Dibenzoarsepins: Planarization of 8 pi-Electron System in the Lowest Singlet Excited State

摘要

Dibenzo[b,f]arsepins possessing severely distorted cores compared to those of other heteropins were synthesized. These derivatives exhibited dual photoluminescence in the green-to-red region (500-700 nm) and the near-ultraviolet region (<380 nm), which could be attributed to the planarization of the arsepin core in the lowest singlet excited (S-1) state. The computational approach for the assessment of the aromatic indices revealed that the dibenzoarsepins studied show aromaticity (8 pi system) in the S-1 states in line with Baird's rule. The lone pair electrons of the arsenic atoms play a crucial role in the aromaticity in the S-1 states.