC (0.363 at 550â
nm). This value significantly exceeds those of commercial birefringent crystals, such as CaCO3 (0.172 at 546â
nm), and is the highest reported value among ultraviolet birefringent crystals. This work presents a novel design strategy that employs halogen bonds as connection sites and modes for birefringent-active units, opening new avenues for developing high-performance birefringent crystals.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
/
Angew. Chem. (Int. ed., Internet)
/
Angewandte Chemie (International ed. Internet)
Año:
2024
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
Alemania