Donor-Acceptor Conjugated Macrocycles with Polyradical Character and Global Aromaticity

Area of Science:

• Organic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Polyradical character and global aromaticity are key for designing conjugated macromolecules.
• Donor-acceptor (D-A) architectures are crucial for tuning electronic properties.

Purpose of the Study:

• To investigate the impact of π-spacer derivatives on polyradical character and aromaticity in D-A macromolecules.
• To explore the optoelectronic properties of these novel macromolecules.

Main Methods:

• Synthesis of D-A conjugated macromolecules with and without π-spacers.
• Computational studies including density functional theory (DFT).
• Analysis of electronic configuration, polyradical character, and aromaticity (Baird's rule).

Main Results:

• Macromolecules without π-spacers exhibit closed-shell configurations and nonaromaticity.
• π-spacer derivatives show unprecedentedly high polyradical character and open-shell diradical nature.
• Singlet states are nonaromatic, while triplet states exhibit global aromaticity (Baird's rule).
• Calculated absorption spectra reveal intense near-infrared absorption up to 2,500 nm.

Conclusions:

• π-spacer incorporation significantly enhances polyradical character in D-A macromolecules.
• These materials demonstrate tunable aromaticity and strong near-infrared absorption.
• The findings suggest potential applications in advanced optoelectronic devices.