'Quenching of Excited States of Metal Complexes

Mg(5,10,15,20-tetraphenylporphyrin)

excited state quenched by 1,4-Benzoquinone

Harriman, A.; Porter, G.; Wilowska, A.
J. Chem. Soc., Faraday Trans. 2 79: 807-16 (1983)

Mg(5,10,15,20-tetraphenylporphyrin) quenched by 1,4-Benzoquinone
Solvent : EtOH

k_q = 3.1 x 10⁹(L mol^–1 s^–1)

Mechanism: oxidative electron transfer
Experimental methods: laser flash, absorption, single shot signal
Electron transfer fraction of quenching = 0.28
Comments: phi = 0.85 (82E428)

Kapinus, E.I.; Staryi, V.P.; Dilung, I.I.
Theor. Exp. Chem. 18: 402-9 (1982)

Mg(5,10,15,20-tetraphenylporphyrin) quenched by 1,4-Benzoquinone
Solvent : Toluene

k_q = 2 x 10⁸ (calc)(L mol^–1 s^–1)

Mechanism: exciplex formation
Experimental methods: conventional flash, absorption, single shot signal
Lifetime in the absence of quencher, air free = 300 micro sec.
Comments: biexponential decay, see Mech. [2]
This value also reported in 81E718

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