Study of lanthanide(III) nitrate complexes in CMPO/TBP systems by nuclear magnetie resonance

not registered   ; Aose, Shinichi; not registered; not registered

THe coordination properties of the lanthanide (La, Ce, Pr, Nd, Sm and Eu) complexes in lanthanide/TBP (tributylphosphate), lanthanide/CMPO (octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine oxide) and lanthanide/CMPO/TBP systems were investigated by the NMR (nuclear magnetic resonance) measurements. The numbers of the coordinated CMPO and TBP to the lanthanide ion were estimated about three and two in the lanthanide/CMPO and lanthanide/TBP systems, respectively. It is considered that TBP and CMPO coordinate to the lanthanide (III) ion in the monodentate and the bidentate manners, respectively. In the lanthanide/CMPO/TBP system, P-NMR spectra suggested that CMPO coordinates to lanthanide(III) ion directly in the bidentate mode, but TBP doesn't exist within the first coordination sphere and coordinates to the lanthanide(III) ion from beyond the first coordination sphere. The activation parameters for the ligand exchange reactions calculated by the CBS (complete bandshape) method suggest that the ligand exchange reactions in the lanthanide (Pr and Eu)/TBP and lanthanide (La, Pr and Sm)/CMPO systems proceed through either the associative (A) mechanism or the dissociative (D) mechanism with an ordering into the second coordination sphere. In the lanthanide (Pr and Sm)/CMPO/TBP systems, it was shown that the CMPO exchange reactions proceed through the mechanism with an ordering into the second coordination sphere, which is caused by TBP in the systems.