Abstract: In this work the singlet oxygen quenching by a series of transition metal complexes was studied.The results showed that the ability of singlet oxygen quenching mainly related to the configuration geometry of the complex molecules.The complexes which have coordinating atoms arranged in a square-planar geometry have high ability for quenching singlet oxygen,because the singlet oxygen molecules easily approach to the center metal atoms from above or below the tetragon and react with them.Contrary,the complexes which have coordinating atoms arranged in a tetrahedron geometry have weak ability for quenching singlet oxygen.

Key words: transition metal complex, quencher, light stabilizer, singlet oxygen quencher