Synthesis of [(C5H5)Y(eta(2)PzMe(2))(mu-PzMe(2))](2) and [Y(eta(2)-PzM(2))(2)(mu-PzMe(2))(mu-THF)](2) and the insertion of Me2SiO into the Y-N bond

3,5-Dimethylpyrazole (HPzMe(2)) reacted with (C5H5)(3)Y in THP to yield din uclear complexes [(C5H5)Y. (eta (2)-PzMe(2))(mu -PzMe(2))](2) (I)and [Y(eta (2)-PzMe(2))2(mu -PzMe(2))OL-THP)]2 (II), revealing a new method for synth esizing tris(pyrazolate) complexes of lanthanide metals. The X-ray crystall ographic analysis showed that complex II crystallizes In space group P (1) over bar, with unit cell dimensions a = 1.0798(1), b=1.0818(1), c=1.1313(1) nm, alpha =76.914(2)degrees, beta = 68.940(2)degrees, gamma = 60.510(2)deg rees, V = 1.0715(2) nm(3), Z = 1. The final R factor is 0.0445. The investi gation results showed that Me2SiO can only be inserted into the Y-N (bridgi ng) bond of complex I to form [(C5H5)Y(eta (2)-PzMe(2))(mu -OSiMe2 PzMe(2)) ](2) (III), but cannot be inserted into the Y-N (bridging) bond of complex II due to the bulky crowding of the tetraple bridge structure.