Patent ID: 8734963

Claim:
A salt of an organometallic complex cation and an organometallic complex anion, wherein the cation as well as the anion consists of a central metal atom M of atomic weight greater than 40 associated to 2 or more ligands, at least one ligand comprising a cyclic organic moiety with a carbon atom bonding to M, and at least one ligand comprising a cyclic organic moiety with a nitrogen atom bonding to M, wherein each the anion and the cation, independently, conforms to the formula I wherein M is a metal of atomic weight greater than 40, CYC is a cyclic organic moiety with a carbon atom bonding to M, CYN is a cyclic organic moiety with a nitrogen atom or carbene bonding to M, L 1 bonding to M is selected from inorganic and organic ligands, wherein L 1 as a neutral ligand is selected from bipyridine and phenanthroline, each of which is unsubstituted or substituted by halogen, C 1 -C 4 haloalkyl, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, phenyl, halophenyl; L 1 as a cationic ligand is selected from the above neutral ligands which carry, in addition, a cationic substituent; and L 1 as an anionic ligand is selected from halogenide and cyano; pyridylcarboxylate which is unsubstituted or substituted by halogen, C 1 -C 4 haloalkyl, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or an anionic substituent; and from the above neutral ligands which carry, in addition, an anionic substituent, where any ionic substituent is selected from groups of the formula —X′-(spacer) x -Y′; where X′ is a direct bond, O, S, CO, COO, COCO, NR, phenylene; x is 0 or 1; spacer is C 1 -C 12 alkylene, C 2 -C 12 alkylene which is interrupted by X′, phenylene, C 2 -C 12 alkenylene; Y′ is an anionic group selected from COO − , SO 3 − , OSO 3 − , or a cationic group selected from NR 3 + , and R is H or C 1 -C 12 alkyl, m is a number from 1 to 3, n is a number from 0 to 4, with the proviso that (m+n) is from the range 2 to 5, and wherein the salt is essentially free of non-complex ions, whose concentration is below 5% by weight of the salt.