Investigation of the Substitution Site Effect on o-Carborane-Based Chromophores by Anthracene Introduction at the B(3) Position

o-Carborane-based emitters have been greatly developed over the last ten years. From the viewpoint of molecular sym-metry, o-carborane has one type of equivalent carbon and four types of equivalent boron atoms. However, in contrast to the vast research of aryl-modified o-carboranes on the carbon atom of o-carborane, substitution on the boron atom is less inves-tigated. Herein, we introduced an anthracene unit on the B(3) position of o-carborane and explored the substitution posi-tion effect by comparison with the previously reported C(1) -substituted regioisomer. Single-crystal structures, optical mea-surements, and quantum chemical calculation revealed the significant impact of the substitution position, especially in the intramolecular charge transfer (ICT) process.

Automated summary

o-Carborane-based emitters have made significant advancements in the past decade. While extensive research has been conducted on aryl-modified o-carboranes at the carbon atom, substitution on the boron atom has been less explored. This study introduced an anthracene unit on the B(3) position of o-carborane and compared it with the previously reported C(1)-substituted regioisomer to investigate the substitution position effect, revealing its significant impact on the intramolecular charge transfer process.