Expanding Yttrium Bis(trimethylsilylamide)
Chemistry Through the Reaction Chemistry of (N<sub>2</sub>)<sup>2–</sup>, (N<sub>2</sub>)<sup>3–</sup>, and (NO)<sup>2–</sup> Complexes
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Abstract
The reaction chemistry of the side-on bound (N<sub>2</sub>)<sup>2–</sup>, (N<sub>2</sub>)<sup>3–</sup>, and (NO)<sup>2–</sup> complexes of the [(R<sub>2</sub>N)<sub>2</sub>Y]<sup>+</sup> cation (R = SiMe<sub>3</sub>), namely, [(R<sub>2</sub>N)<sub>2</sub>(THF)Y]<sub>2</sub>(<i>μ</i>-η<sup>2</sup>:η<sup>2</sup>-N<sub>2</sub>), <b>1</b>, [(R<sub>2</sub>N)<sub>2</sub>(THF)Y]<sub>2</sub>(<i>μ</i>-η<sup>2</sup>:η<sup>2</sup>-N<sub>2</sub>)K, <b>2</b>, and
[(R<sub>2</sub>N)<sub>2</sub>(THF)Y]<sub>2</sub>(<i>μ</i>-η<sup>2</sup>:η<sup>2</sup>-NO), <b>3</b>, with
oxidizing agents has been explored to search for other (E<sub>2</sub>)<sup><i>n</i>−</sup>, (E = N, O), species that
can be stabilized by this cation. This has led to the first examples
for the [(R<sub>2</sub>N)<sub>2</sub>Y]<sup>+</sup> cation of two
fundamental classes of [(monoanion)<sub>2</sub>Ln]<sup>+</sup> 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 (N<sub>2</sub>)<sup>2–</sup>, (NO)<sup>2–</sup>,
(O<sub>2</sub>)<sup>2–</sup> series with <b>1</b> and <b>3</b>. Specifically, the (<i><i>μ</i>-</i>O)<sup>2–</sup> oxide-bridged bimetallic complex, [(R<sub>2</sub>N)<sub>2</sub>(THF)Y}<sub>2</sub>(<i><i>μ</i>-</i>O), <b>4</b>, is obtained as a byproduct from reactions
of either the (N<sub>2</sub>)<sup>2–</sup> complex, <b>1</b>, or the (N<sub>2</sub>)<sup>3–</sup> complex, <b>2</b>, with NO, while the oxide formed from <b>2</b> with N<sub>2</sub>O is a polymeric species incorporating potassium, {[(R<sub>2</sub>N)<sub>2</sub>Y]<sub>2</sub>(<i><i>μ</i>-</i>O)<sub>2</sub>K<sub>2</sub>(<i><i>μ</i>-</i>C<sub>7</sub>H<sub>8</sub>)}<sub><i>n</i></sub>, <b>5</b>. Reaction of <b>1</b> with 1 atm of O<sub>2</sub> generates the (O<sub>2</sub>)<sup>2–</sup> bridging
side-on peroxide [(R<sub>2</sub>N)<sub>2</sub>(THF)Y]<sub>2</sub>(<i>μ</i>-η<sup>2</sup>:η<sup>2</sup>-O<sub>2</sub>), <b>6</b>. The O–O bond in <b>6</b> is cleaved
by KC<sub>8</sub> to provide an alternative synthetic route to <b>5</b>. Attempts to oxidize the (NO)<sup>2–</sup> complex, <b>3</b>, with AgBPh<sub>4</sub> led to the isolation of the tetraphenylborate
complex, [(R<sub>2</sub>N)<sub>2</sub>Y(THF)<sub>3</sub>][BPh<sub>4</sub>], <b>7</b>, that was also synthesized from <b>1</b> and AgBPh<sub>4</sub>. Oxidation of the (N<sub>2</sub>)<sup>2–</sup> complex, <b>1</b>, with the radical trap (2,2,6,6-tetramethylpiperidin-1-yl)oxyl,
TEMPO, generates the (TEMPO)<sup>−</sup> anion complex, (R<sub>2</sub>N)<sub>2</sub>(THF)Y(η<sup>2</sup>-ONC<sub>5</sub>H<sub>6</sub>Me<sub>4</sub>), <b>8</b>