Exploring the Redox Properties of Bench-Stable Uranyl(VI) Diamido–Dipyrrin Complexes

Abstract

The uranyl complexes UO 2 (OAc)( L ) and UO 2 Cl( L ) of the redox-active, acyclic diamido–dipyrrin anion L – are reported and their redox properties explored. Because of the inert nature of the complexes toward hydrolysis and oxidation, synthesis of both the ligands and complexes was conducted under ambient conditions. Voltammetric, electron paramagnetic resonance spectroscopy, and density functional theory studies show that one-electron chemical reduction by the reagent CoCp 2 leads to the formation of a dipyrrin radical for both complexes [Cp 2 Co][UO 2 (OAc)( L • )] and [Cp 2 Co][UO 2 Cl( L • )].

How does chemistry contribute to circular economy in nuclear energy systems to make them more sustainable and ecological?

“…10 Summary of redox potentials of uranyl complexes with different ligands in organic solvent systems reported so far. 25,27,63,[69][70][71][72][73][74][75][76][77][78][79][80] This diagram was originally reported in ref. 63, but corrected to fit to this Perspective.…”

Utility of redox-active ligands for reversible multi-electron transfer in uranyl(vi) complexes

“…10, various U VI O 2 2+ complexes in non-aqueous systems are plotted together with their reduction potentials (E°′) and they are classified by whether their electrochemical reduction takes place as a metal-centered (left) or as a ligandcentered (right) event. [43][44][45][46][47][48][49][50][51][52][53][54][55]57,60,80 In the metal-centered reactions, E°′ strongly depends on the variation of the ligands and varies between −0.95 and −1.78 V vs. Fc 0/+ . [43][44][45][46][47][48][49][50][51][52][53][54][55] This potential range largely overlaps with that of the ligand-centered systems which range from −0.79 to −2.02 V. 57,60,80 Both the first and second reductions of [U VI O 2 (Lx)DMSO y ] (x = 1-3; y = 0-1) occur at the ligand side.…”

Pd(ii), Ni(ii), and Cu(ii) complexes of α,α′-ditolylmethanone dipyrroethene

“…They have an NNOO or NNNO coordination core which can stabilize Ni 2+ and Cu 2+ ions in a four or five-coordinate geometry. 20,21…”

“…They have an NNOO or NNNO coordination core which can stabilize Ni 2+ and Cu 2+ ions in a four or five-coordinate geometry. 20,21 Similar to dipyrromethenes, dipyrroethenes are dipyrrolic ligands but contain an extra meso-carbon and are widely used as a starting material for the preparation of porphycenes. 22 Recently, we used a functionalized dipyrroethene such as α,α′-ditolylmethanone dipyrroethene 4 (Fig.…”