Synthesis, characterization and structural analysis of bis-schiff bases using 3,3′-methylendianiline and salicylaldehyde derivatives

Abstract Seven N,N′ -bis(salicylidene)diamines of common formula (2-OH-(5X)C 6 H 3 C N) 2 -Z [Z = CH 2 ( m -C 6 H 4 ), X = H ( 1a ), X = CH 3 ( 1b ), X = Cl ( 1c ), X = Br ( 1d ), X = NO 2 ( 1e ), X = OH ( 1f ) and (2-OH-(3OH) C 6 H 3 C N) 2 -Z [Z = CH 2 ( m -C 6 H 4 ) ( 1g )] have been synthesized and characterized by IR, NMR and mass spectroscopy. Molecular structures of 1a - 1d and 1g were elucidated by X-ray diffraction, the structures are stabilized by two intramolecular O H⋯N hydrogen bonds. Furthermore, intermolecular bonds as O H⋯O, C H⋯O, C H⋯N and C H···Hal stabilize the structures at supramolecular level. Compound 1g showed in one side and intramolecular O H⋯N hydrogen bond and, at the other side and N H⋯O hydrogen bond, showing the presence of enol and keto tautomers at the same molecule, which could be attractive to use in sensors and no-lineal optics. Besides, compounds 1a-1d showed weak intermolecular π-interactions.