Chemical bonding in actinyl(v/vi) dipyriamethyrin complexes for the actinide series from americium to californium: a computational investigation

Abstract

The separation of minor actinides in their dioxocation (i.e., actinyl) form in high-valent oxidation states requires efficient ligands for their complexation. In this work, we evaluate the complexation properties of...

Computational study of core modified dipyriamethyrin for the competitive complexation of Am3+/Cm3+ from their trichlorides

“…This nature of actinide-ligand bonding is in accordance with the previous studies of minor actinyl-dipyriamethyrin complexation. 18 The An-O bonds are longer (by 0.6 Å) than the An-N bonds, owing to the increase in cavity size of the ligand on O substitution as discussed earlier. There is an overall reduction in the cavity size of the ligand on complexation (Table S1 †).…”

“…Members of the expanded porphyrin family, such as isoamethyrin, pentaphyrin, amethyrin and oxysapphyin, have been studied extensively and are promising candidates for the complexation of minor actinides. 18,19 These ligands usually contain pyrrole and pyridine rings in which the Lewis soft nitrogen (N) donor atoms coordinate to the "slightly softer" hard Lewis acceptors i.e., actinides. As Lewis hard donors such as oxygen (O) and sulfur (S) atoms also show high affinity to the generally hard actinides and possess lone pairs of electrons for donation to actinides on coordination, 20 a significant number of actinide complexation studies have been carried out with mixed donor atoms.…”

“…We have previously reported this ligand to exhibit binding efficiency towards actinyls. 18,40 As shown in Scheme 1, the core modified ligands (L2 1− and L3) were generated through chemically feasible and systematic substitution of O atoms in L1 2− , resulting in ligands with varying N : O ratios: 5 : 1 in L2 1− and 4 : 2 in L3. The resulting neutral (n = 0) An chloride complexes ([An(Cl) m Lm] 0 , m = 1, 2, 3, i.e., [An(Cl)L1] 0 , [An(Cl) 2 L2] 0 and [An(Cl) 3 L3] 0 ; An = Am 3+ /Cm 3+ ) were studied.…”

“…Members of the expanded porphyrin family, such as isoamethyrin, pentaphyrin, amethyrin and oxysapphyin, have been studied extensively and are promising candidates for the complexation of minor actinides. 18,19 These ligands usually contain pyrrole and pyridine rings in which the Lewis soft nitrogen (N) donor atoms coordinate to the “slightly softer” hard Lewis acceptors i.e. , actinides.…”

Theoretical insight on Cm(III) and Eu(III) competing with Am(III) for binding to N‐donor extractants with different dentate numbers

“…and r 2 ρ(r c ) > 0, including ionic, electronic, hydrogen and van der Walls interactions [31,32]. ρ(r c ) at BCP directly quantifies charge accumulation in the bonding region to indicate the degree of covalent character and hence measures overlap-driven covalency [32] because charge accumulation between interacting atoms shows the extent of overlap between their interacting orbitals [42]. The Laplacian r 2 ρ(r c ) at the BCP is related to the local electronic kinetic energy density G(r c ) and local electronic potential energy density V(r c ) by the relation r 2 ρ(r c ) = (4m e /ħ 2 )[2G(r c ) + V(r c )], and also equal to the sum of the three principal curvatures λ 1 (<0), λ 2 (<0), and λ 3 (<0) of electron density at the BCP.…”