Bottom-up synthesis of <i>seco</i>-porphyrazines and their near-infrared optical properties

Reducing the number of synthetic routes is critical for advancing the development of functional dyes and pigments. Herein, we present a novel one-step method for synthesizing seco-porphyrazine skeletons, which are a class of 18[Formula: see text] aromatic porphyrinoids. This bottom-up approach utilizes 1,3-diiminoisoindoline, benzonitrile derivatives, and palladium salts for ring construction. The resulting seco-porphyrazines contain unique twisted moieties, which are difficult to achieve with conventional methods. The absorption spectra reveal a split Q-band due to the asymmetric skeleton, indicating a strong interaction with near-infrared (NIR) light. In addition, molecular orbital calculations and electrochemical measurements support that skeletal asymmetry enhances NIR light utilization.