Homochiral Helicene Covalent Organic Frameworks
Qianqian Yan1, Xingyao Ye2, Shanshan Tao2
1School of Marine Technology and Equipment, State Key Laboratory of Tropic Ocean Engineering Materials and Materials Evaluation, Hainan Provincial Key Lab of Fine Chem, School of Chemistry and Chemical Engineering, Hainan University, Haikou 570228, China.
None:
While chirality is common in nature, creating synthetic macromolecules with controlled chirality remains a significant challenge. Here we report the synthesis of homochiral frameworks by exploring M and P enantiomers of [7]Helicene as building units to create chiral skeletons. The racemic [7]Helicene was separated into its P-[7]Helicene and M-[7]Helicene enantiomers via chiral column chromatography, which, upon aldol condensation reactions with 1,3,5-trimethyltriazine, form crystalline microporous P-[7]Helicene sp2c-COF-1 and M-[7]Helicene sp2c-COF-1, respectively. The resulting homochiral [7]Helicene sp2c-COFs develop a two-dimensional hexagonal lattice and π-conjugated skeleton linked by a C═C bond, displaying distinct circular dichroism of mirror images. Notably, P-[7]Helicene sp2c-COF-1 and M-[7]Helicene sp2c-COF-1 formed homogeneous thin films upon dispersion in a poly(methyl methacrylate) matrix and greatly enhanced circular dichroism signals and circularly polarized luminescence to reach a luminescence dissymmetry factor as high as 1.2 × 10-3 at 570 nm. These findings demonstrate a way to homochiral frameworks for chiro-optical applications.
More Related Videos
08:25Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
09:35Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Related Concept Videos
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
Chirality
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Molecules with Multiple Chiral Centers
Prochirality
Hybridization of Atomic Orbitals II
