The unusual ( syn -/ anti -) 2 conformation of a di-meth-oxy-pyrimidyl-based tennimide.

The tennimide macrocycle, () (CHNO.0.167HO), was synthesized from 2-amino-4,6-di-meth-oxy-pyrimidine and pyridine-2,6-dicarbonyl dichloride. Compound () represents the first tennimide incorporating pyridine rings in the macrocycle scaffold. In the macrocycle ring, the carbonyl groups at each successive dicarbon-yl(pyridine) moiety adopt the (/) conformation. This contrasts with all previously reported tetra-imide macrocycles, which exhibit the () conformation. The effect is to close any potential cavity or by having two of the central pyridine CN rings aligned close to each other [with closest pyridine ⋯ ring centroid separations of 3.5775 (19) Å; closest C⋯C = 3.467 (5) Å]. A partial occupancy water mol-ecule (with s.o.f. = 0.167), resides with its oxygen atom on a twofold axis at hydrogen-bonding distances to the carbonyl O atom, in a mol-ecular between two pyridine rings. Macrocyles of () have all six C=O groups and all eight meth-oxy O atoms present on the macrocycle surface. However, all twelve N atoms are effectively shielded on steric grounds from any potential inter-molecular inter-actions. The remaining two C=O O atoms inter-act with the partial occupancy water mol-ecule two O-H⋯O=C hydrogen bonds. Macrocycles of () stack as one-dimensional chains along the -axis direction with primary inter-molecular inter-actions involving weak C-H⋯O=C/OCH/HO contacts. Chains inter-lock weakly meth-oxy-meth-oxy C-H⋯O inter-actions into two-dimensional sheets.