Hexaphenyl-1,4,5,6,7,10,11,12,13,16,17,18-dodecaazatrinaphthylene

Abstract

Highly N-containing polycyclic aromatic hydrocarbons are attractive because of their significantly electron deficient nature and cation binding ability. The title compound PhDATN, possessing a trinaphthylene skeleton incorporating twelve nitrogen atoms, was synthesized by the condensation reaction of 5,6-diphenylpyrazine-2,3-diamine and cyclohexanehexone in acetic acid, followed by the oxidation by DDQ. A conventional condensation reaction yields a mixture of PhDATN and dihydrated intermediate 5,18-H₂-PhDATN, which requires further oxidation to convert into PhDATN. The compound was characterized by ¹H and ¹³C NMR spectroscopy, FT-IR spectroscopy, high-resolution mass spectrometry and single-crystal X-ray diffraction analysis. Three reversible reduction waves are observed for PhDATN at E_1/2 of −0.83, −1.11 and −1.76 V (vs. Fc/Fc⁺). PhDATN is unstable under photoirradiation conditions. Particularly, the compound is degraded via photoreduction into 5,18-H₂-PhDATN in a chloroform solution. In its crystalline state, PhDATN forms a one-dimensionally stacked columnar structure with a π⋯π stacking distance of ca. 3.1 Å, which is much shorter than usually observed inter-molecular π-stacking distances, providing an electron conductive property.