TETRABENZO[B,G,K,P][1,10,4,6,13,15]DIOXATETRAAZACYCLOOCTADECA[2,4,5,7,11,13,14,16]-OCTAENE (III)

C28H20N4O2, M(r) = 444.49, monoclinic, C2/c, a = 19.532 (3), b = 7.858 (1), c = 14.997 (5) angstrom, beta = 98.91 (2)-degrees, V = 2274 (6) angstrom 3, Z = 4, D(m) = 1.294, D(x) = 1.298 (1) g cm-3, lambda(Cu K-alpha) = 1.54178 angstrom, mu = 5.91 cm-1, F(000) = 928, room temperature, R = 0.0377 for 1897 reflections with I greater-than-or-equal-to 3-sigma(I). The molecule contains an 18-membered heterocyclic ring which adopts a 'saddle-like' conformation with two non-linear diimino systems. A crystallographic two-fold axis passes through the centre of the ring. Two of the four benzene rings are nearly parallel to each other.