Insertion Reactions into the σ-Yttrium-Carbon Bond. Molecular Structure of the Permethylyttrocene Iminoacyl Tetrahydrofuranate (η5-C5Me5)2Y[η2-C{CH2(3,5-Me2C6H3)}=N(2,6-Me2C6H3)]·C4D8O

The reactions of Cp*2YCH(SiMe3)2 (1) (Cp* = η5-C5Me5) with CO2, t-BuCN, and t-BuNC give the monomeric complexes Cp*2Y(η2-O2CCH(SiMe3)2) (3), Cp*2YN=C(t-Bu)CH(SiMe3)2·NC-t-Bu (4), and Cp*2YCH(SiMe3)2·CN-t-Bu (5), respectively. With CS2 and (2,6-xylyl)NC no reaction is observed. The permethylyttrocene benzyl Cp*2YDMB (2) (DMB = 3,5-dimethylbenzyl) reacts with the substrates mentioned before and gives Cp*2Y(η2-O2C(DMB)) (6), Cp*2Y(η2-S2C(DMB)) (7), Cp*2YN=C(DMB)-t-Bu·NC-t-Bu (8), Cp*2Y(η2-C(DMB)=N-t-Bu)·CN-t-Bu (9), and Cp*2Y(η2-C(DMB)=N(2,6-xylyl)) (10) (xylyl = dimethylphenyl). The iminoacyl 10 reacts with THF to give the adduct Cp*2Y(η2-C(DMB)=N(2,6-xylyl))·THF (11). The crystal structure of 11 was determined by X-ray diffraction. The crystals of 11 are monoclinic, space group P21/c, with a = 10.937 (6) Å, b = 18.367 (8) Å, c = 18.04 (2) Å, β = 104.58 (6)°, and Z = 4. The structure was refined to R = 0.032. The molecular structure of 11 clearly shows the η2-coordination of the iminoacyl ligand with an Y-N distance of 2.407 (3) Å, and an Y-C bond length of 2.392 (3) Å