Studies of the complex formation of technetium(IV) with aminopolycarboxylic acids in aqueous solution

Multinuclear NMR spectroscopy of the tetrahedral uranium(IV) complex tetrakis(trihydromethylborato)uranium

“…The optical spectra,2 paramagnetic susceptibility, and EPR spectra of uranium and neptunium tetraborohydrides have recently been analyzed in terms of a parametrized Hamiltonian, with the full Sf^iSf3) basis. 3 Within this basis, optical and magnetic properties could not be satisfactorily explained by the same set of Hamiltonian parameters without the introduction of orbital reduction factors. Furthermore, it was shown that J mixing by the crystal field in these compounds cannot be neglected.…”

A Combined Study of Tc Redox Speciation in Complex Aqueous Systems: Wet-Chemistry, Tc K-/L3-Edge X-ray Absorption Fine Structure, and Ab Initio Calculations

“…The stability of Tc­(VI) and Tc­(V) is remarkably different in nonaqueous solvents or in the presence of specific coordinating ligands, for which a variety of complexes and solid compounds are reported in the literature. − Indeed, gluconate complexes of Tc­(V) are used as precursors of new Tc complexes by ligand exchange. ,, Tc­(III) is stabilized in acidic reducing conditions, , with mixed Tc­(III,IV) soluble species being reported in very acidic sulfate and chloride solutions. , Due to the relatively high electron density provided by the d 4 configuration of Tc­(III), ligands with back donation capabilities are also reported to stabilize this oxidation state: carbonyl, thiourea, and aminopolycarboxylates (EDTA, NTA, etc. ), among others. ,, Rard and co-workers concluded that there is no experimental evidence for the existence of thermodynamically stable Tc­(II) in aqueous solution . However, this elusive oxidation state in the aqueous phase can be stabilized in organic solvents in the presence of ligands with sulfur, halogen, and nitrogen donor atoms. ,− Several nitrosyl and thionitrosyl complexes of Tc­(II) are also reported in the literature.…”

“…), among others. 24,30,31 Rard and co-workers concluded that there is no experimental evidence for the existence of thermodynamically stable Tc(II) in aqueous solution. 10 However, this elusive oxidation state in the aqueous phase can be stabilized in organic solvents in the presence of ligands with sulfur, halogen, and nitrogen donor atoms.…”