Radical formation of 5,10,15,20-tetra(4-sulfophenyl) porphinatopalladium(II)(4−) in the lowest excited triplet states

Excited 5,10,15,20-tetra(4-sulfopheny)porphinatopalladium(II) (PdTPPS4−) was studied by phosphorescence lifetime, phosphorescence quenching, delayed fluorescence, and transient absorption measurements in terms of the dimerization reaction. Lifetimes of monomer and dimer was determined as τ=360 and 270 μs, respectively. The self-association rates of PdTPPS4− in the excited and ground states are the same. Transient absorption unveiled the radical formation resulted from the charge separation after photo excitation.