Question

identify those which are isosteric with each other
(a)Na+ (b) mg2+ (c) AL+3 (D) O2-

Answer 1

B3LYP/6-311+G(d,p) DFT method was used to characterize the 92 gas-phase complexes of 23 neutral and anionic ligands H2O, NH3, PH3, H2S, H2Si, HF, HCl, H2Ge, t-HSiOH, t-HGeOH, H2C=O, NH2(H)C=O, HCOOH, H2Ge=O, H2Si=O, H2C=NH, HCN, CO, OH−, SH−, SiH− and HCOO− with Li+, Na+, Mg2+ and Zn2+. The basicity order of the ligands studied towards those cations exhibits a different ordering. There is no general correlation of basicities towards cations investigated. However, a very good correlation was found between the basicities towards monovalent cations Li+ and Na+ and between the basicities towards divalent cations Mg2+ and Zn2+. Calculated values of interaction enthalpies and free energies vary as Zn2+>Mg2+≫Li+>Na+. The relative basicities of the bases studied depend characteristically on type of cation and co-ordination base.
Thermodynamics of binding of Li+, Na+,... (PDF Download Available). Available from: https://www.researchgate.net/publication/257000355_Thermodynamics_of_binding_of_Li_Na_Mg2_and_Zn2_to... [accessed May 18 2018].