US Patent 7358209 Polymerisation catalysts

A transition metal complex having the following Formula (A): wherein the monovalent groups R1 and R2 are —Ra, —ORb, —NRcRd, and —NHRe: the monovalent groups Ra, Rb, Rc, Rd and Re, and the divalent group R3 are (i) aliphatic hydrocarbon, (ii) alicyclic hydrocarbon, (iii) aromatic hydrocarbon, (iv) alkyl substituted aromatic hydrocarbon (v) heterocyclic groups and (vi) heterosubstituted derivatives of said groups (i) to (v); M is a Group (3) to (11) or lanthanide metal; E is phosphorus or arsenic; X is an anionic group, L is a neutral donor group; n is (1) or (2), y and z are independently zero or integers, such that the number of X and L groups satisfy the valency and oxidation state of the metal M. n is preferably (2) and the two resulting R1 groups are preferably linked. The complex can be used with optional activator to polymerise olefins