Multiple Insertion of Unsaturated Molecules into the Zr−N Bonds of [<i>η</i>⁵:<i>σ</i>-Me₂A(C₉H₆)(C₂B₁₀H₁₀)]Zr(NMe₂)₂ (A = C, Si)

The compounds [η5:σ-Me2A(C9H6)(C2B10H10)]Zr(NMe2)2 (A = C, Si) reacted with CS2, PhCN, CH2CHCN, nBuNCS, and PhNCO to give the mono-, di-, and triinsertion products, depending upon the substrates. These unsaturated substances inserted exclusively into the Zr−N bonds, and the Zr−C(cage) bond remains intact in all reactions. It is believed that the preference of Zr−N over Zr−C(cage) insertion is governed by steric factors. The metal amide compounds also initiated the polymerization of CH2CHCN to produce poly(acrylonitrile) and catalyzed the trimerization of PhNCO. On the other hand, they reacted with methyl methacrylate to afford [{η5:σ-Me2A(C9H6)(C2B10H10)}Zr(OCH3)(μ-OCH3)]2 and CH2C(Me)CONMe2. All insertion products were fully characterized by various spectroscopic data, elemental analyses, and X-ray diffraction studies.