Near-Infrared Absorbing Compounds Based on π-Extended Tetrathiafulvalene Open-Cage Fullerenes

Tetrathiafulvalene (TTF) is attached to open-cage fullerenes through a quinoxaline junction. The resulting linear pi-conjugation system shows intense absorption in the near-infrared region. A unique o-diaminobenzene-induced furan ring formation process from a conjugated 1,4-dione moiety was observed on the rim of a 18-membered orifice.