Synthesis of novel Schiff’s bases of highly potential biological activities and their structure investigation

• Two novel macrocyclic Schiff’s bases (AS1 and AS2) were prepared and characterized.
• Active groups and bonds responsible for their biological activities were checked.
• They of important capacity to bind and transport metal ions from environmental media.
• Thermal and mass practical results are confirmed by semi-empirical MO-calculations.
• Their biological activities were tested to assess their anti-microbial potential.

Novel bisaldehyde-hydrazide Schiff’s bases AS1 (2,2′-(ethane-1,2-diylbis(oxy))dibenzaldehyde terephthalohydrazide) and AS2 (N′,N′″-(((ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))di(benzohydrazide)) were prepared as new macrocyclic compounds via condensation reactions. AS1 had been prepared by condensation between (2,2′-(ethane-1,2-diylbis(oxy))dibenzaldehyde) bisaldehyde and terephthalohydrazide in a ratio1:1. AS2 had been obtained by condensation between (2,2′-(ethane-1,2-diylbis(oxy))dibenzaldehyde) bisaldehyde and benzohydrazide in ratio 1:2. The structures of AS1 and AS2 were characterized by elemental analysis (EA), mass (MS), FT-IR and 1H-NMR spectra, and thermal analyses (TG, DTG). The activation thermodynamic parameters such as ΔE∗, ΔH∗, ΔS∗ and ΔG∗ were calculated from the TG curves using Coats–Redfern method. It is important to investigate their molecular structures to know the active groups and weak bonds responsible for their biological activities. Consequently in the present work, the obtained thermal (TA) and mass (MS) practical results are confirmed by semi-empirical MO-calculations (MOCS) using PM3 procedure. Their biological activities had been tested in vitro against Escherichia coli, Proteus vulgaris, Bacillus subtilis and Staphylococcus aurous bacteria in order to assess their anti-microbial potential.

Novel biologically active Schiff’s bases AS1 (2,2′-(ethane-1,2-diylbis(oxy))dibenzaldehyde terephthalohydrazide) and AS2 (N′,N′″-(((ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))di(benzohydrazide)) were prepared and characterized based on elemental analysis, mass, FT-IR, 1H-NMR spectra and thermal analyses.Figure optionsDownload as PowerPoint slide