新たな酸化状態を持つ希土類元素を発見（Georgia Tech Researchers Make an Elemental Discovery）

2025-06-24 ジョージア工科大学（Georgia Tech）

＜関連情報＞

• https://research.gatech.edu/georgia-tech-researchers-make-elemental-discovery
• https://www.nature.com/articles/s41557-025-01797-w

プラセオジムの正式な+5酸化状態 Praseodymium in the formal +5 oxidation state

Andrew C. Boggiano,Chad M. Studvick,Sabyasachi Roy Chowdhury,Julie E. Niklas,Haruko Tateyama,Hongwei Wu,Johannes E. Leisen,Florian Kleemiss,Bess Vlaisavljevich,Ivan A. Popov & Henry S. La Pierre
Nature Chemistry  Published:07 April 2025
DOI:https://doi.org/10.1038/s41557-025-01797-w

Abstract

Praseodymium in the +5 oxidation state is a long-sought connection between lanthanide, early-transition and actinide metal redox chemistries. Unique among the lanthanide series, evidence for molecular pentavalent praseodymium species has been observed in the gas phase and noble gas matrix isolation conditions. Here we report the low-temperature synthesis and characterization of a molecular praseodymium complex in the formal +5 oxidation state, [Pr⁵⁺(NP^tBu₃)₄][X⁻] (where ^tBu = tert-butyl and X⁻ = tetrakis(pentafluorophenyl)borate or hexafluorophosphate). Single-crystal X-ray diffraction, solution-state spectroscopic, solution magnetometric, density functional theory and multireference wavefunction-based methods indicate a highly multiconfigurational singlet ground state. An inverted ligand field drives this unique electronic structure, which establishes a critical link in understanding the bonding of high-valent metal complexes across the periodic table.