Synthesis, molecular structure, spectroscopic and theoretical investigation of 5-chlorosalicylaldehyde-2,4-dinitrophenylhydrazone

Abstract

A new hydrazone derivative, 5-chlorosalicylaldehyde-2,4-dinitrophenylhydrazone (5Cl-DNPHZ) has been synthesized and characterized by different spectroscopic techniques such as IR, Raman and UVeVis. A combined experimental and quantum chemical approach was performed to study the structural and spectroscopic properties of the title compound. The effect of substituents (chlorine and hydroxyl) on the benzene ring on the structural and electronic properties of 5Cl-DNPHZ and a related compound DNPHZ previously reported are analysed. Natural bond orbital (NBO) analysis was performed to obtain information about the interactions that were responsible for the stability of the different conformers of the title compound. The Atoms in molecules (AIM) calculations revealed that the intramolecular hydrogen bonding interactions observed in both conformations are of core-shell in nature. The molecular electrostatic potential (MEP) surface of the most stable conformer of 5Cl-DNPHZ shows that the oxygens of the nitro groups are prone to electrophilic attack and the hydrogen of the hydrazine group is prone to nucleophilic attack indicating that the intramolecular hydrogen bonding interaction is favoured between both groups