Design and Synthesis of Fluorescent 1,3-Diaryl-β-carbolines and 1,3-Diaryl-3,4-dihydro-β-carbolines.

The 1,3-diaryl-β-carboline derivatives, including 3,4-dihydro variants, were synthesized via a multiple-step approach. These compounds possess rigid and twisted configurations, which are expected to exhibit unique optical properties. The absorption and fluorescence properties of the newly synthesized compounds were investigated. These synthetic 1,3-diaryl-β-carbolines displayed strong emission in the range of 387-409 nm and exhibited absolute photoluminescence quantum yields of up to 74%. Density functional theory calculations were performed to better elucidate the geometric, electronic, and optical properties of these novel 1,3-diaryl-β-carbolines.