Naval Air Warfare Center, Weapons Division, Research Department, Chemistry Division, US Navy, China Lake, California 93555, United States.
Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
J Am Chem Soc. 2023 Apr 26;145(16):8996-9002. doi: 10.1021/jacs.3c00182. Epub 2023 Apr 17.
The recent discovery of metal-metal bonding and valence delocalization in the dilanthanide complexes (Cp)LnI (Cp = pentaisopropylcyclopentadienyl; Ln = Y, Gd, Tb, Dy) opened up the prospect of harnessing the 4f5d electron configurations of non-traditional divalent lanthanide ions to access molecules with novel bonding motifs and magnetism. Here, we report the trinuclear mixed-valence clusters (Cp)LnHI (, Ln = Y, Gd), which were synthesized via potassium graphite reduction of the trivalent clusters (Cp)LnHI. Structural, computational, and spectroscopic analyses support valence delocalization in resulting from a three-center, one-electron σ bond formed from the 4d and 5d orbitals on Y and Gd, respectively. Dc magnetic susceptibility data obtained for reveal that valence delocalization engenders strong parallel alignment of the σ-bonding electron and the 4f electrons of each gadolinium center to afford a high-spin ground state of = 11. Notably, this represents the first clear instance of metal-metal bonding in a molecular trilanthanide complex, and the large spin-spin exchange constant of = 168(1) cm determined for is only the second largest coupling constant characterized to date for a molecular lanthanide compound.
最近在镧系元素配合物（Cp）LnI（Cp=五异丙基环戊二烯基；Ln=Y、Gd、Tb、Dy）中发现了金属-金属键和价电子离域，这为利用非传统二价镧系离子的 4f5d 电子构型来获得具有新型成键模式和磁性的分子开辟了前景。在这里，我们报告了三核混合价簇（Cp）LnHI（，Ln=Y、Gd），它们是通过三价簇（Cp）LnHI 的钾石墨还原合成的。结构、计算和光谱分析支持价电子离域，这是由于 Y 和 Gd 上的 4d 和 5d 轨道形成的三中心、单电子σ键所致。获得的 的直流磁化率数据表明，价电子离域使每个钆中心的σ键电子和 4f 电子平行排列，从而赋予高自旋基态为 = 11。值得注意的是，这代表了分子三镧系元素配合物中金属-金属键的第一个明确实例，并且为 确定的大自旋-自旋交换常数 = 168(1)cm 是目前为止为分子镧系化合物确定的第二大耦合常数。
