Expanding Yttrium Bis(trimethylsilylamide) Chemistry Through the Reaction Chemistry of (N₂)^2–, (N₂)^3–, and (NO)^2– Complexes

The reaction chemistry of the side-on bound (N₂)^2–, (N₂)^3–, and (NO)^2– complexes of the [(R₂N)₂Y]⁺ cation (R = SiMe₃), namely, [(R₂N)₂(THF)­Y]₂(<i>μ</i>-η²:η²-N₂), <b>1</b>, [(R₂N)₂(THF)­Y]₂(<i>μ</i>-η²:η²-N₂)­K, <b>2</b>, and [(R₂N)₂(THF)­Y]₂(<i>μ</i>-η²:η²-NO), <b>3</b>, with oxidizing agents has been explored to search for other (E₂)^<i>n</i>−, (E = N, O), species that can be stabilized by this cation. This has led to the first examples for the [(R₂N)₂Y]⁺ cation of two fundamental classes of [(monoanion)₂Ln]⁺ rare earth systems (Ln = Sc, Y, lanthanides), namely, oxide complexes and the tetraphenylborate salt. In addition, an unusually high yield reaction with dioxygen was found to give a peroxide complex that completes the (N₂)^2–, (NO)^2–, (O₂)^2– series with <b>1</b> and <b>3</b>. Specifically, the (<i><i>μ</i>-</i>O)^2– oxide-bridged bimetallic complex, [(R₂N)₂(THF)­Y}₂(<i><i>μ</i>-</i>O), <b>4</b>, is obtained as a byproduct from reactions of either the (N₂)^2– complex, <b>1</b>, or the (N₂)^3– complex, <b>2</b>, with NO, while the oxide formed from <b>2</b> with N₂O is a polymeric species incorporating potassium, {[(R₂N)₂Y]₂(<i><i>μ</i>-</i>O)₂K₂(<i><i>μ</i>-</i>C₇H₈)}_<i>n</i>, <b>5</b>. Reaction of <b>1</b> with 1 atm of O₂ generates the (O₂)^2– bridging side-on peroxide [(R₂N)₂(THF)­Y]₂(<i>μ</i>-η²:η²-O₂), <b>6</b>. The O–O bond in <b>6</b> is cleaved by KC₈ to provide an alternative synthetic route to <b>5</b>. Attempts to oxidize the (NO)^2– complex, <b>3</b>, with AgBPh₄ led to the isolation of the tetraphenylborate complex, [(R₂N)₂Y­(THF)₃]­[BPh₄], <b>7</b>, that was also synthesized from <b>1</b> and AgBPh₄. Oxidation of the (N₂)^2– complex, <b>1</b>, with the radical trap (2,2,6,6-tetramethylpiperidin-1-yl)­oxyl, TEMPO, generates the (TEMPO)⁻ anion complex, (R₂N)₂(THF)­Y­(η²-ONC₅H₆Me₄), <b>8