摘要:
[Cp(2)degrees ZrCl(PHCy)] (Cy = cyclohexyl, Cp degrees = eta(5)-C5EtMe4) undergoes insertion of MeCN into the Zr-P bond, yielding [Cp(2)degrees ZrCl{N=C(Me)(PHCy)}] (1). Isomers with a Z (1a) or E (1b) configuration at the C-N double bond are obtained in a ratio of 13:1. At room temperature, 1 slowly decomposes in solution with elimination of a PHCy fragment and formation of [Cp(2)degrees(Cl)Zr(mu-N=CMe-CMe=N)Zr(Cl)Cp(2)degrees] (2). Two isomers are obtained with a trans (2a) or cis (2b) arrangement around the C-N double bonds of the bridging butane-2,3-diimino(2-)-N,N' ligand. 1a, 2a, and 2b were isolated and characterized by IR, MS, and NMR spectroscopy (H-1, P-31, C-13), and crystal structure determinations were carried out on 1a and 2a. In the solid state, the short Zr-N bonds and the almost linear Zr-N-C angles of 1a and 2a indicate the presence of Zr-N double bonds.