Synthesis and Chiroptical Properties of a Ring-Fused BODIPY with a Skewed Chiral π Skeleton.

A twisted chiral boron-dipyrrin complex (BODIPY) was synthesized by oxidative annulation of the biphenyl units at the ß positions. The chiral BODIPY has two asymmetric carbons in the large planar skeleton, which were generated upon the ring-fused reaction. Its π-elongated and twisted structure resulted in the Cotton effect in the red region (λmax = 614 nm, Δε = 60 M(-1)·cm(-1)) as well as the strong fluorescence (ΦF = 0.73) and circularly polarized luminescence (CPL).