TY - JOUR
T1 - Isolation of a californium(II) crown–ether complex
AU - Poe, Todd N.
AU - Ramanantoanina, Harry
AU - Sperling, Joseph M.
AU - Wineinger, Hannah B.
AU - Rotermund, Brian M.
AU - Brannon, Jacob
AU - Bai, Zhuanling
AU - Scheibe, Benjamin
AU - Beck, Nicholas
AU - Long, Brian N.
AU - Justiniano, Samantha
AU - Albrecht-Schönzart, Thomas E.
AU - Celis-Barros, Cristian
N1 - Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2023/5
Y1 - 2023/5
N2 - The actinides, from californium to nobelium (Z = 98–102), are known to have an accessible +2 oxidation state. Understanding the origin of this chemical behaviour requires characterizing CfII materials, but investigations are hampered by the fact that they have remained difficult to isolate. This partly arises from the intrinsic challenges of manipulating this unstable element, as well as a lack of suitable reductants that do not reduce CfIII to Cf°. Here we show that a CfII crown–ether complex, Cf(18-crown-6)I2, can be prepared using an Al/Hg amalgam as a reductant. Spectroscopic evidence shows that CfIII can be quantitatively reduced to CfII, and rapid radiolytic re-oxidation in solution yields co-crystallized mixtures of CfII and CfIII complexes without the Al/Hg amalgam. Quantum-chemical calculations show that the Cf‒ligand interactions are highly ionic and that 5f/6d mixing is absent, resulting in weak 5f→5f transitions and an absorption spectrum dominated by 5f→6d transitions. [Figure not available: see fulltext.]
AB - The actinides, from californium to nobelium (Z = 98–102), are known to have an accessible +2 oxidation state. Understanding the origin of this chemical behaviour requires characterizing CfII materials, but investigations are hampered by the fact that they have remained difficult to isolate. This partly arises from the intrinsic challenges of manipulating this unstable element, as well as a lack of suitable reductants that do not reduce CfIII to Cf°. Here we show that a CfII crown–ether complex, Cf(18-crown-6)I2, can be prepared using an Al/Hg amalgam as a reductant. Spectroscopic evidence shows that CfIII can be quantitatively reduced to CfII, and rapid radiolytic re-oxidation in solution yields co-crystallized mixtures of CfII and CfIII complexes without the Al/Hg amalgam. Quantum-chemical calculations show that the Cf‒ligand interactions are highly ionic and that 5f/6d mixing is absent, resulting in weak 5f→5f transitions and an absorption spectrum dominated by 5f→6d transitions. [Figure not available: see fulltext.]
UR - http://www.scopus.com/inward/record.url?scp=85150953405&partnerID=8YFLogxK
U2 - 10.1038/s41557-023-01170-9
DO - 10.1038/s41557-023-01170-9
M3 - Article
AN - SCOPUS:85150953405
SN - 1755-4330
VL - 15
SP - 722
EP - 728
JO - Nature Chemistry
JF - Nature Chemistry
IS - 5
ER -