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Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
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Chiral Distorted Hexa-peri-hexabenzocoronenes Bearing a Nonagon-Embedded Carbohelicene
Miguel A Medel1, Carlos M Cruz2, Delia Miguel3
1Departamento de Química Orgánica, Unidad de Excelencia de Química (UEQ), Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
Angewandte Chemie (International Ed. in English)
|July 30, 2021
Summary
Researchers synthesized novel chiral nanographenes featuring a nine-membered ring, creating the most twisted helicene to date. These nonagon-containing structures exhibit enhanced photophysical properties, advancing molecular design.
Area of Science:
- Organic Chemistry
- Materials Science
- Nanotechnology
Background:
- Hexa-peri-hexabenzocoronene (HBC) derivatives are key nanographene structures.
- Chiral saddle-helix hybrid nanographenes offer unique three-dimensional architectures.
- Incorporating larger rings into helical structures can induce significant non-planarity.
Purpose of the Study:
- To synthesize novel chiral saddle-helix hybrid nanographenes incorporating a nine-membered carbocycle.
- To investigate the structural distortion and photophysical properties of these new nanographene families.
- To explore the synthesis of π-extended carbo[n]helicenes with nonagon units.
Main Methods:
- Synthesis of hexa-peri-hexabenzocoronene (HBC) analogues with nine-membered carbocycles.
- Preparation of π-extended carbo[n]helicenes featuring a nonagon ring within the helical moiety.
- Structural analysis using X-ray crystallography to determine interplanar angles.
- Photophysical characterization, including measurement of absorption dissymmetry factors.
Main Results:
- Successful synthesis of the first hexa-peri-hexabenzocoronene (HBC) analogues containing a nine-membered carbocycle.
- First synthesis of π-extended carbo[n]helicenes incorporating a nonagon ring into the helical structure.
- The nonagon incorporation induced significant distortion, resulting in the most twisted carbohelicene reported (134.8° interplanar angle).
- Improved absorption dissymmetry factors (|gabs |=4.2×10-3) were observed in the nonagon-containing helicenes.
Conclusions:
- A new family of chiral saddle-helix hybrid nanographenes featuring nonagon rings has been successfully synthesized.
- These structures exhibit unprecedented levels of non-planarity and twisting, surpassing previously reported carbohelicenes.
- The enhanced photophysical properties, particularly absorption dissymmetry, highlight the potential of these novel nanographenes for advanced applications.
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