Early-Lanthanide(III) Acetonitrile–Solvento Adducts with Iodide and Noncoordinating Anions

Dissolution of LnI3 (Ln = La, Ce) in acetonitrile (MeCN) results in the highly soluble solvates LnI3(MeCN)5 [Ln = La (1), Ce (2)] in good yield. The ionic complex [La­(MeCN)9]­[LaI6] (4), containing a rare homoleptic La3+ cation and anion, was also isolated as a minor product. Extending this chemistry to NdI3 results in the consistent formation of the complex ionic structure [Nd­(MeCN)9]2[NdI5(MeCN)]­[NdI6]­[I] (3), which contains an unprecedented pentaiodide lanthanoid anion. Also described is the synthesis, isolation, and structural characterization of several homoleptic early-lanthanide MeCN solvates with noncoordinating anions, namely, [Ln­(MeCN)9]­[AlCl4]3 [Ln = La (5), Ce (6), Nd (7)]. Notably, complex 6 is the first homoleptic cerium MeCN solvate reported to date. All reported complexes were structurally characterized by X-ray crystallography, as well as by IR spectroscopy and CHN elemental analysis. Complexes 1–3 were also characterized by thermogravimetric analysis coupled with mass spectrometry to further elucidate their bulk composition in the solid-state.将三碘化镧系元素（LnI₃，Ln=镧La、铈Ce）溶解于乙腈（acetonitrile，缩写MeCN）中，可高产率获得高可溶性的溶剂化配合物LnI₃(MeCN)₅[Ln=La(1)、Ce(2)]。离子型配合物[La(MeCN)₉][LaI₆](4)——其包含罕见的均配型La³+阳离子与阴离子——也作为次要产物被分离得到。将该化学合成体系拓展至三碘化钕（NdI₃）时，可稳定得到具有复杂离子结构的配合物[Nd(MeCN)₉]₂[NdI₅(MeCN)][NdI₆][I](3)，其中包含前所未有的五碘合镧系阴离子。本文还报道了数种含非配位阴离子的早期镧系乙腈均配溶剂化配合物的合成、分离与结构表征，即[Ln(MeCN)₉][AlCl₄]₃[Ln=La(5)、Ce(6)、Nd(7)]。值得注意的是，配合物6是迄今为止首例被报道的均配型铈乙腈溶剂化配合物。所有报道的配合物均通过X射线晶体学（X-ray crystallography）、红外光谱（Infrared Spectroscopy）以及CHN元素分析（CHN elemental analysis）完成了结构表征。配合物1~3还通过热重分析-质谱联用（thermogravimetric analysis coupled with mass spectrometry）技术进一步阐明了其固态本体组成。