Influence of Donor and Acceptor Substituents on the ECL of a Spirobifluorene-Bridged Bipolar System

F. FUNGO, K-T WONG, S-Y KU, Y-Y HUNG AND A. J. BARD.

JOURNAL OF PHYSICAL CHEMISTRY B

acs

Año: 2005 p. 3984 - 3989

1089-5647

The electrochemistry and radical ion annihilation electrogenerated chemiluminescence (ECL) of 9,9¢- spirobifluorene-bridged bipolar systems containing 1,3,4-oxadiazole-conjugated oligoaryl and triarylamine substituents were investigated. The stability of the oxidized spirobifluorenes was improved by functionalization with triarylamine centers. These donor-acceptor (DA) compounds exhibited a good fluorescence efficiency with an emission maximum that correlated with the potential difference between radical anion and cation formation, suggesting a charge transfer (CT) emission band. An ECL mechanism based on the formation of the CT excited state by radical ion annihilation or production of the triplet state followed by triplet-triplet annihilation, with perhaps some excimer contribution, is proposed.