Synthesis and crystal structure of a novel complex with 2,3-bis(2-pyridyl)pyrazine

The interaction of zinc chloride with 2,3-bis(2-pyridyl)pyrazine (bppz), 2,5-pyridinedicarboxylic acid and acetylacetone with methanol and acetonitrile as solvents has yielded a new compound with the formula (Hbppz)2[ZnCl4] in whose formation 2,5-pyridinedicarboxylic acid and acetylacetone were not involved. The X-ray analysis, used to determine the crystal structure, revealed that this compound has an ionic nature. In this structure, one component, the organic cation, is formed by the protonation of bppz, while the anion is the complex anion of zinc tetrachloride. In the crystal between these two components, in addition to interactions of an ionic nature, there are also fine hydrogen bonds of the C–H···Cl type. The latter connect these components in an alternating arrangement of two by two, forming a macrometallocycle of 24 atoms, which in turn are also connected by fine hydrogen bonds. The organic cation in the crystal is stabilized by the strong hydrogen bond N–H···N.