The piperazine ring is an indispensable part of many biomolecules and can be easily modified through substitution on the ring nitrogen for desired application in pharmacology as well as metal binding studies.

The aim of this work was to be combine two pharmocophoric nuclei viz, triazole and chalcone and evaluate their antitubercular activity. Propargylated vanillin was condensed with differently substituted acetophenones to produce various chalcones (3a-c). Propargyl chalcones were then made to react with benzyl azides (2a-d) using the technique of Click chemistry and this reaction yielded triazole-chalcone hybrids (4a-l) in good yields, ranged from 34 to 93%. These hybrids were evaluated for their antitubercular activity, from the results it was found that triazole and chalcone on combination exhibited enhanced bioactivity thereby supported the theory of synergistic effect. The conjugate 4a and 4f were found to be most potent with MIC of 1.6 µg/ml. Molecular docking studies of bioactive compounds were in good congruence with in-vitro studies.

Piperazine based compounds are gaining more attention in today’s research as the piperazine nucleus is found in many biologically active compounds. Substitution in nitrogen atom of piperazine with a suitable fragment containing donor atoms, make it unique for versatile binding possibilities with metal ion. Piperazine derived ligands and their metal complexes have shown applications in different fields like antimicrobial, antioxidant, antihistaminic, anticancer, DNA binding and protein binding, catalyst in ring opening polymerization (ROP), etc. Metal-organic framework derived from piperazine based ligands has also been reported in the literature. This paper presents the synthesis, and characterization of a series of piperazine based ligands. The asymmetrical ligands have been synthesized by cyclization of bis-chloroethyl amine with suitable amine. Some of the representative metal complexes are also synthesized and characterized.

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This paper describes the synthesise of copper complexes of phenylpiperazine ring-based ligands and characterization via physical and spectroscopic methods. Structure of complexes has been proposed on the basis of UV-vis, IR and Mass fragmentation pattern and additionally supported by electrochemical and thermogravimetric analysis. Low molar conductance value of metal complexes in water and DMSO suggest non-ionic nature of complexes which is in agreement of proposed structure. TGA curve, where loss of coordinated solvent molecules starts early followed by loss of ligand itself also support the proposed structures. Percentage ash content analysis also indicate that only one copper metal is binding to the ligands reported here. Antibacterial activity of metal complexes has been performed by agar well diffusion method and indicated these metal complexes possess higher activity than the corresponding ligands. Binding interaction of these complexes were studied with BSA protein by UV-vis spectroscopic methods and binding constant was calculated which indicated that the complexes are having moderate affinity. Some complexes were also geometrically optimized to lowest energy ground state by using DFT calculations. Docking study of these optimized structures with BSA protein revealed these metal complexes exhibit hydrophobic interaction owing to the aromatic bulk in the ligand.