A novel piperazine derivative (3E,3^¢E)-3,3^¢-(((piperazine-1,4-diyl bis (ethane-2,1-diyl)) bis (azanediyl)) bis (ethan1-yl-1-ylidene)) bis (6-methyl-2H-pyran-2,4(3H)-dione) (2E-Peaemp) has been synthesized and characterized by ESI-MS, Single-crystal X-ray diffraction, NMR (¹H NMR, ¹³C NMR and 2D NMR), ATR-FTIR, UV-Visible and SEM. The theoretical study of chemical reactivity of 2E-Peaemp was investigated using DFT method. The oxidation-reduction processes and interaction between 2E-Peaemp and nitrite ions were studied using cyclic voltammetry technique. In addition, the detection of NO₂^- was investigated in 0.1 M PBS solution (pH = 7.0) using a carbon paste electrode modified with reduced graphene oxide-graphite carbon/2E-Peaemp system (rGO-GC/2E-Peaemp). XRD study showed that 2E-Peaemp crystallizes in a monoclinic system with P21/c space group, and the results obtained from theoretical study well support the experimental results. According to DFT study, HOMO (Highest Occupied Molecular Orbitals)-LUMO (Lowest Unoccupied Molecular Orbitals) energy gap (E_gap) and other reactivity descriptors were calculated. The results showed that the ligand exhibits a high chemical reactivity and low kinetic stability. Finally, the cyclic voltammetry measurements showed significant current responses of rGO-GC/2EPeaemp electrode towards NO₂^- in the concentration range of 0–4 mM with a low limit of detection (LOD = 0.83 lM)

New ligand (2E-Peaemp: (3E,3^¢E)-3,3^¢-(((piperazine-1,4-diyl bis (ethane-2,1-diyl)) bis (azanediyl)) bis (ethan1-yl-1-ylidene)) bis (6-methyl-2H-pyran-2,4(3H)-dione)) has been synthesized and characterized by XRD technique. The reactivity descriptors have been calculated by DFT. The ligand was used for electrochemical recognition of nitrite anion. The cyclic voltammetry showed that the modified electrode with 2E-Peaemp exhibits low detection limit towards NO2New ligand (2E-Peaemp: (3E,3′E)-3,3′-(((piperazine-1,4-diyl bis (ethane-2,1-diyl)) bis (azanediyl)) bis (ethan1-yl-1-ylidene)) bis (6-methyl-2H-pyran-2,4(3H)-dione)) has been synthesized and characterized by XRD technique. The reactivity descriptors have been calculated by DFT. The ligand was used for electrochemical recognition of nitrite anion. The cyclic voltammetry showed that the modified electrode with 2E-Peaemp exhibits low detection limit towards NO₂^-