INFRARED AND NMR-STUDIES ON RHENIUM(VII) COMPLEXES WITH CMPO AND TBP

The infrared and NMR studies have been carried out on Re(VII) (a stand-in for Tc(VII)) complexes with n-octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) and tributyl phosphate (TBP). In the IR study, changes in the absorption bands of the carbonyl and phosphoryl stretching regions were monitored when Re was extracted. The phosphoryl group was also investigated by using a phosphorus NMR. The spectra obtained in the mixed CMPO-TBP system were compared with those obtained in the CMPO or TBP system in order to discuss their bond-structures. It was found that CMPO showed semi-bidentate [1] and bidentate bonding and that TBP could extract HReO4 in the mixed CMPO-TBP system. The IR and NMR results showed evidence of enhancement in the Re (Tc) extraction in the mixed CMPO-TBP system.