Synthesis, solid-state structures, and properties of linear and tripodal flexible molecules with pyrazinopyrazine moieties

Abstract

Abstract Pyrazino[2,3-b]pyrazine, which is a naphthalene analog with iminium nitrogen atoms at 1,4,5,8-positions instead of sp2-carbon atoms, is attractive as a building block for nitrogen highly contained π-conjugated systems. In this study, we synthesized pyrazino[2,3-b]pyrazine-based linear and tripodal molecules, in which pyrazino[2,3-b]pyrazine moieties are bonded with the central benzene ring at 1,4-positions and 1,3,5-positions, respectively, giving conformationally flexible and moderately π-conjugated molecules. It is noteworthy that the tripodal one forms unique interdigitated dimer with a small cavity in a crystalline state because of flexible tripodal molecular shape.