Quenching of singlet oxygen by nickelocene

The rate constants kΔq for the quenching of singlet oxygen by nickelocene were determined in various solvents at 295 K by employing the competition technique based on 532 nm laser flash photolysis and 1,3-diphenyl-isobenzofuran bleaching kinetics. Contrary to the behavior of paramagnetic nickel(II) complexes in general, nickelocene is an efficient quencher of singlet oxygen (kΔq = (2.8 – 6.8) × 109 M−1 s−1). The quenching mechanism involves both energy transfer and reversible charge transfer interactions.