Chemistry Letters, Vol.33, No.11, 1500-1501, 2004
Novel photo-excited triplet state arising from four unpaired electrons: pi-topology and spin alignment in excited state of organic spin system
A novel photo-excited state with the intermediate spin (S = 1) arising from four unpaired spins and a nearly degenerate quintet (S = 2) excited state were detected for 1, which was designed utilizing the photo-excited triplet spin coupler by taking pi-topology into account. The unique triplet state has an interesting electronic structure, which D value is reduced by the antiferromagnetic spin alignment between two radical spins through the excited spin coupler.