In this article are summarized general properties, synthesis, reactivity, and catalysis of Group 4 transition metal amide complexes. Thermally robust but moisture sensitive compounds of the type M (NR2)4 and MYn(NR2)4-n [M=Ti, Zr, Hf; R=H, alkyl, aryl; Y=X(halogens), OR; n=1-3) are generally synthesized from MX4 and amines or alkali metal amides, by disproportionation reactions of M(NR2)4 with MY4, or by ligand exchange reactions of M(NR2)4 and MYn(NR2)4-n. Since nitrogen atoms in these compounds form both σ- and π-donor bonds to the metal center, the amide complexes typically have planar MNR2 units with shorter M-N lengths. The amide complexes are highly reactive towards carbonyl compounds or Brønsted acids such as cyclopentadiene. These reactions are useful for chemical transformation of carbonyl compounds and synthesis of metallocene derivatives; some of the latter are excellent catalysts for olefin polymerization. Besides metallocene derivatives, Group 4 transition metal amide complexes themselves have recently received much attention as catalysts for ethylene and α-olefins and for hydroamination of acetylenes.
|Number of pages||10|
|Journal||Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry|
|Publication status||Published - 1999|
All Science Journal Classification (ASJC) codes
- Organic Chemistry