The effect of ancillary ligands on hydrocarbon C-H bond functionalization by uranyl photocatalysts.

The aqueous uranyl dication has long been known to facilitate the UV light-induced decomposition of aqueous VOCs (volatile organic compounds), the long-lived highly efficient, uranyl excited state. The lower-energy visible light excited uranyl ion is also able to cleave unactivated hydrocarbon C-H bonds, yet the development of this reactivity into controlled and catalytic C-H bond functionalization is still in its infancy, with almost all studies still focused on uranyl nitrate as the precatalyst. Here, hydrocarbon-soluble uranyl nitrate and chloride complexes supported by substituted phenanthroline (Phphen) ligands are compared to each other, and to the parent salts, as photocatalysts for the functionalization of cyclooctane by H atom abstraction.

Current and emerging technologies for the remediation of difficult-to-measure radionuclides at nuclear sites.

Difficult-to-measure radionuclides (DTMRs), defined by an absence of high energy gamma emissions during decay, are problematic in groundwaters at nuclear sites. DTMRs are common contaminants at many nuclear facilities, with (often) long half-lives and high radiotoxicities within the human body. Effective remediation is, therefore, essential if nuclear site end-state targets are to be met.

Developing field-scale, gentle remediation options for nuclear sites contaminated with Cs and Sr: The role of Nature-Based Solutions.

The remediation of contaminated land using plants, bacteria and fungi has been widely examined, especially in laboratory or greenhouse systems where conditions are precisely controlled. However, in real systems at the field scale conditions are much more variable and often produce different outcomes, which must be fully examined if 'gentle remediation options', or GROs, are to be more widely implemented, and their associated benefits (beyond risk-management) realized. These secondary benefits can be significant if GROs are applied correctly, and can include significant biodiversity enhancements.

Towards the application of electrokinetic remediation for nuclear site decommissioning.

Contamination encountered on nuclear sites includes radionuclides as well as a range of non-radioactive co-contaminants, often in low-permeability substrates such as concretes or clays. However, many commercial remediation techniques are ineffective in these substrates. By contrast, electrokinetic remediation (EKR), where an electric current is applied to remove contaminants from the treated media, retains high removal efficiencies in low permeability substrates.

Differential uranyl(v) oxo-group bonding between the uranium and metal cations from groups 1, 2, 4, and 12; a high energy resolution X-ray absorption, computational, and synthetic study.

The uranyl(vi) 'Pacman' complex [(UO)(py)(HL)] (L = polypyrrolic Schiff-base macrocycle) is reduced by CpTi(η-MeSiC[triple bond, length as m-dash]CSiMe) and [CpTiCl] to oxo-titanated uranyl(v) complexes [(py)(CpTiOUO)(py)(HL)] and [(ClCpTiOUO)(py)(HL)] . Combination of Zr and Zr synthons with yields the first Zr-uranyl(v) complex, [(ClCpZrOUO)(py)(HL)] . Similarly, combinations of Ae and Ae synthons (Ae = alkaline earth) afford the mono-oxo metalated uranyl(v) complexes [(py)(ClMgOUO)(py)(HL)] , [(py)(thf)(ICaOUO)(py) (HL)] ; the zinc complexes [(py)(XZnOUO)(py)(HL)] (X = Cl , I ) are formed in a similar manner.

Thermal and Photochemical Reduction and Functionalization Chemistry of the Uranyl Dication, [UO].

The uranyl ion, [UO], possesses rigorously , strongly covalent, and chemically robust U-oxo groups. However, through the use of anaerobic reaction techniques, both one- and two-electron reductive functionalization of the uranyl oxo groups has been discovered and developed. Prior to 2010, this unusual reactivity centered around the reductive silylation of the uranyl ion which entailed conversion of the oxo ligands into siloxy ligands and reductive metalation of the uranyl oxo with Group 1 and -block metals.

Complexes of Group 2 dications with soft thioether- and selenoether-containing macrocycles.

A new route to cationic complexes of Mg, Ca, Sr and Ba with 18-membered ring O4S2, O4Se2 and O2S4 donor macrocycles from metal acetonitrile complexes with weakly coordinating [BAr(F)](-) anions is described. The precursors used were [M(MeCN)x][BAr(F)]2 (M = Mg, x = 6; M = Ca, x = 8) and [M'(acacH)(MeCN)5][BAr(F)]2 (M' = Sr or Ba). Reaction of these with the heterocrowns, [18]aneO4S2 (1,4,10,13-tetraoxa-7,16-dithiacyclooctadecane), [18]aneO4Se2 (1,4,10,13-tetraoxa-7,16-diselenacyclooctadecane) or [18]aneO2S4 (1,10-dioxa-4,7,13,16-tetrathiacyclooctadecane) in anhydrous CH2Cl2 solution gave [M(heterocrown)(MeCN)2][BAr(F)]2 for M = Mg, Ca or Sr, whilst the larger Ba forms [Ba(heterocrown)(acacH)(MeCN)][BAr(F)]2.