Abstract: Active intermediate produced during photolysis of[Rh(CO)₂Cl]₂ and eight cis-dicarbonyl (didentate N-donor ligand) Rh (Ⅰ) tetraphenyl borate[Rh(CO)₂ (Chel)] Bph₄ were investigated by combining spin trapping technique with ESR. The results show that the primary process of photolysis in[Rh(CO)₂Cl]₂ is homolytic cleavage of the Rh-Rh bond to produce Rhodium-centered free radicals. They can be trapped by PBN, ND and TBN. And the photolysis of cisdicarbonyl (bidentate N-donor ligand) Rhodium (Ⅰ) tetraphenyl borate produced ph radicals of Bph₄ anion, and stability of the spin adducts are related to the bidentate N-donor ligand.

Key words: Spin trapping technique, Cis-dicarbonyl Rhodium complex, Radicals, ESR