Molecular and crystal structures of the products of crystallization of (N '-furfurylidene)isonicotinoylhydrazide from aqueous solutions of hydrochloric and acetic acids

Crystals of (N'-furfurylidene)isonicotinoylhydrazide (I), which have been i solated from a water-methanol solution of hydrochloric acid (Ia) and an acq ueous solution (similar to 50%) of acetic acid (fb), are studied by X-ray d iffraction. In Ia, the nitrogen atom of the pyridine ring is protonated. In the crystal, the intermolecular C=O...HN(Py) hydrogen bonds link the I Hf cations into chains which are bound through centrosymmetric NH...W...Cl-... W-t...H'N' bridges. In molecule Ib, no protonation occurs; however, its py ridine N atom is blocked by the hydroxyl H atom of a solvate molecule of ac etic acid. Crystals Ib have a layered structure. The crystallization water molecule is involved in the formation of three intermolecular hydrogen bond s, namely, those with the H atom of the amide group and the carbonyl O atom s of molecule I and an acetic acid molecule of the neighboring layer (C) 20 01 MAIK "Nauka/lnterperiodica".