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 (N-2)(2-) complex {[(Me3Si)(2)N](2)Y(THF)}(2)(mu-eta(2):eta(2)-N-2) (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 (S-2)(2-) and S2- ligands. The crystals of 2 contain both the (mu-S-2)(2-) complex {[(Me3Si)(2)N](2)Y(THF)}(2)(mu-eta(2):eta(2)-S-2) (3) and the (mu-S)(2-) complex {[(Me3Si)(2)N](2)Y(THF)}(2)(mu-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 H-1 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)(2)N](2)Y[eta(2)-S3N(SiMe3)(2)](THF) (5), obtained from the mother liquor of 2. In contrast to the sulfur chemistry, the (mu-Se-2)(2-) analogue of 3, namely, {[(Me3Si)(2)N](2)Y(THF)}(2)(mu-eta(2):eta(2)-Se-2) (6), can be cleanly synthesized in good yield by reacting 1, with elemental selenium. The (mu-Se)(2-) analogue of 4, namely, {[(Me3Si)(2)N](2)Y(THF)}(2)(mu-Se) (7), was synthesized from Ph3PSe.