NMR-spectra of the pure title compound and its complexes with La(III), Sm(III), and Eu(III) at different metal-to-ligand ratios as well as pD values. TRLFS spectra of the title compound with Eu(III) as well as Cm(III). Measured and calculated IR spectra of the title compound and EDTA and EGTA with Eu(III). DFT calculations of the ligand with La(III), Eu(III), and Cm(III) as well as EDTA and EGTA comparisons.