One-Step Synthesis of a Triangular Donor/Acceptor-Accumulated Compound with Long-Wavelength Absorption

Abstract 1,6-Dihydro-7,12,13,18-hexaazatrinaphthylene (HATN–H2) was synthesized for the first time via a one-step reaction of hexaketocyclohexane (HKC) with 1,2-phenylenediamine (PDA) above 130 °C, whereas well-known 1,6,7,12,13,18-hexaazatrinaphthylene was prepared at temperatures below 130 °C. The structure of HATN–H2 was determined via various analyses, and a quantitative yield was achieved when a large excess of PDA to HKC was used in the absence of solvents. HATN–H2 exhibited long-wavelength absorption at 667 nm, which was attributed to the compact triangular structure comprising one electron-donating amino group and two electron-withdrawing imino groups.