A Redox-Non-Innocent Catecholate Shifts the Oxidation State Break in the Actinides
6 affiliations
- 1Department of Chemistry
- 2University of California, Berkeley
- 3Chemical Sciences Division
- 4Lawrence Berkeley National Laboratory
- 5Theoretical Division
- 6Los Alamos National Laboratory
Abstract
Realizing the full potential of actinide-based systems requires strategies to differentiate elements whose similar chemical properties complicate their selective use. Redox-active ligands offer a promising approach: their ability to participate in electron transfer provides a means to tune the oxidation states and electronic structures of both lanthanides and actinides. To explore this approach, we conducted a theory-guided study of (Tp*)2An(dtbsq) complexes (1-An; An = U, Np, Pu, Am, Bk; Tp* = [HB(C3N2Me2H)3]-; dtbsq•− = [C6O2 tBu2H2]-), which contain a redox-active semiquinone ligand. This study reveals a shift in the preferred actinide oxidation state from An(IV) to An(III) between the chemically similar elements Np and Pu. Such an effect is made possible due to differential stabilization of oxidation states by the ligated redox-active ligand. Structural and spectroscopic data are consistent with this trend, as exemplified by the experimentally characterized complexes 2-U ([(Tp*)(Bp*)UIV 2(dtbc)3], Bp* = [H2B(C3N2Me2H)2]-, dtbc = [C6O2 tBu2H2]2-) and 1-Pu [(Tp*)2PuIII(dtbsq)]. In these systems, the radical ligand is reduced to a catecholate only in the presence of UIII but it remains in its radical form with PuIII. Electronicstructure calculations for (Tp*)2An(dtbsq) (An = U, Np, Pu, Am, Bk) reveal tunable AnIII/IV oxidation states—supported by highly multiconfigurational ground states—and oxidation-statedependent covalency. This study advances our fundamental understanding of actinide bonding and highlights oxidation-state control as a promising strategy for tuning reactivity and selectivity across f-block chemistry.
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BibTeX
@misc{fiszbein2026redoxnoninnocent,
title = {{A Redox-Non-Innocent Catecholate Shifts the Oxidation State Break in the Actinides}},
author = {David J. Fiszbein and Maria J. Beltran-Leiva and Mikaela M. Pyrch and Enrique R. Batista and Polly L. Arnold and Ping Yang},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010136/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010136/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A Redox-Non-Innocent Catecholate Shifts the Oxidation State Break in the Actinides
AU - David J. Fiszbein
AU - Maria J. Beltran-Leiva
AU - Mikaela M. Pyrch
AU - Enrique R. Batista
AU - Polly L. Arnold
AU - Ping Yang
PY - 2026
DA - 2026/10/09
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010136/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010136/v1
AB - Realizing the full potential of actinide-based systems requires strategies to differentiate elements whose similar chemical properties complicate their selective use. Redox-active ligands offer a promising approach: their ability to participate in electron transfer provides a means to tune the oxidation states and electronic structures of both lanthanides and actinides. To explore this approach, we conducted a theory-guided study of (Tp*)2An(dtbsq) complexes (1-An; An = U, Np, Pu, Am, Bk; Tp* = [HB(C3N2Me2H)3]-; dtbsq•− = [C6O2 tBu2H2]-), which contain a redox-active semiquinone ligand. This study reveals a shift in the preferred actinide oxidation state from An(IV) to An(III) between the chemically similar elements Np and Pu. Such an effect is made possible due to differential stabilization of oxidation states by the ligated redox-active ligand. Structural and spectroscopic data are consistent with this trend, as exemplified by the experimentally characterized complexes 2-U ([(Tp*)(Bp*)UIV 2(dtbc)3], Bp* = [H2B(C3N2Me2H)2]-, dtbc = [C6O2 tBu2H2]2-) and 1-Pu [(Tp*)2PuIII(dtbsq)]. In these systems, the radical ligand is reduced to a catecholate only in the presence of UIII but it remains in its radical form with PuIII. Electronicstructure calculations for (Tp*)2An(dtbsq) (An = U, Np, Pu, Am, Bk) reveal tunable AnIII/IV oxidation states—supported by highly multiconfigurational ground states—and oxidation-statedependent covalency. This study advances our fundamental understanding of actinide bonding and highlights oxidation-state control as a promising strategy for tuning reactivity and selectivity across f-block chemistry.
ER -