Patent ID: 7589224

Claim:
A process for the preparation of iridium(III) complexes containing structural units of formula (1) [L n IrX a Y a ] x Formula (1) wherein X and Y are, identically or differently on each occurrence, a monodentate, monoanionic ligand which is bonded to the iridium via a heteroatom; n is on each occurrence 2 or 3; a is 0 if n is 3 and is 1 if n is 2; x is −1 when n is 2 and a is 1 and x is 0 when n is 3 and a is 0; L is on each occurrence, identically or differently, a ligand of formula (2) which coordinates to Ir via both oxygen atoms wherein R 1 and R 2 are, identically or differently on each occurrence, H, CN, a straight-chain, branched or cyclic alkyl group having up to 20 C atoms, or a straight-chain, branched or cyclic alkoxy group having up to 20 C atoms, wherein one or more non-adjacent CH 2 groups of said alkyl or alkoxy groups are optionally replaced by —O—, —S—, —NR 3 —, —CONR 3 —, —CO—O—, —CR 3 ═CR 3 — or —C≡C— and wherein one or more H atoms may be replaced by F, or an aromatic or heteroaromatic ring system having 4 to 14 C atoms, wherein said aromatic or heteroaromatic ring systems may be substituted by one or more non-aromatic radicals R 1 ; and wherein a plurality of substituents R 1 and/or R 2 together optionally define a monocyclic or polycyclic aliphatic ring system or a monocyclic or polycyclic aromatic ring system; and R 3 is, identically or differently on each occurrence, H or an aliphatic or aromatic hydrocarbon radical having up to 20 C atoms, comprising the steps of (1) reacting an iridium(III) salt starting compound with compounds containing anions of the formula (2) in a first solvent or solvent mixture, (2) partially or fully exchanging the first solvent or solvent mixture with a second solvent or solvent mixture, which is different from the first solvent or solvent mixture, while substantially retaining the amount of the salt-like components of the reaction mixture, and (3) completing the reaction in said second solvent or solvent mixture.