Two-photon photosensitized production of singlet oxygen in water.
Singlet molecular oxygen (a(1)Delta(g)) has been produced and optically detected in time-resolved experiments upon nonlinear two-photon excitation of a photosensitizer dissolved in water. For a given sensitizer, specific functional groups that impart water solubility and that give rise to larger two-photon absorption cross sections are, in many cases, not conducive to the production of singlet oxygen in high yield. This issue involves the competing influence of intramolecular charge transfer that can be pronounced in aqueous systems; more charge transfer in the chromophore facilitates two-photon absorption but decreases the singlet oxygen yield. This phenomenon is examined in a series of porphyrins and vinyl benzenes.
Frederiksen
Peter K
PK
Department of Chemistry, University of Aarhus, DK-8000 Arhus, Denmark.
McIlroy
Sean P
SP
Nielsen
Christian B
CB
Nikolajsen
Lars
L
Skovsen
Esben
E
Jørgensen
Mikkel
M
Mikkelsen
Kurt V
KV
Ogilby
Peter R
PR