It is shown that molecular oxygen in D2O is efficient in deactivating the lowest excited state of an insoluble hydrophilic polymeric equivalent of [Ru(bpy)3]2+ (see structure 1). The rate constant for quenching by molecular oxygen of the lowest excited triplet charge transfer state of 1 in D2O saturated gel is found to be 4.4±0.5×108M-1s-1. Singlet molecular oxygen, which is characterized by its emission at 1270nm, is generated during quenching and decays with a lifetime of 18±3μs. The lifetimes for the decay of singlet oxygen, when it is generated by exciting D2O-solved sensitizers in the presence and absence of the unfunctionalized polymeric skeleton in the form of a D2O saturated gel, are 34±3 and 63±5μs, respectively. These shorter lifetimes for singlet oxygen in the polymeric gels are consistent with quenching of singlet oxygen by the hydroxyl groups present in the polymer. © 2001 Elsevier Science B.V.
|Journal||Journal of Photochemistry and Photobiology A: Chemistry|
|Publication status||Published - 1 Jan 2001|
- Hydrophilic polymer
- Singlet oxygen sensitization
- Tris(bipyridyl)ruthenium(II) complex