Patent ID: 7803948

Claim:
A process for converting a compound C 1 of the formula I in a mer isomer form into an isomeric compound C 2 of the formula I in a fac isomer form, where the variables have the following meanings: n is 2 or 3; M is Pd or Pt, in each case in the formal oxidation state +II, when n is 2; and is Ru, Os, Co, Rh or Ir, in each case in the formal oxidation state +III, when n is 3; Do is a donor atom selected from the group consisting of N and P; r is 1 when Do is N or P; Y 1 , Y 2 are each, independently of one another, hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, alkyloxy, aryloxy, alkylthio, arylthio, alkylcarbonyl, arylcarbonyl, carboxyl, alkyloxycarbonyl, aryloxycarbonyl, hydroxysulfonyl, alkyloxysulfonyl, aryloxysulfonyl, halogen, CN, CHO, NO 2 or NO, or Y 1 and Y 2 together with the carbon atoms to which they are bound form a six-membered aromatic ring which may comprise one or two nitrogen atoms and may optionally be fused with a further, optionally fused and optionally heteroatom-comprising ring; Y 3 is alkyl, alkenyl, alkynyl, aryl or heteroaryl; A is a bridge having three or four atoms of which one or two atoms may be heteroatoms and the remaining atoms are carbon atoms, so that the group forms a five- or six-membered heteroaromatic ring or benzene ring which may optionally be substituted by substituents selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroaryl, alkyloxy, aryloxy, alkylthio, arylthio, alkylcarbonyl, arylcarbonyl, carboxyl, alkyloxycarbonyl, aryloxycarbonyl, hydroxysulfonyl, alkyloxysulfonyl, aryloxysulfonyl, halogen, CN, CHO, NO 2 and NO and may optionally be fused with a further, optionally heteroatom-comprising ring which may likewise be fused and substituted by substituents selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroaryl, alkyloxy, aryloxy, alkylthio, arylthio, alkylcarbonyl, arylcarbonyl, carboxyl, alkyloxycarbonyl, aryloxycarbonyl, hydroxysulfonyl, alkyloxysulfonyl, aryloxysulfonyl, halogen, CN, CHO, NO 2 and NO; which comprises allowing a Brönsted acid or a mixture of Brönsted acids to act on C 1 in the presence of a solvent or solvent mixture at a temperature of from 0° C. to the boiling point of the solvent or the solvent mixture, with the proviso that a) the formation of C 2 from C 1 occurs under the conditions of the process and b) when both C 1 and C 2 are present as a mixture prior to the Brönsted acid acting on C 1 , the respective isomer ratios of C′ and C 2 are different before and after the Brönsted acid acts on C 1 .