Synthesis of Mono and Bis-Substituted Compounds 1-(2-hydroxybenzylidene) Carbonohydrazide and 1, 5-bis(2-Hydroxybenzaldehyde) Carbohydrazone: Study Spectroscopy and X-ray Diffraction

The unsymmetric monocarbonohydrazide Schiff base (H5L1) (1) and the symmetric dicarbonohydrazone (H4L2) (2) were prepared from a monocondensation reaction between carbonohydrazide and 2-hydroxybenzaldehyde, respectively, in 1/1 and 1/2 ratio. The compounds were characterized by elemental analysis, 1H and 13C NMR and FTIR spectroscopy. The NMR and FTIR data analysis revealed that compounds (1) and (2) are in the amide form in the solid state as well as in DMSO solution. The molecular structure of each Schiff base compound has been elucidated by single crystal X-ray diffraction analysis. Compound H5L1 (1) crystallizes in the monoclinic system in P21/c space group with cell parameters: a = 17.0790(2) Å, b = 11.07410(10) Å, c = 10.56110(10) Å, b = 106.5730(10) °, V = 1914.49(3) Å3 , Z = 4, R1 = 0.0432, wR2 = 0.1275 . The compound H4L2 (2) crystallizes in the orthorhombic system  in C2221 space group with cell parameters; a = 4.5494 (1) Å, b = 12.2213 (2) Å, c = 27.4001 (6) Å, V = 1523.43 (5) Å3 , Z = 4, R1 = 0.039 , wR2 = 0.125 . Both compounds exhibit inter and intramolecular hydrogen bonds which consolidate the structures into three-dimensional networks.