Temperature dependence of 1 H paramagnetic chemical shifts in actinide complexes, beyond Bleaneyâs theory: The AnVIO22+ â Dipicolinic Acid Complexes (An = Np, Pu) as an example.
Actinide +VI complexes (AnVI = UVI, NpVI and PuVI) with dipicolinic acid derivatives were synthesized and characterized by powder XRD, SQUID magnetometry and NMR spectroscopy. In addition, NpVI and PuVI complexes were described by first principles CAS based and two-component spin-restricted DFT methods. The analysis of the 1H paramag-netic NMR chemical shifts for all protons of the ligands according to the X-rays structures shows that the Fermi contact contribution is negligible. The magnetic susceptibility tensor is determined by combining SQUID, pNMR shifts and Evansâ method. The SO-RASPT2 results fit well the experimental magnetic susceptibility and pNMR chemical shifts. The role of the counterions in the solid phase is pointed out; their presence impacts the magnetic properties of the NpVI complex. The temperature dependence of the pNMR chemical shifts has a strong 1đâ contribution, contrarily to Bleaneyâs theory for lanthanide complexes. The fitting of the temperature dependence of the pNMR chemical shifts and SQUID magnetic susceptibility by a two-Kramers-doublet model for the NpVI complex and a non-Kramers-doublet model for the PuVI complex allows for the experimental evaluation of energy gaps and magnetic moments of the paramagnetic center.
AUTILLO Mathieu;
MD. ASHRAFUL Islam;
HĂRON Julie;
GUĂRIN Laeticia;
ACHER Eleonor;
TAMAIN Christelle;
ILLY Marie-Claire;
MOISY Philippe;
COLINEAU Eric;
GRIVEAU Jean-Christophe;
BERTHON Claude;
BOLVIN HĂ©lĂšne;
2021-11-03
WILEY-V C H VERLAG GMBH
JRC123739
0947-6539 (online),
https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10.1002/chem.202005147,
https://publications.jrc.ec.europa.eu/repository/handle/JRC123739,
10.1002/chem.202005147 (online),
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