A Hexameric Cationic Copper(II) Metallacrown as a Pertechnetate and Perrhenate Scavenger

Abstract

Materials based on the cationic copper(II) hexanuclear 18-membered metallacrown [18-MCCuII-N(2ph)-6](6+) (2phH=2-piconyl hydrazide) and tetrafluoroborate, perchlorate, nitrate, sulfate, and perrhenate anions were prepared by an easy method in aqueous medium. Single-crystal X-ray characterization of six members of this new family of complexes showed that the anions are attached to the metallacrown by direct coordination to a copper cation or by hydrogen-bonding interaction with the center of the hexamer. The stable cationic nature of the complexes and their ability to bind different anions allows them to adsorb and immobilize environmentally relevant anions such as MO4(-) (M=Tc, Re). The MO4(-) trapping capacities suggest that these materials would be useful in the treatment of oxoanionic contaminants in water.

Synthesis, Structure, and Ammonia Oxidation Catalytic Activity of Ru-NH3 Complexes Containing Multidentate Polypyridyl Ligands

“…A similar phenomenon also occurs when 2 reacts with NH 3 (aq) at RT generating trans-[Ru II (tda-κ-N 3 )(py) 2 (NH 3 )], 4, (Scheme 1), whereupon NH 3 coordinates to Ru and the tda 2− ligand decreases its coordination mode from κ-N 3 O to κ-N 3 as can be observed in Figure 1 (Supporting Information Figure S12). Interestingly, the reaction of 2 with hydrazine also produces the coordination at the equatorial position, accompanied by a formation of a new C(O)−N bond between the hydrazine and the carboxylate, thus generating an unusual acyl hydrazine derivative, 57 trans-[Ru II (tda-κ-N 3 )(N-NH 2 )-(py) 2 ], 5, as outlined in Scheme 1 and proved by the X-ray diffraction crystal structure presented in Figure 1 (Supporting Information Figure S13).…”

Separation and Remediation of 99TcO4– from Aqueous Solutions

“…Previously, small cationic metal–organic complexes have been reported to sense or immobilize TcO 4 – /ReO 4 – , but they all lack extended structures, resulting in high solubility in aqueous solution. , Fei et al first reported a cationic layered [Ag 2 (4,4′-bipy) 2 (O 3 SCH 2 CH 2 SO 3 )·4H 2 O] (SLUG-21) MOF material for the efficient removal of ReO 4 – . The sorption process represented a new paradigm for anion separation entitled single-crystal-to-single-crystal transformation, giving a high sorption capacity of 602 mg/g for ReO 4 – .…”

“…In used nuclear fuel and high-level radioactive waste, technetium-99 ( 99 Tc), which is a β-emitter with a long half-life of 2.13 × 10 5 years, is one of the most-problematic radionuclides. 1 With a high fission yield of ∼6%, 21 kg of 99 Tc is annually produced by a 1 GWe-scale nuclear reactor, leading to a large inventory of ∼155 tons accumulated over the past 20 years all over the world. 2 99 Tc predominately exists in the form of the pertechnetate anion (TcO 4 − ) in both the nuclear fuel cycle and environments under oxic conditions.…”

A H-Bonding and Electrostatic Interaction Combined Strategy for TcO4– Separation by a Nitrotriacetate-Derived Amine–Amide Extractant

“…Among the long-lived radioactive nuclides, β-emitting radionuclide 99 Tc with a long half-life of 2.13 × 10 5 years and the fission yield as high as about 6% has lasting impacts on the environment and human health and is recognized as one of the most problematic radionuclides. , It primarily exists as 99 Tc­(VII) in the form of 99 TcO 4 – under aerobic conditions. , Because of large solubility in water (11.3 mol/L for its sodium salt, 20 °C) and nearly noncomplexing nature, TcO 4 – has extremely high mobility in the environment. ,− Besides, the generation of volatile Tc 2 O 7 during the vitrification process of nuclear waste increases the difficulty of handling 99 Tc. − Therefore, to mitigate long-term nuclear waste storage issues, it is necessary that 99 Tc should initially be removed from the nuclear waste before vitrification, followed by transmutation into short-lived or stable nuclides, such as ruthenium isotopes. , …”