31P NMR study of the stoichiometry, stability and thermodynamics of new complexation between uranyl (II) nitrate and N-methyliminobis(methylenephosphonic acid) in two binary D2O-DMSO-d6 solvent mixtures

► The Kf of a new complex was evaluated from integration of two 31PNMR signals. ► The 31PNMR study has been utilized to calculate thermodynamic data of complex. ► The solvent was found to play a key role in calculation of the thermodynamic data. ► Both of phosphor atoms in a bidentate ligand have similar position in the complex.