1-(3-Chlorophenyl)-4-(3-phenylseleno propyl) piperazine (L); synthesis, spectroscopic characterization, DFT studies, antimicrobial evaluation and its reactivity toward group 12 metal chlorides

Abstract

C₆H₅Se⁻Na⁺ (generated in situ by NaBH₄ reduction of (C₆H₅Se)₂) on reaction with ClC₃H₆C₄H₈N₂ClC₆H₅ under N₂ atmosphere results in C₆H₅SeC₃H₆C₄H₈N₂ClC₆H₅ (L) as a cream-colored solid. Its 1:1 metal complexes having the general formula [MLX₂], where M = Zn, Cd, Hg, and X = Cl, have been prepared. Ligand L and its complexes 1–3 are characterized on the basis of physico-chemical and spectral (FT-IR, ESI Mass, ¹H, ¹³C, DEPT 135° ¹³C {¹H}, and ⁷⁷Se{¹H} NMR) studies. IR spectroscopy revealed that L is coordinated solely through selenium and nitrogen to zinc, cadmium, and mercury ions forming a six-membered chelate ring around M(II) ions. Elemental analysis measurements along with ¹H, ¹³C, DEPT 135° ¹³C {¹H}, and ESI-mass data also confirm the bidentate coordination mode of the ligand. Moreover, the coordination from selenium atom is also supported by the downfield shift of signal in ⁷⁷Se{¹H} NMR spectroscopy. Using DFT-based optimization of structures, the HOMO-LUMO energy gaps and molecular electrostatic potential surface of ligand L and complexes 1–3 were theoretically calculated at the B3LYP/LANL2DZ level of theory. Ligand L and complexes 1–3 display significant antibacterial and antifungal activity.

Graphical Abstract

Keywords:

• Reduction
• selenium
• bidentate
• coordination
• DFT
• biological activity

Acknowledgments

The authors are very thankful to IIIM Srinagar and IIT Delhi for ¹H, ¹³C, DEPT 135° ¹³C, ⁷⁷Se NMR, and elemental analysis. We are also thankful to Department of Chemistry, Dr. H.S. Gour University, Sagar for IR analysis and SIAF IIT Kanpur for mass analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.