Synthesis and Structural Diversification of Circularly Polarised Luminescence Active, Helically Chiral, Confused N,N,O,C-BODIPYs

Helically chiral boron-chelated dipyrromethene (BODIPY) dyes are known to exhibit solution phase circularly polarized luminescence (CPL), but examples are limited to a few synthetically accessible molecular architectures. We report a B-N chelation, SNAr, Suzuki cross-coupling, B-O chelation cascade reaction for the synthesis of understudied helically chiral, N,N,O,C-boron chelated, confused BODIPYs, from readily accessible 3,5-dibromo-BODIPY starting materials. Using this approach we have prepared a series of helically chiral confused BODIPYs with variation of the 3,5-subsitutents. Following resolution by chiral HPLC, absolute stereochemistry was assigned through comparison of the experimental and calculated ECD spectra, and solution phase chiroptical properties including CPL were determined (vertical bar g(lum)vertical bar from 2.1 to 3.7x10(-3); B-CPL from 11.3 to 27.2).

Automated summary

A method for the synthesis of helically chiral BODIPY dyes and preparation of a series of helically chiral BODIPYs with different substituents has been reported in this study. Absolute stereochemistry was determined by comparing experimental and calculated spectra, and solution phase chiroptical properties were characterized.