Porphyrins cyclic organic structures containing tetrapyrrole rings ( four joined rings , each consisting of four ch units and one nh unit ) that have the important characteristic property of forming complexes with metal ions 卟啉：包括了四吡咯环（四个连接的环，每个环包括了4个- ch基和1个- nh基）的环状有机结构，具有与金属离子形成复合物的特征。
