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(μ-η2:η2-N2), 1, [(R2N)2(THF)­Y]2(μ-η2:η2-N2)­K, 2, and [(R2N)2(THF)­Y]2(μ-η2:η2-NO), 3, with oxidizing agents has been explored to search for other (E2) n−, (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 1 and 3. Specifically, the ( μ-O)2– oxide-bridged bimetallic complex, [(R2N)2(THF)­Y}2( μ-O), 4, is obtained as a byproduct from reactions of either the (N2)2– complex, 1, or the (N2)3– complex, 2, with NO, while the oxide formed from 2 with N2O is a polymeric species incorporating potassium, {[(R2N)2Y]2( μ-O)2K2( μ-C7H8)} n , 5. Reaction of 1 with 1 atm of O2 generates the (O2)2– bridging side-on peroxide [(R2N)2(THF)­Y]2(μ-η2:η2-O2), 6. The O–O bond in 6 is cleaved by KC8 to provide an alternative synthetic route to 5. Attempts to oxidize the (NO)2– complex, 3, with AgBPh4 led to the isolation of the tetraphenylborate complex, [(R2N)2Y­(THF)3]­[BPh4], 7, that was also synthesized from 1 and AgBPh4. Oxidation of the (N2)2– complex, 1, with the radical trap (2,2,6,6-tetramethylpiperidin-1-yl)­oxyl, TEMPO, generates the (TEMPO)− anion complex, (R2N)2(THF)­Y­(η2-ONC5H6Me4), 8.