(E)-4-[(2-Carbamoylhydrazinylidene)methyl]-3-hydroxy-5-hydroxymethyl-2-methylpyridin-1-ium nitrate

Abstract

The title compound, C9H13N4O3+center dot NO3-, is the first structurally characterized Schiff base derived from semicarbazide and pyridoxal. Unusually for an unsubstituted semicarbazone, the compound adopts a syn conformation, in which the carbonyl O atom is in a cis disposition relative to the azomethine N atom. This arrangement is supported by a pair of hydrogen bonds between the organic cation and the nitrate anion. The cation is essentially planar, with only a hydroxymethyl O atom deviating significantly from the mean plane of the remaining atoms (r.m.s. deviation of the remaining non-H atoms = 0.01 angstrom). The molecules are linked into flat layers by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds. O-H center dot center dot center dot O hydrogen bonds involving the hydroxymethyl group as a donor interconnect the layers into a three-dimensional structure.