Near‐Infrared Emissive Molecular Carbons Based on Quadruple [n]Helicenes

Abstract

Abstract We present a molecular design strategy that combines structural multiplicity and π‐extension on a quaterrylene diimide scaffold to construct efficient near‐infrared (NIR) circularly polarized luminescence (CPL) emitters. Through a carefully controlled synthesis involving sequential regioselective Suzuki coupling followed by Sholl‐type oxidative cyclization, we successfully obtained two novel quadruple [n]helicenes ( QnH ). Comprehensive experimental characterization and theoretical calculations demonstrated their distinct configurational preferences: Q5H exclusively adopted the meso ( P , P , M , M ) configuration, while Q6H produced only the ( P , P , P , P )/( M , M , M , M ) enantiomeric pair. Single‐crystal X‐ray diffraction unambiguously confirmed the unique “four‐bladed propeller” structure of ( P , P , M , M )‐ Q5H . Both compounds demonstrated intense NIR fluorescence emission with photoluminescence quantum yields ( Φ PL ) of 47% for Q5H and 37% for Q6H . The chiral ( P , P , P , P )/( M , M , M , M )‐ Q6H enantiomers showed exceptional chiroptical properties, including intense Cotton effects reached 719 M −1 cm −1 at 410 nm, a high absorption dissymmetry factor | g abs | of 0.035, and prominent CPL activity across 600–800 nm with a CPL brightness ( B CPL ) of 93 M −1 cm −1 .