Synthesis of Hydrazinylpyridine and Phenylthiosemicarbazide Derivatives: Spectroscopic Study and X-ray Diffraction Structure Determination

Abstract

Hydrazinyl and thiosemicarbazide derivatives were used for synthetizing two new dissymmetrical Schiff bases. and 1-benzylidene-4-(4-chlorophenyl)thiosemicarbazide (H2L2) (2), respectively. Compound (1) (((2-hydroxyphenylmethylidene)hydrazinyl)pyridine (H2L1)) was first prepared by condensation reaction of hydrazinyl pyridine and salicylaldehyde. Then, compound 2 (1-benzylidene-4-(4-chlorophenyl)thiosemicarbazide (H2L2)) was obtained by condensation reaction of 4-(4-chlorophenyl)thiosemicarbazide and benzaldehyde. For both compounds, crystals suitable for X-ray analysis were obtained by slow evaporation. The prepared compounds were characterized by elemental analysis, infrared and 1H and 13C NMR spectroscopy techniques, and the structure of both compounds were determined by single-crystal X-ray diffraction study. The compound 1 C12H11N3O crystallizes in the monoclinic space group P21/n while the compound 2 C14H12ClN3S crystallizes in the triclinic space group Pī. In the structure of 1, the oxygen atom O1 of the hydroxyl group and the pyridine nitrogen atom N3 are not in the same side of the molecule avoiding intramolecular hydrogen bonding interaction between them. The crystal packing of compound 1 is stabilized by O(phenol)–H···N(hydrazinyl) and intermolecular N(hydrazinyl)–H···N(pyridine) hydrogen bonds which form layers parallel to a axis. In the structure of 2, the molecule adopts an E configuration relative to the C2—N2 bond. The crystal packing of compound 2 is stabilized by intramolecular N(amine)–H···N(azomethine) and intermolecular N1(thiosemicarbazide)–HN1···S1i(thiocarbonyl) hydrogen bonds and intermolecular which form layers parallel to the b axis.