Thomas E. Albrecht-Schönzart, Florida State University, Tallahassee, USA, and colleagues have synthesized and studied the sixth berkelium compound for which a single crystal structure has been solved. The team reacted freshly-prepared Bk(NO3)3·n H2O with 4′-(4-nitrophenyl)-2,2′:6′,”-terpyridine (terpy*) in tetrahydrofuran (THF). They obtained Bk(terpy*)(NO3)3(H2O)·THF in the form of golden columns.
The large polarizability of the ligand leads to enhanced Bk–N interactions with terpy*. Surprisingly, the induced polarization by terpy* creates a plane in which the M–L bonds trans to terpy* are shorter than expected. The 6p orbitals are normally considered to be core orbitals that are not involved in bonding. Here, they are involved in covalent interactions with the water molecule in the complex. The team also synthesized the analogous complex Ce(terpy*)(NO3)3(H2O)·THF, which shows a similar planar structure involving the terpy* ligand and the bound water molecule.
According to the researchers, it might be possible to develop tailored ligands with fine-tuned polarization properties. This could be useful, e.g., to target specific metals during the recycling of radioactive waste and selectively extract certain elements.
- Creation of an unexpected plane of enhanced covalency in cerium(III) and berkelium(III) terpyridyl complexes,
Alyssa N. Gaiser, Cristian Celis-Barros, Frankie D. White, Maria J. Beltran-Leiva, Joseph M. Sperling, Sahan R. Salpage, Todd N. Poe, Daniela Gomez Martinez, Tian Jian, Nikki J. Wolford, Nathaniel J. Jones, Amanda J. Ritz, Robert A. Lazenby, John K. Gibson, Ryan E. Baumbach, Dayán Páez-Hernández, Michael L. Neidig, Thomas E. Albrecht-Schönzart,
Nat. Commun. 2021.