In the pursuit for better actinide ligands: an efficient strategy for their discovery

Henk H. Dam, Hans Beijleveld, David Reinhoudt, Willem Verboom

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16 Citations (Scopus)


A novel method for the efficient discovery of new types of minor actinide (MA) ligands is based on the unique combination of “tea bag” split pool combinatorial chemistry and screening based on the inherent radioactivity of the complexed cations. Four multicoordinating Am3+ chelating groups, such as CMPO (diphenylcarbamoylmethyl)phosphine oxide), PICO (picolinamide), DGA (N,N′-dimethyldiglycoldiamide), and MPMA (N-methyl-N-phenylmalonamide), on a trityl platform immobilized on TentaGelS served as a model library for the development of the screening method. This model library was screened under various conditions (i.e., 0.001 M ≤ [HNO3] ≤ 3 M, NaNO3 ≤ 4 M, and [Eu] ≤ 10 × [ligand]) showing competitive extraction of the four ligands. Other libraries of 9 and 72 members were synthesized by functionalization of the trityl platform with ligating groups that are composed of four building blocks (including at least one amide and one (phosphoric) hydrazone moiety). The screening of these two libraries resulted in the discovery of two multicoordinate ligands that contain ligating groups previously not known to complex Am3+. Both are N-isopropyl amides terminated with a p-methoxyphenyl hydrazide (A2B1C1D10 KD(Am) = 2197) or a p-nitrophenyl hydrazide (A2B1C1D11 KD(Am) =1989) moiety, respectively. They are more efficient than the immobilized tritylCMPO ligand (KD(Am) = 1280) at 3 M HNO3. This method has the advantages of a high analytical sensitivity and the direct comparison of the extraction results. The method also allows the competitive screening of multiple nuclides which can be quantified by their radioactive emission spectrum
Original languageEnglish
Pages (from-to)5542-5551
Number of pages10
JournalJournal of the American Chemical Society
Issue number16
Publication statusPublished - 2008

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