Persistent Ambipolar Heptacenes and Their Redox Species
Nico Zeitter1, Nikolai Hippchen1, Steffen Maier1
1Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Angewandte Chemie (International Ed. in English)
|April 4, 2022
Summary
Chemists synthesized stable, soluble heptacene and tetrabenzononacene using TIPS-ethynylation and bromination. Tetrabromoheptacene exhibits ambipolar transistor properties, confirmed by generating its charged states.
Area of Science:
- Organic chemistry
- Materials science
- Nanoscience
Background:
- Acenes are polycyclic aromatic hydrocarbons with potential electronic applications.
- Achieving stability and solubility in larger acenes remains a significant challenge.
- TIPS-ethynylation and bromination are key synthetic strategies in organic electronics.
Purpose of the Study:
- To synthesize and characterize novel, stable, and soluble large acenes.
- To explore the electronic properties of these synthesized acenes, particularly as transistor materials.
- To investigate the effect of specific functionalization on acene stability and performance.
Main Methods:
- Sixfold TIPS-ethynylation and fourfold bromination of armchair edges.
- π-extension via Stille coupling for tetrabenzononacene synthesis.
- Characterization of acene solubility, stability, and electronic properties.
Main Results:
- A long-lived, soluble heptacene derivative was successfully synthesized.
- A persistent tetrabenzononacene was accessed through π-extension.
- Tetrabromoheptacene demonstrated ambipolar transistor behavior with an n-channel mobility of up to 0.036 cm²/Vs.
- Generation of monoanion and monocation confirmed the electronic properties of tetrabromoheptacene.
Conclusions:
- Double TIPS-ethynylation on alternating benzene rings provides optimal stabilization for these large acenes.
- Tetrabromoheptacene is a promising ambipolar material for organic electronics.
- The synthetic strategies employed enable the creation of stable, functional polycyclic aromatic hydrocarbons.
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