C-H Borylation/Cross-Coupling Forms Twisted Donor-Acceptor Compounds Exhibiting Donor-Dependent Delayed Emission

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Donor-acceptor (D-A) compounds are crucial in organic electronics.
• Developing efficient synthetic routes to complex D-A architectures remains a challenge.
• Understanding structure-property relationships is key for tuning optoelectronic properties.

Purpose of the Study:

• To develop a facile synthetic strategy for twisted D-A compounds.
• To explore the synthesis of borylated D-A and D-A-D systems.
• To investigate the photophysical properties and structure-dependent emission characteristics.

Main Methods:

• Benzothiadiazole (BT) directed C-H borylation using BCl3.
• B-Cl hydrolysis and Suzuki-Miyaura cross-coupling reactions.
• Photophysical characterization (emission studies) and computational modeling (excited state analysis).

Main Results:

• Facile access to twisted D-A compounds via sequential C-H borylation and cross-coupling.
• Synthesis of borylated twisted D-A and D-A-D compounds.
• Long-lifetime emission observed exclusively with triphenylamine donors.
• Computational analysis identified S1/T2 and T1 excited state energy gaps as critical for emission properties.

Conclusions:

• The developed synthetic route offers efficient access to novel twisted D-A architectures.
• Triphenylamine donors are essential for achieving long-lifetime emission in these systems.
• The energy gap between specific excited states dictates the observed photophysical behavior.