The dominant form of elemental nitrogen on Earth is dinitrogen, but elemental phosphorus is found predominantly as white phosphorus or other singly bonded allotropes. Thus, there is interest in studying diphosphorus derivatives, most notably trapping between metal ions affording diphosphorus in +2, +1⋅, 0, 1−⋅, 2−, and 4− charge states. However, the diphosphorus radical trianion form had previously remained elusive due to the instability of main-group diatomics with large, odd negative charges. Here, we disclose a crystalline diuranium diphosphorus radical trianion complex with strong antiferromagnetic uranium-phosphorus magnetic exchange coupling parameters of up to −731 cm⁻¹. This value is over five times greater than that of lanthanide analogues and is comparable to or exceeds d-block metal-metal and metal-ligand exchange couplings, despite being based on a 5f metal, which is typically regarded as possessing contracted valence orbitals compared with d-block ions. This highlights exchange-coupled f-element-p-block radical bridged character that can be engendered in molecular magnetism.

中文翻译：

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结晶二磷自由基三阴离子锕系元素配合物中的强铀磷反铁磁交换偶联物


地球上元素氮的主要形式是二氮，但元素磷主要以白磷或其他单键同素异形体的形式存在。因此，人们有兴趣研究二磷衍生物，最显着的是捕获在 +2、+1⋅、0、1-⋅、2-和 4-电荷态的二磷金属离子之间。然而，由于具有大而奇数负电荷的主族硅藻的不稳定性，二磷自由基三阴离子形式以前仍然难以捉摸。在这里，我们揭示了一种结晶二铀二磷自由基三阴离子络合物，具有高达 -731 ^cm-1 的强反铁磁铀-磷磁交换耦合参数。该值比镧系元素类似物大五倍以上，与 d 区金属-金属和金属-配体交换偶联相当或超过，尽管它基于 5f 金属，与 d 区离子相比，它通常被认为具有收缩的价轨道。这突出了分子磁性中可以产生的交换耦合 f-element-p-block 自由基桥接特性。