The synthesis of lanthanides other than cerium in the oxidation state +IV has remained a desirable but unmet target until recently, when two examples of TbIV with saturated coordination spheres were isolated. Here we report the third example of an isolated molecular complex of terbium(IV), where the supporting siloxide ligands do not saturate the coordination sphere. The fully characterized six-coordinate complex [TbIV (OSiPh3 )4 (MeCN)2 ], 2-TbPh , shows high stability and the labile MeCN ligands can be replaced by phosphinoxide ligands. Computational studies suggest that the stability is due to a strong π(O-Tb) interaction which is stronger than in the previously reported TbIV complexes. Cyclic-voltammetry experiments demonstrate that non-binding counterions contribute to the stability of TbIV in solution by destabilizing the +III oxidation state, while alkali ions promote TbIV /TbIII electron transfer.

中文翻译：

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氧化硅负载Ter化合物中氧化态+ IV的稳定化。

直到最近，当分离出两个带有饱和配位球的TbIV的例子时，氧化态+ IV的铈以外的镧系元素的合成一直是理想的目标，但尚未得到满足。在这里，我们报告isolated（IV）分离的分子复合物的第三个例子，其中支持的氧化硅配体不饱和配位球。具有完整特征的六配位配合物[TbIV（OSiPh3）4（MeCN）2] 2-TbPh具有高稳定性，并且不稳定的MeCN配体可被次膦氧化物配体取代。计算研究表明，稳定性是由于强大的π（O-Tb）相互作用所致，该相互作用比以前报道的TbIV配合物更强。