Synthesis, Characterization, Antibacterial Properties and DFT Studies of Two New Polypyrazolic Macrocycles

Two novel symmetrical macrocycles containing four pyrazolic units, with two different side arms were synthesized and characterized. Their antibacterial activity was investigated by determining the inhibition zone diameter in agar gel and minimal inhibitory concentration. The obtained results show that the tetrapyrazolic macrocycle with a hydroxyl group in its side chain presents the best inhibitory effect against all tested bacterial strain. Molecular geometries, HOMO-LUMO analysis and molecular electrostatic potential of macrocycles are investigated by theoretical calculations with B3LYP/6-31G* level. The molecular electrostatic potential surface showed that the presence of electrophile site in the lateral arms of these macrocycles enhances the antibacterial activity of such compounds.