The syntheses of lanthanide metal complexes with diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid and the comparison of their crystal structures

Spectroscopic and Computational Characterization of Diethylenetriaminepentaacetic Acid/Transplutonium Chelates: Evidencing Heterogeneity in the Heavy Actinide(III) Series

“…[31] Further, DTPA and its derivatives are studied for industrial processes that aim at recycling nuclear waste and separating An from Ln fission products as, for example, in the TALSPEAK process. [32] In the frame of this study, DTPA is also convenient because it is one of the rare ligands for which the crystal structures of several Ln 3+ complexes have been determined, [28,29,[33][34][35][36][37][38] in addition to two EXAFS data sets [39,40] available on the Eu 3+ and Gd 3+ chelates. DTPA was also chosen in this study because it exhibits high stability constants with the An 3+ ions (log β110 ≈ 23 at 25ºC) [41] but its affinity for tetravalent ions is not strong enough to spontaneously oxidize Bk 3+ to Bk 4+ , as recently observed for more powerful chelators such as the hydroxypyridinonates.…”

Spectroscopic and Computational Characterization of Diethylenetriaminepentaacetic Acid/Transplutonium Chelates: Evidencing Heterogeneity in the Heavy Actinide(III) Series

“…The An III −O bond length evolves as follows: 2.41(1), 2.41(1), 2.42(2), and 2.36(1) Å for Am, Cm, Bk, and Cf, respectively (Table and Figure ). As mentioned above, the previously published crystal structures of nine Ln III /DTPA compounds (Table S4) can be used as a benchmark for their An counterparts. In the Ln 3+ complexes, the metal is always nonacoordinated by five carboxylate oxygen atoms, three nitrogen atoms, and one extra oxygen atom coming from either a water molecule or a bidentate carboxylate.…”

“…The crystallization methods reported in the literature for the Ln III /DTPA compounds cannot be applied to the transplutonium systems owing to the large amount of metal needed. However, the geometry of the An III complexes can be optimized computationally.…”

Investigation on coordination number and geometrical conformation of rare earth complexes with catenulate aminopolycarboxylic acid ligands

“…The REM complexes in this series, [90,91], possess a binuclear nine-coordinate molecular structure. It is not affected by the electronic configuration and ionic radius of the central REM, and there is no exact explanation to this phenomenon.…”