Patent ID: 7601859

Claim:
An organometallic complex having the formula (I): [(Z(L) 3 ) p M]A q (I) wherein Z is a carbon atom or R 1 (B)— fragment; p is 1,2 or 3; q is 3-p; A is a counterion; R 1 is: (i) hydrogen, aryl or aralkyl each optionally substituted with from one to five halogen or C 1 to C 6 alkyl groups; or (ii) C 1 to C 6 alkyl, C 1 to C 6 alkenyl or C 1 to C 6 alkynyl each optionally substituted with one or more halogen atoms; each L is covalently bound to Z and is independently selected from a group of the formula (II) or (III) wherein R 2 and R 3 are independently selected from: (i) halogen, cyano, nitro, sulphono, amino, C 1 to C 6 alkylamino, C 1 to C 6 alkylamido, carboxyl, C 1 to C 6 alkyloxycarbonyl, hydroxy, C 1 to C 6 alkoxy, C 1 to C 6 alkylcarbonyloxy, C 1 to C 6 alkylcarbonyl, C 1 to C 6 haloalkoxy; (ii) aryl or aralkyl each optionally substituted on the aryl ring or, for aralkyl, on the alkylene chain with from one or more of the groups mentioned under (i) above; and (iii) C 1 to C 6 alkenyl or C 1 to C 6 alkynyl each optionally substituted with one or more of the groups mentioned under (i) and (ii) above; R 2 is —(CX 2 ) n X wherein n is 0 or a positive integer from 1 to 6 and X is halogen; or R 2 and R 3 are linked so as to form a fused aromatic or non-aromatic ring system with the pyrazolyl ring of L; and R 4 is trifluoromethyl; and M is a trivalent lanthanide metal ion.