Electronic Effects of Ring Fusion and Alkyne Substitution on Acene Properties and Reactivity

This paper describes the synthesis and systematic study of substituted acenes that have differences in conjugation both along their long axes (by the number of fused benzene or thiophene rings) and along their short axes (by the number of arylethynyl substituents). These acenes include what we believe to be the first reported examples of five new subclasses of substituted acenes. Systematic analyses of data obtained using absorbance and fluorescence spectroscopies, cyclic voltammetry, and DFT calculations reveal clear correlations between these common structural perturbations to acene structure and the key parameters, such as HOMO-LUMO gap, frontier molecular orbital energies, and reactivity with singlet oxygen.