Theoretical Study of Complexes of Tetravalent Actinides with DOTA

1,4,7,10-Tetraazacyclododecane-N,N′,N″,N′″-tetraacetic acid (H4DOTA) is a prominent chelating ligand with potential application in various field from radiotherapy to separation of fission products. The present study explores the stability, structure and bonding properties of its complexes with tetravalent actinides (Th, U, Np, Pu) using density functional theory and relativistic multireference calculations. The neutral complexes prefer to form symmetric (C4) structures with DOTA. The first coordination sphere of the actinide ions is readily saturated by a weakly-bonded H2O ligand. The latter ligand reduces the molecular symmetry while exerts only marginal effects on the properties of the mother complex. The An-ligand bonding is mainly electrostatic, but there are also significant charge transfer contributions from DOTA to the An 6d/5f orbitals. The charge transfer interactions and the covalent character of bonding increase gradually in the order Th < U < Np < Pu as indicated by analysis of the electron density distribution using Quantum Theory of Atoms in Molecules.

KOVACS Attila; 

2022-11-22

MDPI

JRC131068

2073-8994 (online),   

https://www.mdpi.com/jornal/symmetry,    https://publications.jrc.ec.europa.eu/repository/handle/JRC131068,   

10.3390/sym14112451 (online),