Tridecacyclene tetraimide, an easy-to-make molecular saddle, will accept up to eight electrons when reduced by chemical or electrochemical means. Strong near-infrared absorptions are observed for the resulting anionic species. The ultimate octaanion is an exception: it absorbs only in the visible region and has an even larger energy gap than the neutral form.
Tridecacyclene tetraimide, TCTI, an electron-deficient non-benzenoid nanocarbon with a C56N4 polycyclic framework was obtained in a concise synthesis. TCTI has a non-planar structure and forms π-stacked dimers in the solid state. In solution, it undergoes eight single-electron reductions, yielding a range of negatively charged states up to an octaanion. Except for the latter species, which has a remarkably large electronic gap, the anions feature extended near-infrared absorptions, with a particularly strong band at 1692 nm observed for the dianion. A computational analysis of the TCTI anions shows that their stability originates from the combined effects of electron-deficient imide groups and the local aromaticity of reduced acenaphthylene units. The properties of TCTI make it potentially useful in electrochromic and charge storage applications.Zum Volltext