The C(2)N surface as a highly selective sensor for the detection of nitrogen iodide from a mixture of NX(3) (X = Cl, Br, I) explosives

Explosives are quite toxic and destructive; therefore, it is necessary to not only detect them but also remove them. The adsorption behavior of NX(3) analytes (NCl(3), NBr(3) and NI(3)) over the microporous C(2)N surface was evaluated by DFT calculations. The nature of interactions between NX(3) and C(2)N was characterized by adsorption energy, NCI, QTAIM, SAPT0, NBO, EDD and FMO analysis. The interaction energies of NX(3) with C(2)N are in the range of −10.85 to −16.31 kcal mol(−1) and follow the order of NCl(3)@C(2)N > NBr(3)@C(2)N > NI(3)@C(2)N, respectively. The 3D isosurfaces and 2D-RGD graph of NCI analysis qualitatively confirmed the existence of halogen bonding interactions among the studied systems. Halogen bonding was quantified by SAPT0 component energy analysis. The SAPT0 results revealed that ΔE(disp) (56.75%) is the dominant contributor towards interaction energy, whereas contributions from ΔE(elst) and ΔE(ind) are 29.41% and 14.34%, respectively. The QTAIM analysis also confirmed the presence of halogen bonding between atoms of NX(3) and C(2)N surface. EDD analysis also validated NCI, QTAIM and NBO analysis. FMO analysis revealed that the adsorption of NI(3) on the C(2)N surface caused the highest change in the E(HOMO–LUMO) gap (from 5.71 to 4.15 eV), and resulted in high sensitivity and selectivity of the C(2)N surface towards NI(3), as compared to other analytes. It is worth mentioning that in all complexes, a significant difference in the E(HOMO–LUMO) gap was seen when electronic transitions occurred from the analyte to the C(2)N surface.