Synthesis and Reactivity of Bis(tetramethylcyclopentadienyl) Yttrium Metallocenes Including the Reduction of Me3SiN3 to [(Me3Si)2N]- with [(C5Me4H)2Y(THF)]2(μ-η2:η2-N2)

The metallocene precursors needed to provide the tetramethylcyclopentadienyl yttrium complexes (C5Me4H)(3)Y, [(C5Me4H)(2)Y(THF)](2)(mu-eta(2):eta(2)-N-2), and [(C5Me4H)(2)Y(mu-H)](2) for reactivity studies have been synthesized and fully characterized, and their reaction chemistry has led to an unexpected conversion of an azide to an amide. (C5Me4H)(2)Y-(mu-Cl)(2)K(THF)(x), 1, synthesized from YCl3 and KC5Me4H reacts with allylmagnesium chloride to make (C5Me4H)(2)Y-(eta(3)-C3H5), 2, which is converted to [(C5Me4H)(2)Y][(mu-Ph)(2)BPh2], 3, with [Et3NH][BPh4]. Complex 3 reacts with KC5Me4H to form (C5Me4H)(3)Y, 4. The reduced dinitrogen complex, [(C5Me4H)(2)Y(THF)](2)(mu-eta(2):eta(2)-N-2), 5, can be synthesized from either [(C5Me4H)(2)Y](2)[(mu-Ph)(2)BPh2], 3, or (C5Me4H)(3)Y, 4, with potassium graphite under a dinitrogen atmosphere. The N-15 labeled analogue, [(C5Me4H)(2)Y(THF)](2)(mu-eta(2):eta(2)-N-15(2)), 5-N-15, has also been prepared, and the N-15 NMR data have been compared to previously characterized reduced dinitrogen complexes. Complex 2 reacts with H-2 to form the corresponding hydride, [(C5Me4H)(2)Y(mu-H)](2), 6. Complex 5 displays similar reactivity to that of the analogous [(C5Me4H)(2)Ln(THF)](2)(mu-eta(2):eta(2)-N-2) complexes (Ln = La, Lu), with substrates such as phenazine, anthracene, and CO2. In addition, 5 reduces Me3SiN3 to form (C5Me4H)(2)Y[N(SiMe3)(2)], 7.