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.