Maltsev Dmitry S, Driscoll Darren M, Zhang Yuanpeng, Neuefeind Joerg C, Reinhart Benjamin, Agca Can, Ray Debmalya, Halstenberg Phillip W, Aziziha Mina, Schorne-Pinto Juliano, Besmann Theodore M, Bryantsev Vyacheslav S, Dai Sheng, Roy Santanu, Ivanov Alexander S
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States.
J Am Chem Soc. 2024 Aug 7;146(31):21220-21224. doi: 10.1021/jacs.4c05765. Epub 2024 Jul 23.
Uranium is arguably the most essential element in the actinide series, serving as a crucial component of nuclear fuels. While U is recognized for engaging the 5 orbitals in chemical bonds under normal conditions, little is known about its coordination chemistry and the nature of bonding interactions at extreme conditions of high temperature. Here we report experimental and computational evidence for the shrinkage of the average U-ligand distance in UCl upon the solid-to-molten phase transition, leading to the formation of a significant fraction of short, transient U-Cl bonds with the enhanced involvement of U 5 valence orbitals. These findings reveal that extreme temperatures create an unusual heterogeneous bonding environment around U(III) with distinct inner- and outer-coordination subshells.
铀可以说是锕系元素中最重要的元素，是核燃料的关键组成部分。虽然人们认识到在正常条件下铀会在化学键中参与5个轨道，但对于其配位化学以及在高温极端条件下键合相互作用的本质却知之甚少。在此，我们报告了实验和计算证据，表明在UCl从固态到熔融态的相变过程中，平均U-配体距离会收缩，导致形成了相当一部分短的、瞬态的U-Cl键，且U的5个价轨道的参与度增强。这些发现揭示，极端温度会在U(III)周围创造一个不寻常的异质键合环境，其中存在不同的内配位和外配位子壳层。
