| abstract |
A nitrogen containing transition metal complex useful for the polymerisation of 1-olefins is disclosed, which has Formula (I) wherein M is Fe[II], Fe[III], Co[I], Co[II], Co[III], Mn[I], Mn[II], Mn[III], Mn[IV], Ru[II], Ru[III] or Ru[IV]; X represents an atom or group covalently or ionically bonded to the transition metal M; T is the oxidation state of the transition metal M and b is the valency of the atom or group X; R?1, R2, R3, R4, R6, R19, R20, R¿21, R?22, R23, R25, R26 and R28¿ are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R?1, R2, R3, R4 and R6¿ and are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents; characterised in that R?24 and R27¿ are either both halogen or at least one of them has two or more carbon atoms. |