Complex salts

1. 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.

2. The salt of claim 1 , wherein the net charge of the central metal atom M and its ligands in the cation is +1 and in the anion is −1.

3. The salt of claim 1 conforming to the formula II

wherein

M 1 and M 2 are selected from metals as defined for M,

CYC 1 and CYC 2 are cyclic organic moieties as defined for CYC,

CYN 1 and CYN 2 are cyclic organic moieties as defined for CYN,

L 2 is independently as defined for L 1 ,

m 1 and m 2 are numbers as defined for m,

n 1 and n 2 are numbers as defined for n,

with the proviso that

i) each of (m 1 +n 1 ) and (m 2 +n 2 ) is from the range 2 to 5,

ii) the sum of charges in [CYC 1 CYN 1 ] multiplied by m1+L 1 multiplied by n1+M 1 is +1, and

iii) the sum of charges in [CYC 2 CYN 2 ] multiplied by m2+L 2 multiplied by n2+M 2 is −1.

4. The salt of claim 1 wherein, independently,

CYC and CYN are interlinked by one or more chemical bonds to form a bidentate ligand selected from

wherein the dashed line in each formula indicates the N-metal bond while the straight line in each formula indicates the carbon-metal bond, and wherein carbon atoms not bonding to metal are unsubstituted or substituted;

M is selected from Tl, Pb, Bi, In, Sn, Sb, Te, Mo, Cr, Mn, Ta, V, Zn, Fe, Ni, Co, Rh, Re, Os, Ag, Au, lanthanides including Eu, Tb, Nd, Yb, Er, and Cu, Ru, Ir, Pt, Pd; and

any substituent, if present, is selected from halogen, hydroxy, C 1 -C 8 alkyl, C 1 -C 8 -fluoroalkyl, C 1 -C 8 alkoxy, phenyl, phenyloxy, COR, OCOR, COOR, SO 2 R, CN, NHR NRR′, and ionic substituents —X′-(spacer) x -Y′; where R, R′ independently are selected from C 1 -C 12 alkyl or together are pentylene or (CH 2 ) 2 O(CH 2 ) 2 or (CH 2 ) 2 NH(CH 2 ) 2 and R may also be hydrogen; 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 − , OCOO − , SO 3 − , OSO 3 − , PO 3 2− , OPO 3 2− , or a cationic group selected from NR 3 + .

5. The salt of claim 1 wherein, independently,

the metal M is selected from Ir and Pt,

CYC and CYN are interconnected to commonly form a bidentate ligand selected from 2-phenylpyridines of the formulae

which are unsubstituted or substituted by halogen, C 1 -C 4 haloalkyl, C 1 -C 4 alkyl or C 1 -C 4 alkoxy or by a ionic 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.

6. An organic electronic device, comprising an emitting or conducting layer which contains a salt according to claim 1 .

7. The device of claim 6 , further comprising a hole transport material, selected from polyvinyl-carbazol, N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (TPD), 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N′-bis(4-methylphenyl)-N,N-bis(4-ethylphenyl)-[1,1′-(3,3′-dimethyl)biphenyl]4,4′-diamine (ETPD), tetrakis-(3-methylphenyl)-N,N,N′,N-2,5-phenylenediamine (PDA), a-phenyl-4-N,N-diphenylaminostyrene (TPS), p-(diethylamino)benzaldehyde-diphenylhydrazone (DEH), triphenylamine (TPA), bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP), 1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]pyrazoline (PPR or DEASP), 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB), N,N,N′,N′-tetrakis (4-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TTB), 4,4′-N,N-dicarbazole-biphenyl (CBP), N,N-dicarbazoyl-1,4-dimethene-benzene (DCB), porphyrinic compounds, (phenylmethyl) polysilane, poly(3,4-ethylendioxythiophene) (PEDOT), polyaniline, and combinations thereof, or one or more of the above components doped into a polymer.

8. A device selected from stationary and mobile displays, including displays for computers, mobile phones, laptops, pdas, TV sets, displays in printers, kitchen equipment, billboards, lightings, information boards and destination boards for example in trains and buses, containing an organic light emitting diode or light emitting cell according to claims 6 .

9. A method of using a salt according to claim 1 , the method comprising: adding the salt according to claim 1 in an electronic device, as conductor or ionic liquid in a photovoltaic device or in a battery, as an oxygen sensitive indicator, as a pH sensitive indicator, as a phosphorescent indicator in a bioassay, or as a catalyst.

10. A method for the preparation of a light emitting device, which method comprises providing an organic substance layer containing a complex salt according to claim 1 between a pair of electrodes on a substrate.

11. The method according to claim 10 for the preparation of an organic light emitting diode or light emitting cell wherein a fraction or all light emission is white light, wherein the complex salt contains ions whose light emission essentially is of complementary colour.

12. Process for the preparation of a salt of an organometallic complex cation and an organometallic complex anion as defined in claim 1 , which process comprises

i) combining equivalent amounts of a compound comprising a cyclometallated complex anion of a metal M and a non-complex organic or inorganic cation with a compound comprising a cyclometallated complex cation of a metal M and a i.e. non-complex inorganic anion, preferably in the form of a solution and/or dispersion,

ii) subjecting the combination obtained in step (i) to a technique substantially reducing the concentration of non-complex anions and cations, such as extraction or dialysis using a polar solvent,

iii) and, optionally, isolating the complex salt of claim 1 .