title: Electrogenerated chemiluminescence. 81. Influence of donor and acceptor substituents on the ECL of a spirobifluorene-bridged bipolar system.
abstract: 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.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Fungo
authors.forename: Ken-Tsung
authors.initials: KT
authors.lastname: Wong
authors.forename: Sung-Yu
authors.initials: SY
authors.lastname: Ku
authors.forename: Ying-Yueh
authors.initials: YY
authors.lastname: Hung
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard