Triplet-state electron transfer in poly(methacrylic acid) with covalently bound phenanthrene and naphthalene

Abstract

Poly(methacrylic acid) was prepared with small loadings of the aromatic chromophores phenanthrene and naphthalene (r-MPh and r-MNaph, respectively), and the quenching of the triplet state by the zwitterionic viologen 4,4{prime}-bipyridinio-1,1,{prime}-bis(propanesulfonate)(SPV) was characterized. It was found that the quantum yield for separation of ion-pair states per electron-transfer quenching event exceeded 0.4 in all cases, and for favorable cases, approached unity. The optimal pH for ion-pair separation was 6 for PMA-Ph and 11 for PMA-Naph. The triplet state yield was found to decrease dramatically with increased chromophore loading, which the authors believe to be the result of singlet-state self-quenching.