Isolation and characterization of a californium metallocene

Conrad A P Goodwin; Jing Su; Lauren M Stevens; Frankie D White; Nickolas H Anderson; John D Auxier 2nd; Thomas E Albrecht-Schönzart; Enrique R Batista; Sasha F Briscoe; Justin N Cross; William J Evans; Alyssa N Gaiser; Andrew J Gaunt; Michael R James; Michael T Janicke; Tener F Jenkins; Zachary R Jones; Stosh A Kozimor; Brian L Scott; Joseph M Sperling; Justin C Wedal; Cory J Windorff; Ping Yang; Joseph W Ziller

doi:10.1038/s41586-021-04027-8

Isolation and characterization of a californium metallocene

Nature. 2021 Nov;599(7885):421-424. doi: 10.1038/s41586-021-04027-8. Epub 2021 Nov 17.

Authors

Conrad A P Goodwin^#¹, Jing Su^#^{2

3}, Lauren M Stevens¹, Frankie D White¹, Nickolas H Anderson¹, John D Auxier 2nd¹, Thomas E Albrecht-Schönzart⁴, Enrique R Batista⁵, Sasha F Briscoe⁶, Justin N Cross¹, William J Evans⁷, Alyssa N Gaiser⁴, Andrew J Gaunt⁸, Michael R James¹, Michael T Janicke¹, Tener F Jenkins⁹, Zachary R Jones¹, Stosh A Kozimor¹⁰, Brian L Scott¹¹, Joseph M Sperling⁴, Justin C Wedal⁹, Cory J Windorff⁴, Ping Yang¹², Joseph W Ziller⁹

Affiliations

¹ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
² Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
³ College of Chemistry, Sichuan University, Chengdu, China.
⁴ Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA.
⁵ Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA. [email protected].
⁶ Radiation Protection Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
⁷ Department of Chemistry, University of California, Irvine, CA, USA. [email protected].
⁸ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA. [email protected].
⁹ Department of Chemistry, University of California, Irvine, CA, USA.
¹⁰ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA. [email protected].
¹¹ Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
¹² Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA. [email protected].

^# Contributed equally.

PMID: 34789902
DOI: 10.1038/s41586-021-04027-8

Abstract

Californium (Cf) is currently the heaviest element accessible above microgram quantities. Cf isotopes impose severe experimental challenges due to their scarcity and radiological hazards. Consequently, chemical secrets ranging from the accessibility of 5f/6d valence orbitals to engage in bonding, the role of spin-orbit coupling in electronic structure, and reactivity patterns compared to other f elements, remain locked. Organometallic molecules were foundational in elucidating periodicity and bonding trends across the periodic table^1-3, with a twenty-first-century renaissance of organometallic thorium (Th) through plutonium (Pu) chemistry^4-12, and to a smaller extent americium (Am)¹³, transforming chemical understanding. Yet, analogous curium (Cm) to Cf chemistry has lain dormant since the 1970s. Here, we revive air-/moisture-sensitive Cf chemistry through the synthesis and characterization of [Cf(C₅Me₄H)₂Cl₂K(OEt₂)]_n from two milligrams of ²⁴⁹Cf. This bent metallocene motif, not previously structurally authenticated beyond uranium (U)^14,15, contains the first crystallographically characterized Cf-C bond. Analysis suggests the Cf-C bond is largely ionic with a small covalent contribution. Lowered Cf 5f orbital energy versus dysprosium (Dy) 4f in the colourless, isoelectronic and isostructural [Dy(C₅Me₄H)₂Cl₂K(OEt₂)]_n results in an orange Cf compound, contrasting with the light-green colour typically associated with Cf compounds^16-22.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.