A photosensitizer with conformational restriction for enhanced photodynamic therapy

A rigid hemicyanine CSZ-J and a flexible molecule ESZ-J were synthesized. In particular, the conformationally restrained CSZ-J had higher fluorescence quantum yields, longer fluorescence lifetimes and higher triplet state quantum yields. CSZ-J could generate highly cytotoxic ROS simultaneously via type I and type II processes. This will contribute to the design and development of new photosensitizers in the future.