Lanthanide Complexes with Allyl Acetoacetate in Mixed Water–Organic Media: Formation, Stability and Bonding

• DOI: 10.1007/s10953-015-0396-z
• Publication Date: 2015-10-20T12:52:14Z
• Authors: Artem M. Mishchenko; Elena K. Trunova; Alexandra S. Bere...
• Keywords: 02 engineering and technology; 0210 nano-technology

The equilibrium between unsaturated $$\beta $$ -ketoester allyl acetoacetate and certain lanthanide ions (La3+, Pr3+, Nd3+, Sm3+, Gd3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+) was studied in mixed dioxane–water–ethyl acetate media. The formation of cationic 1:1 and 1:2 type complexes was shown and their formation constants were determined by potentiometric titration. For the 1:2 type complexes a molecular mechanics geometry optimization was performed and the bonding parameters were calculated on the basis of their electronic absorption spectra using the lanthanide aqua-ions as reference standards. The correlation between the nephelauxetic ratio and the relative metal–ligand bond length shortening due to the complexation was revealed and clarified.