The pentadentate coordination environment of a 2,6-bis[1-[(2-hydroxyphenyl)imino]ethyl] pyridine ligand scaffold was designed to accommodate the larger atomic radius of uranium as the uranyl dioxo cation, while fully occupying its equatorial plane. Here, two new uranyl (UO) complexes utilizing this scaffold have been synthesized from successive condensation reactions and subsequent metal complexation. Surprising Zn fluorescence is also discussed.

Condensation of a 2,3-diaminophenazine or 2,3-diamino-2-quinoxalinol with two equivalents of 3,5-ditertbutylsalicylaldehyde affords new Schiff base ligands. Here, we describe and compare the synthesis, UV-Vis, electrochemical, solution, and solid state behaviour of the free base, salphenazine ligand [L(I)], and M[L(I)] complexes, where M = UO2(vi), Cu(ii), VO(iv), Zn(ii), Co(ii), and Ni(ii). The change in π-overlap and π-stacking between molecules and long-range ordering of the solid-state structure is vastly different depending on the size and electronic character of the metal. A sterically constrained μ-oxo Fe(iii) dimer complex is also reported.

Chemical structures for ALSEP extractants, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and N,N,N',N '-tetra(2-ethylhexyl) diglycolamide (TEHDGA) and truncated extractants employed in the computational analysis, ethylphosphonic acid monoethyl ester (HE[EP]) and N,N,N',N'-tetraethyldiglycolamide (TEDGA).

The actinide lanthanide separation (ALSEP) process is a modern solvent extraction approach used for the separation of the minor actinides americium and curium from the lanthanide fission products for transmutation, a process that can significantly reduce the long-term radioactivity and heat loading of nuclear waste. This process, inspired by existing chemistry, uses the aminopolycarboxylate N -(2-hydroxyethyl)ethylenediamine- N , N′ , N′ -triacetic acid (HEDTA) to selectively separate the actinides by stripping them from the organic phase while leaving the lanthanides behind. HEDTA is used in this separation as it has been shown to exhibit faster extraction kinetics than other aminopolycarboxylates, but its lower coordination number can allow for the formation of higher order complexes with the typically 8- to 9-coordinate f-elements. ALSEP uses a carboxylic acid buffer in the aqueous phase to control the pH of the system during metal stripping, and this buffer has the ability to complex actinide(III) and lanthanide(III) ions. The presence of a previously uncharacterized ternary lanthanide-HEDTA-citrate complex was detected during single-phase spectroscopy experiments. A combination of partitioning experiments and spectrophotometric titrations led to the identification of a 1:1:1 complex containing a partially protonated citrate ligand and determination of the stability constant of its neodymium complex.