Yttrium Methanide and Methanediide Bis(silyl)amide Complexes

The yttrium methanediide complex [Y(BIPM)(I)(THF)2] (BIPM = {C(PPh2NSiMe3)2}) was reacted with a series of potassium bis(silyl)amides to produce heteroleptic complexes by salt metathesis protocols. The methanediide complexes [Y(BIPM)(N″)(THF)] (1; N″ = {N(SiMe3)2}) and [Y(BIPM)(N**)(THF)] (2; N** = {N(SiMe2tBu)2}) were obtained for those relatively small bis(silyl)amides. Complex 2 undergoes thermal decomposition under vacuum to yield the methanide cyclometalate complex [Y(H-BIPM){N(SitBuMe2)(SitBuMeCH2)-κ2-N,C}] (3) as part of an otherwise intractable mixture of products. Complex 3 was also observed in trace amounts in mixtures of [Y(BIPM)(I)(THF)2] and KN**. In contrast, [Y(BIPM)(I)(THF)2] reacted with the more sterically demanding potassium bis(silyl)amides KN*† (N*† = {N(SiMe2tBu)(SiiPr3)}) and KN†† (N†† = {N(SiiPr3)2}) to afford the methanide cyclometalate complexes [Y(H-BIPM){N(SiiPr3)(SitBuMeCH2)-κ2-N,C)}] (4) and [Y(H-BIPM){N(SiiPr3)[SiiPr2(CHMeCH2)]-κ2-N,C}] (5), respectively. Complexes 1–5 were characterized as appropriate by multinuclear NMR and FTIR spectroscopy, elemental analyses, and single-crystal X-ray diffraction.