Time-resolved resonance Raman spectra of octaethylporphinato copper(II) in the lowest excited triplet state

Time-resolved resonance Raman spectra were observed with the pump/probe technique using two 7 ns pulsed lasers for octaethylporphinato Cu(II) [(OEP)Cu] and its isotopomers (OEP-meso-d4 and OEP-15N) in the lowest excited triplet state. Raman bands were assigned on the basis of depolarization ratios and isotope shifts. Then ν2, ν3 and ν4 modes of the macrocycle in the T1 state were shifted to lower frequencies by 7, 37 and 57 cm−1, respectively, compared with those of the ground state, but the peripheral ethyl internal modes were shifted little. The porphyrin skeletal modes exhibited significant broadening in the T1 state but the ethyl modes did not.