TY - JOUR
T1 - Effect of oxygen-enhanced intersystem crossing on the observed efficiency of formation of singlet oxygen
AU - McLean, Andrew J.
AU - McGarvey, David J.
AU - Truscott, T. George
AU - Lambert, Christopher R.
AU - Land, Edward J.
PY - 1990
Y1 - 1990
N2 - The effects of O2-induced enhanced intersystem crossing (EISC) have long been recognised by workers investigating O2(1Δg) quantum yields, ϕΔ. However, no previous study employing techniques allowing direct O2(1Δg) luminescence observation has addressed itself to quantifying such effects. Employing energy-transfer techniques and investigating O2 concentration dependence of ϕΔ, allowed us to determine SΔ, the fraction of triplets quenched by O2 giving rise to O2(1Δg), under conditions where O2 EISC can and cannot operate. The values of SΔ were found to be 0.65, 0.78, 0.76, 0.74, 0.78, 0.98 and 0.31 for pyrene, perylene, PPDME, TPP, ZnTPP, phenazine and benzophenone, respectively. With the exception of phenazine and benzophenone all compounds exhibited significant EISC effects. We have also observed O2(1Δg) generation directly by O2 quenching of the first excited singlet state of perylene and pyrene.
AB - The effects of O2-induced enhanced intersystem crossing (EISC) have long been recognised by workers investigating O2(1Δg) quantum yields, ϕΔ. However, no previous study employing techniques allowing direct O2(1Δg) luminescence observation has addressed itself to quantifying such effects. Employing energy-transfer techniques and investigating O2 concentration dependence of ϕΔ, allowed us to determine SΔ, the fraction of triplets quenched by O2 giving rise to O2(1Δg), under conditions where O2 EISC can and cannot operate. The values of SΔ were found to be 0.65, 0.78, 0.76, 0.74, 0.78, 0.98 and 0.31 for pyrene, perylene, PPDME, TPP, ZnTPP, phenazine and benzophenone, respectively. With the exception of phenazine and benzophenone all compounds exhibited significant EISC effects. We have also observed O2(1Δg) generation directly by O2 quenching of the first excited singlet state of perylene and pyrene.
U2 - 10.1039/FT9908603075
DO - 10.1039/FT9908603075
M3 - Article
VL - 86
SP - 3075
EP - 3080
JO - Journal of the Chemical Society, Faraday Transactions
JF - Journal of the Chemical Society, Faraday Transactions
IS - 18
ER -