Complex of antamanide with the nitrate anion.

Anionic complex of antamanide with the nitrate anion has been proven by electrospray ionization mass spectrometry (ESI-MS) method. Further, applying quantum chemical DFT calculations, the most probable structure of this complex was derived. The nitrate anion is embedded in the molecule of antamanide and its oxygens atoms are bonded by seven bonds to the hydrogen atoms of the ligand. Finally, the interaction energy, E(int), of the antamanide-NO₃⁻ complex was calculated as E(int) = -175.9 kJ/mol. Highlights: Antamanide-NO₃⁻ complex has been proved using the ESI-MS method. The structures of this complex has been determined applying quantum chemical DFT calculations. The interaction energies of antamanide-NO₃⁻ complex has been calculated. [ABSTRACT FROM AUTHOR]