| abstract |
Organometallic compounds of Formula (1), wherein R?1, R2, R3, and R4¿ are independently hydrogen, alkyl, aryl, or one of R?1 and R2 or R2 and R3 or R3 and R4¿ together with the atoms to which they are attached forms a 5- or 6- membered ring; R?5, R6, R7 and R8¿ are independently hydrogen, alkyl or aryl, or is a group of formula -Si(R11)3, -P(R12)2 or -N(R13)2, where each R?11, R12 and R13¿ are independently alkyl or aryl, provided that at least one of R?5, R6, R7 and R8¿ is an alkyl group comprising 5 or more carbon atoms and which is branched at the carbon alpha to the cyclopentadienyl ring, or is a group of formula -Si(R11)3, -P(R12)2 or -N(R13)2; R?9 and R10¿ are independently alkyl or aryl; M is a metal selected from the group consisting of Ti, Zr and Hf; n is 2; and X is halo or aryloxy, or (X)¿n? may with the metal atom to which it is attached form a 5-, 6- or 7-membered ring are provided. Preferred compounds contain a menthyl or neomenthyl group. Compounds of Formula (1) are useful as catalysts, particularly in optically active form. |