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This paper deals with complex formation of Bi(III) with 3-mercaptopropionic acid (H2MPA, H2L) in aqueous perchloric solutions. An extensive investigation on stoichiometry, stability and geometry of complex species in aqueous solutions and of solid H[Bi(MPA)2]·H2O complexes has been carried out by UV-Vis, 1H-NMR, Raman, ICP-AES and EXAFS spectroscopic methods combined with ab initio research. All complex species have cyclic S,O-chelate structures. An ab initio simulation on the thermodynamics of complexation of Bi(III) by H2MPA has been carried out aiming to choose an appropriate quantum chemical methodology. The most accurate results have been achieved with M06 density functional, a SMD solvation model and the Def2-TZVPP basis set with discrepancies of stability constants within ± 1.0 logarithmic units. |
