Synthesis, characterization, and electronic properties of a thermally-labile isoindigo

Abstract

Addition of tert-butoxycarbonyl (Boc) groups to 6,6′-dibromoisoindigo (3a) provides a highly soluble material that displays π-stacking in the solid state as evidenced by a single crystal X-ray study. This Boc-substituted molecule (3b) was compared to an alkyl-substituted isoindigo using techniques such as TGA, UV–Vis and cyclic voltammetry. TGA analysis reveals the thermolabile Boc groups of 3b can be removed at elevated temperatures to afford the parent isoindigo. Electrochemical analyses, in conjunction with density functional theory (DFT) calculations, reveals enhanced electron affinities of 3b relative to alkyl-substituted isoindigos.