Patent ID: 7345006

Claim:
A system comprising a) Ni(0) b) from 4 to 10 mol per mol of Ni(0) in a) of a compound (I) of the formula ( o -Tolyl-O) w ( m -Tolyl-O) x ( p -Tolyl-O—) y (Phenyl-O—) z P where w, x, y, z are each a natural number and w+x+y+z=3 and w, z are each less than or equal to 2, and c) from 1 to 4 mol per mol of Ni(0) in a) of a compound (II) of the formula where X 11 , X 12 , X 13 , X 21 , X 22 , X 23 are each oxygen, R 11 , R 12 are identical or different, phenyl radicals which are unsubstituted or mono- or polysubstituted by C 1 -C 4 -alkyl, R 21 , R 22 are identical or different, phenyl radicals which are unsubstituted or mono- or polysubstituted by C 1 -C 4 -alkyl, and Y is a substituted or unsubstituted pyrocatechol, bis(phenol) or bis(naphthol) group, which is suitable as a catalyst.