THE SYNTHESIS AND X-RAY STRUCTURES OF YTTERBOCENE(II) COMPLEXES CONTAINING PENDANT PYRIDYL GROUPS, [YB(CPX)2] (CPX=ETA(5)-C5H3(R)[CME2(CH2)NC5H4N-2]-1,3 - R=H OR SIME3 AND N=0 OR 1)

Metallation Of C5H5[C(Me)2CH2C5H4N-2] (=Cp(py)H), C5H4(SiMe3)[{C(Me)2C H2C5H4N-2}-3] (=Cp'(py)H), C5H5[C(Me)2C5H4N-2] (=Cp(py(s))H), and C5H4 [(SiMe3){C(Me)2C5H4N-2}-3] [=Cp'py(s)H] with KH in THF yielded the pot assium complexes KCp(py) (1), KCp'py (2), KCp(py(s)) (3), or KCp'py(s) (4). Compounds 1-4 were readily converted into their homoleptic solve nt-free ytterbium(II) complexes [Yb(Cppy)2] (5), [Yb(Cp'py)2] (6), [Yb (Cppy(s))2] (7) and [Yb(Cp'py(s))2] (8). The crystal structures of 5 a nd 8 show that both of the pyridyl groups in each complex are coordina ted to the ytterbium. Some angles in 5 are Cp(1)-Yb-Cp(2) 137.7-degree s and N(1)-Yb-N(2) 100.8(2)-degrees, and the corresponding angles in 8 are Cp(l)-Yb-Cp(2) 136.9-degrees and N(1)-Yb-N(2) 84.0(4)-degrees (wh ere Cp refers to the centroid of the cyclopentadienyl ring).