Solution and solid-state structural chemistry of actinide hydrates and their hydrolysis and condensation products.

Oxo ligand functionalization in the uranyl ion (UO22

Actinide oxalates, solid state structures and applications

Metal hexacyanoferrates are very efficient sorbents for the recovery of alkali and base metal ions (including radionuclides such as Cs). Generally produced by the direct reaction of metal salts with potassium hexacyanoferrate (the precursors), they are characterized by ion-exchange and structural properties that make then particularly selective for Cs(I), Rb(I) and Tl(I) recovery (based on their hydrated ionic radius consistent with the size of the ion-exchanger cage), though they can bind also base metals. The major drawback of these materials is associated to their nanometer or micrometer size that makes them difficult to recover in large-size continuous systems. For this reason many techniques have been designed for immobilizing these ion-exchangers in suitable matrices that can be organic (mainly polymers and biopolymers) or inorganic (mineral supports), carbon-based matrices. This immobilization may proceed by in situ synthesis or by entrapment/encapsulation. This mini-review reports some examples of hybrid materials synthesized for the immobilization of metal hexacyanoferrate, the different conditionings of these composite materials and, briefly, the parameters to take into account for their optimal design and facilitated use.

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Immobilization of Metal Hexacyanoferrate Ion-Exchangers for the Synthesis of Metal Ion Sorbents--A Mini-Review.

The use of radiopharmaceuticals for molecular imaging of biochemical and physiological processes in vivo has evolved into an important diagnostic tool in modern nuclear medicine and medical research. Positron emission tomography (PET) is currently the most sophisticated molecular imaging methodology, mainly due to the unrivalled high sensitivity which allows for the studying of biochemistry in vivo on the molecular level. The most frequently used radionuclides for PET have relatively short half-lives (e.g. 11C: 20.4 min; 18F: 109.8 min) which may limit both the synthesis procedures and the time frame of PET studies. Iodine-124 (124I, t1/2 = 4.2 d) is an alternative long-lived PET radionuclide attracting increasing interest for long term clinical and small animal PET studies. The present review gives a survey on the use of 124I as promising PET radionuclide for molecular imaging. The first part describes the production of 124I. The second part covers basic radiochemistry with 124I focused on the synthesis of 124I-labeled compounds for molecular imaging purposes. The review concludes with a summary and an outlook on the future prospective of using the long-lived positron emitter 124I in the field of organic PET chemistry and molecular imaging.

https://www.mdpi.com/1420-3049/15/4/2686/pdf

Iodine-124: A Promising Positron Emitter for Organic PET Chemistry

The centrosymmetric title compound, [(NpO2)2(C7H4FO2)2(C10H8N2)2], contains the dimeric dioxocation (NpO2+)2 in which two of the four O atoms bridge the Np atoms Two bidentate chelating-bridging fluoro­benzoate anions link the Np atoms of the dimeric cation The N atoms of the 2,2′-bipyridine ligand occupy two positions in the equatorial plane of the distorted penta­gonal bipyramid, forming a five-membered metallacycle

Dimeric dioxocations, (NpO2+)2, in the structure of bis­(μ‐2‐fluoro­benzoato‐κ2O:O′)di‐μ‐oxo‐bis­[(2,2′‐bipyridine‐κ2N,N′)oxoneptunium(V)]

Single crystals of [NpO 2 L(H 2 O)].1/3H 2 O (I) and [PuO 2 L(H 2 O)].H 2 O (II) (H 2 L - orthophthalic acid) have been synthesized, their structures have been determined by X-ray structural analysis. Actinide atoms in both compounds are seven-coordinated. The interaction between actinide dioxocations and phthalate anions results in formation of infinite tubes in I and layers in II. The structures are compared with those of other phthalate compounds of hexa- and pentavalent actinides, in particular, with the structure of [UO 2 L(H 2 O)].H 2 O which differs from the structure II.

Crystal structures of Np(VI) and Pu(VI) phthalates, [NpO2{(OOC)2C6H4}H2O]·1/3H2O and [PuO2{(OOC)2C6H4}H2O]·H2O

Peculiarities of complex formation of hexavalent Np and Pu with tetrahedral XO42− oxoanions (X=S, Se, Cr, Mo)

The crystal structure of the K2[(NpO2)2(CrO4)3(H2O)] · 3H2O compound was established. The structure consists of anionic layers [(NpO2)2(CrO4)3(H2O)]n2n, between which K+ ions and crystallization water molecules are located. The coordination polyhedra of Np atoms are distorted pentagonal bipyramids. All chromate ions are bound in a tridentate-bridging fashion.

Synthesis and X-ray diffraction study of complex neptunium(VI) potassium chromate K2[(NpO2)2(CrO4)3(H2O)] · 3H2O

Complex benzoates [{UO2(C10N2H8)C6H5COO}2O2], [NpO2(C10N2H8)(C6H5COO)2], and [PuO2(C10N2H8)(C6H5COO)2] (C10N2H8 is 2,2′-bipyridine) were synthesized in the form of single crystals, and their structure was determined by X-ray diffraction analysis. The absorption spectra of the crystalline U(VI), Np(VI), and Pu(VI) complexes were measured and analyzed.

A. A. Bessonov

Papers

Dimeric dioxocations, (NpO2+)2, in the structure of bis(μ‐2‐fluorobenzoato‐κ2O:O′)di‐μ‐oxo‐bis[(2,2′‐bipyridine‐κ2N,N′)oxoneptunium(V)]

Crystal structures of Np(VI) and Pu(VI) phthalates, [NpO2{(OOC)2C6H4}H2O]·1/3H2O and [PuO2{(OOC)2C6H4}H2O]·H2O

Peculiarities of complex formation of hexavalent Np and Pu with tetrahedral XO42− oxoanions (X=S, Se, Cr, Mo)

Synthesis and X-ray diffraction study of complex neptunium(VI) potassium chromate K2[(NpO2)2(CrO4)3(H2O)] · 3H2O

Synthesis, crystal structure, and absorption spectra of 2,2′-bipyridine complexes of benzoates of hexavalent U, Np, and Pu

A. A. Bessonov

Papers

Dimeric dioxocations, (NpO2+)2, in the structure of bis­(μ‐2‐fluoro­benzoato‐κ2O:O′)di‐μ‐oxo‐bis­[(2,2′‐bipyridine‐κ2N,N′)oxoneptunium(V)]

Crystal structures of Np(VI) and Pu(VI) phthalates, [NpO2{(OOC)2C6H4}H2O]·1/3H2O and [PuO2{(OOC)2C6H4}H2O]·H2O

Peculiarities of complex formation of hexavalent Np and Pu with tetrahedral XO42− oxoanions (X=S, Se, Cr, Mo)

Synthesis and X-ray diffraction study of complex neptunium(VI) potassium chromate K2[(NpO2)2(CrO4)3(H2O)] · 3H2O

Synthesis, crystal structure, and absorption spectra of 2,2′-bipyridine complexes of benzoates of hexavalent U, Np, and Pu

Dimeric dioxocations, (NpO2+)2, in the structure of bis(μ‐2‐fluorobenzoato‐κ2O:O′)di‐μ‐oxo‐bis[(2,2′‐bipyridine‐κ2N,N′)oxoneptunium(V)]