Synthesis and molecular structure of the twelve-membered metallamacrocycle [Hg2(μ-2,6-dapy)2] (2,6-dapyH2 = 2,6-diacetamidopyridine)

Reaction of 2,6-diacetamidopyridine (2,6-dapyH2) with mercury acetate in ethanol affords the 12-membered metallamacrocycle, [Hg2(μ-2,6-dapy)2], in high yields resulting from deprotonation of both amide groups. The crystal structure shows that two 2,6-dapy dianions bridge the dimercury centre being bound through the amide nitrogens. The mercury atoms adopt the expected linear two-coordinate geometry [N–Hg–N 169.2 (4) and 173.5 (4)°] and the two 2,6-dapy ligands are twisted by ca. 19.3° with respect to one another. The metallamacrocycles form a coordination polymer with each mercury centre being weakly coordinated to two oxygen atoms of neighboring 2,6-dapy ligands [Hg⋯O 2.970 and 3.223 Å].