Theoretical study on the interaction between metal cations and dimethyl phosphate anion

The interactions of dimethyl phosphate anion (DMP-) with Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ cations were calculated with DFT/B3LYP method by using the standard 6-31G(d,p) basis set, while the remaining coordination bonds are saturated with water molecules ((H2O)(4)). All geometries were optimized without symmetry restrictions. The interaction energies of complexes provide a comparatively reliable quantification of the selectivity of dimethyl phosphate anion for the studied metal ions, which is in reasonable agreement with the Irving-Williams list. Moreover, the cations with an unfilled state of d-electrons may be sensitive to the changing of ligands. In addition, the population of changes of the complexes and the significant donor-acceptor natural bond orbital interaction were analyzed with the method of Natural Bond Orbital analysis.