Cocrystallization of (μ‑S₂)^2– and (μ-S)^2– and Formation of an [η²‑S₃N(SiMe₃)₂] Ligand from Chalcogen Reduction by (N₂)^2– in a Bimetallic Yttrium Amide Complex

The reactivity of the (N2)2– complex {[(Me3Si)2N]2Y­(THF)}2(μ-η2:η2-N2) (1) with sulfur and selenium has been studied to explore the special reductive chemistry of this complex and to expand the variety of bimetallic rare-earth amide complexes. Complex 1 reacts with elemental sulfur to form a mixture of compounds, 2, that is the first example of cocrystallized complexes of (S2)2– and S2– ligands. The crystals of 2 contain both the (μ-S2)2– complex {[(Me3Si)2N]2Y­(THF)}2(μ-η2:η2-S2) (3) and the (μ-S)2– complex {[(Me3Si)2N]2Y­(THF)}2(μ-S) (4), respectively. Modeling of the crystal data of 2 shows a 9:1 ratio of 3:4 in the crystals of 2 obtained from solutions that have 1:1 to 4:1 ratios of 3/4 by 1H NMR spectroscopy. The addition of KC8 to samples of 2 allows for the isolation of single crystals of 4. The [S3N­(SiMe3)2]− ligand was isolated for the first time in crystals of [(Me3Si)2N]2Y­[η2-S3N­(SiMe3)2]­(THF) (5), obtained from the mother liquor of 2. In contrast to the sulfur chemistry, the (μ-Se2)2– analogue of 3, namely, {[(Me3Si)2N]2Y­(THF)}2(μ-η2:η2-Se2) (6), can be cleanly synthesized in good yield by reacting 1, with elemental selenium. The (μ-Se)2– analogue of 4, namely, {[(Me3Si)2N]2Y­(THF)}2(μ-Se) (7), was synthesized from Ph3PSe.本研究针对双核二氮根二阴离子(μ-η²:η²-N₂)²⁻配合物{[(三甲基硅基(Me₃Si))₂N]₂Y(四氢呋喃(THF))}₂（编号1）与硫、硒的反应活性展开探究，旨在揭示该配合物的特殊还原化学特性，并拓展双金属稀土酰胺配合物的种类。配合物1与单质硫反应，生成化合物混合物2，这是首例共结晶获得的二硫根二阴离子(S₂)²⁻与硫离子(S²⁻)配体的配合物体系。2的晶体中同时分别包含桥联二硫根二阴离子(μ-S₂)²⁻配合物{[(Me₃Si)₂N]₂Y(THF)}₂(μ-η²:η²-S₂)（编号3）以及桥联硫配体(μ-S)²⁻配合物{[(Me₃Si)₂N]₂Y(THF)}₂(μ-S)（编号4）。通过¹H核磁共振波谱(¹H NMR spectroscopy)表征，对应反应溶液中3与4的摩尔比介于1:1至4:1之间；而对2的晶体数据进行结构解析后发现，所获晶体中3与4的摩尔比为9:1。向2的样品中加入石墨插层钾(KC₈)，可分离得到4的单晶。从2的母液中获得的配合物{[(Me₃Si)₂N]₂Y[η²-S₃N(SiMe₃)₂](THF)}（编号5）的晶体中，首次分离得到了[S₃N(SiMe₃)₂]⁻配体。与硫的反应体系不同，配合物3的二硒根二阴离子(μ-Se₂)²⁻类似物，即{[(Me₃Si)₂N]₂Y(THF)}₂(μ-η²:η²-Se₂)（编号6），可通过1与单质硒反应，以优异收率实现高纯度合成。配合物4的桥联硒配体(μ-Se)²⁻类似物{[(Me₃Si)₂N]₂Y(THF)}₂(μ-Se)（编号7），可由三苯基膦硒化物(Ph₃PSe)制备得到。