General ConsiderationsCaution: 254 Es (t 1/2 = 275.7 days, 70.9 TBq g −1 ) and 249 Cf (t 1/2 = 351 years, 150 GBq g −1 ) are highly radioactive, and decay to α-, β-and γ-emitting isotopes. These isotopes and their decay daughters present substantial health risks, and were manipulated only in facilities specifically designed for the safe handling of long-lived radioactive materials. All measurements were taken in controlled facilities and/or using multiple containment procedures.
Metal complexes from perfluoroalkylamide terpyridine self-assemble into anion selective gels, which manifest self-healing and thermal rearrangement in aqueous dimethyl sulfoxide.
An ideal chelator for f-elements features rapid kinetics of complexation, high thermodynamic stability, and slow kinetics of dissociation. Here we present the facile synthesis of a macrocyclic ligand bearing four 1-hydroxy-2-pyridinone units linked to a cyclen scaffold that rapidly forms thermodynamically stable complexes with lanthanides (Sm 3 + , Eu 3 + , Tb 3 + , Dy 3 +) and a representative late actinide (Cm 3 +) in aqueous media and concurrently sensitizes them. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed an increase in the Ln/ AnÀ O bond lengths following the trend Cm > Eu > Tb and EXAFS data were compatible with time-resolved luminescence studies, which indicated one to two water molecules in the inner metal coordination sphere of Eu(III) and two water molecules for the Cm(III) complex. Spectrofluorimetric ligand competition titrations against DTPA confirmed the high thermodynamic stability of DOTHOPO complexes, with pM values between 19.9(1) and 21.9(2).
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