Structure of complexes of lasalocid m-nitrobenzyl ester with monovalent metal cations

The complexes between m-nitrobenzyl ester of lasalocid acid (m-ELAS) and Li+, Na+ and K+ cations were synthesised and studied by ESI-MS, 1H NMR, 13C NMR and FT-IR spectroscopic methods. The ESI-MS spectra indicate that the ester forms stable complexes of exclusively 1:1 stoichiometry, preferentially with Li+ cations. With increasing cone voltages, fragmentation of the respective complexes is observed. The results of the PM5 semiempirical calculations are in agreement with the spectroscopic data and allow visualisation of the structure of the m-ELAS complexes with monovalent cations. The structures of the complexes are discussed in detail.